physical pharmacy i-ii sem jntuk lab manual
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7/23/2019 Physical pharmacy I-II sem JNTUK Lab manual
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Ajman University of Science & Technology Faculty of Pharmacy & Health Sciences
.………………….
LAB!AT!" #A$UAL F!
PH"S%AL PHA!#A"'%%
entral ommittee(e)artment of Pharmaceutics
………………….. *+++ ' *++,
1
7/23/2019 Physical pharmacy I-II sem JNTUK Lab manual
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Dear Students,
The central committee of department of pharmaceutics, Faculty of
Pharmacy and Health Sciences, is pleased to introduce to you the
Laboratory Manual of Physical Pharmacy-II !""#1#$% The manual
co&ers e'periments deal (ith the principles discussed in didacticlectures% These e'periments employ fundamental principles of physical
pharmacy re)uired to desi*n, prepare physically and chemically stable
hetero*eneous dosa*e forms and ensure their therapeutic safety and
efficacy% The central committee set this manual for all the branches to
ensure the uniformity of student outcome%
+est e*ards
entral ommitteeDepartment of pharmaceutics,
Faculty of Pharmacy and Health Sciences
#
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Ta-le of ontents
Part
$o.
ontent Page
$o.
Part , Analysis of (rugs -y isi-le S)ectrosco)y /0).1,2 • Determination of the standard cur&e of potassium
perman*anate at .!" and ./"nm%
• Determination of the standard cur&e of sodium
salicylate reacted (ith ferric nitrate$ at ./" and."" nm
1"
Part * (rug sta-ility 1 solution 3inetics 2
/0).1*2 • Determination of the rate constants and half-life of the
al0aline hydrolysis of P-nitrophenyl acetate in the presence of
Tris buffer pH %. and concentration "%".$
• 2ffect of temperature and determination of the acti&ation
ener*y of the al0aline hydrolysis of P-nitro-phenyl acetate in
the presence of Tris buffer
1.
/0).142 • +uffer catalysis of the al0aline hydrolysis of
P-nitrophenyl acetate%
#!
Part 4 %nterfacial Phenomena
/0).152 • Micellar Solubili3ation by 4on-ionic Surfactants 5
/0).162 • Spreadin* oefficient and 2mulsification /1
/0).172 • Determination of The 6dsorption Parameters of
7'alic 6cid on harcoal
/8
Part 5 olloi8al 8is)ersion
/0).192 Purification of colloids 9
• preparation of hydrophobic colloids
• preparation of hydrophilic colloids
.1
/0).1:2 Properties of colloidal dispersion 9
• Determination of the diffusion coefficient for crystal
&iolet throu*h *elatin *el%• Determination of the type of char*e of a colloid
./
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• Determination of the iso-electric point of e** albumin
/0).1;2 • Stability of colloidal dispersions
• Incompatibilities of pharmaceutical colloids
• Protecti&e action of hydrophilic colloids
.:
Part 6 Heterogeneous (osage forms <
/0).1,+2 • Dispensin* of pharmaceutical suspensions
• Preparation of the effects of &arious a*ents on the
flocculation properties of suspendin* materials%
8.
Part 7 !heology
/0).1,,2 • Measurement of &iscosity of 4e(tonian fluid by
capillary tube and Failin* Sphere%
!/
/0).1,*2 • Measurement of &iscosity of 4on-4e(tonian fluid by
otational ;iscometer%
!.
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Part %
Analysis of (rugs -y isi-le S)ectrosco)y
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%ntro8uction
<hen matter interacts (ith an ener*y source heat, sound, electricity, li*ht, etc%$
some of the ener*y can be absorbed, causin* the particles to be ele&ated to different
ener*y le&els% In some cases, the particles can be e'cited totally out of the ori*inal
chemical system holdin* them in place% =nder certain conditions, thou*h, the amount of
ener*y absorbed can be controlled, and information about the chemical system can beobtained% This is the case in absorption spectroscopy%
If (e monitor a beam of li*ht shinin* throu*h a sample containin* a substance that can
absorb one of the beam>s (a&elen*ths, (e can obtain a plot of the amount of li*ht
absorbed &ersus the (a&elen*th% This plot is 0no(n as an absorption spectrum, and
sho(s (hich particular (a&elen*ths of li*ht a chemical species can absorb%
6 primary use of absorption spectroscopy lies in its applicability to )uantitati&e
measurements% This is a function of ho( much li*ht is absorbed, and ho( that relates to
the amount of the absorber present in the sample% The follo(in* deri&ation presents the
basics of this relationship%
<hen (e shine a li*ht beam of a certain (a&elen*th λ$ and initial intensity I " $
throu*h an absorbin* sample contained in a spectrophotometer cell, the intensity of the
li*ht beam transmitted throu*h the sample I t $ is dependent on three factors%
•1 The first factor is (hether the sample (ill absorb li*ht at that (a&elen*th
•2 The second is the amount of sample that the li*ht must pass throu*h or,
the cell width b$%
•3 The third factor is the concentration of the absorbing species in the
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sample solution $%
The fraction of li*ht transmitted, or transmittance T$, is defined as the follo(in*9
1$
and,
Percenta*e of li*ht transmitted ? T$ @ T A 1"" #$
(here,
I " @ initial intensity of the li*ht beam, and
I t @ transmitted intensity of the li*ht beam
The transmittance of the sample &aries lo*arithmically (ith the cell (idth and the
concentration of the absorbin* species in the follo(in* (ay9
lo* 1BT$ @ -lo* T @ proportionally constant$ b 5$
The proportionality constant depends on9
•1 The chemical nature of the indi&idual absorber%
•2 The (a&elen*th at (hich the measurements are bein* made%
•3 The units of b and %
In &isible absorption spectroscopy, b is normally measured in centimeters% If is
also measured in molBL molar concentration, M$, the proportionality constant is defined
as the molar absorptivity ε$, (hich has units of lBM-cm% If is measured in any other
units e%*%, *Bl$, the constant is simply called the absorptivity a$, (hose units (ill depend
on % =nder normal operatin* conditions, CεC or Ca are determined e'perimentally by
measurin* a standard of 0no(n concentration%
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Factors that (etermine Transmitte8 Light %ntensity
The precedin* relationship relates the amount of li*ht transmitted throu*h the sample to
the concentration and cell (idth% <e fre)uently li0e to thin0 in terms of ho( much li*ht
is absorbed by the sample, so (e define a ne( term, absorbance 6$9
6 @ lo* 1BT$ @ -lo* T /$
Ma0in* all of the appropriate substitutions, (e *et9
6 @ ε b (hen @ molBL or M$ .$
or,
6 @ a b (hen @ *Bl or other units$ 8$
This e)uation is 0no(n as Beer=s La>, (hich sho(s the linear relationship bet(een theabsorbance and the concentration of the absorbin* species%
In chemical analysis, the following two methods can utilize Beer's Law:
1% Absolute Calculations
6bsorpti&ity or molar absorpti&ity is calculated by measurin* the absorbance of a
standard of 0no(n concentration in a cell 0no(n cell (idth% This calculated &alue is then
used to determine an un0no(n concentration of the same absorbin* species from the
absorbance measurement at that concentration%
#% or!ing Curve Analysis
The absorbance of a series of three to fi&e standard solutions are measured and
plotted on *raph paper a*ainst the concentrations of these standards% This is 0no(n as a
Beer=s La> )lot% The absorbance of an un0no(n concentration is then measured, and its
concentration is determined directly from the plot%
"his method is more commonly used than the absolute calculation,
because e#perimental error will average out over the number of standards$
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Beer=s La> Plot
/0)eriment ,
• (etermination of the stan8ar8 curve of )otassium
)ermanganate at 69+ an8 65+nm.
