Formulation and process optimization of naproxen nanosuspensions stabilized by hydroxy propyl methyl cellulose

•HPMC stabilized nanosuspensions have optimized to improve dissolution of naproxen.•Controlled precipitation–ultrasonication technique adopted.•Mean particle size, % drug content, and dissolution time correlated with HPMC.•Response surface methodology have adopted for formulation optimization. In present study precipitation–ultrasonication was used to obtain nanosuspensions of poorly water-soluble drug, naproxen (NPX). We investigated the effects of HPMC concentration (X1) and time of ultrasonication (X2) on imperative attributes like mean particle size (Y1), % drug content (Y2), and time required to 90% drug release (Y3) via 32 factorial design. The morphology of nanosuspensions was found almost spherical by SEM observation. DSC and XRD studies suggested slight crystalline change in drug. FT-IR revealed lack of significant interactions between NPX and HPMC. Nanosuspensions of mean particle size 530.55nm was achieved. Dissolution rate obtained from all nanosuspensions were markedly higher than pure NPX. Response surface methodology and optimized polynomial equations were used to select optimal formulation i.e. 1.36%W/V of X1 and 13.9min of X2 to get desired response Y1; 727.97nm, Y2; 95.59% and Y3; 8.67min that were in reasonable agreement with observed value.