The document discusses fundamental operations in compounding and dispensing medicines, highlighting key techniques such as weighing, measuring liquids, dissolution, filtration, mixing, size reduction, and size separation. It emphasizes the importance of precision and proper techniques for each operation to ensure the accurate preparation of pharmaceutical products. Each operation is detailed with methods and best practices to achieve successful compounding in pharmacy.

1. FUNDAMENTAL OPERATIONS IN
COMPOUNDING
Dr. Marriam Zaka
Lecturer
Institute of Pharmacy,
Faculty of Pharmaceutical and Allied Health Sciences
LCWU, Lahore.

2. FUNDAMENTAL OPERATIONS IN
COMPOUNDING
•COMPOUNDING & DISPENSING IS CONCERNED WITH THE
PREPARATION OF MEDICINES FROM BASIC INGREDIENTS IN
SMALL QUANTITIES.
• THE ACCURATE & ELEGANT COMPOUNDING OFMEDICINES
REQUIRES EXPERTISE IN SEVERAL FUNDAMENTAL
OPERATIONS WHICH ARE FOLLOWING :
1. WEIGHING,
2. MEASUREMENT OF LIQUIDS,
3. DISSOLUTION,
4. FILTRATION,
5. MIXING,
6. SIZE REDUCTION,
7. SIZE SEPARATION

3. 1. WEIGHING:
• MOST IMPORTANT STEP UPON WHICH SUCCESS OF ALL THESE
OPERATIONS IN PHARMACY DEPENDS.
•PROPER WEIGHING DEPENDS ON A THOROUGH KNOWLEDGE
OF BALANCE, ITS PRINCIPLE, ITS CARE &PROPER USE.
•DURING COMPOUNDING
& DISPENSING OF MEDICINES,WEIGHING IS CARRIED OUT ON
A DISPENSING BALANCE. ALLOF YOU HAVE BEEN PROVIDED
WITH SUCH A BALANCE.
•WHEN THE LOAD IS PLACED ON THE PANS OF THE
BALANCE,THE HORIZONTAL METAL BEAM MOVES AROUND
THECENTRAL FULCRUM AND DEFLECTION FROM
THEHORIZONTAL IS INDICATED BY THE MOVEMENT OF
APOINTER FIXED IN THE CENTER OF THE
BEAM WHICH COMESIN THE CENTER WHEN THE WEIGHTS
IN THE TWO PANS ARE EQUALLY BALANCED.

4. WEIGHING IN PHARMACY
• FOLLOWING TECHNIQUE SHOULD BE FOLLOWED
WHILEWEIGHING THE MEDICINAL INGREDIENTS:
•PLACE THE BALANCE IN A WELL LIT AREA FREE FROM DUST&
PLACE IT OVER THE RUBBER SHEET TO PROTECT THE
BALANCE FROM CORROSION,
•ADJUST THE LEVEL OF THE BALANCE
•CLEAN THE BALANCE PANS WITH A DRY DUSTER BEFOREUSE,
•KEEP EQUAL SIZE PIECE OF CLEAN WHITE PAPER IN EACHPAN &
BALANCE THE PANS,
•PLACE THE REQUIRED WEIGHTS ON THE LEFT HAND SIDEPAN
WITH THE HELP OF FORCEPS SO THAT SWEAT, DUST &GREASE
FROM HANDS MAY NOT MAKE THE WEIGHTS INACCURATE,
•THE DRAWER OF THE BALANCE IN ORDER TOPREVENT SPILLAGE
OF INGREDIENTS ON THE WEIGHTS LYING IN THE DRAWER,