Proce8ure <
1% Prepare 8 different dilutions of Potassium Perman*anate by usin* a "%"1?stoc0 solution ss$ as in Table 1%
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#% Set up the (a&elen*th of spectrophotometer to ./" nm% =se distilled (ater as
a blan0%
5% inse one of the cu&ette (ith distilled (ater and fill it (ith the (ater% Place it
in the first sample compartment% inse another cu&ette (ith small portions of
the first standard solution, and fill it (ith the solution% Put the cu&ette in thesecond sample compartment% epeat the rinseBfill for the other solutions usin*
additional cells and put them in sample compartments%
/% Put the sample tray in the blan0 position% Push E6uto eroG% Then measure the
absorbance of each of your solutions%
.% Set up the (a&elen*th of spectrophotometer to .!" nm% =se distilled (ater as
a blan0% epeat steps 5-/ and list results in Tables #%
Ta-le ,< Potassium Permanganate 8ilutions using +.+,? stoc3 solution 1ss2@
their concentrations an8 the resulte8 a-sor-ance at 65+ nm.
mls of ss mls of >ater ? of 8ilution onc. of solution A-sor-ance
, , ; ,+ +.++,
* * : *+ +.++*
4 5 7 5+ +.++5
5 7 5 7+ +.++7
6 : * :+ +.++:
7 ,+ + ,++ +.+,
Ta-le *< Potassium Permanganate 8ilutions using +.+,? stoc3 solution 1ss2@
their concentrations an8 the resulte8 a-sor-ance at 69+ nm.
mls of ss mls of >ater ? of 8ilution onc. of solution A-sor-ance
, , ; ,+ +.++,
* * : *+ +.++*
4 5 7 5+ +.++5
5 7 5 7+ +.++7
6 : * :+ +.++: 7 ,+ + ,++ +.+,
1"
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Analysis of !esults
Plot absorbance &%s concentration to construct +eers plot% alculate the slope of the plot
usin* the follo(in* 2)%
Slope @ 6bs# 6bs1$ B onc# onc1$ @ absorpti&ity @ a
The concentration of the un0no(n sample can be obtained by di&idin* absorbance
by the slope%
• (etermination of the stan8ar8 curve of so8ium salicylate
1reacte8 >ith ferric nitrate2 at 65+ an8 6++ nm
Proce8ure
• Prepare 8 different dilutions of sodium salicylate by usin* a "%"1?
stoc0 solution ss$ as in Table 5% Ta0e ml of each (or0in* solution and add
# ml of the ferric nitrate solution pro&ided to produce a color %
• Set up the (a&elen*th of spectrophotometer to ./" nm% =se ferric nitrate
rea*ent 1? ferric nitrate in 1? nitric acid$ as a blan0%
• inse one of the cu&ette (ith ferric nitrate rea*ent and fill it (ith the rea*ent%
Place it in the first sample compartment% inse another cu&ette (ith small
portions of the first colored standard solution, and fill it (ith the solution% Put
the cu&ette in the second sample compartment% epeat the rinseBfill for the
other solutions usin* additional cells and put them in sample compartments%
• Put the sample tray in the blan0 position% Push E6uto eroG% Then measure the
absorbance of each of your solutions%
• Set up the (a&elen*th of spectrophotometer to ."" nm% =se ferric nitrate
rea*ents as a blan0% epeat steps 5-/ and list results in Tables /%
Ta-le 4< So8ium salicylate 8ilutions using +.+,? stoc3 solution 1ss2@ their
concentrations an8 the resulte8 a-sor-ance at 65+ nm
mls of ss mls of >ater ? of 8ilution onc. of ferric com)le0 A-sor-ance
, , ; ,+ +.+++:
* * : *+ +.++,7 4 5 7 5+ +.++4*
5 7 5 7+ +.++56
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6 : * :+ +.++75
7 ,+ + ,++ +.++:
Ta-le 5< So8ium salicylate 8ilutions using +.+,? stoc3 solution 1ss2@ their
concentrations an8 the resulte8 a-sor-ance at 6++ nm
mls of ss mls of >ater ? of 8ilution onc. of ferric com)le0 A-sor-ance
, , ; ,+ +.+++:
* * : *+ +.++,7
4 5 7 5+ +.++4*
5 7 5 7+ +.++56
6 : * :+ +.++75
7 ,+ + ,++ +.++:
Analysis of !esults
Plot absorbance &%s concentration to construct +eers plot at the t(o (a&elen*ths%
alculate the slope of the plots usin* the follo(in* 2)%
Slope @ 6bs# 6bs1$ B onc# onc1$ @ absorpti&ity @ a
The concentration of the un0no(n sample can be obtained by di&idin* absorbance by the
slope%
(etermining concentrations of un3no>n<
1% Ta0e the # ml remainin* from each test tube of the pre&ious e'periment for sodium
salicylates and add them as follo(s to *et at the end 5 test tubes9
,* C 45 C 67
#% 6dd 1 ml of Ferric 4itrate to the 5 tubes
5% Set up the Spectrophotometer at ./"nm (a&elen*th and proceed as before%
/% Measure absorbance of the samples and use the standard cur&e or its slope to calculateconcentrations%
1#
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Un3no>n Theoretical
oncentration in ,+'4
A-sor-ance
,* ,.6
45 6
67 ;
First metho8• oncentration of the first mi0ture @ 6bs1 B slope
• oncentration of the secon8 mi0ture @ 6bs# B slope
• oncentration of the thir8 mi0ture @ 6bs5 B slope
Secon8 metho89
Is *raphical as sho(n on the plot itselfJ it consists on relayin* the absorbance to the
plot itself and then findin* the correspondin* concentration%
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Part *
(rug Sta-ility 1 Solution Dinetics 2
/0)eriment *
This e'periment pro&ides an introduction to the simplest type of solution 0inetics
usually encountered% <e (ill study in this e'periment a specific reaction that is the 2ster
Hydrolysis%
-77 K H#7 77H K 7H
The ester used is9 )'nitro)henylacetate.
7
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47# 7 H5
In this e'periment (e (ill determine the rate constant of the al0aline hydrolysis of p-
nitrophenylacetate in the presence of Tris +uffer pH @ %. and at "%. M$%
The 0inetic parameters you (ill determine are 9
1% The obser&ed ate constant of the hydrolysis and the half life of the reaction at
different temperatures #!, 5! and /!o $%
#% The heat of acti&ation for the o&erall reaction%
5% +uffer catalysis of the al0aline hydrolysis of p% nitrophenylacete%
Theoretical consi8erations
Let 2 represent the ester % Then in the absence of buffer the rate &elocity$ of the
hydrolysis reaction o&er the entire pH ran*e can be (ritten9
& @ H E2G EHKG K < E2G K 7H
E2GE7H-G ---------------------- 1 $
<here
& 9 reaction rate H
K 9 second order rate for acid cataly3ed hydrolysis%
7H- 9 second order rate for base cataly3ed hydrolysis%
< 9 first order constant for the uncataly3ed hydrolysis%
6t &ery lo( pH only the term containin* HK (ill be important , (hile at &ery
hi*h pH only the term containin* 7H- (ill be important% 6t an intermediate pH it may
be necessary to (rite all three terms, because at least one of them (ill al(ays be
relati&ely small%
In the presence of buffer catalysis, the rate of the hydrolysis reaction o&er the entire
pH can be (ritten9
&@ H E2G EHKG K < E2G K 7H
E2GE7H-G K + E+G E2G------- # $
<here + @ second order rate constant for buffer catalysis and E+G @ buffer
concentration% onsiderin* the hi*h pH ran*e only 7H and + are important % Then the
reaction rate becomes9
& @ 7H E2GE7H-G K + E+G E2G------------------------------------- 5 $
1.
