Prediction of drug release from HPMC matrices: effect of physicochemical properties of drug and polymer concentration

Abstract

A working equation to predict drug release from hydroxypropyl methylcellulose (HPMC) matrices was derived using a training set of HPMC matrices having different HPMC concentration (w/w, 16.5–55%) and different drugs (solubilities of 1.126–125.5 g/100 ml in water and molecular volumes of 0.1569–0.4996 nm 3). The equation was log( M t / M ∞)=−0.6747+1.027 log t −0.1759 (log C s) log t +0.4027 (log V) log t −1.041 C H +0.3213 (log C s) C H −0.4101 (log V) C H −0.3521 (log V) log C s ( n=263, r=0.9831), where M t is the amount of drug released at time t, M ∞ the amount of drug released over a very long time, which corresponds in principle to the initial loading, t the release time (h), C s the drug solubility in water (g/100 ml), V the volume of drug molecule (nm 3), and C H is HPMC concentration (w/w). The benefit of the novel model is to predict M t / M ∞ values of a drug from formulation and its physicochemical properties, so applicable to the HPMC matrices of different polymer levels and different drugs including soluble drugs and slightly soluble drugs.