Preparation of Spray-Dried Multicomponent Crystals of Trimethoprim-Mandelic Acid and Its Physicochemical Characterization

Abstract

Objective: Trimethoprim is a wide-spectrum antimicrobial compound belonging to Class II of the Biopharmaceutics Classification System (BCS), with high permeability but low solubility. This study aimed to prepare a multicomponent crystal (MCC) of trimethoprim-mandelic acid to enhance the solubility of trimethoprim.
 Methods: MCC trimethoprim–mandelic acid was prepared by spray drying technique. Solid-state characterizations were performed by using PowX-ray diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier-transform infrared (FT IR) spectroscopy, Scanning Electron Microscopy (SEM), and polarized microscopy. The solubility test was performed in distilled water. The amount of dissolved trimethoprim was analyzed by High-Performance Liquid Chromatography (HPLC) using acetonitrile and phosphoric acid 1 % (10:90 v/v) as the mobile phase.
 Results: MCC characterizations showed a different diffraction pattern from its intact materials according to PXRD analysis, a decrease in the melting point in the DSC thermogram, a shift of the wave number in the FT-IR spectra, and a new crystalline habit compared to the intact materials was presented by SEM analysis. The MCC also showed the color of interference under polarized microscopy, indicating the crystalline phase. The solubility of trimethoprim in MCC increased significantly by 3.98 times in comparison to intact trimethoprim.
 Conclusion: The MCC trimethoprim-mandelic acid by spray drying technique enhanced the solubility of trimethoprim.