Page 297 - Biodegradable Polyesters

275

11
Electrospun Biopolymer Nanofibers and Their Composites for
Drug Delivery Applications
Yue-E Miao and Tianxi Liu

11.1
Introduction

With modern therapeutics increasingly emphasizing pharmacokinetic and
pharmacodynamics principle-driven administration of drugs, new development
of drug delivery systems has been urgently excited to realize the therapeutic
potential of delicate and macromolecular bioactive agents. Since the drug release
rate in body should be kept at constant speed to avoid the “burst” phenomenon,
enhance the treatment effectiveness, and reduce the toxic side effects of drugs,
controlled drug release is especially important in a drug delivery system [1]. A
drug delivery system usually consists of a formulation or a device that enables
introduction of a therapeutic agent in the body and enhances its efficacy and
safety by controlling the rate, time, and site of release within the body [2]. During
the past few decades, various methods have been employed to fabricate polymeric
micro/nanostructures such as micro/nanospheres, nanorods, nanoplatelets, and
micro/nanofibers for drug delivery systems.
Electrospinning is a versatile technique for fabricating micro/nanostructured
polymer fibers or particles with controllable shape, size, morphology, and com-
position [3]. The outstanding properties of high surface area to volume ratio, high
porosity, and unique hierarchical structures make electrospun fibers or particles
excellent candidates for filtration, catalysis, and sensors, as well as in biomed-
ical applications [4–6]. Therefore, drug delivery systems based on the electro-
spinning technique have attracted increasing interest in the pharmaceutical field.
Biodegradable and biocompatible polymers, for example, chitosan, cellulose, as
well as aliphatic polyesters, such as polylactide (PLA) and polycaprolactone (PCL),
have received significant attention for clinical applications as they are environ-
mentally friendly and capable of adapting to the physiological conditions of the
human body [7–9]. Kenawy et al. [10] first examined the release properties of
tetracycline hydrochloride from PLA and poly(ethylene-co-vinyl acetate) fibrous
mats. Their study indicated that the release kinetics of the fiber mat was highly
influenced by the state of the drug and the structure of the polymer that forms
the fibers. Other studies also reveal that the release profiles of entrapped drugs

Biodegradable Polyesters, First Edition. Edited by Stoyko Fakirov.
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2015 by Wiley-VCH Verlag GmbH & Co. KGaA.