Formulation and Evaluation of Metoprolol Tartrate Loaded Niosomes Using 23 Factorial Design

Abstract

The purpose of this study was to formulate and evaluate metoprolol tartrate (MT) loaded liposomes using factorial design. Preparation of niosomal drug delivery of MT increased its bioavailability which led to being better therapeutic effects, reduced the frequency of dosing and decreased side effects of hypertensive patients. Ether injection method (EIM) and thin film hydration method (TFHM) were used for the preparation of all formulations as per full factorial design to study the effect of two independent variables X1 (amount of span-60), and X2 (amount of cholesterol) on three dependent variable Y1 (percent drug entrapment efficiency), Y2 (percent drug content) and Y3 (percent cumulative drug release) respectively. The relation between the dependent and independent variables was drawn out from the mathematical equation and response surface methodology (RSM). Statistical analysis was performed using ANOVA. Microscopic observation confirmed that all particles were uniform in size and shape. The particle size of niosomes measured by SEM was between 3 μm to 4.5 μm that given the evidence of large uni-lamellar vesicles formed by EIM and TFHM.The percent drug entrapment efficiency was found to be highest for formulations MTEIM-8 and MTTFHM-8 with values 97.11% and 95.56% respectively. In vitro dissolution studies were carried out in phosphate buffer (pH 6.8) for 8 hours at 100 rpm and maintained at 37 ± 0.50C according to USP-II paddle method and absorbance was taken at 226 nm.The probable drug release mechanism may be fickian (class I) diffusion as the correlation coefficient (R2) best fitted with zero order and release exponent (n) was less than 0.43.  The FTIR studies have been done to confirm no interaction along with drug and polymer. In vitro and ex vivo comparative studies showed that niosomes had controlled the release of drug for a longer period. Finally, it can be concluded that niosomes could be an effective vesicle for delivery of MT with increased bioavailability.