Release of dextromethorphan hydrobromide from freeze-dried enzyme-degradable hydrogels

Abstract

Abstract Dextromethorphan hydrobromide was incorporated into albumin-crosslinked polyvinylpyrrolidone hydrogels by equilibrating the gels in a saturated drug solution followed by freeze drying to entrap the drug in the network. Through freeze drying, highly porous hydrogels containing uniformly dispersed drug were produced. Drug content in the gel increased as a function of the number of drug loading-freeze drying cycles. Solvent penetration into freeze-dried gels resulted in an initial isotropic collapse of the network followed by a gradual increase in gel size due to swelling. In the presence of pepsin, freeze-dried networks degraded at a much faster rate than non-freeze-dried control samples. Drug release from freeze-dried hydrogels was degradation-independent and inconsistent with conventional solute transport mechanisms through swellable low surface area devices. The rate of drug release was dependent on the amount of drug loaded into the freeze-dried matrix. The potential use of these devices for long-term oral drug delivery is discussed.