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A. #easuring of the o-serve8 rate constant <
For hi*h pH and in the presence of buffer catalysis, the rate of the reaction can be
2)% 5 $ Ho(e&er, if the pH and the buffer concentration are held essentially constant
throu*hout the reaction , 2)% 5 $ becomes9
& @ 7H E7H-G K + E+G N E2G @ obs E2G---------------- / $
<here Do-s E D H H'G D B BG ''''''''''''''''''''''''''''''1 6 2
2)% / $ represents a first order reaction % This (ould be called a pseudo or apparent
first order reaction $ % The dependence of O2 on time can be (ritten9
Lo* E2B2oG @ E obsB#%5"5G t ---------------------- 8 $
<here E2o Gis the ester concentration at time 3ero and E 2 G is its concentration at time t %
4o( suppose that durin* the hydrolysis of this ester the solution 6bsorbance under*oes a
chan*e % If +eers la( is follo(ed by all absorbin* species , it can be sho(n that 9
E 2 GB E2o
G @ E6 ∝ 6t GB E6 ∝ 6t G---------------------------- ! $
(here 6 7 is the 6bsorbance at t @ " , 6t at t @ t , and 6 ∝ at t @ ∝
Thus, 2)% 8$ +ecomes 9
Lo* E6 ∝ 6t GB E6 ∝ 6t G @ - obs t --------------------- $
7r
Lo* E1""E6 ∝ 6t GB E6 ∝ GG @ Lo* 1"" - obs t
Therefore, a plot of E6 oo 6t $G 6bsorbance$ or E1""E6 ∝ 6t GB E6 ∝ GG as ?$ one
of the &ertical a'is of a semi-lo* paper &s time should *i&e a strai*ht line % The slope of
this line is e)ual to E obs B #%5"5G, (hich, therefore, permits the e&aluation of
obs%
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B. (etermination of the Halflife of the reaction <
6 )uantity often used in the discussin* first-order reaction is the half-life, t Q ,
(hich is the time re)uired for the concentration to decrease to one-half its initial &alue %
The half-life of a first-order reaction is related to the rate constant by 2)% :$9
t Q @ E "%8:5 B obs G ------------------------------------------------------- : $
The dimension of a first-order rate constant is time-1J and the usual units are sec-1%
. (etermination of the Heat of Activation <
The temperature of the en&ironment al(ays influences the obser&ed rate constant of any reaction% This influence can be )uantitati&ely follo(ed by the use of 6rrhenius
2'pression,
@ 6 e -HR BT$
<here
@ The rate constant
@ The *as constant6 @ Pre-e'ponential coefficient
HR @ The heat of acti&ation
T @ The temperature of the en&ironment in el&in o$
2)uation 1"$ predicts that the hi*her the temperature the *reater the rate constant
and therefore the faster the rate of reaction% 7n the other hand at constant temperature To
$ the pre e'ponential coefficient, the *reater the acti&ation ener*y, the slo(er thereaction, and more rate is influenced by the *i&en temperature% 2)uation 1"$ can be
re*ulated to read9
Lo* 0 Lo* 6 HR B#%5"5T$
Therefore a plot of lo* on the &ertical a'is $ &s % 1 B To
should *i&e a strai*ht
line % The slope of this line is e)ual to -HR B #%5"5 %
1!
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• (etermination of the 3inetic )arameters 1 D o-s@ t I @ H 2 of the
al3aline hy8rolysis of )'nitro)henylacetate in the )resence of Tris-uffer 1 )H E :.6 an8 +.6 #2<
/0)erimentation<
In this e'periment students (ill be di&ided into si' *roups% 2ach *roup (ill
determine the rate constant and the half-life of the al0aline hydrolysis of p-
nitrophenyl acetate in Tris buffer of pH %. and "%". M $ at one temperature% Therefore,
t(o *roups (ill study the ester hydrolysis at #!
o
, others at 5!
o
and the last t(o*roups at /!
o %
1
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#aterials<
2ach *roup of students (ill be pro&ided (ith the follo(in* 9
1% <ater bath adusted to a specific temperature eitherJ #!, 5! or /!o %
#% 6 1"" ml &olumetric flas0 preheated to the temperature of your (ater bath containin*
: ml of Tris buffer solution of pH %. and "%".M of total Tris buffer%5% 6 Stop(atch%
/% 6 buc0et of ice%
.% Ten test tubes%
8% 6 .-ml pipette%
!% P-nitrophenylacetate stoc0 solution in acetonitrile$ containin* "%. m*Bml
% Spectrophotometer ##S, and t(o cu&ettes%
Proce8ure<
1% 2ach *roup should di&ide the duties bet(een themsel&es (ith the help of the T6 in
char*e
#% Set the (a&elen*th of s)ectro)hotometer **!S to 5:%.nm and chec0 its
operation usin* a blan0 solution Tris buffer at pH %55 and contains"%".M total
Tris buffer$%
5% Pipette #%" ml of ester stoc0 solution into the flas0, sha0e (ell and note the time
i%e%9, 6t @ " (hen t @ "$%
/% <ithdra( . ml from the flas0 as function of time and tabulate your data in columns
(ith headin*s as in table .$%.% Immediately after (ithdra(in* the sample, measure the 6bsorbance at ma' @
5:%. a*ainst buffer$ other(ise, place the sample in ice to stop the reaction until
you are ready to measure the 6bsorbance%
8 8% Since the laboratory period is less than the time re)uired for the
complete hydrolysis of P-nitrophenyl acetate, you are pro&ided (ith
absorbance at time infinity i%e% 6; E 1%"1. $
Ta-le 6
Tem)erature<JJJJJJJJJJ
Time 1 min 2 At 1A; At 2 ?E 1AU At 2 V ,++
A U
" " 1%"1. W
1.
1:
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5"
/.
8"
!.
:"
1".
1#"
15.
1."
U 1%"1.W
#"
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#1
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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Ta-le 7
Tem)erature<JJJJJJJJJJ
Time 1 min 2 At 1A; At 2 ?E 1AU At 2 V ,++
A U
" " 1%"1. W
1.
5"
/.
8"
!.
:"
1".
1#"
15.
1."
U 1%"1.W
##
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#5
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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Ta-le 9
Tem)erature<JJJJJJJJJJ
Time 1 min 2 At 1A; At 2 ?E 1AU At 2 V ,++
A U
" " 1%"1. W
1.
5"
/.
8"
!.
:"
1".
1#"
15.
1."
U 1%"1.W
#/
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#.
