In vitro study of drug release from various loaded polyurethane samples and subjected to different non-pulsed flow rates

Abstract

Drug-eluting implants with a polymeric matrix are currently widely used and the interest of modeling their behavior is increasing. This article aims to present preliminary results of an in vitro under steady flow, study the behavior of drug-loaded polyurethane samples used as drug delivery matrices. Polyisocyanate and polyol synthesis supplied the polyurethane studied in this work. A molding and heat at 50°C for about 30 min make it possible to prepare films from these components. The prepared samples are placed in the impermeable Plexiglas tube and they are in contact with the medium (distilled water). Tests have been performed without flow and three other cases with steady flow, at a temperature of 37°C. The substance active incorporated in these films, as the drug, for carrying out the release tests is the C 20 H 24 C 12 N 2 O 3. This drug supplied in granular form is composed of a mixture in the following proportions, 15 mg of diclofenac epolamine and 50 mg of diclofenac-sodium. Four sample variants were carefully prepared: pure-PU and PU loaded in a mass ratio of 10, 20 or 30%. Weighing, DSC, FT-IR, and DMTA are the methods used to analyze the samples. In addition, SEM micrographs are used to explore qualitatively the microstructure during the release tests. The kinetics in vitro of the drug release and water absorption by the polyurethane films are discussed in detail. The results show that these two quantities depend on the initial drug loading and the flow rate value, as a function of the in vitro incubation time.

Development of a Model Based on Physical Mechanisms for the Explanation of Drug Release: Application to Diclofenac Release from Polyurethane Films

“…As the physical stability of the DE in the polyurethane samples were important for considering the mechanisms of release, therefore, it was checked during the samples preparation by microscopic observations. Diclofenac particles were stayed in their initial particle shape, solid-state, after the samples were prepared [ 14 ]. These experiments were carried out in vitro on samples loaded by 10%, 15% (for model verification), 20% and 30%, and assessed at four different flow rates: 0, 7.5, 6.5 (for model verification), and 23.5 mL/s.…”

“…For each mechanism, diverse factors affect the release kinetics [ 9 , 10 , 11 ]. Among these factors, temperature [ 12 ], initial drug load [ 13 ], circulating flow [ 14 ] pH [ 15 , 16 ], ionic strength, redox and enzymes are, for example, elements whose influence deserves to be studied. In addition, many studies have been conducted to explore the possibilities offered by polymeric biomaterials in regulating drug liberation from stimuli-responsive drug delivery systems.…”

“…Mathematical models for the evaluation of drug-release profiles proceed by solving the equations of the involved physical mechanisms [ 14 , 16 ]; and considering the evolution of kinetics [ 35 , 36 ].…”

“…The method selected is employed to applications of a non-degradable polyurethane matrix loaded with specific doses of the anti-inflammatory hydrophilic drug (diclofenac epolamine). Experimental data used consider several flow rates of the fluid circulating in a bio-reactor simulating in vitro blood-flow in stented arteries [ 14 ]. Identified mechanisms for these polymeric carriers are burst-release, diffusion and osmosis.…”

Controlled release from polyurethane films: Drug release mechanisms

“…8,9 Polyurethane has always been used in biomedical applications due to the good biocompatibility and mechanical properties. 4,[10][11][12][13][14][15] Polyurethane due to show the favorable ability to drug release profiles in various modes such as microparticles, films, and also as a coating on implants and stents has been the focus of many studies. In some studies, it is noted that the release from the nondegradable polymeric system is controlled by diffusion.…”