Nelfinavir mesylate is an inhibitor of the human immunodeficiency virus (HIV) protease.
The chemical name for nelfinavir mesylate is [3S - [2(2S*, 3S*), 3 alpha,4a beta,8a beta]] - N - (1,1-dimethylethyl) decahydro - 2 - [2 - hydroxy - 3 - [(3 - hydroxy - 2 - methylbenzoyl)amino] - 4 - (phenylthio)butyl] - 3 - isoquinolinecarboxamide mono - methanesulfonate (salt) and the molecular weight is 663.90 (567.79 as the free base).

Nelfinavir mesylate is a white to off-white amorphous powder, slightly soluble in water at pH less than or equal to 4 and freely soluble in methanol, ethanol, isopropanol and propylene glycol.