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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(ata analysis <
1% The data *enerated by the si' *roups (ill be posted on the blac0board%
#% 2&ery student should ta0e the si' sets of data and analy3e it as follo(s 9
a% Plot ? 6; 6t $ v.s. time for the three temperatures or plot 6; 6t $
calculate the slope and then D o-s E slo)e 0 *.4+4
b% alculate half-life t Q $ for the ester hydrolysis at three temperatures
t Q @ "%8:5 B obs $
c% Plot lo* obs
$ &%s% 1 B To $ and calculate the heat of acti&ation for the
reaction from the slop%
#8
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/0)eriment 4
Solution Dinetics
• Tris -uffer catalysis of the al3aline hy8rolysis of )'nitro)henyl
acetate at )H :.6 <
Last (ee0s (e determined the 0inetic parameters for the al0aline hydrolysis of p-
nitrophenylacetae% in this e'periment (e plan to study
Tris +uffer catalysis of this reaction at #!o %
Theoretical consi8erations<
Let us consider the ester hydrolysis at pH %. and at #!o %
=nder this condition, pH and the temperature are constant and H
and <
are ne*li*ible
then the rate of ester hydrolysis can be (ritten as9
& @ 7H
E7H G- K
+
E+ G N E2G
<here
obs
@ 7H
- E7H G K
+E+ G
Terms are defined in e'periment #$$%
Therefore a plot of obs
$ &s% +uffer concentration E+G (ill yield strai*ht line (ith slope
@ +
and intercept @ 7H
E7H-G%
/0)erimentation<
<e (ill di&ide you in si' *roups %2ach *roup (ill conduct a e'periment inetics
of the al0aline hydrolysis of p-nitrophenylacetate in Tris buffer $ at #!o and at
different buffer concentrations%
#!
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#aterials<
2ach *roup of students (ill be pro&ided (ith the follo(in* 9
1% <ater bath adusted by a thermostat $ to #! o %
#% 6 1"" ml &olumetric flas0 containin* : ml of Tris buffer solution of pH %. and
either "%1#. M of "%"#. M total Tris %
5% Stop-(atch %
/% 6 buc0et of ice %
.% Ten test tubes%
8% . ml pipette %
!% p-nitrophenylacetae stoc0 solution in acetonitrite $ containin* "%. m*Bml
% spectrum #" , and t(o cu&ettes%
Proce8ure <
1% Pipette # ml of p-nitrophenylacetae stoc0 solution into the 1"" ml &olumetric flas0
containin* : ml of Tris buffer solution (ith proper concentration "%"1#. or "%"#.$
are preheated to#!o %
#% <ithdra( . ml from the flas0 e&ery 1. minutes and measure the absorbance at 5:%.
nm a*ainst buffer $%
5% Tabulate your data in Table -1" %
Ta-le :
#
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Buffer onc. JJJJJJJJ
Time 1 min 2 At 1A oo At 2 log 1A oo At 2
" " 1%"1. -
1.
5"
/.
8"
!.
:"
1".
1#"
15.
1."
U 1%"1.
#:
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5"
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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5#
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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Ta-le ,+
Buffer onc. JJJJJJJJ
Time 1 min 2 At 1A oo At 2 log 1A oo At 2
" " 1%"1. -
1.
5"
/.
8"
!.
:"
1".
1#"
15.
1."
U 1%"1.
55
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5/
1
10
100
0 50 100 150 200
Time (min)
P e r c e n t a g e R e m a i n i n g
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(ata analysis <
1%The data *enerated by the si' *roups (ill be posted on the blac0board %
#%2&ery student should ta0e the si' sets of data and analy3e it as follo(s 9
a% plot lo* 6 oo 6t $ &s time for all the data *enerated
b% calculate D o-s
an8 t Q $ at each buffer concentration
c% plot obs
&s Tris conc% "%"1#.,"%"#. and "%". from e'p% 4o%# $ and calculate +
Tris catalytic constant$and 7H
$ote < ( EHKG E7H-G - 1" 1/ $
5.
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58
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Part 4
%nterfacial Phenomena
5!
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/0)eriment 5
• #icellar Solu-iliKation
%ntro8uction <
The solubili3in* po(er of (ater surfactant solutions is of *reat importance in the
preparation of dosa*e forms containin* sparin*ly soluble dru* % The factors affectin*
micellar solubili3ation are many and their interrelationship comple'% In *eneral, the
de*ree of solubili3ation is a function of the physiochemical properties of the surfactant
and solubili3ate %
In this e'periment, the effect of surfactant structure on the solubility of
undissociated salicylic acid (ill be in&esti*ated% The surfactants used (ill be nonionic
T(een 8" polyo'yethelene #"$ sorption monostearate$ , T(een /" polyo'yethelene
#"$ sorbitan monopalmitate $% Solubility determinations (ill also be conducted in T(een8" solutions buffered at hi*her pHs to determine the effect of solute ioni3ation on
solubili3ation% 6t the conclusion of this e'periment you should be a(are of the effect of
surfactant structure and solubili3ate Ioni3ation State on solubili3ation%
/0)erimental <
A. you (ill find on the side bench saturated solutions of salicylic acid in the &arious
surfactant solutions % They are labeled (ith the name and concentration ?<B; $ of the
particular surfactant % +esides surfactant, each solution contain "%14 HL to insure that
the salicylic acid remains undissociated in solution% 2ach solution, after dilution, (ill be
assayed by the usual method usin* Trindars rea*ent %=se distilled (ater as a blan0%
T>een *+
1? >v 2
A-sor-ance oncentration
1mgml2
(ilution Solu-ility
1mgml2
"
"%.
1%"1%.
5%"
.%"
5
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T>een 5+
1? >v 2
A-sor-ance oncentration
1mgml2
(ilution Solu-ility
1mgml2
"%.
1%"
1%.
5%"
.%"
T>een 7+
1? >v 2
A-sor-ance oncentration
1mgml2
(ilution Solu-ility
1mgml2
"%.
1%"
1%.
5%"
.%"
B. 6fter completin* part A , analy3e the salicylic acid saturated solutions of T(een 8"
buffered at pH 5%" and pH 5% %
pH 5%"
T>een 7+1? >v 2
A-sor-ance oncentration1mgml2
(ilution Solu-ility 1mgml2
"
"%.
1%"
1%.
5%"
.%"
5:
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pH 5%
T>een 7+
1? >v 2
A-sor-ance oncentration
1mgml2
(ilution Solu-ility
1mgml2
"
"%.
1%"1%.
