New cryogels based on polymers and zeolite L for controlled Enalapril maleate release

Abstract

New composite cryogels for controlled release of Enalapril Maleate (EM) were developed based on two biodegradable polymers, poly(vinyl alcohol) (PVA) and pullulan (PU) as polymer matrix, and zeolite L (ZL) as inorganic filler. The cryogels were prepared by freeze-thaw technique using different concentrations of the components, the EM being introduced directly during the cryogel preparation. The samples were characterized by FTIR spectroscopy, scanning electron microscopy and water vapor sorption-desorption isotherms. The presence of PU and ZL in the cryogels led to the modification of FTIR characteristic absorption bands of EM and contributed to the modification of the cryogel morphology. The sample moisture absorption was in the range 5.28–18.20%, determined at a relative humidity RH = 82%. Cryogels based on PVA, PU and ZL components showed a longer EM release period compared to cryogels containing only PVA. The analysis of in vitro EM release kinetics was performed using three predictable models: zero and first order kinetics, and Korsmeyer-Peppas model. Korsmeyer-Peppas model best fitted the release data.