Clindamycin phosphate is a water-soluble ester of the semisynthetic antibiotic produced by a 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent antibiotic lincomycin. The chemical name for clindamycin phosphate is methyl 7-chloro-6,7,8-trideoxy-6-(1-methyl-trans-4-propyl-L-2-pyrrolidinecarboxamido)-1-thio-L-threo-?-D-galacto-octopyranoside 2-(dihydrogen phosphate). The monohydrate form has a molecular weight of 522.98, and the molecular formula is C18H34ClN2O8PSH2O. The structural formula is represented below:

Each rectal suppository contains 12.5 mg or 25 mg promethazine HCl with ascorbyl palmitate, silicon dioxide, white wax, and cocoa butter. Promethazine hydrochloride suppositories are for rectal administration only.

Prochlorperazine is a clear, pale yellow, viscous liquid. It is sensitive to light, very slightly soluble in water, freely soluble in alcohol, in chloroform, and in ether.