Formulation and Evaluation of Solid Lipid Nanoparticle of Valsartan Incorporated into Self Emulsifying Drug Delivery System

In the present study, an attempt was made to develop and optimize a novel drug delivery system for valsartan, a poorly water-soluble antihypertensive agent, using solid lipid nanoparticles (SLNs) incorporated into self-emulsifying drug delivery systems (SEDDS). SLNs were selected as they provide a controlled release matrix, while SEDDS were employed to enhance solubility, dissolution and oral bioavailability. SLNs were prepared by solvent evaporation method using glyceryl monostearate, Tween 80 and Poloxamer 188 and a 2³ factorial design was employed with drug-to-lipid ratio, surfactant concentration and homogenization time as independent variables. The dependent responses were particle size, entrapment efficiency, and % drug release. The optimized SLN formulation exhibited a particle size of 192 nm, entrapment efficiency of 89.25%, drug content of 99.16% and sustained in-vitro release of 73% at 24 hours, fitting Higuchi and Korsmeyer–Peppas kinetics. For SEDDS, isopropyl myristate, Tween 80 and Capryol 90 were selected as oil, surfactant and co-surfactant, respectively, based on solubility and pseudo-ternary phase diagram studies. Mixture design was employed, and the optimized formulation showed high transmittance (>96%), rapid emulsification (<1 min) and thermodynamic stability. The optimized liquid SEDDS was adsorbed onto Aerosil 200 to obtain solid SEDDS with good flow properties. Invitro dissolution studies demonstrated enhanced drug release of 93% within 120 minutes compared to pure drug and SLNs alone. Stability studies indicated no significant change in physical appearance, pH or drug content during the study period. Thus, it can be concluded that valsartan-loaded SLNs provide prolonged release characteristics, while incorporation into may improves solubility and bioavailability. The combined SLN– SEDDS system is therefore a promising approach for the oral delivery of poorly water-soluble drugs such as valsartan.