The use of excipients other than polymers for enhancing the physical stability of amorphous active pharmaceutical ingredients (APIs) has largely been unexplored. We investigated several organic acids (oxalic, tartaric, citric and succinic acid) for the purpose of stabilizing a weakly basic API, ketoconazole (KTZ), in the amorphous state.
Caffeine–oxalic acid cocrystal, widely reported to be stable under high humidity, dissociated in the presence of numerous pharmaceutical excipients. In cocrystal–excipient binary systems, the water mediated dissociation reaction occurred under pharmaceutically relevant storage conditions.
The present article provides a novel technique for the co-amorphous formation of acyclovir and oxalic acid as an excipient. Designated as ACV-oxalic acid, methods for the preparation thereof and its use in pharmaceutical applications are described.