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EVALUATION OF FLOATING TABLETS

GUIDED BY-Asst. Prof. Patil M.S.

Asst. Prof.Bathe R.S.

PRESENTED BY:-SHINDE SHIVAJI VASUDEO

M.PHARM.SEM-2

(Dept. of Pharmaceutics)

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1) PREFORMULATION STUDY2) PRECOMPRESSIONAL EVALUATION3)POSTCOMPRESSIONAL EVALUATION 4) INVITRO STUDY5) INVIVO STUDY6) STABILITY STUDY7) CONCLUSION8) REFERENCES

CONTENTS

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PREFORMULATION STUDY:• Yield a key information necessary to guide the formulator and analyst toward the development

of an elegant, stable dosage form with good bioavailability.

• 1.Particle size ,shape and crystallinity: Particle size and shape characteristics can be determined by optical microscopy and sieving method. A polarizing microscope and x-ray diffraction used to determine crystallinity.

• 2.Colour: Generally it is a function of unsaturation. It is determined by spectroscopic methods. Colour change under stress conditions can be used in stability study.

• 3.Odour: The odour is due to major functional group present in molecule.e.g.Garlic

• 4.Melting point: Thermodynamically defined as the temperature at which the solid and liquid phases are in equilibrium.

5.Thermal Analytical Profile: Basic technique used to study is DTA. It detect changes in compound whether it is exothermic or endothermic. Also DSC is used to determine energy absorbed or desorbed.

6.U.V.Spectroscopy: Molecules with structural unsaturation are able to absorb light with specific frequency range. Ultraviolet-400-190nm Visible -800-400nmBeer’s-Lambert’ Law a = A / bc. Standard calibration curve is plotted using U.V. spectroscopy widely used for the quantitative purpose.

7.I.R.Spectroscopy: Individual compound graph is recorded for the identity of compounds with their functional groups. Physical mixture of formulation is scanned for checking the compatibility with other ingredients. If IR spectral differences are found then interactions should be taken.

PRECOMPRESSIONAL EVALUATION:• 1. Angle of repose: Angle of repose is defined as the maximum

angle possible between the surface of pile of powder and horizontal plane. Determined by funnel method.

•

= tan-1 (H / R)

Angle of Repose (Degree) Nature of Flow

25-35 Good

37-40 Fair

Beyond 40 Poor

2.Bulk Density: Depends upon particle size, shape and cohesiveness. May influence the compressibility, tablet porosity and dissolution.

Bulk Density= Bulk Mass/ Bulk Volume

3.Tapped Density: Helps to determine packing geometry and floability of powder blend. Tapped Density= Bulk Mass/Tapped Volume

4. Carr’s Index: An indirect method of measuring powder flow from bulk and tapped densities. Compressibility= Tapped Density – Bulk Density/ Tapped Density

5.Hauner’s Ratio: Essential to determine compressibility strength of powder andto estimate flow properties.

Hausner’s Ratio= Tapped Density/ Bulk Density

POSTCOMPRESSIONAL EVALUATION:• 1. Tablet Thickness and Diameter: Important for the uniformity of tablet size and

measured by using Vernier Caliper.

• 2. Hardness: The resistance of tablet to shipping or breakage under conditions of storage, transportation and handling before use depends upon its hardness. Measured by Monsanto hardness tester in terms of Kg/cm2.

• 3. Friability of tablet: Friability is the measure of tablet strength. Roche friabilator was used for testing the friability .

Initial weight of tablets – Final weight of tablets % Loss = ------------------------------------------------------------------- x 100 Initial wt. of tablets Not more than 0.1% weight loss takes place according to I.P.

4.Weight Variation: Weigh 20 tablets selected at random and calculate the average weight. Not more than two of the individual weights deviate from the average weight .

I.P. Standards for weight variation

Avrg. Wt. of Tablet % of deviation

80mg or < 80mg 10

> 80mg - <250mg 7.5

>250mg or more 5

5. Drug content uniformity or Assay: Twenty tablets were weighed and powdered. The powder equivalent to 10 mg was taken and dissolved in 10 ml 0.1 N HCl. This stock solution was shaken for 20 min. on a sonicater. This resulting solution is further diluted with 0.1 N HCl to achieve concentration up to 10 μg /ml. and the absorbance measured at its maximum absorbable wavelength( nm).

