Preparation and characterization of valsartan nanoparticles

Abstract

Valsartan is an orally active, highly selective angiotensin II receptor blocker widely used to treat hypertension. However, its low oral bioavailability (only 23%) limits its effectiveness. This poor bioavailability is attributed to inadequate absorption in the gastrointestinal tract and rapid drug elimination. To enhance its oral bioavailability, solid lipid nanoparticles (SLNs) and polymeric nanoparticles (PNs) formulations of valsartan were developed. The SLNs formulation was prepared using glyceryl monostearate, while the PNs formulation utilized a pH-dependent polymer. Optimization of the formulations was carried out using Design Expert® software, considering five key response factors: drug content, drug entrapment efficiency, particle size, zeta potential, and polydispersity index. The optimized formulations underwent further characterization, including surface morphology analysis, in vitro drug release studies, cell line toxicity assessments, and pharmacokinetic evaluations. Toxicity studies confirmed that the optimized nanoformulations were non-toxic. Additionally, the relative bioavailability was determined by calculating the ratio of the area under the curve (AUC) of the valsartan SLNs or PNs formulation to that of standard valsartan. The values obtained were 4.07 for SLNs and 2.47 for PNs, demonstrating a significant improvement in bioavailability.