Cyproterone acetate-loaded solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs): preparation and optimization

Due to limited water solubility of cyproterone acetate and also limited skin permeation; lipid base nanocarriers with different size ranges were considered for topical delivery of cyproterone acetate. Lipid nanoparticles were prepared by solvent diffusion evaporation technique. Different variables including; surfactant/lipid ratio, mixing rate and addition time of organic phase to aqueous phase were utilized in optimization process in order to fabricate nanoparticle at specified particle size ranges to target the particle to hair follicles. Statistical data showed that the model is significant (p-value of 0.0001) to prepare lipid based nanoparticle having specified size ranges. The results showed that there is interaction between different parameters and 3-D graphs indicated the optimum point of interactions between various parameters. Drug entrapment efficiency was 99.03% and loading capacity was 1.91%. Release studies showed that 50- 75% of drug will be releasable from the nanoparticles within the first 24 hours depend on the size range of the nanoparticles. The R-square value of 0.9839 indicated that there is a good relationship between experimental data and the fitted models suggested by Design-Expert software. Cyproterone acetate release from these lipid-based nanoparticles, was significantly slower than the permeation of the free drug from dialysis tubing, which confirm that this delivery system is capable to control the release rate of the cyproterone acetate. Drug release pattern from nanoparticles was best fitted to Higuchi model which is a suitable model for matrix based delivery systems.