COCRYSTAL FORMATION OF EFAVIRENZ-MALEIC ACID VIA ULTRASOUND-ASSISTED SOLUTION CO-CRYSTALLIZATION METHOD: CHARACTERIZATION AND MECHANICAL PROPERTY EVALUATION

Abstract

Efavirenz (EFV), a crucial drug for HIV infection, possesses unfavorable mechanical properties that complicate tablet production via direct compression. This study aimed to improve the mechanical properties, such as flowability and tabletability, of efavirenz (EFV) through co-crystal formation with maleic acid (MLT). The EFV-MLT co-crystal was prepared using the Ultrasound-assisted Solution Cocrystallization (USSC) method, employing distilled water as the solvent. To confirm its properties, the resultant co-crystal was characterized using polarizing microscopy, Powder X-ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), and Fourier-transform infrared (FTIR) spectroscopy. The mechanical properties of the co-crystals, including the compressibility index, Hausner ratio, tensile strength, and elastic recovery, were evaluated. Comprehensive characterization confirmed successful co-crystal formation using polarizing microscopy (revealing smaller needle-shaped crystals), PXRD (showing new diffraction peaks), DSC (indicating a lower melting point), and FTIR (demonstrating a wave shift). The findings of this study clearly demonstrate that the formation of EFV-MLT co-crystals via the USSC method significantly improves their mechanical properties compared with those of pure EFV.

 Keywords: evafirenz, maleic acid, co-crystals, mechanical properties, USSC