Abstract
OBJECTIVES: This study aimed to develop nanosuspensions (NSs) of cyclosporine A (CycA) using a top-down technology [high-pressure homogenization-(HPH)] for oral administration. MATERIALS AND METHODS: Formulas were prepared using different ratios of hydroxypropyl methylcellulose (HPMC) (1% and 0.5%) and sodium dodecyl sulfate (SDS) (1%) to improve the solubility of CycA. The HPH method was optimized by investigating the effects of critical formulation parameters (stabilizer ratio) and critical process parameters (number of homogenization cycles) on the particle size (PS), polydispersity index (PDI), and zeta potential (ZP) of NS using the Design of Experiment (DoE). After lyophilization, differential scanning calorimetry, X-ray diffraction, fourier-transform infrared spectroscopy, and morphological evaluation with scanning electron microscopy were performed. Stability studies were conducted at 4 °C and 25 °C storage conditions. The solubility of the optimum CycA NS was investigated by comparing it with a coarse CycA powder and a physical mixture (PM). In vitro dissolution studies were conducted in four media using United States Pharmacopeia apparatus I. RESULTS: PS, PDI, and ZP values for the NS were approximately 250 nm, 0.6, and 35 mV, respectively. Under storage conditions, the CycA NS exhibited significant physical stability at both 4 °C and 25 °C for 9 months. The solubility of CycA was improved 1.9 and 1.4 times by NS in the presence of CycA powder and PM, respectively. CycA NS exhibited higher dissolution than CycA coarse powder in 0.1 N HCl, fasted simulated intestinal fluid, and fed simulated intestinal fluid. CONCLUSION: CycA NS was successfully developed using the DoE approach with the HPH method with HPMC:SDS combination in a 1:0.5 ratio, and the solubility and dissolution of CycA in the NS were improved.