Functionalized silica nanoparticles as a carrier for Betamethasone Sodium Phosphate: Drug release study and statistical optimization of drug loading by response surface method.

Mesoporous silica nanoparticles with a hexagonal structure (SBA-15) were synthesized and modified with (3-aminopropyl) triethoxysilane (APTES), and their performance as a carrier for drug delivery system was studied. Chemical structure and morphology of the synthesized and modified SBA-15 were characterized by SEM, BET, TEM, FT-IR and CHN technique. Betamethasone Sodium Phosphate (BSP) as a water soluble drug was loaded on the mesoporous silica particle for the first time. The response surface method was employed to obtain the optimum conditions for the drug/silica nanoparticle preparation, by using Design-Expert software. The effect of time, pH of preparative media, and drug/silica ratio on the drug loading efficiency was investigated by the software. The maximum loading (33.69%) was achieved under optimized condition (pH: 1.8, time: 3.54 (h) and drug/silica ratio: 1.7). The in vitro release behavior of drug loaded particles under various pH values was evaluated. Finally, the release kinetic of the drug was investigated using the Higuchi and Korsmeyer-Peppas models. Cell culture and cytotoxicity assays revealed the synthesized product doesn't have any cytotoxicity against human bladder cell line 5637. Accordingly, the produced drug-loaded nanostructures can be applied via different routes, such as implantation and topical or oral administration.

Process optimization of electrospun polycaprolactone and nanohydroxyapatite composite nanofibers using response surface methodology.

Electrospinning is a process that produces continuous polymer fibers in the sub-micron range through the action of an external electric field imposed on a polymer solution or melt. In this study the effects of process parameters on the mean diameter of electrospun polycaprolactone and nanohydroxyapatite (nHA) composite nanofibers were investigated. The fiber morphology and mean fiber diameter of prepared nanofibers were investigated by scanning electron microscopy. Response surface methodology (RSM) was utilized to design the experiments at the settings of nHA concentration, applied voltage, spinning distance and the flow rate of polymer solution. It also used to find and evaluate a quantitative relationship between electrospinning parameters and average fiber diameters. Mean fiber diameter was correlated to these variables using a third order polynomial function. Value of R-square for the model was 0.96, which indicates that 96% of the variability in the dependent variable could be explained and only 4% of the total variations cannot be explained by the model. It was found that nHA concentration, applied voltage and spinning distance were the most effective parameters and the sole effect of flow rate was not important. The predicted fiber diameters were in good agreement with the experimental results.