5%"
.%"
(ata Analysis <
1% Plot salicylic solubility vs. surfactant concentration for each surfactant%
#% Plot the ratio of total solubility to a)ueous solubility vs. surfactant concentration for each pH%
onclusion<
/"
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/0)eriment 6
• S)rea8ing oefficient an8 /mulsification
%ntro8uction <
+echer has define an emulsion as a hetero*eneous system , consistin* of at least
one immiscible li)uid in the form of droplets , (hose diameter , in *eneral e'ceeds "%1 u %
Such systems possess a minimal stability (hich may be accentuated by such additi&es as
surface acti&e a*ents , finely di&ided solids , etc%
The process of emulsification in&ol&es the adsorption of an emulsifyin* surface
acti&e a*ent $ a*ent at the interface bet(een the oil and (ater phase , resultin* in a
lo(erin* of the interfacial tension e'istin* bet(een the t(o phase %
Dependin* on the nature and concentration of the emulsifier and the phase &olume ratiothe resultant emulsion may be of the 7il-in-<ater or <ater-in-7il type%
7n completin* this e'periment , each student should 9
1% eali3e the relationship bet(een spreadin* coefficient and emulsion formation %
#% +e able to test for the difference bet(een 7B< and <B7 emulsion %
5% +e able to prepare emulsions usin* the hand homo*eni3er %
/% eali3e the potential for incompatibilities (hen usin* surface acti&e a*ents in the
preparation of emulsions %
Proce8ure <
A. S)rea8ing coefficient an8 /mulsification
1% Fill t(o lar*e bea0ers (ith tap (ater , after thorou*hly cleanin* (ith soap and (ater ,
and rinsin* thorou*hly % Li*htly sprin0le some lycopodium po(der into the surface of the
(ater in both bea0ers % 6fter (aitin* for the po(der to stop spreadin*
,place a drop of mineral oil onto the surface in the center of one of the bea0ers and a dropof oleic acid in the same manner in the second bea0er %
a% describe (hat occurs in the case of 9
Mineral oil
7leic acid
/1
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b% The initial spreadin* coefficients of mineral oil and oleic acid are
15%/ and #/%8, respecti&ely % Do these &alues a*ree (ith your
obser&ations W
c% (hy (as the surface of the (ater co&ered initially (ith the
lycopodium po(der W
#% 6dd /" ml of (ater and 1" ml of mineral oil to a ." ml stoppered cylinder % epeat this
(ith oleic acid in place of the mineral oil% Sha0e both cylinders &i*orously for t(o
minutes and set the cylinders do(n on the lab bench % ompare the times re)uired foreach of the systems to separate completely into t(o phases %
a% Separation times 9
Mineral oil emulsion
7leic acid emulsion
b% Ho( does the separation time compare (ith the relati&e spreadin*
coefficients W
5% Sha0e the t(o emulsions a*ain and pass them throu*h a hand homo*eni3er , Sa&e
the products until ne't (ee0 %
a% Ho( do the emulsions appear at the end of the first lab W
b% Ho( do the emulsions appear at the end of a (ee0 W
c% Dose the homo*eni3er aid in the end of a (ee0 W
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. (etermination of /mulsion Ty)e
1% (ilution #etho8 % Place a drop of the emulsions
homo*eni3ed $ prepared in parts +-# and +-5 of this e'periment onto a (ater surface %
If it tends to this out o&er the (ater , or if it mi'es readily (ith the (ater , the emulsion is
of the 7B< type % If on the other hand the oil phase is the e'ternal phase of the emulsionthen the emulsion does not tend to mi' or spread %
#% (ye'#etho8 % 6dd # to / drops of a 1 ? F%D% ! % ed 4o% 1
solution
(ater soluble dye $ to a portion of the emulsion % If (ater is the continuous e'ternal $
phase the color (ill spread throu*hout the emulsion % If , on the other hand , the on a
spec0led appearance %
a% 2mulsion +-# is a <B7 $ 7B< $ emulsion%
b% 2mulsion +-5 is a <B7 $ 7B<$ emulsion %
(. om)ati-ility of Surface Active Agents
Prepare 1"" ml % of 1 ? a)ueous solutions of the follo(in* surface acti&e a*ents % Store
in / o3% Prescription bottles %
a% Sodium lauryl sulfate b% +en3al0onium chloride already prepared $
c% T(een "
1% 6dd . ml % of a 1? aL# of each of the abo&e solutions % =se test tubes % <hich
surfactants could not be used to prepare emulsions containin* aL# W 2'plain%
#%Place . ml of the sodium lauryl sulfate solution and . ml of the T(een " solution in
separate test tube % To each tube , add 1 ml of the ben3al0onium chloride solution % <hich
surfactant could be used to prepare an emulsion containin*
/. Phase olume !atio
Place #. ml of a 1" ? solution of 6rlacel 5 dissol&e in mineral oil in a #." ml bea0er %
6dd (ater in . ml increments (ith repaid manual stirrin* until #. ml % of (ater has been
added %=se a *lass test tube for stirrin* the emulsion % 4ote the *radual chan*es in theapparent &iscosity % <hy does the &iscosity chan*e (ith the addition of (ater W
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ontinue to add (ater in small increments , (ith &i*orous a*itation after each addition ,
until a total of #"" ml % of (ater has been added %Homo*eni3e and determine if the
emulsion is 7B< or <B7
F. /mulsion Sta-ility
Ta0e one of the 7B< emulsions and di&ide into /'1" ml portions and subect to the
follo(in* conditions 9
1% Heat in boilin* (ater
#% Put in an ice bath%
5% 6dd . ml of ethanol%
/% 6dd . ml of 1%" M 4al
ecord your obser&ations %
/.
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/0)eriment 7
• (etermination of The A8sor)tion Parameters of 0alic Aci8
on harcoal
This e'periment (ill demonstrate the adsorption phenomena and teach us to
determine to determine the adsorption parameters%
%ntro8uction<
In *eneral, colloidal dispersions ha&e the property of adsorbin* solutes at their
surfaces% Thermodynamically, such adsorption process occurs to reduce the surface free
ener*y of the dispersion and therefore increases its stability% The de*ree of adsorption of a
solute adsorbate$ on the adsorbent, depends on . factors:
1% The chemical nature of the adsorbent and the adsorbate%
#% The specific surface area of the adsorbent%
5% The temperature of the adsorbate
/% The concentration of the adsorbate
.% The pressure of the adsorbate
6t a constant temperature, the relation bet(een the amount adsorbed and the
concentration in a limited concentration ran*e may be represented by one of three
adsorption isotherms%
These 5 adsorptions theories (ere found by9
1 Freundlich9 " E M m ED. e ,n
1 Lan*muir9 " E M m E N1"m.-.e2 1, -e2O
1
1 +runer, 2mmett, Teller @X +2T9
1
1 " E N1"m.-.02 1,'02 M ,1-',20GGO
Qhere<
' 9 (ei*ht of adsorbate in *rams, adsorbed by m *rams of the adsorbent%%
Y n 9 Freundlichs 2mpirical constants
e 9 2)uilibrium onstant
Zm 9 <ei*ht of the adsorbate in *rams, adsorbed by one *ram of the adsorbent to
form a mono layer%
+ 9 2)uilibrium constant of the adsorption process
/8
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0alic Aci8 f 0alic Aci8
, 6+ + ,$
* 5+ ,+ +.:$
4 4+ *+ +.7$
5 *+ 4+ +.5$
6 ,+ 5+ +.*$
7 6 56 +.,$
5% Sha0e occasionally for 1. min and set aside for half an hour to achie&e
e)uilibrium
/% Filter and reect the first portion of the filtrate after (ashin* the recei&er
(ith it%
.% Triturate #.ml of the ali)uot filtrate in each case (ith "%.4 Sodium
Hydro'ide usin* Phenolphthalein as an indicator # drops$%8% alculate the amount adsorbed in each case and list your result in the
follo(in* table%
0alic
Aci8
onc.
#l
from
,$
0alic
ml
of H*+
to 6+ml
%nitial
onc.
1i2
/n8
Point
,$ 6+ + *.*6
+.:$ 5+ ,+ ,.:
+.7$ 4+ *+ ,.46
+.5$ *+ 4+ +.;
+.*$ ,+ 5+ +.56
+.,$ 6 56 +.**6
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After calculations the ta-le >ill -e as follo>s<
(ata Analysis<#a3e the follo>ing )lots.
