Formulation Optimization and Characterization of Tizanidine Hydrochloride-Loaded Gold Nanoparticles Using Quality by Design Approach.

Abstract

Gold nanoparticles (GNP) have been used extensively in cancer biologics and as drug carrier systems for improved pharmacokinetics and effective therapeutic action. GNPs also ensure reliable diagnosis with sensitive imaging. This study aimed to synthesize tizanidine hydrochloride (TZN)-biodegradable gold (Au) nanoparticles by the reduction of chloroauric acid (HAuCl4) with trisodium citrate using a microwave synthesizer and quality by design approach. The formulation method used was optimized using a 32 (two-factor, three-level design) factorial experiment. Temperature (X1) and concentration of gold salt (X2) were the two independent factors, and particle size (Y1), Percent drug entrapment efficiency (Y2), and polydispersity index (Y3) were the responses recorded for the study. The results of the study revealed that the optimized nanoparticles (TGN8) had a particle size (Y1) of 195 ± 1.2 nm, a polydispersity index of 0.2, and entrapment efficiency of 99.0 ± 2.9% at an optimized concentration of 14 mM gold salt (X1) and 100 0C temperature (X2). Atomic Force Microscopy showed the spherical shape particles. In vitro drug release was found to be 62.1 ± 0.5% release of TZN in simulated gastric buffer (pH 1.2) and 45.5 ± 2.8% in physiological buffer (pH 7.4). Overall, the study identified the optimal formulation conditions for TZN GNPs by considering the effects of independent variables on desired responses.