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Thermoresponsive amphiphilic conetworks comprising poly(2-ethyl-2-oxazoline) (PEtOx), 2-hydroxyethyl methacrylate, and 2-hydroxypropyl acrylate segments have been studied as new platforms for delivery of drug with limited solubility. Series of conetworks of varied composition were synthesized and swelling kinetics in aqueous media and ethanol were followed. The platforms were loaded with the hydrophobic drug ibuprofen by swelling in its ethanol solution. The structure and properties of the drug carriers were investigated by scanning electron microscopy and differential scanning calorimetry. The release kinetics profiles of ibuprofen from the studied platform were established. The investigation proved the feasibility of the PEtOx-based amphiphilic conetworks as highly effective platforms for sustained ibuprofen delivery.

SummaryInterpenetrating polymer networks (IPNs) of poly(acrylic acid) (PAA) and polyacrylamide (PAAm) were synthesized and applied as drug delivery systems for verapamil hydrochloride (VPM). The IPN network density was controlled by changing IPN composition. Thus, when increasing the PAAm to PAA weight ratio, the network density increases as revealed by the equilibrium swelling ratio and microhardness measurements. The SEM study of the IPNs’ morphology showed phase separation at nano level where PAAm domains with size below 100 nm are finely dispersed into the PAA matrix. The thermal study on the IPNs confirmed that both components are finely mixed as one Tg was detected for all IPNs’ compositions. Tg vs. composition dependence obeyed the Gordon–Taylor equation and deviated negatively from the Fox equation thus confirming weak interactions between PAA and PAAm. The VPM loading into PAA/PAAm IPNs resulted into amorphization of the drug as well as in a IPNs’ Tg increase as revealed by differential scanning calorimetry (DSC). The in vitro release of VPM shows that the IPNs of PAA/PAAm are suitable systems for sustained drug delivery. It was established that by changing IPNs’ composition it is possible to obtain different drug release kinetic profiles.