An overview of nanofibers and microfibers for improved oral delivery of medicines: Challenges and advances

Nanofibers and microfibers are polymer-based drug delivery systems commonly fabricated through the electrospinning technique. They can be fabricated using natural, synthetic, or hybrid polymers. Electrospun nanofibers and microfibers are capable of incorporating various types of active ingredients for drug delivery through different routes of administration. The application of nanofibers and microfibers as oral drug delivery systems is promising as a solubility promoter and for enhancing the rate and extent of bioavailability of poorly water-soluble drugs. These delivery systems exhibit high entrapment efficiency for both hydrophilic and hydrophobic drugs. Additionally, they offer drug protection against the harsh gastrointestinal environment and enable controlled drug release profiles, including immediate burst release, sustained release, biphasic release, pulsatile release, and smart stimuli-responsive drug release. Furthermore, electrospun nanofibers have been utilized as fast-dissolving and gastro-retentive (floating) oral drug delivery systems. Consequently, it appears that fiber technologies, especially nanofibers, with enhanced specific surface area and high encapsulation efficiency, hold promise as drug delivery systems for targeted oral delivery purposes.