Lidocaine Release from Polycaprolactone Threads
Industrie Biomediche Insubri S/A, Via Cantonale, Mezzovico, Ticino, Switzerland Journal of Applied Polymer Science
(Impact Factor: 1.77).
09/2010; 117(6):3610 - 3614. DOI: 10.1002/app.32262
In the field of resorbable devices, drug eluting sutures represent an applied research field on which the reliability of both production processes and mathematical prediction modeling were tested. Indeed, poly-ε-caprolactone pellets were compounded with lidocaine and then extruded to obtain highly loaded threads. The complete and rapid release demonstrated that the extrusion process does not alter the drug, which is confirmed to be embedded in an open porous matrix, being free to be solvated by uptaken water and to diffuse. Release profile and polymer degradation were simulated through a mathematical model based on conservation laws that allowed to assess release kinetic and to confirm the understanding of involved phenomena, as it fit experimental data. Reliability and robustness of chosen model allow to monitor the overall quality of manufacturing because any discrepancy between experimental and simulated data can be adopted to assess drug distribution uniformity within the device. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Available from: Bahareh Azimi
- "In another study, lidocaine release from PCL suture threads produced by micro-extrusion was investigated to assess the reliability of the manufacturing process. The full and rapid release of the loaded drug demonstrates that the extrusion process does not alter the drug and that the loaded amount is embedded in an open structure porosity that allows it to be available for the release . An et al.  have reported a novel technique, named microfiber melt drawing, to fabricate a bundle of three dimensionally aligned PCL microfibers of about 10 μm fiber diameters without using any organic solvent. "
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ABSTRACT: Poly (ε-caprolactone), (PCL) or simply polycaprolactone as it is usually referred to, is a synthetic biodegradable aliphatic polyester which has attracted considerable attention in recent years, notably in the biomedical areas of controlled-release drug delivery systems, absorbable surgical sutures, nerve guides, and three-dimensional (3-D) scaffolds, for use in tissue engineering. Various polymeric devices like microspheres, microcapsules, nanoparticles, pellets, implants, and films have been fabricated using this polymer. It can be transformed by spinning into filaments for subsequent fabrication of desirable textile structures. Spinning may be accomplished by various approaches. The fibers may be fabricated into various forms and can be used for implants and other surgical applications such as sutures. Although numerous studies have investigated different properties and applications of PCL, there is no comprehensive study investigating different fabrication methods of PCL fibers and their biomedical applications. The present article presents a review on the production of PCL fiber via various methods, along with correlations between structure and properties of the fibers. The applications of these fibers in biomedical domains are also discussed.
Available from: Roberto Scaffaro
- "In order to prevent hydrolytic scissions during processing, PCL was dried under vacuum at 40 °C for about 24 h according to previous studies (Charuchinda et al. 2003; Perale et al. 2010). PCL and PCL/CHX blends were spun after drying at 40 °C for 6 h by using a capillary rheometer (Rheoscope 1000, CEAST Italy) equipped with a capillary having D0 1 mm and L/D040. "
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ABSTRACT: Bacterial infections on a sutured wound represent a critical problem, and the preparation of suture threads possessing antimicrobial properties is valuable. In this work, poly(caprolactone) (PCL) monofilaments were compounded at the concentration of 1, 2 and 4 % (w/w), respectively, to the antiseptic chlorhexidine diacetate (CHX). The incorporation was carried out in the melt by a single-step methodology, i.e. "online" approach. Mechanical tests revealed that the incorporation of CHX does not significantly change tensile properties of PCL fibres as the thermal profile adopted to prepare the compounded fibres does not compromise the antibacterial activity of CHX. In fact, CHX confers to compounded PCL fibres' antimicrobial property even at the lowest CHX concentration as revealed by microbiological assays performed on Escherichia coli, Micrococcus luteus and Bacillus subtilis strains. The scanning electron microscope micrographs and energy-dispersive X-ray analysis of compounded threads revealed that CHX is uniformly distributed on fibre surface and that the overall amount of superficial CHX increases by increasing compounded CHX concentration. This distribution determines a biphasic CHX release kinetics characterized by an initial rapid solubilisation of superficial CHX micro-crystals, followed by a slow and gradual release of CHX incorporated in the bulk. Interestingly, the compounded threads did not show any toxic effect compromising cell viability of human fibroblasts in vitro, differently from that observed using an equal amount of pure CHX. Thus, this study originally demonstrated the effectiveness of an "online" approach to confer antimicrobial properties to an organic thermoplastic polymeric material commonly used for medical devices.
Available from: PubMed Central
- "These mechanisms are strongly correlated, since fast degradation kinetics implies a burst release of the active compound, while a slower hydrolysis is responsible of a more prolonged delivery of the interested molecules. A great number of experimental studies regarding the synergy between these phenomena can be found in the literature [4,10,12,15], but none of them couple experimental results with simulations at atomistic level, a test bed for a deep comprehension of involved mechanisms. Molecular dynamics could be a useful tool to study polymer structures in aqueous environment and diffusion phenomena, which can be related to both the behavior in water and in polymeric matrices. "
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ABSTRACT: Structural characterization of poly-l-lactic acid (P(L)LA) and poly(glycolic acid) (PGA) oligomers containing three units was carried out with an atomistic approach. Oligomer structures were first optimized through quantum chemical calculations, using density functional theory (DFT); rotational barriers concerning dihedral angles along the chain were then investigated. Diffusion coefficients of l-lactic acid and glycolic acid in pure water were estimated through molecular dynamic (MD) simulations. Monomer structures were obtained with quantum chemical computation in implicit water using DFT method; atomic charges were fitted with Restrained Electrostatic Potentials (RESP) formalism, starting from electrostatic potentials calculated with quantum chemistry. MD simulations were carried out in explicit water, in order to take into account solvent presence.
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