Drug Release Mechanism of Slightly Soluble Drug from Nanocomposite Matrix Formulated with Zeolite/ Hydrotalcite as Drug Carrier

Purpose: To evaluate the mechanism of drug release of a slightly soluble drug (theophylline) from nanocomposite of zeolite (ZLT) or hydrotalcite (HTC) used as drug carrier.
Methods: Nanocomposite was prepared with dispersion of either ZLT or HTC as drug carrier and theophylline (THP) as drug in drug to clay ratios of 1:2, 3:4 and 1:1. The formulations were characterized for drug release and loading. Dependent and independent kinetic models were employed to analyze the drug release data. Fourier transform infrared spectroscopy (FTIR) was used for the structural characterization of the formulations.
Results: Nanocomposite was formed due to incorporation of the drug in the basal spacing of ZLT/HTC. The drug loading of THP/ZLT and THP/HTC composites were 38.10 % for 2 h and 27.35 % for 3 h, respectively. HTC and ZLT nanocomposite retarded drug release for 6 h. Non-linear and Peppas-Sahlin were the best fitting kinetic release models based on the goodness of fit.
Conclusion: ZLT provides better drug loading capacity than HTC. However, both ZLT and HTC are suitable for the formulation of controlled release products. The drug release kinetics and mechanism were a combination of Fickian and non-Fickian diffusion.

Keywords
Zeolite; Hydrotalcite; Clays; Nanocomposite; Theophylline; Drug release kinetics; Basal spacing