Mefenamic Acid Lab Report

1. Introduction

Mefenamic Acid (MA) a non-steroidal anti-inflammatory drug is used extensively for clinical applications [1]. This particular drug provides relief from pain caused by muscle pain, dental pain, pre-menstrual syndrome, headaches and postoperative surgeries. It is mainly a derivative of fenamic acid where there is coplanarity between the carboxylic group and the nitrogen atom of the aromatic ring [2]. This type of coplanarity is generally found in most of the fenamates which is responsible for their conformational similarities. Different conformations in crystalline state and crystal packing in the same compound results in the formation of polymorphs. These polymorphic forms need to be identified and only the desired form should

Crystallization is attained by a three step process, first supersaturation state, second nucleation and third growth of crystals. For solute to leave the solution a certain degree of supersaturation is necessary, where the solvent will contain excess of solute that it can contain at a particular temperature [5], [7]. Some of the methods that induce supersaturation are methods based on change in temperature, solvent removal, drowning out and reaction partners [8]. Crystallization of APIs has been studied using various methods though cooling crystallization [9] and anti-solvent crystallization [10] have been most common. Even though cooling crystallization and anti-solvent crystallization are convenient, it has major drawbacks in terms of slow rate of crystallization, high supersaturation degree [10], solvent and anti-solvent selection based on solubility[11]. Some of the newer methods for crystallization include ultrasound assisted (UA) cooling crystallization [12], UA anti-solvent crystallization [13] and melt sonocrystallization [6], [14]. Ultrasound based approach has been found to initiate nucleation at lower supersaturation. Reduction in induction time has been observed in most of the APIs when the supersaturated solution is subjected to ultrasonic irradiation