Compatibility studies of selected mucolytic drugs with excipients used in solid dosage forms: Thermogravimetry analysis

Abstract

The drugs except active pharmaceutical ingredient (API) contain excipients in formulations. In drugs formulations, it is important that API and excipient are compatible. As a quick and cheap method of testing the compatibility of API with an excipient, thermal methods can be used, including thermogravimetry analysis. In this study, the assessed compatibility of selected mucolytic drugs (ambroxol, bromhexine, acetylcysteine) with excipients (magnesium stearate, lactose monohydrate, starch) is used in solid dosage form. TG and DTG analysis were done for pure API, excipients, and binary mixture API/excipient with different ratio. The study has shown that the tested mucolytic drugs are compatible with magnesium stearate, but are incompatible with lactose monohydrate. The Maillard reaction is responsible for this incompatibility, which was additionally confirmed by a colorimetric method. The starch and acetylcysteine are compatible, but starch and ambroxol are incompatible. The measurements for compatibility bromhexine witch starch are ambiguous. The obtained results proved the usefulness of TG and DTG measurements for initial examination of compatibility API/excipient in preformulation studies.