Simvastatin-loaded PLGA nanoparticles for improved oral bioavailability and sustained release: Effect of formulation variables

Aman Soni, Anand Gadad, Panchaxari Dandagi, Vinayak Mastiholimath


The objective of this study was to prepare a nanoparticulate formulation of simvastatin (SV) for improving oral bioavailability and sustaining the drug release while investigating the effect of various formulation parameters on characteristics of nanoparticles. Nanoparticles containing SV were prepared by a modified emulsification solvent evaporation technique using a biodegradable polymer, poly(d,l-lactide-coglycolide) (PLGA) as a sustained release carrier.The effect of various formulation parameters such as drug polymer ratios (SV:PLGA, 1:4 to 1:1), organic solvents (methanol/dichloromethane), and surfactants
(PVA/polysorbate-80) in a fixed concentration (0.5%, w/v) were studied for particle size, drug loading, and entrapment efficiency. Nanoparticles were characterized by differential scanning calorimetry (DSC) and their shapes were observed by scanning electron microscopy (SEM). An aqueous solubility study indicated that the dissolution rates were remarkably increased for nanoparticles compared with the drug alone.The in vitro drug release study of the nanoparticles showed a biphasic release pattern: one initial burst release of 40.56% in the first 4 h which can be helpful to improve the penetration of drug
followed by a second slow-release phase (extended release) consistent with a Higuchi diffusion mechanism.The hypolipidemic activity of nanoparticles was determined in comparison with SV in male Wistar rats for changes in total cholesterol (CH) and triglyceride (TG) levels in blood. Nanoparticles showed a significantly better in vivo performance than SV in reducing total CH and TG levels which is primarily attributed to the improved solubility and dissolution of nanoparticles. Together, these results indicate that nanoparticulate formulations are ideal carriers for oral administration of SV having great potential
to improve the oral bioavailability and sustain the drug release, thereby minimizing the dose-dependent adverse effects and
maximizing the patient’s compliance.

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