Characterization of palygorskite clay from Piauí, Brazil and its potential use as excipient for solid dosage forms containing anti-tuberculosis drugs

Abstract

Clays play an important role in health products as it has been used as excipients for solid dosage forms and as active ingredients. Usually, excipients are pharmacologically inert, but they can interact with drugs in the solid dosage form and affect their bioavailability. Thus, the aim of this work was to determinate the physicochemical properties of palygorskite clay from Piaui, Brazil, and to investigate the potential use of this mineral as excipient for solid dosage forms containing rifampicin and isoniazid, which are drugs currently used to treat tuberculosis. Palygorskite was analyzed by X-ray fluorescence, X-ray diffraction, transmission electron microscopy, and particle size analyzer. According to the results, the main component found was SiO2, and its mineral composition contains palygorskite, dolomite, and quartz. The particles appear as fibers with bundle-like aspect that cluster together to form aggregates. The results from thermal analysis indicate that there is no interaction between both rifampicin and isoniazid with palygorskite. Moreover, the presence of palygorskite did not interfere on the dissolution of these drugs, which suggests that this material can be potentially used as an excipient for these drugs.