The thermal stability of triprolidine hydrochloride and its mixtures with cyclodextrin and glucose

Abstract

Triprolidine hydrochloride (C19H22N2·HCl·H2O) (TPH) is a well-known antihistamine drug which is reported as being photosensitive. The thermal stabilities of TPH and of 1:1 molar and 1:1 mass ratio physical mixtures of TPH with β-cyclodextrin (BCD) and with glucose have been examined using DSC, TG and TG-FTIR, complemented by X-ray powder diffraction (XRD) and infrared spectroscopic (IR) studies. Thermal studies of the solid TPH/BCD mixtures indicated that interaction between the components occurs and it is possible that the TPH molecule may be least partially accommodated in the cavity of the BCD host molecule. XRD results support this indication of inclusion. The results of molecular modelling suggest that TPH is most likely to be accommodated in the BCD cavity as a neutral triprolidine molecule with the toluene portion of the molecule preferentially included in the cavity. The results obtained illustrate the general stability of TPH. The study has also shown TPH to be compatible with both glucose and BCD, which are potential excipients both in solid and liquid dosage forms. The presence of these excipients in dosage forms will thus not adversely affect the stability and the therapeutic efficacy of TPH.