Indomethacin electrospun nanofibers for colonic drug delivery: preparation and characterization.

PURPOSE The objective of this study was to prepare a suitable form of nanofiber for indomethacin using polymers Eudragit RS100 (ERS) and Eudragit S100 (ES) and to evaluate the effect of some variables on the characteristics of resulted electrospunnanofibers. METHODS Electrospinning process was used for preparation of nanofibers. Different solutions of combinations of ERS, ES and indomethacin in various solvents and different ratios were prepared. The spinning solutions were loaded in 10 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospunnanofibers were collected and evaluated by scanning electron microscopy, differential scanning calorimetry and FTIR for possible interaction between materials used in nanofibers. The effect of solvent and viscosity on the characteristics of nanofibers also was investigated. RESULTS Fiber formation was successful using a solvent ethanol and mixture of ERS and ES. Increase in viscosity of ethanolic solutions of ERS followed by addition of ES in the solution led to preparation of smooth fibers with larger diameters and less amounts of beads. DSC analysis of fibers certified that indomethacin is evenly distributed in the nanofibers in an amorphous state. FTIR analysis did not indicate significant interaction between drug and polymer. CONCLUSION It was shown that drug-loaded ERS and ES nanofibers could be prepared by exact selection of range of variables such as type of solvent, drug: polymer ratio and solution viscosity and the optimized formulations could be useful for colonic drug delivery.