Medical chemistry

A solution is isotonic with plasma at ~0.9% NaCl (saline) or ~5% glucose. Plasma osmolarity ~285–295 mOsm/L.

Sodium chloride equivalent (E): substance mass × E + NaCl = 0.9% equivalent. For a 1% drug with E=0.2: add 0.7% NaCl.

% mass/volume: 1% = 1 g per 100 ml. Dilution C1V1=C2V2. Chlorhexidine 0.05% from 20% concentrate — 1:400.

Eye drops — pH 6.5–8.5, active stability — in narrow ranges. Phosphate buffer is the standard for solutions.

Antibiotics/peptides from powder: solvent volume → mg/ml concentration. Reconstituted storage — per instructions, usually fridge, days.

Sterile preparations aren't made at home — sepsis risk. Isotonic rinses/washes — yes; injections — only ready-made drugs.