5. WEIGHING IN PHARMACY
•ADD OR REMOVE THE MEDICAMENT IN THE RIGHT HAND PAN
WITH THE HELP OF THE SPATULA UNTIL THE POINTER
RETURNS TO THE NULL POINT. REMEMBER IN PHARMACY
RIGHT HAND PAN IS USED FOR WEIGHING THE
MEDICAMENTS,
•WHEN THE WEIGHING IS COMPLETED PUT THE BALANCE BEAM
AGAIN IN FIXED POSITION,
•TRANSFER THE WEIGHED INGREDIENT IN A CONTAINER OR A
PIECEOF PAPER, AS PER REQUIREMENT,
•RETURN THE WEIGHTS TO THE DRAWER WITH FORCEPS
ANDCAREFULLY CLEAN THE BALANCE PAN & THE SPATULA,
•RETURN THE EXCESS LEFT OVER INGREDIENT TO THE
STOCKBOTTLE AFTER CAREFULLY READING ITS NAME ON THE
LABEL.SIMILARLY WEIGH ALL OTHER INGREDEINTS.
•WITH THE DISPENSING BALANCE PROVIDED TO YOU THE
MINIMUM WEIGHABLE QUANTITY IS 100 MG.

6. 2.MEASUREMENT OF LIQUIDS
2. MEASUREMENT OF LIQUIDS IS GENRALLY DONE WITH THE
HELP OF VARIOUS CYLINDRICAL OR CONICAL
MEASURESPROVIDED TO YOU. BUT THE CONICAL
MEASURES AREPREFERRED BECAUSE IT IS EASY- TO FILL
THEM WITHOUT SPILLAGE,- TO DRAIN OUT WHOLE
LIQUID,- TO RINSE OUT THE RESIDUE AFTER DRAINING
OUT LIQUID SESPECIALLY, VISCOUS LIQUIDS AND- ALSO
EASY TO CLEAN THEM AS COMPARED TO CYLINDRICAL
MEASURES.
• THE MINIMUM MEASUREABLE QUANTITY IS 1 ml. USING
A 10ml, CONICAL MEASURE. UPTO 0.1 ml, LIQUID CAN BE
MEASURED USING A GRADUATED GLASS PIPETTE.

7. MEASUREMENT OF LIQUIDS
• Measuring technique for conical measures:
• Always use clean & dry measures
• Always choose the smallest measure that will hold the required volume
to be measured. Do not split the volume into two measurements as this
would double the error,
• Check the label of the stock bottle for the correct name of the liquid to
be measured,
• Hold the bottle in the right hand with label in the upper side so that it is
visible during measurement & also to prevent its spoilage if some liquid
trickles down,
• Remove the stopper of the bottle and hold it between the little finger
and palm of the left hand,
• Straighten the conical measure with the graduated side in front and put
it on a flat surface or a tile,

8. 3.DISSOLUTION
• IT INVOLVES DISSOLVING SOLIDS IN TO LIQUID TO PREPARE A
SOLUTION.
• IT IS NECESSARY TO KNOW THE SOLUBILITY OF THE
MEDICAMENTS INTO VARIOUS LIQUIDS OR SOLVENTS.
• THE SOLUBILITY OF A LIQUID IN A GIVEN LIQUID CAN BE
INCREASED BY FOLLOWING WAYS:
- POWDER THE SOLID INTO FINE PARTICLES, THIS INCREASES THE SURFACE
AREA FROM WHICH MOLECULES CAN DIFUSE INTO LIQUID,
- BY AGITATING THE SOLUTION IN A CONICAL FLASK WHICH HELPS RAPID
DIPERSION OF THE SOLUTE THROUGHOUT THE LIQUID, AND
- BY INCREASING THE TEMPERATURE WHICH DECREASES THE VISCOSITY &
INCREASES THE DIFFUSION CO-EFFICIENT AND ALSO INCREASES THE
SOLUBILITY OF MOST OF THE DRUGS

9. DISSOLUTION
TECHNIQUE OF DISSOLUTION:
• GENERALLY A CONICAL FLASK IS SELECTED AS A VESSEL FOR
MAKING A SOLUTION BECAUSE OF FOLLOWING
ADVANTAGES:
-THE CONTENTS CAN BE EASILY AGITATED BY SHAKING
WITHOUT ANY SPILLAGE,
- THE CONTENTS CAN BE READILY HEATED IF DESIRED,
-THE CONTENTS CAN ALSO BE READILY COOLED UNDER
RUNNING TAP WATER WITHOUT CONTAMINATION