• Plot ,< " vs e
• Plot *< e" vs e
•3 Plot 4< Log " vs Log e
• The first plot Plot 1$ sho(s that the adsorption phenomena deals (ith theoccupancy at the surface and as the &acancy increases, the rate of occupancy
increases, and at the end, (hen no more &acancy is a&ailable, the rate of occupancy
(ill be e)ual to "%
• The second plot Plot #$ reflects the lineari3ed form of Lan*muir e)uation% It
(ill help us findin* the Lan*muir adsorption parameters9 Zm and b%
• The third plot Plot 5$ in fact, reflects the lineari3ed form of Freundlich
adsorption isotherm e)uation% It is useful to find the Freundlich adsorption parameters9 and n%
/Ruili-rium conc.
1e22O/.P M +.+**6 1volumeNM 6+
Amount A8sor-e8
V @ i e
Log e " E M m Log " e "
/:
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Part 5
olloi8al 8is)ersion
."
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/0)eriment 9
• Pre)aration an8 Purification
There are t(o main methods of preparin* a colloid9
1% Dispersion i%e% splittin* coarse a**re*ations of a substance intocolloidal units% This may be achie&ed by use of9
a% Mechanical millin* or *rindin* e%*% colloid mills%
b% Irradiation (ith ultrasonic (a&es%
c% 2lectrical dispersion methods 2lectrolytic disinte*ration $
Pepti3ation e%*% (ith sol&ents or electrolytes$%
#% ondensation Method i%e% a**re*atin* &ery small atoms, ions, and
small molecules into colloidal particles% This may be achie&ed by9a% hemical reactions%
b% Decreasin* the solubility by lo(erin* the temperature or
chan*in* the sol&ent%A. Pre)aration of olloi8s
#aterials
6rsenius o'ide, ferric chloride, sil&er nitrate, sodium chloride, sulphur,alcohol, *elatin, hydro*en sulphide, acacia, sodium carbonate, tannic acid%
,. Pre)aration of hy8ro)hilic olloi8als <
a% Preparation of 6cacia Mucila*e9
Prepare #. ml of a .? dispersion of acacia in (ater%
b% Preparation of [elatin Dispersions9
Prepare #. ml of dispersions of each of 1%"? (B& and #%.?
(B& *elatin in (ater
*. Pre)aration of hy8ro)ho-ic olloi8als <
a. Preparation of Ferric hydro'ide sol%9
Into !. ml% of boilin* distilled (ater and poured 1%# ml of
5#? Ferric chloride solution% The hydrolysis \ of the Ferric
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chloride occurs instantly and a deep red \ sol% of Ferric
hydro'ide forms%
-. Preparation of Sil&er chloride sol% 9
Mi' 1" ml of each of .? sil&er nitrate and 1"? sodium
chloride solution% The precipitate of sil&er chloride formed isfiltered% The residue on the filter paper may be pepti3ed by
(ashin* (ith distilled (ater to produce the re)uired colloidal sol%
c. Preparation of Sulphur sol. <
This may be prepared by pourin* a saturated solution of
sulphur in alcohol or acetone into (ater ust belo( the boilin*
point% The alcohol or acetone &apori3es lea&in* the (ater insoluble
sulphur colloidal dispersion (hen alcoholic solution of resins and balsams are poured into (ater%
•4Preparation of olloidal Sil&er sol%9
To ."" ml distilled (ater add #" ml of "%14 6*475 and 1"
ml of 1? tannic acid solution% Heat this solution to !"-"o and
slo(ly add 1" ml of 1? 4a#75 solution (ith stirrin* a Ctea-
coloredC colloidal sil&er solution results (hich has the appearanceof the sol%
B. Purification of Ferric Hy8ro0i8e Sol. By (ialysis Using ello)haneBag <
Purification is concerned essentially (ith the remo&al of e'cess
electrolytes (hich usually *et absorbed onto colloidal particles durin* their
preparation% Purification may be achie&ed by &arious methods9
a% Dialysis%
b% 2lectrodialysis%
c% =ltrafilteration%
.#
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The most important of (hich is the dialysis% 2lectrolytes passes throu*h
semi permeable membrane but not the colloidal particles% Therefore placin*
ferric hydro'ide sol% in a cellophane ba* immersed in distilled (ater (ill
purify Ferric hydro'ide sol% from any adsorbed chloride ions%
Proce8ure<
1% Form a cellophane ba* on the stem of a *lass funnel%
2. Fill the ba* to 1B# of its &olume (ith Ferric hydro'ide sol%and immerse in
#." ml bea0er full of distilled (ater%
3. Test for chloride ions in the (ater of the bea0er at a series of time
inter&als%
/% han*e the (ater in the bea0er at re*ular time inter&als and find out the
time necessary for the complete remo&al of electrolyte from the sol%
/0)eriment :
• Pro)erties of colloi8al 8is)ersion
A. (etermination of the 8iffusion coefficient for crystal violet through
gelatin gel.
The diffusion coefficient D$ of a neutral particle can be determined usin*
e)uation 1, if the solution of this substance (ith a concentration , is placed
on a *el and the distance, V, of the diffused particle in the *el is determined as
a function of time t$% The diffusion measurement V$ can be done by the aid
of a standard *el (ith a concentration %
.5
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t @ o 2'p -V# B/Dt$
Ln t @ Ln o - -V# B/Dt$
D is defined as the amount of solute (hich (ould diffuse across unit
area under concentration *radient of unity, in unit time, if the rate (asconstant durin* that time%
In this e'periments, the diffusion coefficient of crystal &iolet in
*elatin solution containin* "%:? sodium chloride (ill be determined%
It is assumed that the dye diffuses throu*h the (ater held by the
*el% [elatin sol% (as chosen because the crystal &iolet does not interact
or *et hold by *elatin
Proce8ure<
1% Prepare #." ml of .? *elatin in saline solution "%:? 4al $
#% Distribute the *elatin into se&en test tubes%
5% =se one tube of *elatin to prepare standard *el% (ith a concentration
of 1 in ."",""" (B( crystal &iolet in (ater this (ill be used as the
standard for the color diffusion measurements%
/% Prepare three solutions of crystal &iolet in distilled (ater containin* 1
in #"" (B(, 1 in /"" (B(, and 1 in 8"" (B( crystal &iolet in (ater%.% Place about . ml of each solution on the top of t(o *els, co&er to
pre&ent e&aporation and place in test tube rac0 at room temperature%
8% Measure accurately the distance bet(een the solutionB*el interface
and the diffused crystal &iolet that is e)ui&alent to concentration of 1 in
."",""" the standard *el prepared in step 5$% The mean of the readin*s
should be ta0en-this &alue is ' mm%
!% ecord ' &alues in Table 8 as a function of time%
1% alculate the a&era*e of D for each dye concentration as sho(n in the
Table I %
Ta-le %
Time
1hrs2M M*
M*
(E'''''''''''''''''''''
5t1logo ' log2*.4+4
./
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1,*++2
1,5++2
1,7++2
1,*++2
1,5++2
1,7++2
+.6
,.+
,.6
*.+*.6Q//D
oE ,*++ >> ,5+ >> ,7+ >> crystal violet .
E ,6+++ >> crystal violet .
