Propranolol Hydrochloride Film Coated Tablets Using Natural Rubber Latex Blends as Film Former

The aim of this study was to investigate the feasibility of concentrated natural rubber latex (CNRL), a major polymer, blended with either hydroxypropylmethylcellulose (HPMC) or ethylcellulose (EC) for film coated tablets. Propranolol hydrochloride tablets were used as core materials for coating. The blended films were preliminary casted and characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) techniques. The in vitro drug releases of film coated tablets were evaluated and their results fitted to zero, first, and Higuchi’s kinetic models to investigate the mechanism of drug released. The results showed that CNRL–HPMC and CNRL–EC blended films did not change in DSC, XRD, and SEM results from their raw properties. CNRL–HPMC and CNRL–EC could form the coated films on the tablets completely, and the in vitro drug release data showed the retardation effect of drug release in all formulations. The drug releases from 5%CNRL–1, 2, or 5%HPMC, and 5%CNRL–5%EC film coated tablets fitted to Higuchi’s model, and those from 5%CNRL–1 or 2%EC film coated tablets fitted to first order kinetics. HPMC and EC amounts also affected the properties of film coated tablets. Increasing the HPMC amount in the coating dispersion provided the increase of release rate of drug. On the other hand, increasing amount of EC, the release rate decreased. SEM photographs showed the thickness of coated film on core tablets that depended on amount of coating levels. Thus, this work successfully used CNRL blending as film forming agent in tablet coating. The results confirmed that CNRL blends were possible to be used as film former for pharmaceutical coating applications.