15.1 Determining Required Formulations

14.1 Determining Required Formulations

Quick Answer: Under Standard 3.4, first decide whether compounding is needed at all. Prefer a commercially available proprietary product when it meets the clinical need. If compounding is justified, select a formulation using the Australian Pharmaceutical Formulary and Handbook (APF) and other evidence-based sources, check suitability (dose form, stability, patient factors), assign a beyond-use date (BUD) and storage conditions, and match the task to simple vs complex risk and sterile vs non-sterile capability. The Intern Written Examination is restricted open-book with APF (and AMH)—know where formulation, quality, and labelling guidance lives.

Compounding is the preparation of a medicine for an individual patient when a ready-made product is unsuitable or unavailable. It is a core pharmacist competency, but it is not a default solution. Every compounding decision starts with a clinical and practical filter: Is there a safer, more consistent commercial option?

---

When compounding is appropriate vs when proprietary products are preferred

Prefer proprietary products when they are suitable

Proprietary (commercial) medicines are manufactured under Good Manufacturing Practice (GMP), with validated processes, shelf-life data, and consistent content uniformity. For the exam and practice, treat commercial availability as a quality and safety advantage, not only a convenience.

Prefer a proprietary product when:

• The required drug, strength, and dose form are already on the Australian market and clinically appropriate
• A different but therapeutically equivalent commercial option can meet the goal (for example an oral liquid vs crushing tablets when a licensed liquid exists)
• The request is mainly for preference (flavour, colour, “natural” base) without a clinical barrier to the commercial product
• The pharmacy lacks facilities, equipment, or competency for the complexity requested

When compounding is often justified

Exam trap: A prescriber request alone does not make compounding mandatory. You still assess clinical necessity, formulation suitability, legal schedule, and whether a commercial product exists. If a licensed product fits, recommend it and document the rationale.

---

The APF as the key open-book formulation reference

For the APC Intern Written Examination you may bring one paper APF. Use it as your operational handbook for compounding—not as optional background reading.

What to look up in the APF under time pressure

1. Standard formulae for common non-sterile preparations (solutions, suspensions, creams, ointments, pastes, powders)
2. General compounding principles (weighing, measuring, mixing order, bases, vehicles)
3. Stability and beyond-use dating guidance for compounded preparations
4. Labelling requirements and advisory statements for compounded medicines
5. Quality and hygiene expectations linked to professional standards

When a standard APF formula exists for the requested preparation (or a closely related template), prefer that validated community-practice formula over inventing proportions from memory. If the APF has no formula, you may need primary literature, manufacturer stability data, hospital formularies, or referral to a specialist compounding service—do not improvise high-risk recipes under exam or practice pressure.

Linking APF use to AMH

• AMH: clinical suitability of the drug (indication, dose, interactions, cautions, paediatric notes)
• APF: how to prepare an appropriate formulation safely and label it

Both books together answer: Should this patient receive this drug, and if so in which compounded form with what BUD?

---

Suitability of formulation types

Paediatric liquids

Children often need oral liquids because of age, taste, or inability to swallow solids. Suitability checks include:

• Accurate dose concentration so measuring devices deliver practical volumes (avoid extreme concentrations that force tiny or huge volumes)
• Excipients: alcohol content, sugar (dental/metabolic concerns), propylene glycol in neonates, colourants, and known allergens
• Palatability and adherence without compromising stability
• Whether a commercial paediatric product already exists for the same drug

Reconstituting a proprietary antibiotic powder according to the product information is not the same as designing a novel compound from raw powder—see Section 15.3. Both need correct diluent, volume, storage, and expiry, but risk and documentation differ.

Dermatological preparations

Topical compounding is common (dilutions, combinations, alternative bases). Suitability includes:

• Potency after dilution (especially corticosteroids)—document the final percentage and base
• Base selection (cream vs ointment vs gel) for site, occlusion, and patient preference
• Incompatibilities between actives or between active and base
• Irritancy and infection risk on broken skin

Allergen-free and excipient-restricted products

When a patient has a documented allergy or intolerance to an excipient in the commercial product, compounding may be justified if the allergen cannot be avoided another way. Document the specific excipient problem. Do not compound solely because a patient dislikes an inactive ingredient without clinical significance.

Modified dose or strength

Modified strengths are common in titration, palliative care, and paediatrics. Confirm the prescribed strength is interpretable (mg/mL vs % w/w vs ratio), calculable, and measurable with available equipment. Prefer strengths that reduce calculation and measurement error.

---

Stability and beyond-use dating (high-level)

Expiry date on a manufacturer’s pack applies to the unopened proprietary product under stated storage. A beyond-use date (BUD) is the date after which a compounded preparation should not be used. BUD assignment is a professional responsibility informed by:

• APF guidance for preparation type (aqueous oral liquid, topical cream, non-aqueous solid, etc.)
• Known chemical, physical, and microbiological stability of ingredients
• Water activity and contamination risk
• Packaging (light-protective, airtight) and storage (room temperature, refrigerate)
• Whether the preparation is multi-dose and how it will be handled at home

Principles for interns:

• Aqueous preparations generally carry shorter BUDs than anhydrous solids or many non-aqueous topicals because of microbial risk
• Refrigeration may extend usability for some preparations but can worsen physical instability for others—follow APF/product-specific guidance
• “Looks fine” is not a stability test; appearance alone does not prove chemical potency
• If stability data are poor and clinical need is non-urgent, prefer commercial alternatives or specialist compounders with documented formulas

Always state storage conditions with the BUD on the label and in counselling.

---

Risk assessment: simple vs complex compounding

Australian professional guidance distinguishes levels of compounding risk. For exam purposes, use a practical risk lens:

Simple non-sterile compounding (for example many APF creams, simple solutions/suspensions) may be within community pharmacy competence when procedures, equipment, and training are adequate. Complex compounding (hazardous drugs, advanced dosage forms, high-risk populations, sterile production) requires specialised facilities, training, and quality systems. Interns must recognise when not to proceed and when to refer.

---

Sterile vs non-sterile scope awareness

• Non-sterile compounding: oral liquids, capsules, creams, ointments, some ear preparations (as appropriate), powders—subject to hygiene and BUD rules
• Sterile compounding: injections, infusions, many ophthalmic preparations, irrigations for sterile body sites—requires aseptic technique, validated cleanrooms/equipment, and quality assurance beyond routine community dispensing

Most community intern experience is non-sterile. Questions may still test whether you recognise that sterile products are out of scope for an ordinary bench without aseptic facilities. Never “approximate” sterility for injections or eye drops by ordinary mixing.

---

Decision pathway for the exam

1. Confirm the clinical indication and legal supply pathway (prescription, schedule).
2. Search for a suitable proprietary product (including alternative strengths/forms).
3. If compounding is needed, open APF for formula, method notes, BUD concepts, and labelling.
4. Check patient factors (age, allergies, ability to measure doses).
5. Classify risk (simple/complex; sterile/non-sterile) and competence/facilities.
6. Only then compound—or refer/decline with a clear alternative plan.

Putting it together for the exam

Standard 3.4 rewards systematic formulation decisions. Show that you default to commercial quality, use APF deliberately under open-book conditions, justify paediatric and dermatological compounds by need, apply BUD and storage thinking, and escalate complex or sterile work appropriately.