Fundamental Operations in Compounding.ppt

Dispensing Pharmacy

1. FUNDAMENTAL OPERATIONS
IN COMPOUNDING
LECTURE # 02
PHARMACY PRACTICE-IIA
(DISPENSING PHARMACY)
PHM-3624

2. COMPOUNDING
(EXTEMPORANEOUS DISPENSING)
•The process of combining, mixing, or altering existing drugs to
create a medication tailored to the needs of an individual
patient is called “Pharmaceutical Compounding”.
•This might be necessary when a commercially available
product isn't suitable for a specific patient due to allergies,
dosage requirements, or other factors.
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3. WHY TO COMPOUND?
•Nowadays, most medicines are manufactured by the
pharmaceutical industry under well-controlled conditions and
packaged in suitable containers designed to maintain the
stability of the product (e.g. sealed in an inert atmosphere).
Extemporaneous dispensing, which cannot be as
well-controlled, should only be used when a manufactured
product is unavailable.
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4. WHY TO COMPOUND?
•Non-licensed products
•Products no longer on the market or unavailable from the
manufacturer
•Products requiring an individualized dose, e.g. for pediatric or
geriatric patients
•Products requiring an individualized formulation for a patient, e.g.
the removal of coloring agents
•Veterinary products, e.g. formulations for different species.
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5. SOME PRACTICAL EXAMPLES
•Bioidentical Hormone Replacement Therapy (BHRT) :
Some patients may require hormone replacement therapy
using hormones that are identical in molecular structure to
those naturally produced by the body. Compounded BHRT
can be tailored to individual hormone levels and needs.
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6. SOME PRACTICAL EXAMPLES
•Pediatric Dosages: Children often require medications in dosages
or forms that are not available in commercially manufactured
products. Compounding pharmacies can prepare medications in
forms like flavored liquids or lower-dosage capsules.
•Allergy-Friendly Formulations: Patients with allergies to certain
dyes, preservatives, or fillers may need medications that are free
from these allergens. A compounding pharmacy can create
customized formulations without the problematic ingredients.
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7. SOME PRACTICAL EXAMPLES
•Specialized Pain Management: Some patients may require
specific combinations of pain medications or formulations that are
not available in standard preparations. Compounding allows for
tailoring pain relief to individual needs.
•Dermatological Preparations: Creams, ointments, and gels can
be compounded with specific combinations of active ingredients for
skin conditions like psoriasis, eczema, or acne, or to avoid
allergenic additives.
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8. SOME PRACTICAL EXAMPLES
•Veterinary Medications: Animals, especially pets, may require
medications in forms or dosages that are not readily available in
commercial products. Compounding allows for formulations that are
palatable and suitable for various animal species.
•Oral Suspensions for Geriatric Patients: Some elderly patients
may have difficulty swallowing tablets or capsules. A compounding
pharmacy can prepare liquid formulations for easier administration.
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9. SOME PRACTICAL EXAMPLES
•Discontinued or Shortage Medications: When a manufacturer
discontinues a medication or there is a shortage, compounding
pharmacies may step in to provide the needed medication,
ensuring that patients continue to receive necessary treatment.
•Combination Medications: In cases where specific combinations
of medications are required and not available in a single product, a
compounding pharmacy can create a custom formulation.
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10. WORKING ENVIRONMENT
✔ORGANIZATION
✔CLEANLINESS & HYGIENE
✔DOCUMENTING PROCEDURES & RESULTS
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12. ORGANIZATION
•The working environment needs to be organized, with well
trained, efficient staff. A safe system of working is essential for
a dispensary and the development and use of SOPs should
be followed.
•Additionally, health and safety regulations must be applied in
the dispensary.
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13. CLEANLINESS & HYGIENE
•The dispensing bench, the equipment, utensils and the
container which is to hold the final product must all be clean.
Lack of cleanliness can cause contamination of the
preparation with other ingredients.
•For example, a spatula which has been used to remove an
ingredient from one container will adulterate subsequent
containers if not washed before being used again. Cleanliness
will also minimize microbial contamination.
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14. CLEANLINESS & HYGIENE
•Dispensing staff should have a high standard of hygiene and
hand-washing facilities should be readily available. A clean
overall should be worn, hair tied back and, preferably, be
covered with a disposable hat/cap and any skin lesions
covered with a dressing.
•Disposable gloves should be worn during preparative work
and discarded afterwards. Consideration should be given to
the use of masks if volatile substances or fine powders are to
be handled.
