Study of interaction between PEG carrier and three relevant drug molecules: piroxicam, paclitaxel, and hematoporphyrin.

Molecular dynamics simulation has been used to study the specific interactions between poly(ethylene glycol) (PEG) and three drug molecules for which PEG is used to aid delivery: paclitaxel and piroxicam, where PEG is a carrier agent, and hematoporphyrin, where PEG is covalently attached to form a "stealth shield". Simulating at physiological salt concentration, we found no evidence of any specific interaction between paclitaxel or piroxicam with PEG, but found a strong interaction for the case of hematoporphyrin. This interaction is lipophilic in nature, between the nonpolar (CH(2))(2) groups of the PEG and the porphin ring of the hematoporphyrin.

Physical solid-state properties and dissolution of sustained-release matrices of polyvinylacetate.

Solid-state compatibility and in vitro dissolution of direct-compressed sustained-release matrices of polyvinylacetate (PVAc) and polyvinylpyrrolidone (PVP) containing ibuprofen as a model drug were studied. Polyvinylalcohol (PVA) was used as an alternative water-soluble polymer to PVP. Differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) were used for characterizing solid-state polymer-polymer and drug-polymer interactions.