B. (etermination of the ty)e of the charge of a colloi8
If one end of a filter paper strip is dipped into a colored hydrosol, the
ascent of the color (ill depend on the char*e of the colloid% If the colloid has a
positi&e char*e a distinct preparation bet(een the dispersed phase and the
dispersin* medium occurs in the ascendin* portion of the sol% such a
separation does not occur if a ne*ati&ely char*ed colored sol% is used% This
phenomenon is probably due to the fact that the (etted filter paper ac)uirin* a
ne*ati&e char*e% The ne*ati&ely char*ed cellulose fibers (ill allo( ne*ati&ely
char*ed colloids to rise but it (ill attract and hold positi&ely char*ed colloids
pre&entin* the ascent of a positi&e hydrosol%
Proce8ure<
1% Prepare 1? a)ueous solution of 6maranth and a 1? a)ueous solution of
methylene blue%
#% Place !" ml of each solution in 1"" ml bea0er%
5% Into each solution place the end of a strip of filter paper holded specially by
a stand, and obser&e at different time inter&als%
/% eport your obser&ation and conclusion to your instructor%
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. (etermination of the %soelectric )oint of /gg Al-umin
Proteins e%*% 6lbumin$ beha&e as amphoteric colloid and ioni3e
both as acids and bases% There is a definite hydro*en ion concentration at(hich there is no resultant char*e on the protein molecule and its
electrophoteric mobility is &ery small% This particular pH &alue is 0no(n as
the isoelectric point, and the solubility of protein at this point passes throu*h a
minima%
In this particular e'periment the e'tent of turbidity or precipitation
of a colloid at certain pH &alues is determined% This turbidity increased to a
ma'imum at the isoelectric point%
#aterial <
6lbumin, ethyl alcohol, Mc li&aine>s buffer solutions 6 "%# Molar
disodium phosphate and 6 "%1 Molar citric acid% "%1 M sodium hydro'ide$
Proce8ure<a. Pre)aration of /gg Al-umin Solution<
1% 6ppro'imately "%. *ram of e** albumin is placed in 1"" ml bea0er
and (etted drop (ise (ith distilled (ater%
5% 6s each drop is added it is *round into the po(der until paste is
formed%
/% This paste should be carefully thinned do(n to about ."-!" ml%
.% The solution is clarified by the addition of . ml "%1 M sodiumhydro'ide%
8% The solution is subse)uently diluted to 1"" ml% and at this sta*e
any solid matter must be filtered off%
-. /ffect of )H on /gg Al-umin<
.8
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1% 6 series of ei*ht test tubes containin* buffer solution in the pH
ran*e of 5- are prepared by mi'in* Mcli&ain standard solutions 6
Y + as in the Table II %
#% 7ne milliliter of protein solution is added to each of these tubes and
mi'ed rapidly%
5% The series of test tubes should be left to stand for a fe( minutes, andthe relati&e turbidities matched at each pH &alue%
/% The pH (hich sho(s the most intense turbidity is the isoelectric
point of 2** 6lbumin%
Ta-le %%
Test
tu-e$o.
)H #L of A #L of B , ml
)rotein
-servation
1 5 #%". !%:.
# / 5%. 8%1.
5 /%. .%1. /%.
/ . .%.! /%/5
. .%. .% /%#"
8 8 8%5# 5%8! ! %#/ 1%!8
:%!5 "%#!
6@ Disod% Phosphate "%# Molar 5.%8" *BL$ 4a#HP7/%#H#7%
+@ itric acid "%1 Molar #1%"1 *BL$ citric % 1#H#7%
.!
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/0)eriment ;
• Sta-ility of olloi8al (is)ersions
Lyophobic colloids ha&e been affinity or the dispersin* medium and are
not sol&ated% They are stabili3ed by a char*e ac)uired by preferential
absorption of ions% Lyophilic colloids on the other hand, are hi*hly sol&ated as
(ell as char*ed% The char*e is usually a result of ioni3ation% Their stability,
ho(e&er, stems mainly from sal&ation effects%Lyophobic colloids (ill precipitate if their electrical char*e is
neutrali3ed often remain dispersed as they sol&ated%
#aterials<
Ferric hydro'ide sol% sil&er sol%, #? acacia mucila*e, 1? *elatin sol%
at pH #% Different electrolyte concentrations as sho(n in Table :"? ethanol%
Proce8ure<
1% Triturate . ml of each of the abo&e mentioned solutions in a test tube (ith
each of the electrolyte solutions in turn% eport the appro'imate
concentration in molBL necessary for the precipitation of the colloid% Time
may be allo(ed for precipitation to ta0e place%
#% The &arious solutions may be mi'ed (ith an e)ual &olume of ethanol%
5% 2&aporate . ml of each of the abo&e solutions on a (ater bath to dryness%
2'amine the residue and try to redisperse it by the *radual
addition of . ml of (ater%
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nly hy8ro)hilic colloi8s .
• Some %ncom)ati-ilities of Pharmaceutical olloi8s
Sensiti3ation in colloidal systems may result from any of the factors
(hich cause a decrease in stability of the colloid% Thus electrolytes of opposite
char*e may precipitate lyophobic colloids% Dehydration by alcohol or too hi*h
salt concentrations may lead to instabilities in hydrophilic sols% 2&en
protecti&e colloids in concentrations belo( that (hich may protect can cause
precipitation in colloidal systems%
#aterials <
Dil% Hl, [elatin Pharma*el 6 Y Pharma*el +$, 6rsenius sulphide sol%
Ferric
hydro'ide sol%, Sil&er sol%
Proce8ure<
1% To . ml of a #? mucila*e of acacia add . ml of dil% Hl and report your
obser&ation%
#% To . ml of a #? mucila*e of acacia dd 1 ml of Ferric chloride T%S%
ecord your obser&ation%
5% To 5 ml of a #? mucila*e of acacia add . ml of each of 1? Pharma*el 6
solution lime treated *elatin, I%2%P% /%! - .$ and 1? Pharma*el + solution,
acid treated *elatin, I%2%P% !-:$% ecord your obser&ation%/% Mi' . ml of each sil&er sol%, and Ferric hydro'ide sol% ecord your
8"
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turbid and &isually identical (ith the solution in test tube 4o% ! i%e% tube (ith
the ma'imum )uantity of protecti&e colloid%
!/SULTS
=sin* starch as a protecti&e colloids
Test tu-e
$o.
Sol. 1ml2 Starch sol.
1ml2
So8ium
chlori8e
sol.1ml2
-servation after a
minimum )erio8 of *5
hours.
1 . " 1
# . 1 1
5 . # 1
/ . 5 1
. . / 1
8 . . 1
! . 81
. 8 "
=sin* 6cacia mucila*e as a protecti&e colloids
Test tu-e
$o.
Sol. 1ml2 Acacia
mucilage 1ml2
So8ium
chlori8e
sol.1ml2
-servation after a
minimum )erio8 of *5
hours.
1 . " 1
# . 1 15 . # 1
/ . 5 1
. . / 1
8 . . 1
! . 8 1
. 8 "
=sin* [elatin sol% as a protecti&e colloids
Test tu-e
$o.
Sol. 1ml2 elatin sol.
1ml2
So8ium
chlori8e
-servation after a
minimum )erio8 of *5
8#
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sol.1ml2 hours.
