Electrospun nanofibers have the potential to achieve high drug loading and the ability to sustain drug release. Mechanical properties of the drug-incorporated fibers suggest the importance of drug–polymer interactions. In this study, we investigated the mechanical properties of electrospun polycaprolactone (PCL) and poly (D,L-lactic-co-glycolic) acid (PLGA) fibers at various blend ratios in the presence and absence of a small molecule hydrophilic drug, tenofovir (TFV). Young?s modulus of the blend fibers showed dependence on PLGA content and the addition of the drug. At a PCL/PLGA (20/80) composition, Young?s modulus and tensile strength were independent of drug loading up to 40 wt% due to offsetting effects from drug–polymer interactions. In vitro drug release studies suggested that release of TFV significantly decreased fiber mechanical properties. In addition, mechanically stretched fibers displayed a faster release rate as compared to the non-stretched fibers. Finally, drug partition in the blend fibers was estimated using a mechanical model and then experimentally confirmed with a composite of individually stacked fiber meshes. This work provides scientific understanding on the dependence of drug release and drug loading on the mechanical properties of drug-eluting fibers.
Electrospun fibers; Mechanical properties; Drug loading; Drug release; Drug–polymer interaction; Drug partition
Citation: Shih-Feng Chou, Kim A. Woodrow Relationships Between Mechanical Properties And Drug Release From Electrospun Fibers Of PCL And PLGA Blends http://dx.doi.org/10.1016/j.jmbbm.2016.09.004
Received: 8 July 2016, Revised: 1 September 2016, Accepted: 4 September 2016, Available online: 9 September 2016
Copyright: © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by/4.0/).
In summary, we report correlations between mechanical properties and drug release rates of electrospun blend fibers. Our results showed that incorporating TFV into PCL/PLGA fibers significantly modified the mechanical properties from blank fibers, suggesting a high level of drug-polymer interactions. TFV release decreased mechanical properties significantly at early time points. Pre-stretched PCL/PLGA blend fibers to failure showed higher release rates as compared to the non-stretched samples. Drug partitioning in PCL/PLGA fibers was evaluated using a mechanical model, and experimental data using stack fiber configurations confirmed that 80% of the TFV is in the PCL phase and 20% of TFV is in the PLGA phase. Our study contributes to scientific understanding of mechanical performance of drug-eluting fibers.
This work is supported by a grant from the US National Institutes of Health (AI112002) and a grant from the Bill and Melinda Gates Foundation (1067729) awarded to K.A.W. We thank D. Carson for critical discussions and review of the manuscript.