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Oily liquid drugs are not convenient for oral administration. We developed a powder containing clofibrate (CF), a model of an oily drug, using aminoalkyl methacrylate copolymer (EPO) or methacrylic acid copolymer (L100). CF or a mixture of CF and soybean oil was emulsified with EPO or L100 aqueous solution. Using a high-pressure homogenizer, a stable emulsion was obtained, and a powder was then obtained by lyophilization of the emulsion. The content of CF in the powder depended on the formulation, with the highest contents being 24.6% and 27.1% for EPO and L100, respectively. The incorporation ratio of CF was higher for L100 than for EPO. The powder using EPO was sticky because of leaked CF and the low glass transition temperature of EPO. The powder using L100 was a typical powder obtained by lyophilization. The leakage of CF from the powder was <2%, lower than for EPO powder. The dissolution of CF from powder using EPO was fast, regardless of the pH of the medium, but the powder using L100 showed enteric-soluble characteristics, indicating that CF is well incorporated in L100. [ABSTRACT FROM AUTHOR]

New interpolyelectrolyte complexes (IPECs) between oppositely charged Eudragit EPO and Eudragit L100 were investigated with a view to the development of oral controlled drug delivery systems (DDS). Structural features of the samples were evaluated by modulated-temperature differential scanning calorimetry (MTDSC). The results confirmed that all IPECs were chemically homogeneous and were characterized by only one glass-transition temperature. Evaluation of the diffusion-transport properties of the investigated IPECs revealed the basic mechanisms responsible for the controlled delivery of drugs with different physicochemical properties. The results showed that the synthesized IPECs have great potential to be used as pH-sensitive oral controlled DDS. [ABSTRACT FROM AUTHOR]

New interpolyelectrolyte complexes (IPECs) between oppositely charged types of Eudragit EPO and Eudragit L100 were synthesized at pH 6.0, 6.5, and 7.0 with a view to their application in oral controlled drug delivery systems. Differences among the obtained IPECs were evaluated by FTIR spectroscopy and elemental analy- sis. The results confirm that the polycomplexes are stabilized by intermacromolecular ionic bonds and have compositions Z = 1.02, 1.49, and 2, respectively. Monitoring of microenvironmental changes in the polycomplex matrices during swelling in model gastrointestinal fluids indicates that all IPECs can be considered as potential pH-sensitive carriers due to structural and compositional transformations. The established properties of the synthesized IPECs suggest that they have high potential to be used as pH-dependent oral drug delivery systems. [ABSTRACT FROM AUTHOR]