1 . " 1
# . 1 1
5 . # 1
/ . 5 1
. . / 1
8 . . 1
! . 8 1
. 8 "
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+% Phenacetin Sus)ension
'
Phenacetin
[lycerin
Methyl cellulose 6romatic eli'ir
m%f%t% , Mist % mette dim
si* % Fl to be ta0en e&ery / hours for pain %
alculations an8 Proce8ure <
1% alculate the metric e)ui&alents and prepare half the amount %#% Phenacetin is a sparin*ly soluble po(der so it is prepared as suspension usin* a
dispersion stabili3er%
5% Methyl cellulose is used as dispersion stabili3er and is &ery often used in the form of
mucila*e in the prescription compoundin* % So it can be handled by 9
a% mi'in* the methyl cellulose thorou*hly (ith 1B5 of the re)uired amount of
(ater as hot (ater " to :" o $
b% 6fter complete dispersion cool and immerse in a bea0er contains crushed ice%
c% 6dd the remainder of (ater as cold (ater drop by drop (ith continuous stirrin*
till a clear *el is obtained %
/% Phenacetin po(der is (ei*hed and triturated thorou*hly in mortar into fine po(der %
.% 6dd Methyl cellulose mucila*e *radually (ith trituration %
8% 6dd aromatic eli'ir and complete the &olume %
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• (etermination of the effect of various agents on the Flocculation
)ro)erties of sus)en8e8 materials <
%ntro8uction <
6 pharmaceutical suspension may be defined as a coarse dispersion containin*
finely di&ided insoluble material suspended in a li)uid medium or a&ailable in dry form
to be distributed in the li)uid (hen desired % <e are only concerned (ith the former in
the present e'ercise%
For a suspension to be acceptable it must be composed of small uniformly si3ed
particles (hich do not settle rapidly% Those particles that do not settle should not pac0
into a hard ca0e but should be redispersed completely and uniformly (ith the minimum
of a*itation% In addition, the suspension should not be so &iscous that it does not pourfreely from a bottle%
Deflocculated particles in suspension settle slo(ly but the sediment, (hich is
ultimately, formed pac0s closely in the bottom of the &essel% The result is a ca0e, (hich is
difficult to redisperse% onse)uently, it is more desirable to prepare a flocculated
dispersion% The floccules produced are lar*e in comparison (ith the indi&idual particles
and hence settle rapidly% Ho(e&er, the floccules form a loose, open scaffold-li0e
structure, (hich is easily dispersed (ith the minimum of a*itation% The theory behind this
approach has been co&ered in lecture% The main purpose of this e'periment is to
determine the effect of &arious a*ents on the flocculation properties of suspended
materials%
Proce8ure<
This e'periment (ill re)uire t(o- lab periods% Durin* the first session , you (ill
prepare the &arious systems described belo( and ma0e initial measurements and
obser&ations % In t(o (ee0s , you (ill accomplish the second phase of the (or0 by
ma0in* final measurements and compilin* the results % The follo(in* are pro&ided
Solution A Surfactant$ 6erosol "%! 1%8! *%
Distilled (ater to 1 L %
Solution B cationic flocculatin* a*ent$
6LL5, 8H#7 "%:. *%
Distilled (ater to 1"" ml%
Solution anionic flocculatin* a*ent$
H#P7/ #%" *%Distilled (ater to 1"" ml%
Solution ( suspendin* a*ent$
8!
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System * < Prepare the follo(in* 9
Solution 6 1%" ml
Sulfametha3ine "% *
Distilled (ater to #"%" ml
Place Sulfametha3ine in a test tube , add solution 6 and in&ert se&eral times % 6dd
(ater to #" ml% Then sha0e (ell%
System 4 < Prepare the follo(in* 9
Solution 6 1%" ml
Sulfametha3ine "% *
Solution + #%" ml
Place Sulfametha3ine in a test tube , add solution 6 and in&ert se&eral times % 6dd
Solution + then sha0e (ell% eport your obser&ations%
System 5 < Prepare the follo(in* 9Solution 6 1/%" ml
Sulfametha3ine "% *
Solution + #%" ml
Solution 2 /%" ml
Place Sulfametha3ine in a test tube , add solution 6 and in&ert se&eral times % Then add #
ml of Solution + , cap and sha0e % Finally add /%" ml of Solution 2 and sha0e (ell %
System 6< To 1%8 * of bismuth subnitrate in a test tube add (ater to #" ml % Sha0e, sa&e
for # (ee0s and obser&e % eport your findin*s
System 7 < Prepare the follo(in* 9
Solution #%" ml
+ismuth subnitrate 1%8 *
Distilled (ater to #"%" ml
Place bismuth subnitrate in a test tube , add (ater , sha0e and then add solution % Sha0e
(ell , label and 0eep for # (ee0s%
System 9 < Prepare the follo(in* 9
Solution D 1%" ml
Solution #%" ml
+ismuth subnitrate 1%8 *
6dd solution D to +ismuth subnitrate in a test tube , sha0e , and add solution % Sha0e
and obser&e product % Sa&e for # (ee0s and then record your obser&ations%
System : < Prepare the follo(in* 9
Solution 2 1%" ml
Solution #%" ml
+ismuth subnitrate 1%8 *Prepare as in R ! abo&e %
8:
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TABL/ %%
%tem (escri)tion /0)lanation
1
#
5
/
.
8
!
!"
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Part 7
!heology
!5
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/0)eriment ,,
• #easurement of viscosity using an st>al8 iscometer
a$ Determine the flo( time of the li)uid of 0no(n &iscosity as (ater η @ 1 c p $
b$ Determine the flo( rate Time$ of the li)uid of un0no(n &iscosity at the same
temperature%
c$ alculate the &iscosity inematics$ of the un0no(n li)uid usin* the follo(in*
formula%
η1 B η# @ t1 B t#
<here η1 and t1 are the &iscosity and time of flo( of the un0no(n fluid andη# and t# are the &iscosity of (ater 1 c p$ and time of flo( respecti&ely%
Proce8ure<
1% lean and dry the &iscometer%
#% Fill by means of arm h*$ so that the le&el in this arm stand is (ithin "%#mm of the
mar0 *$ (hen the tube is clamped &ertically%
5% +y means of a rubber tube suc0 the li)uid to about 1 cm abo&e mar0 b$%
/% 4ote the time of flo( bac0 throu*h the tube bet(een the mar0s b$ and c$%
.% Ta0e three readin* and find the a&era*e%
8% alculate the 0inematics &iscosity of the li)uid of un0no(n &iscosity usin* the abo&e
e)uation%
!/
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/0)eriment ,*
• Tem)erature 8e)en8ency of viscosity
The &iscosity of a li)uid is in&ersely proportional to the temperature of this li)uid%This relationship is )uantitati&ely e'pressed by the modified 6rrhenius e)uations%
Lo* η @ lo* 6 2&B#%5"5 %1BT
Firstly, Study the &iscosity chan*e of 1? *elatin solution by temperature% Secondly,
determination of the e)uations constants 6 and 2& form the constructed *raph%
Proce8ure<Determine the dynamic &iscosity of the *elatin solution #? usin* 7st(ald &iscometer at
#.°, 5.° , /.° %
Tabulate your results, lo*η, T °$ and 1BT and plot lo*η a*ainst 1BT% alculate the
&alues of 6 and 2& form the intercept of the y- a'is and slope of the strai*ht line,
respecti&ely%
onclusion<
no(in* the onstants 6 and 2& for a particular system enablesPrediction of &iscosity &alues at any desired temperature (ithout
repeatin* the e'perimental (or0%