PLLA-PHB fiber membranes obtained by solvent-free electrospinning for short-time drug delivery

Abstract

Fibers of poly(L-lactic acid) (PLLA)/polyhydroxybutyrate (PHB) with different concentrations of the drug dipyridamole (DPD) were prepared using solvent-free melt electrospinning to obtain a polymeric drug delivery system. The electrospun fibers were morphologically, structurally, thermally, and dynamically characterized. Crazes that resemble lotus root crevices were interestingly observed in the 7:3 PLLA/PHB fibers with 1% DPD. The crystallinity of PLLA slightly decreased as PHB was incorporated, and the addition of DPD significantly reduced the melting temperature of the composite. The interactions between PLLA and PHB mainly occurred at a proportion of 7:3, and drug encapsulation in the fibers was verified. The kinetic profiles of drug release demonstrated the predominant multiple patterns involving a diffusional stage in the short-term mode of release and kinetic process related to the hydrolysis of the biopolymers. Furthermore, the dynamic behavior of the polymer molecules was evaluated based on the segmental mobility using probe electron spin resonance spectroscopy. The segmental mobility in the amorphous fraction of PLLA decreased with increasing PLLA content. The 9:1 PLLA/PHB system was more resistant to polymer hydrolysis than to the 7:3 system and the rate of diffusion transport was approximately two times higher for the 7:3 PLLA/PHB fibers than for the 9:1 PLLA/PHB fibers.

Comparative Characterization of Melt Electrospun Fibers and Films Based on PLA‐PHB Blends: Diffusion, Drug Release, and Structural Features

“…The supercooling degree for the PLA/PHB film loaded by 5% DPD is 10 °C higher than for the ultrathin fiber of similar composition. As it was reported in the previous work, the lowering in crystallization temperature reveals a faster crystallization rate of PLA in the blend fibers compared to that in pristine PLA fibers due to the ability of PHB to promote the recrystallization of PLA. However, after the increment of drug content from 1 to 5% the increase in this characteristic is observed as a result of drug impact upon segmental motion of the biopolymer.…”

“…As can be seen from the figure, the curves belonging to the fibers are located below the corresponding curves for the films and the rates of release for them are remarkably lower. In accordance with the proposed diffusion‐kinetic model, the initial nonlinear section of each curve reflects principally the drug diffusion process, whereas the linear section corresponds to the kinetic process of the surface hydrolytic fiber destruction with the corresponding loss in polymer weight strongly on the polymer surfaces. As a result of zero‐order hydrolytic reaction, the immobilized fraction of the encapsulated drug releases from the cylindrical filaments and from fibrillar mat as the whole system at a constant rate.…”

“…In our previous paper [9] it was reported, that the PHB loading to PLA matrix decreases the mean fiber diameter from 20.0 AE 2.5 μm at the 9:1 ratio to 18.8 AE 2.5 μm at the 7:3 ratio and finally to 10.6 AE 2.5 μm at the PLA/PHB ratio equals to 6:4. The drug embedding in the polymer system decreases the mean fiber diameter up to 10.7 AE 2.5 μm for 7:3 þ1% DPD system and simultaneously leads to narrower diameter distribution.…”

“…The purpose of this manuscript is to conduct the comparative analysis of drug diffusion (DPD) based on diffusivity impact upon general process of release. In a sense, the content outlined here presents the development of our recently published data on the ecologically friendly, melt electrospinning technology of nanofibers for drug delivery . Here we have used the melt‐spun ultrathin fibers on the base of PLA/PHB compositions and simultaneously the analogous films produced via a melt moulding under the analogous temperature conditions.…”

“…In a sense, the content outlined here presents the development of our recently published data on the ecologically friendly, melt electrospinning technology of nanofibers for drug delivery. [9] Here we have used the melt-spun ultrathin fibers on the base of PLA/PHB compositions and simultaneously the analogous films produced via a melt moulding under the analogous temperature conditions. Additionally the structure and dynamic characteristics of these biopolymer vehicles have been represented, that should clarify the drug release features in polymer therapeutic systems of different geometry, namely macro-and submicron specimens.…”