Pharmacy professional knowledge: pharmacology, pharmaceutics and drug law
Core areas
The UPSSSC Pharmacist paper tests applied pharmacy rather than isolated definitions. Revise pharmaceutics (dosage forms, routes, bioavailability), pharmacology (ADME, receptors, agonists and antagonists), pharmacognosy (alkaloids such as morphine and quinine; glycosides such as digitalis), pharmaceutical chemistry (functional groups, stability), and hospital/community pharmacy (prescription handling, dispensing, storage). Drug law is high-yield: the Drugs and Cosmetics Act 1940 and Rules 1945, Schedule H, H1 and X, and the Pharmacy Act 1948.
Rules and concepts
- First-order elimination: a constant fraction is removed per unit time; half-life is constant. Zero-order elimination: a constant amount is removed per unit time, so half-life changes with dose.
- Bioavailability depends on route, formulation and first-pass metabolism; oral drugs can be extensively metabolised in the liver before reaching systemic circulation.
- Schedule H drugs are prescription-only; Schedule X needs special record-keeping and licensing; Schedule H1 has additional sale-record requirements.
- Agonists activate receptors; antagonists block them without intrinsic activity.
Worked example
A 200 mg dose follows first-order kinetics with a half-life of 6 hours. How much remains after 18 hours? 18 ÷ 6 = 3 half-lives. 200 → 100 → 50 → 25 mg. The answer is 25 mg. Showing the half-life count earns method marks and avoids arithmetic slips.
Traps
Do not apply first-order half-life to phenytoin or ethanol at saturating doses; these can show zero-order kinetics. Do not confuse antiseptics with disinfectants, or Schedule H with Schedule X. Read whether the question asks for amount remaining or amount eliminated.