PERCOLATION

Presented by:Hassan MuJtaba

43-E-14

INTRODUCTION

‘per’ means ‘through’ ‘colare’ mean ‘to strain’Definition

The process in which a comminuted drug is extracted of its soluble constituents by the slow passage of suitable solvent through a column of drug.

COMMON EXAMPLES Coffee: In coffee percolation soluble compounds

leaves the coffee and join the water. Insoluble components remain within the coffee filter.

COFFEE PERCOLATION

PROCESS The process of percolation includes five steps. Comminution of drug Imbibition of drug Packing Maceration Percolation

COMMINUTION It is the size reduction of drug usually

from coarse powder to fine powder so that....

To increase surface area To ensure complete removal of drug To slow down the movement of menstrum For uniform packing

IMBIBITION Swelling of drug by absorbing menstrum.It is

allowed to stand for 4 hours in a closed container.

It is done to achieve following objectives; To avoid choking(difficulty in movement) To remove air To avoid washing out of fine particles

PACKING After imbibition drug is evenly packed into

the percolator. The a filter paper is placed on the bottom to

support the column of drug. Then the moistened drug is placed on the

filter paper. Over the moistened drug another filter paper

is placed having weight on it. Then menstrum is added. Close the lid if

menstrum is volatile.

HOW TO PACK ?

MACERATION After packing sufficient menstrum is added

and covered with lid. When liquid begins to drop the lower orifice

is closed. Then percolator is set aside 24 hours.

PERCOLATION After 24 hours lower orifice is opened and

menstrum is collected with a controlled speed until ¾ of menstrum is collected.

Then more menstrum is added and collected from the lower orifice so that marc does not become dry.

Then marc is pressed to get extract which is combined with previous liquid.

Then it is allowed to stand and then it is filtered.

MODIFIED PERCOLATION Reserved percolation Continuous hot percolation Continuous cold percolation Reserved percolation: This type of percolation is done to get concentrated preparation. process: In this method the first portion(about ¾ portion) of percolate

contains maximum amount of active constituent(70 to 80%) is reserved as such.

The last portion of percolate(about ¼ ) is collected separately and menstrum is evaporated to get syrupy consistency and mixed with reserved percolate.

Final volume is adjusted by adding more menstrum. Usually alcohol is use as menstrum for reserved percolation. example: Liquorice liquid extract.

CONTINUOUS HOT PERCOLATION This process is done for those drugs in which

percolation of menstrum into cellular tissues is very low.

Apparatus: The apparatus use for this process is called as

KUMAGAWA EXTRACTOR. Process: The menstrum present in the flask is heated and

vapours are taken to a condenser where the condensed liquid is return to the drug to continue extraction.

ADVANTAGES: Smaller volume of menstrum can be use again and

again.

KUMAGAWA EXTRACTOR

CONTINUOUS COLD PERCOLATION THE APPARATUS IS CALLED AS SOXHELT EXTRACTOR.

DISADVANTAGES OF CONTINUOUS PERCOLATIONS This type of percolation is not suitable for

those drugs which contains heat sensitive active constituents.

TYPES OF PERCOLATORS Percolators vary in their..... Shape Capacities Compositions Use

COMMON LABORATORY PERCOLATOR Cylindrical It is use for minimum expenditure of

menstrum.

Roundish Coffee maker

Conical or Funnel shaped It is use for those drugs that swell a lot

during maceration.