Methylphenidate Hydrochloride

Abstract

Methylphenidate hydrochloride is methyl α -phenyl-2-piperidineacetate hydrochloride. It occurs as a white, odorless, fine, and crystalline powder. The infrared spectrum of a mineral oil suspension of methylphenidate hydrochloride and the spectral assignments are presented in the chapter. The nuclear magnetic resonance (NMR) spectrum is determined on a Perkin–Elmer R-24B 60 MHz spectrometer at ambient temperature. Although the methylphenidate hydrochloride molecule has two asymmetric carbon atoms, the drug exhibits no optical activity as it is a racemic mixture. The diastereoisomer of the drug is also referred to as an “erythro isomer.” Methylphenidate hydrochloride melts between 224°C and 226°C. The differential scanning calorimetry (DSC) thermogram of methylphenidate hydrochloride shows a melt endotherm between 195°C and 235°C with a melting point, with decomposition, of approximately 220°C. The thermogravimetric analysis (TGA) of methylphenidate hydrochloride exhibits a weight loss of 0.34% between 30°C and 150°C. Methylphenidate hydrochloride may be titrated in glacial acetic acid containing mercuric acetate with perchloric acid in glacial acetic acid as titrant. The titration can be carried out potentiometrically or with p -naphtholbenzein as indicator.