Melt-spun bioactive sutures containing nanohybrids for local delivery of anti-inflammatory drugs

In this work, a novel concept is introduced in drug-eluting fibres to ensure a good control of drug delivery features and wide applicability to different bioactive compounds. Composite bioactive sutures based on fibre grade poly(ε-caprolactone) (PCL) and loaded with the anti-inflammatory drug Diclofenac (Dic) or a Dic nanohybrid where the drug is intercalated in a synthetic hydrotalcite (Mg/Al hydroxycarbonate) (HT–Dic) were developed. Fibres were prepared by melt-spinning at different PCL/HT–Dic/Dic ratios and analysed in terms of morphology, mechanical properties and drug release features. Results emphasized that tensile properties of fibres are clearly affected by Dic or HT–Dic addition, while the presence of knots has limited influence on the mechanical behaviour of the sutures. Release of Dic strongly depends on how Dic is loaded in the fibre (as free or nanohybrid) whereas the combination of free Dic and HT–Dic can allow a further tuning of release profile. In vivo experiments show a reduction of inflammatory responses associated with Dic-loaded fibers. Thus, a proof of principle is provided for a novel class of bioactive sutures integrating advanced controlled-release technologies.