Purpose: Ropinirole (RP), is a selective dopamine agonist that is used alone or with other medications to treat the symptoms of Parkinson’s disease (PD). RP has low bioavailability of only about 50% due to the first-pass metabolism, and it requires frequent dosing during oral administration.
Aim: The objective of the current research was to develop RP loaded solid lipid nanoparticles (RP-SLNs), nanostructured lipid carriers (RP-NLCs), and their corresponding hydrogels (RP-SLN-C and RP-NLC-C) that could enhance RP therapeutic outcomes during PD treatment.
Methods: RP nanoparticles were prepared by homogenization followed by probe sonication and optimized based on particle size, polydispersity index (PDI), zeta potential (ZP), % assay, % entrapment efficiency, and in vitro release studies. Optimized formulations were converted to hydrogel formulations using Carbopol 934 as a gelling polymer and optimized based on rheological and release characteristics. Optimized formulations were further evaluated using differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), scanning electron microscopy (SEM), freeze-drying, and stability study at refrigerated and room temperatures.
Results: The optimized RP-SLN formulation showed particle size and entrapment efficiency of 213.5±3.8 nm and 77.9±3.1% compared to 190.6±3.7 nm and 85.7±1.7% for optimized RP-NLC formulation. PXRD supplemented and confirmed DSC results, RP was entrapped in a molecularly dispersed state inside the core of the lipid nanocarrier. Furthermore, RP loaded lipid nanocarriers revealed a spherical shape in SEM images. In vitro release studies demonstrated sustained release profiles for RP from SLNs, NLCs, and their hydrogels over 24 h. Optimized SLN, NLC, and nanocarrier loaded hydrogel formulations were stable over three months at 4ºC and 25ºC storage conditions.
Conclusion: Overall, the results demonstrated that lipid nanocarriers and their corresponding hydrogel formulations can be considered as a topical drug delivery vehicle for RP during the treatment of PD.