Mechanism of a long-term controlled drug release system based on simple blended electrospun fibers

Background: Drug delivery systems based on electrospun fibers have been under development for many years. However, studies of controllable long-term drug release from electrospun membrane systems and the underlying release mechanisms have seldom been reported. Methods: In this study, electrospun membrane drug delivery systems consisting of the antibiotic ciprofloxacin hydrochloride and FDA-approved polymers are fabricated. Different second-component polymers are introduced to change the properties of a poly(D,L-lactide-co-glycolide) (PLGA) matrix, thereby altering the drug release behavior. On the basis of observations of morphology, cumulative release profiles, and determinations of release duration, the drug release kinetics and critical characteristics influencing drug release behavior are discussed. Results: It is found that the drug release profiles can be divided into three stages according to the rate of drug release. Stage I is controlled by fiber swelling and diffusion according to Fick's second law. Stage II is controlled by diffusion through a fused membrane structure, which results in very slow drug release. Stage III is controlled by polymer degradation and involves release of the remaining drug. Conclusions: The results of this study of release mechanisms should provide a basis for adjustments of drug release dosage and duration, thereby contributing to the development of drug delivery systems satisfying clinical requirements.