Electrospun formulation of acyclovir/cyclodextrin nanofibers for fast-dissolving antiviral drug delivery

Acyclovir is an effective antiviral drug which suffers from limited water solubility and low bioavailability. However, it is possible to eliminate these limitations by forming inclusion complexes with cyclodextrins. In this study, we have reported the electrospinning of polymer-free and free-standing acyclovir/cyclodextrin nanofibers for the first time. This is a promising approach for developing a fast-dissolving delivery system of an antiviral drug molecule. Here, hydroxypropyl-beta-cyclodextrin (HP-βCD) was used as both complexation agent and electrospinning matrix. The acyclovir/HP-βCD system was prepared by incorporating ~7% (w/w) of acyclovir into the highly concentrated aqueous solution of HP-βCD (180%, w/v). The control sample of acyclovir/polyvinylpyrrolidone (PVP) nanofiber were also generated using ethanol/water (3/1, v/v) solvent system and the same initial acyclovir (7%, w/w) content. Due to the inclusion complexation, acyclovir/HP-βCD nanofibers provided better encapsulation and so loading efficiency. The loading efficiency of acyclovir/HP-βCD nanofibers was determined as ~98%, while it was ~66% for acyclovir/PVP nanofibers. It was found that acyclovir/HP-βCD nanofibers contained some crystalline form of acyclovir. Even so, it showed faster dissolving/release and faster disintegration profiles compared to acyclovir/PVP nanofibers which had higher amount of crystalline acyclovir. The inclusion complexation property and high water solubility of HP-βCD (> 2000 mg/mL) ensured the fast-dissolving property of acyclovir/HP-βCD nanofibers. Briefly, acyclovir/HP-βCD nanofibers are quite promising alternative to the polymeric based system for the purpose of fast-dissolving oral drug delivery. The enhanced physicochemical properties of drug molecules and the use of water during whole process can make drug/cyclodextrin nanofibers a favorable dosage formulation for the desired treatments.