Incorporation of active nano-hybrids into poly(e-caprolactone) for local controlled release: antifibrinolytic drug

The antifibrinolytic drug trans-4-(aminomethyl)cyclohexanecarboxylate (tranexamic anions) was intercalated by anion exchange into Mg/Al layered double hydroxide (LDH). The hybrid, of formula [Zn0.65Al0.35(OH)2]Trx0.24(CO3)0.055•1.5H2O, was characterized by chemical and thermal analyses and X-ray powder diffraction. Different amounts of the hybrid material were incorporated into poly(-caprolactone) by high energy ball milling technique and processed as films. The composite materials were analyzed by X-ray diffractometry, thermogravimetry and FT-IR spectroscopy to clarify the filler-polymer structural organization. An investigation of the mechanical properties of the composite showed an improvement of mechanical parameters, in particular the elastic modulus, when compared to of the pristine polymer. Thus, the inorganic component, even in small quantities, beside acting as a reservoir of active molecular anions, can improve the physical properties. A new method for the quantitative determination of tranexamic anions by infrared spectroscopic analysis was proposed and the release process of the tranexamic anions from the composite into a physiological solution was monitored. The release consisted of two stages: a first stage, very rapid as a burst, in which a small fraction of intercalated drug was released and of a second stage over longer time, much slower than the first. The composites are very promising in the preparation of new hybrid polymeric materials to be used for the molecular delivery of drugs in topical applications, as suture threads or medicate scaffolds.