In situ co-amorphisation in coated tablets – the combination of carvedilol with aspartic acid during immersion in an acidic medium

Publication date: Available online 12 January 2019Source: International Journal of PharmaceuticsAuthor(s): Ina Petry, Korbinian Löbmann, Holger Grohganz, Thomas Rades, Claudia S. LeopoldAbstractIn the present study the feasibility of an in situ co-amorphisation of the basic drug carvedilol with the acidic co-former aspartic acid was investigated by immersion of film-coated tablets consisting of the two compounds in 0.1 M HCl. Tablets containing either crystalline carvedilol with aspartic acid or only crystalline carvedilol were prepared and coated with a gastro-resistant but water-permeable coating of a methacrylic acid – ethyl acrylate copolymer (Eudragit® L 55). The film-coated tablets were immersed in 0.1 M HCl for 0, 45, and 120 min and their solid-state properties were analysed by X-ray powder diffractometry (XRPD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and Fourier transformed infrared spectroscopy (FTIR). The drug release behaviour from these tablets was investigated at pH 6.8. It was shown that the formulation containing carvedilol with aspartic acid formed a co-amorphous system during immersion, while the formulation containing only carvedilol remained crystalline. FTIR spectroscopy indicated molecular interactions in the co-amorphous carvedilol-aspartic acid system, which explained the single Tg found using DMA (106 ± 4 °C). However, because of a lack of sufficient disintegration...
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research