Polymer nanofibers are a promising nanosystem for drug delivery due to the unique properties of the materials in nanoscale dimensions, such as high specific surface area, and porosity of the nanofiber mat. These properties can significantly improve the solubility and dissolution rate of drugs incorporated in the nanofibers. The nanofiber properties are affected by the matrix-forming polymers, excipients, and the manufacturing method and conditions. The inclusion of drugs may also have a significant impact on nanofiber properties. Thus, this study aimed to examine how the incorporation of drugs affects the properties of the nanofibers. Nanofibers were produced by electrospinning of polyethylene oxide and poloxamer 188 in a 1:1 weight ratio, and by incorporation of 20% (w/w) of one of four drugs with different physicochemical properties, namely ibuprofen, carvedilol, paracetamol, or metformin hydrochloride. Nanofibers were electrospun under identical conditions (needle tip-to-collector distance, 15 cm; voltage, 15 kV; needle outer diameter, 0.7 mm; polymer solution flow rate, 1.40 mL/h; electrospinning time, ~2 h; relative humidity < 50%; room temperature), followed by precise characterization. We showed that different properties of the drugs do not significantly affect the electrospinning process or the formation of nanofibers. However, the incorporation of drugs, which have a considerable impact on the viscosity of the electrospinning solution, resulted in the creation of non-continuous fused nanofibers. Furthermore, the study revealed that the incorporation of drugs with lower solubility in 96% (v/v) ethanol results in nanofibers with particles on the surface of nanofibers. Additionally, it was demonstrated that drugs containing a hydroxyl group in their structure form hydrogen bonds with the polymers in nanofibers, which may significantly affect the stability of the amorphous form of the drug in the nanofibers. It was also shown that more hydrophobic drugs decrease the hydrophilicity of the nanofiber surface, while more hydrophilic drugs do not have a significant effect on the hydrophilicity of the nanofiber surface. According to our results, the drug incorporation efficiency is not dependent on the properties of the drug. However, the release profile of the drug from nanofibers is significantly affected by the morphology of the nanofibers and their dispersibility in the drug-release medium. Our findings have brought new knowledge to research in the field of preparation of polymer nanofibers as delivery systems.
|
