Pharmaceutics and Pharmaceutical Technology
Pharmaceutics and Pharmaceutical Technology tests whether a candidate can translate a drug's physicochemical and biopharmaceutical properties into a reproducible dosage form. Questions often link formulation variables to dissolution, bioavailability, stability, and manufacturing quality rather than asking for definitions alone.
Core rules
- BCS classes I-IV predict oral absorption from solubility and permeability; class I usually dissolves fast and permeates well, while class IV is the hardest.
- Dissolution is rate-limiting for many solid oral forms; test with an appropriate medium, volume, and sink conditions.
- Stability follows Arrhenius behavior, but photolysis, hydrolysis, oxidation, and moisture also matter; choose packaging and storage conditions accordingly.
- Sterile compounding requires validated aseptic technique, environmental monitoring, and terminal sterilization where possible.
Worked example
How much hydrocortisone is needed for 50 g of a 2% w/w ointment? A 2% w/w preparation contains 2 g drug per 100 g product, so 50 g contains 0.02 x 50 = 1.0 g. The base is added q.s. to 50 g, meaning to a final mass of 50 g, not 50 g of base plus 1 g drug. If the drug is a salt, convert to the active base equivalent before weighing.
Traps
Do not confuse % w/w with % w/v; for semisolids, 1 mL is not necessarily 1 g. Do not add overage without a validated rationale. Do not assume a higher dose always means higher exposure if solubility limits absorption. In stability questions, distinguish assay loss from appearance change and check whether the storage zone is real-world relevant.