10. FOLLOWING STEPS ARE TAKEN IN
DISSOLUTION TECHNIQUE
- POWDER THE DRUG IN MORTAR & WEIGH THE REQUIRED
QUANTITY OF THE POWDERED DRUG,
-PUT THE DRUG WITH THE LITTLE VOLUME OF THE SOLVENT IN THE
CONICAL FLASK AND STIR WITH A GLASS ROD & AGITATE BY
SHAKING OR BY USING A MECHANICAL STIRRER,
- HEAT THE SOLUTION IF NEEDED AND OBTAIN A CLEAR SOLUTION,
-BRING THE SOLUTION TO ROOM TEMPERATURE BY COOLING,
- TRANSFER THE SOLUTION TO A CONICAL MEASURE AND ADD MORE
SOLVENT TO MAKE THE REQUIRED VOLUME OF THE SOLUTION

11. 4.FILTRATION
• FILTRATION IS THE PROCESS BY WHICH THE SOLID PARTICLES ARE
REMOVED FROM LIQUID OR GAS BY PASSING IT THROUGH APOROUS
MEDIUM WHICH RETAINS THE SOLID PARTICLES BUT ALLOWS THE
LIQUID TO PASS.
•THE RATE OF FILTRATION CAN BE INCREASED BY FOLLOWING WAYS:
- INCREASING THE SURFACE AREA OF THE FILTER,
- REDUCING THE VISCOSITY OF THE LIQUID BY HEATING THELIQUID,
- INCREASING THE PRESSURE ACROSS THE FILTERING DEVICEEITHER BY
APPLYING VACCUM BELOW IT OR BY INCREASING THE PRESSURE OVER
THE LIQUID BEING FILTERED,
- BY USING HIGH POROSITY FILTERING MEDIUMS SUCH AS SINTERED
GLASS FILTER OR MEMBRANE FILTERS. GENERALLY A NO.3 FILTER IS
USED FOR SMALL VOLUMES FOR FILTRATION BY GRAVITY AND NO.4
FILTER FOR LARGE VOLUMES BY VACCUM OR PRESSURE.
•SINTERED GLASS FILTERS ARE MADE FROM BOROSILICATE, VERY
EXPENSIVE, NOT USED IN PHARMACY LAB. OR FOR ROUTINE USE

12. FILTRATION
• A HIGH DEGREE OF CLARITY IS REQUIRED IN CASE OF ORAL SOLUTIONS
AND SOLUTIONS FOR APPLICATION TO SKIN OR MUCOUS MEMBRANES
OR ULCERATED AREAS.
• IT IS NECESSARY TO ADJUST SOLUTIONS TO VOLUME THROUGH THE
FILTER AS FOLLOWS;
- WASH THROUGH THE FILTER USING A LITTLE OF THE VEHICLE AND
DISCARD THE WASHINGS,
- MAKE THE SOLUTION TO VOLUME AND PASS THROUGH THE FILTER INTO A
MEASURING DEVICE,
-RINSE THROUGH THE FILTER WITH THE SUFFICIENT QUANTITY OF VEHICLE
TO MAKE THE FINAL REQUIREDVOLUME.

13. 5.MIXING & MIXTURES
• MANY PHARMACEUTICAL PREPARATIONS CONSIST
OFHOMOGENOUS MIXTURES OF TWO OR
MORECOMPONENTS & DEPENDING UPON THE
COMPONENTSTHE MIXTURES ARE DIVIDED INTO FOUR
CLASSES:
I.MIXTURES OF LIQUIDS,
II. MIXTURES OF LIQUIDS AND SOLIDS,
III. MIXTURES OF SOLIDS,
IV. MIXTURES OF SEMISOLIDS.

