Polyvinyl alcohol-pectin cryogel films for controlled release of enrofloxacin.

The release of enrofloxacin entrapped in polyvinyl alcohol (PVA) cryogel at pH 5.5 showed a first-order kinetic, releasing 69.7% of the antibiotic after 4.5 h at 37 °C. In order to slow down the fluoroquinolone release rate, high-methoxylated pectin was added into the cryogel (PVA-P). A film containing 1.0% (w/v) HM pectin and 5.0 μg/ml enrofloxacin released only 3.7% of the antibiotic after 4.5 h. Since the FTIR spectrum showed that most of the interactions between PVA-P matrix and enrofloxacin were due to polar groups (carboxylate and amine), a two-layer film system was designed to modulate the releasing rate of the drug. The top film equilibrated with 0.75 or 1.5 M NaCl release up to 41.9% and 89.0% of the enrofloxacin in 4 h, respectively. The release rate of enrofloxacin was found dependent on NaCl concentration in the upper gel layer. The two-layer cryogel system showed attractive features for transcutaneous antibiotic delivery.