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15. DOCUMENTING PROCEDURES &
RESULTS
•Keeping comprehensive records is an essential part of the
dispensing process. Records must be kept for a minimum of 2
years (ideally 5 years) and include the formula and any
calculations, the ingredients and quantities used, their
sources, batch numbers and expiry date. All calculations or
weights/volumes should be checked by two people and
recorded.
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16. DOCUMENTING PROCEDURES &
RESULTS
•Any substances requiring special handling techniques or
hazardous substances should be recorded with the
precautions taken. The record for a prescribed item should
also include the patient and prescription details and date of
dispensing.
•A record must be kept of the personnel involved, including the
responsible pharmacist. Any deviations from a SOP should be
recorded.
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17. EQUIPMENT
Not only is the selection of the correct equipment for the
job essential, but the equipment must be used in the
correct way and maintained in good order.
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18. WEIGHING EQUIPMENT
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Weighing equipment can be divided into nonautomatic and
automatic weighing equipment.
AUTOMATIC NON-AUTOMATIC
Non-automatic weighing equipment
requires an operator to place and/or
remove the items from the balance pan.
Such weighing equipment can be a
mechanical beam balance, which has a
pan on one end of the beam for weights
and a pan on the other end of the beam
for the material to be weighed.
it can be an electronic top pan balance,
in which case the substance to be
weighed is placed on the pan and an
electronic display gives the weight.
Automatic weighing equipment is
designed to automatically fill a package
to the required weight without the
intervention of an operator.

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20. ANALYTICAL BALANCE
•Such equipment is used in the pharmaceutical industry, and
nowadays for extemporaneous dispensing. Whichever type of
weighing equipment is used, it must be suitable for its
intended use and be sufficiently accurate. In the UK, weighing
equipment must be calibrated in metric units and must be
marked with maximum and minimum weights that can be
weighed.
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21. GENERAL RULES FOR THE USE &
MAINTENANCE OF WEIGHING EQUIPMENT
•Balances must be placed on a level surface; most will incorporate a
level indicator device to allow adjustment for a non-level surface.
•Balances’ readings must indicate zero, before use. If zero is not
indicated, then incorrect readings, and hence weights, may be
obtained.
•Strong draughts, caused by air conditioning or a breeze, can affect
some balances and make a correct reading impossible. Therefore
always site a balance in a draught-free area
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22. GENERAL RULES FOR THE USE &
MAINTENANCE OF WEIGHING EQUIPMENT
•Always keep the balance pan clean and free from debris
•Regular checks with stamped weights should be made to
ensure the balance is working correctly
•If possible keep a record of when, and by whom, the check
was carried out, as well as the result
•Never weigh less than the declared minimum weight or more
than the maximum weight declared on the balance
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23. GENERAL RULES FOR THE USE &
MAINTENANCE OF WEIGHING EQUIPMENT
•Do not weigh ingredients on a piece of paper, as this introduces
a potential inaccuracy. The exception is when weighing greasy or
semi-solid materials, e.g. white soft paraffin, when a
counterbalanced piece of paper should be used
•Always read the manufacturer’s instructions before using an
electronic balance
•Use tweezers to handle weights, if used. Never handle weights,
as this will affect their accuracy and risks contamination.
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24. MEASURING LIQUIDS
•All measures for liquids must comply with
current weights and measures regulations
and should be stamped accordingly.
Traditionally, conical measures have been
used in dispensing.
•When using a measure always ensure the
following:
•The level of liquid is read to the bottom of the
meniscus at eye level
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25. MEASURING LIQUIDS
•The measure is vertical when reading the meniscus. If this is
not done, considerable errors in quantities can occur
•The measure is thoroughly drained to deliver the correct
volume
•Always select the smallest measure which will hold the
desired volume because this gives the greatest accuracy
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26. MEASURING LIQUIDS
•If the substance being measured is so viscous that it would be
very difficult to drain the measure effectively, then the volume
should be measured by difference. This is done by pouring an
excess into the measure and then pouring off the liquid until
only the excess volume remains.

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27. MEASURING SMALL VOLUMES
•Graduated pipettes can be used for small volumes from 5 mL
down to 0.1 mL. For volumes smaller than this, a dilution
should be made. The viscosity of the substance being
measured should also be considered.
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28. CORRECT USE OF PIPETTES
•Pipettes can be either the ‘drainage’ or ‘blowout’ variety. A rubber bulb or
teat should be used.
•Never use mouth suction.
•A bulb or teat should be placed over the mouth of the pipette
•Only a short length of the pipette should be immersed in the liquid
•The correct amount of liquid should be drawn up the pipette
•The measured liquid is then released into the desired container.