14. MIXTURES OF LIQUIDS
THESE ARE OF TWO TYPES:
A. HOMOGENOUS MIXTURES OF LIQUIDS CALLED SOLUTIONS:
• Contain readily miscible liquids, a mechanical stirrer or
glass rod may be needed to mix them. Sometimes, an
electric stirrer may be needed to mix liquids of high
viscosity
B. HETEROGENOUS MIXTURES OF LIQUIDS OR EMULSIONS:
• THESE INVOLVE MIXING OF TWO IMMISCIBLE LIQUIDS
WITH THE HELP OF SUSPENDING AGENTS OR EMULGENTS
AND BY LOCAL MIXING IN WHICH SHEAR IS APPLIED TO THE
GLOBULES OF LIQUIDSI N A MORTAR & PESTLE ON SMALL
SCALE.

15. II. MIXTURES OF LIQUIDS & SOLIDS
THESE ARE ALSO OF TWO TYPES:
A. HOMOGENOUS MIXTURE OR SOLUTIONS:
• IT INVOLVES SIMPLE DISSOLUTION OF A SOLUBLE
SOLID INTO A LIQUID WHICH MAY BE ACHIEVED
BY SHAKING OR STIRRING.
B. HETEROGENOUS MIXTURES OR SUSPENSIONS:
• IN THIS VARIETY THE DISPENSED SOLID TENDS TO
SEPARATE FROM DISPERSION MEDIUM SO
PROPER MIXING IS REQUIRED TO OBTAIN A
STABLE SUSPENSION. THIS IS GENERALLY DONE
USING A MORTAR & PESTLE ON SMALL SCALE.

16. III. MIXTURES OF SOLIDS:
• IT INVOLVES HOMOGENOUS MIXING OF SOLIDS IN POWDER STATE WHICH IS
GENERALLY DIFFICULT TO ACHIEVE BECAUSE SOLIDS DO NOT MIX READILY
AND ESPECIALY SO WHEN MINUTE QUANTITIES OF ONE SOLID IS TO BE MIXED
WITH THE LARGER QUANTITIES OF OTHERS. THIS IS GENERALLY DONE IN
MORTAR & PESTEL AND FOLLOWING STEPS ARE OBSERVED IN THE PROCESS:
- ADD TO THE MORTAR THAT INGREDIENT FIRST WHICH IS PRESENT IN THE
SMALLEST QUANTITY AND POWDER,
- ADD A QUANTITY OF THE SECOND SOLID THAT WILL APPROXIMATELY DOUBLE
THE BULK OF MEDICAMENTS ALREADY PRESENT IN THE MORTAR,MIX LIGHTLY
TO OBTAIN A POWDER WITHOUT ALLOWING PRESSURE WHICH MAY CAUSE
CAKING OF INGREDIENTS.
- EVERY ADDITION OF INGREDIENT SHOULD BE SUCH THAT IT DOUBLES THE
QUANTITY ALREADY PRESENT IN THE MORTAR. THIS ASSISTS HOMOGENOUS
MIXING OF SOLIDS. REPEAT THE PROCESS UNTIL ALL THE SOLIDS HAVE BEEN
CONSUMED,
- SEPARATE THE POWDER FROM THE BASE & SIDES OF THE MORTAR USINGA
SPATULA AND TRANSFER IT ON TO A CLEAN PAPER AND PEPARE THE REQUIED
NUMBER OF DOSES BY ACCURATE WEIGHING

17. IV.MIXTURES CONTAINING
SEMISOLIDS:
• IT INVOLVES MIXING A SOLID AND / OR A LIQUID INTO A BASE CONSISTING
OF ONE OR MORE SEMISOLIDS. FOR EXAMPLE:
- OINTMENT,
- PASTE,
- SUPPOSITORIES.
• THE FOLLOWING PROCEDURE IS ADOPTED:
1. PREPARE THE BASE OF OINTMENT OR PASTE
WHICH MAY CONTAIN LIQUIDS, SUCH AS LIQUID PARAFFIN, SEMI-SOLIDS
SUCH AS WOOL FAT & SOFT PARAFFIN AND ALSO SOLIDS SUCH
ASCETOSTEARYL ALCOHOL & HARD-PARAFFIN.
- THE INGREDIENTS ARE MELTED TOGATHER IN A DISH OVER A WATER BATH
AND STIRRED WELL TAKING CARE TO AVOID OVERHEATING. THIS IS DONE
TO OBTAIN A HOMOGENOUS MIXTRURE.