INVITRO EVALUATION:

• 1. In -Vitro Buoyancy Study: The in-vitro buoyancy was characterized by floating lag time and total floating time. The test was performed using a USP type II paddle apparatus (Electrolab) using 900 ml of 0.1 N HCl at paddle rotation of 50 rpm at 37 ± 0.5oC.

• 2. Swelling Characteristics (Water uptake study): Determined by placing the tablet matrices in the dissolution test apparatus, in 900 ml of 0.1 N HCl at 37 0.5 0C.

Weight of swollen tablet – Initial weight of the tablet WU % = -------------------------------------------------------------------------- x 100 Initial weight of the tablet

3.Invitro Drug Release: Equipment used:1. Dissolution Test Apparatus USP Type II (Electrolab India)

Details of Dissolution Test 2. Apparatus : USP Type II3. Speed : 50 rpm4. Volume of medium : 900 ml5. Stirrer : Paddle type6. Aliquot taken at each time interval : 5 ml7. Medium used : 0.1 N HCl8. Temperature : 37 ± 0.5 °C

INVIVO STUDY: • The in vivo X-ray evaluation of floating ability studies in healthy human volunteers in

the fasted and fed state was carried out by administering floating tablets incorporating with barium sulphate (BaSO 4) as X-ray opaque material.• a) Fasted state: The subjects fasted overnight then swallowed the gastric floating tablets with

200 mL of water. No food was allowed up to 3 hrs of dosing. A glass of water (200 mL) was given to volunteers for every one hour. All the subjects were not allowed to lay down for sleeping. • b) Fed state: The subjects fasted overnight and in the morning they were given a high calorie-

high fat breakfast with a total calorie value of approximately 900 KCal (Bread slice with 25 gms of butter-250 KCal, chicken tikka 75 gms-350 KCal, egg omelet 40 gms-150 KCal and fruit juice-150 KCal). The gastric floating tablet was administered with 200 mL of water after half an hour after the breakfast. The subjects were not allowed to eat anything up to 6 hrs but were given a glass of water (200 mL) every hour.

In each subject, digital X-ray photograph of the gastric region was taken at time intervals of 0.5, 3, 6 and 9 hrs.

STABILITY STUDY: The storage conditions for accelerated testing (as per ICH and WHO) are 400 ± 20 C and 75 ± 5% RH for solid dosage forms for 6 months. WHO prescribed testing at 0, 1, 2, 3 and 6 months during storage. ICH has not given testing time frequency. The tablets were packed in screw capped HDPE bottles and were stored at 400 ± 20 C and 75 % RH for 6 months. After storage for 6 months, the products were tested for drug content floating characteristics and drug release rate as per the methods described earlier.

CONCLUSION:• Controlled released floating drug delivery system to provide a potential approach for

gastric retention. This seminar gives an overview on the main concepts used to design pharmaceutical dosage forms with prolonged gastric retention time.

REFERENCES:

1.Silverstein R.M., Webster F.X., Spectrophotometric identification of organic compounds, Wiley J. and Sons Inc, 2003, 71 - 109. 2.Chauhan B., Mahadik K.R., Paradkar A.R. et. al., Preparation and evaluation of floating risedronate sodium, Gelucire 39/01 matrices, Acta Pharm., 2004, 54, 205– 214. 3.Deshpande A.A., Shah N.H., Christopher T., Development of a novel controlled release system for gastric retention, Pharmaceutical Research, 1997, 14(6), 815 – 819. 4.Li S., et al, Statistical optimization of gastric floating system for oral use controlled release system of calcium, Pharm.Sci.Tech. 2001, 1 -12. 5.Chein Y.W., Novel Drug Delivery Systems. 2nd Edn. Marcel Dekker. Inc. New York. 1992, 50, 1 -139.