•Nowadays, semi-automatic pipettes can be used for dispensing.
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30. MIXING & GRINDING
Mortar and pestle
•The mortar (bowl) and pestle (pounding device) are used to
reduce the size of powders, mix powders, mix together
powders and liquids and to make emulsions. Two types, each
available in a range of sizes, are used.
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31. GLASS MORTAR & PESTLE
•These are generally small. The smooth
surface of the glass reduces the friction
which can be generated, so they are only
suitable for size reduction of friable
materials (such as crystals). Glass
mortars and pestles are useful for mixing
small quantities of fine powders and for
the mixing of substances such as dyes
which are absorbed by and stain
composition or porcelain mortars.
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32. PORCELAIN MORTAR & PESTLE
•These mortars have a rough
surface. They are ideal for size
reduction of solids and for
mixing solids and liquids, as in
the preparation of suspensions
and emulsions.
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33. SIZE REDUCTION USING PESTLE &
MORTAR
•Selection of the correct type of mortar and pestle is vital for
this operation. A flat-bottomed mortar and a pestle with a flat
head should be chosen.
•Adequate mixing will only be achieved if there is sufficient
space. Overfilling of the mortar should be avoided. The pestle
should be rotated in both right and left directions to ensure
thorough mixing. Undue pressure should not be used, as this
will cause impaction of the powder on the bottom of the
mortar.
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34. FILTERS
•There are occasions when clarification of a liquid is required.
Where filtration is required, filter paper or membrane filters
should be used. Filter paper and membrane filters come in
different grades and selection of the correct grade is
determined by the size of the particles to be removed. Filter
paper has the disadvantages of introducing fibers into the
filtrate and may also absorb significant amounts of active
ingredient. This is less likely with membrane filters.
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36. HEAT SOURCES
•In the dispensing process it may be
necessary to heat ingredients, e.g.
melt semi-solids in the preparation of
ointments/creams, warm liquids to
aid dissolution of solids.
•Nowadays, water baths or
electrically heated hot plates are
used for heating.
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37. MIXING
•The goal of any mixing operation should be to ensure even distribution of all the
ingredients has occurred. If a sample is removed from any part of the final preparation, it
should be identical to a sample taken from any other part of the container.
Mixing of liquids
•Simple stirring or shaking is usually all that is required to mix two or more liquids. The
degree of stirring or shaking will be dependent on the viscosities of the liquids.
Mixing solids with liquids
•Particle size reduction will either speed up the dissolution process or improve the uniform
distribution of the solid throughout the liquid. When a solution is being made, a stirring rod
will be adequate. However, a suspension will require a mortar and pestle.
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38. MIXING
Mixing solids with solids
Where the quantity of material to be mixed is small and the
proportions are approximately the same, the materials can be
added to an appropriately sized mortar and effectively mixed.
Where a small quantity of powder has to be mixed with a large
quantity, in order to achieve effective mixing, it must be done in
stages:
•The ingredient with the smallest bulk is placed in the mortar
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39. MIXING
•A quantity of the second ingredient, approximately equal in
volume to the first, is added and carefully mixed, using the
pestle
•A further quantity of the second ingredient, approximately
equal in volume to the mixture in the mortar, is now added
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40. MIXING SEMI-SOLIDS
•If all the ingredients are semi-solids or liquids, they can be
mixed together by rubbing them down on an ointment slab,
using a spatula. If there is a significant difference in the
quantities of the ingredients, a ‘doubling-up’ process should be
used. An alternative method is the fusion method.
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41. THE FUSION METHOD
•Place the bases in an evaporating basin and gently heat until they have just
melted. Excess heat should not be used, as overheating may cause physical or
chemical changes in some materials
•The basin is then removed from the heat and the contents are stirred
continuously, but gently, until the mixture has cooled and set. Stirring at this stage
is of vital importance as otherwise the components may segregate on cooling.
Rapid stirring should be avoided as it will introduce air bubbles into the mixture.
•When using the fusion method, do not be tempted to add any solid active
ingredients to the basin before the bases have set. Addition of any further
ingredients is best done by rubbing down on an ointment slab.
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42. TARED CONTAINERS
•Liquid preparations should, as far as possible, be made up to
volume in a measure. There are, however, instances when
accurate transfer of the preparation to the final container is
difficult, e.g. with some suspensions it can be almost
impossible to remove all the insoluble ingredients when
pouring from one container to another. Emulsions and viscous
preparations can also be difficult to transfer accurately. In
these cases, a tared container should be used.
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43. TO TARE A BOTTLE
•A volume of potable water identical to the volume of the product
being dispensed is accurately measured.