18. IV.MIXTURES CONTAINING
SEMISOLIDS
2. INCORPOATE ANY SOLID INGREDIENTS
• BY FIRST RUBBING THEM INTO A SMALL QUANTITY OF THE BASE.
THE REST OF THE BASE IS ADDED GRADUALLY AND MIXING
CONTINUED UNTIL THE MEDICAMENTS ARE THOROUGHLY MIXED.
3. INCORPORATE ANY LIQUIDS WITH THE BASE
AFTER COOLING IT TO THE ROOM TEMPERATURE. VOLATILE
LIQUIDS AND HEAT LABILE LIQUIDS SHOULD NOT BE ADDED UNTIL
THE TEMPERATURE OF THE BASE IS BELOW 40-C.
• THE SOLIDS AND LIQUIDS INGREDIENTS ARE GENERALLY ADDED
WITH THE BASE ON LARGE WARM TILE USING A FLEXIBLE SPATULA
OR IN A WARM MORTAR USING PESTLE.

19. 6.SIZE-REDUCTION
• SIZE REDUCTION OR COMMUNITION:
• IS THE PROCESS OF REDUCING DRUGS INTO SMALLER PIECES WHICH MAY
BE COARSE PARTICLES OR FINE POWDERS.
• THE ADVANTAGES OF SIZE REDUCTION ARE FOLLOWING:
1. PROMOTES MIXING,
2. PROMOTES SUSPENDING,
3. FACILITATES DISSOLUTION,
4. INCREASES RATE OF ABSORPTION FROM GIT,
5. YIELDS PREPARATION SUITABLE FOR USE ON MUCUSMEMBRANES OR
SKIN BECAUSE IT PREVENTS GRITTINESS AND IRRITATION ON
APPLICATION.
6. ON SMALL SCALE THIS IS ACHIEVED BY THE PROCESSES OF:
-DRY GRINDING, AND
- WET GRINDING OR LEVIGATION

20. SIZE-REDUCTION
1. DRY GRINDING:
• IT INVOLVES BREAKING THE INGREDIENT IN A MORTAR &
PESTLE. SIZE REDUCTION IS DONE BY COMPRESSION
BETWEEN THE FLAT HEAD OF PESTLE AND BOTTOM OF THE
MORTAR AND ATRITION BY SHEARING ACTION OF THE
PESTLE.
2. WET GRINDING OR LEVIGATION:
• THIS INVOLVES PREPARING AQUEOUS SUSPENSIONS. THE
INGREDIENTS ARE MADE INTO PASTE WITH WATER AND
GROUND IN MORTAR. IN CASE OF PREPARATION OF SEMI-
SOLID PREPARATIONS, THE MEDICAMENT IS RUBBED
DOWN WITH THE WARM BASE ON A WARM TILE OR IN
WARM MORTAR

21. 7.SIZE SEPARATION
• SIZE SEPARATION IS DONE TO SEPARATE PARTCLES
OF THE SPECIALIZED SIZE FROM A MEDICAMENT
BY SIFTING.
• GENERALLY WIRE MESH SIEVES ARE USED.
• FOR DUSTING POWDERS FINE POWDERS ARE
PASSED THROUGH THE APERTURE OF 180
MICRO-MILIMETER (NO. 85 SIEVE).
•FOR ORAL POWDERS OR FOR POWDERS FOR
EXTERNAL USE MESH SIZE OF 250 MICRO
MILIMETER OR SIEVE NO. 120 IS USED.
•FOR ABRASIVE TOOTH POWDERS A NO. 60 SIEVE
IS USED.