Design, Optimization and Characterization of Nanostructured Lipid Carriers of Raloxifene Hydrochloride for Transdermal Delivery

Raloxifene Hydrochloride (RXL), a BCS class II drug, is used for the treatment of invasive breast cancer and osteoporosis in post menopausal women. Even though the drug is highly efficient, it shows poor bioavailability of 2% when administered orally. The aim of the study was to develop, statistically optimize, and characterize Raloxifene Hydrochloride loaded Nanostructured Lipid Carriers (NLC) for transdermal delivery to overcome the bioavailability issue.

Methods: The RXL-NLC’s were developed using glyceryl behenate (Compritol® 888 ATO), glyceryl monostearate (GMS), and capric triglyceride (Miglyol® 810) as solid and liquid lipids, and Polysorbate 80 (Tween 80) and cremophor EL were used as surfactants and co-surfactant. A response surface methodology was applied for the optimization of NLC, using Box-Behnken experimental design. Amount of the drug, tween 80 and polyethoxylated castor oil (cremophor EL), each at three levels, were selected as independent variables, while particle size and polydispersity index were identified as dependent variables.

The optimized batch was characterized for Particle size (79.8 nm±3), Polydispersity index (0.229±0.05), Zeta potential (-12.3±5) and Entrapment efficiency (79.14%±5). Surface morphology of the NLC’s were studied using Transmission Electron microscopy (TEM) and the shift in the endotherm of Differential scanning calorimetry confirmed the entrapment of the drug within NLC. In vitro drug release studies were performed using dialysis bag (12000-14000 Da) method. The optimized NLC dispersion was then incorporated into gel and characterized for gel uniformity, spreadability, pH, viscosity and drug content.

Results: In vivo skin penetration study was carried out by tape stripping method, which showed increase in penetration when incorporated into nanogel as compared to plain drug gel.

Conclusion: Based on the above result it can be concluded that transdermal delivery of NLC’s can be a superior alternative for orally low bioavailable drugs such as RXL which undergoes rapid first pass metabolism.

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