•This is then poured into the chosen medicine container and the
meniscus marked with the upper edge of a small adhesive label,
effectively making the bottle into a single-point measure.
•The container is then emptied and allowed to drain thoroughly.
•The preparation is then poured into the container and made up to
volume, using the tare mark as the guide. Remove the tare label.
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44. INGREDIENTS
•All ingredients must be sourced and obtained from reputable suppliers
and be of a quality suitable for the preparation and dispensing of
pharmaceutical products. Additionally, ingredients must be suitably stored
to preserve stability and integrity. For example, regular checks on expiry
dates of stored products should be made and any ingredient outside its
expiry date should be discarded. Some ingredients may require special
storage conditions and these should be provided. Many pharmaceutical
ingredients and products require storage in a refrigerator, which should be
fitted with a maximum/minimum thermometer and both maximum and
minimum temperatures checked and recorded on a daily basis.
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45. SELECTION
•When dispensing, selection of the correct product is vital. The
label on each container must be read carefully and checked to
ensure that it contains the required product. There are many
examples of drugs and preparations where names may be
misread if care is not taken; examples include folic acid and
folinic acid, cefuroxime and cefotaxime.
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46. VARIETY OF FORMS
•Some ingredients of extemporaneously dispensed medicines
may occur in a variety of forms or a synonym is used. Coal tar,
for example, is available as coal tar solution, strong coal tar
solution and coal tar. Some other materials where confusion
can occur are listed in Table (next slide). This list is not meant
to be comprehensive and only contains common exemplars.
To reduce the risk of errors you need to read the container
label carefully and have it checked by a second person.
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48. PROBLEM SOLVING IN
EXTEMPORANEOUS DISPENSING
•For extemporaneous dispensing, it is helpful if a method detailing
how to prepare the product is available. Methods for ‘official’
preparations can sometimes be found in reference sources such as
the Pharmaceutical Codex. However, on many occasions, no
method is available. In such a situation, it may be helpful to
consider similar formulas in reference sources. Additionally, the
application of simple scientific knowledge, especially of physical
properties, is often all that is needed. The following gives an
example of how this is done.
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49. SOLUBILITY
•Always check the solubility of any solid materials. If they are soluble in the
main vehicles, then a solution is likely to be produced. If solubility is
limited to one liquid, this will assist in achieving uniform dose distribution.
Solution will be achieved more quickly if the particle size is small and so
size reduction should be considered for any soluble ingredients which are
presented in a lumpy or granular form. It is also necessary to add less
soluble solids before more soluble solids. If the substance is not soluble,
then a suspension will need to be produced. Whether a suspending agent
will be required should be considered. Where one material is an oil and
another aqueous, it is likely that an emulsifying agent will be required to
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50. VOLATILE INGREDIENTS & VISCOSITY
•If an ingredient is volatile then it should be added near the end
of the dispensing process and often directly into the final
container. If it is added too early, much may be lost due to
evaporation.
•The viscosity of a liquid will have a bearing on how it is
measured, i.e. is a pipette or measure suitable, or should it be
measured by difference, and how will it be incorporated
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51. EXPIRY DATE
•All extemporaneously prepared products should be labelled
with an expiry date. Ideally, stability studies should be
undertaken in order to predict an accurate shelf-life for all
products. This is not usually possible for ‘one-off ’ preparations
and most hospital pharmacies have guidelines based on
previous stability studies. If in doubt, use the shortest possible
expiry date, e.g. 3 days, and be prepared to produce the
medicine in small quantities every 3 days.
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52. CONCLUSION & KEY POINTS
•Developing good practice in dispensing takes time and requires attention to detail.
•Extemporaneous dispensing should only be used when manufactured medicines are not
available
•Accurate dispensing requires clean and methodical work
•Always comply with SOPs
•Comprehensive records of extemporaneous dispensing are required to be kept for at least
2 years
•Always use all equipment correctly
•Ensure that liquid measures comply with the weights and measures regulations
•Always use the bottom of the meniscus when measuring liquids
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53. CONCLUSION & KEY POINTS
•Viscous liquids should be measured ‘by difference’
•Select the smallest measure or pipette for the volume of liquid to be measured
•A glass mortar and pestle can be used for size reduction of friable materials and
mixing small quantities of fine powder
•A porcelain mortar and pestle is used for larger quantities, for mixing solids and
liquids, making emulsions and for size reduction
•Confusion can arise with different forms of the same material and the use of
synonyms
•Simple problem-solving techniques can produce a satisfactory method of dispensing
a product
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