Pharmaceutics and Pharmaceutical Technology
Core concepts
A candidate must be fluent in the physical pharmacy that governs dosage-form behaviour: solubility and dissolution (Noyes–Whitney), pH–partition (Henderson–Hasselbalch), particle size and surface area, polymorphism and hydrates, and the Biopharmaceutics Classification System. Understand the excipient functions - diluents, binders, disintegrants, lubricants, glidants, coatings - and how each affects release. Know the unit operations: milling, blending, granulation (wet vs dry), drying, compression, coating, and the quality attributes each controls (content uniformity, hardness, friability, disintegration, dissolution). Be able to interpret a dissolution profile and distinguish immediate-, delayed-, and extended-release mechanisms (matrix, reservoir, osmotic). Sterile products require knowledge of isotonicity, pyrogens, sterilisation methods (moist heat, dry heat, filtration, radiation, aseptic processing) and their validation (F0, D-value, SAL).
Traps
Questions often swap terms: friability (mechanical strength) versus hardness/crushing strength; disintegration versus dissolution (a tablet can disintegrate without dissolving). Bioavailability versus bioequivalence; Cmax versus Tmax direction of change. Remember that lubricants (magnesium stearate) are hydrophobic and retard dissolution if over-blended. Moist-heat sterilisation is for aqueous/heat-stable items; dry heat for glassware and oils; filtration for heat-labile solutions.
Worked rule of thumb
For a Class II drug (low solubility, high permeability), dissolution rate limits absorption - particle-size reduction or a solubilising formulation improves bioavailability. For Class IV, both are limiting and formulation gains are modest. Use this to predict which formulation change a question expects.
Exam strategy
Anchor each dosage-form question to the rate-limiting step and the quality attribute that detects it.