Solid lipid nanoparticles of stearic acid for the drug delivery of paliperidone

Abstract

Paliperidone is an antipsychotic drug having poor water solubility and bioavailability. Solid lipid nanoparticles of stearic acid loaded with paliperidone were prepared to enhance the bioavailability. Spherical nanoparticles of stearic acid containing paliperidone were prepared with a surfactant, biz. Gelucire® 50/13 forming a stabilizing layer over the nanoparticles. The particle size of the SLNs was found to exponentially decrease with the increase in surfactant concentration. Dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) imaging revealed that the average particle size of SLNs was 230 ± 30 nm. Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis revealed that there was no chemical interaction between the ingredients of the SLNs. However, molecular dispersion of the paliperidone in the stearic acid matrix led to a reduction in the crystallinity of stearic acid. The entrapment efficiency of paliperidone in the lipid was calculated as 42.4 (% w/w). The corresponding % drug loading was calculated as 4.1 (% w/w) of the total lipid content. A controlled release pattern was observed in the in vitro release kinetics studies. In vitro cell culture studies against RAW 264.7 murine macrophages revealed that the paliperidone loaded SLNs have some cytotoxicity. But the observed toxicity was not concentration dependent as there was at least 60% viability of the cells in the concentration range of 30–120 μg ml⁻¹.