In vitro release control of ketoprofen from pH-sensitive gels consisting of poly(acryloyl-l-proline methyl ester) and saturated fatty acid sodium salts

Light-sensitive intelligent drug delivery systems of coumarin-modified mesoporous bioactive glass

Functionalized mesoporous bioactive glasses (MBG) with photoactive coumarin demonstrates photo-responsive dimerization resulting in reversible gate operation. Coumarin-modified MBG was used as a drug delivery carrier to investigate drug storage/release characteristics using phenanthrene as a model drug. Irradiation with UV light (>310 nm) induced photo-dimerization of the coumarin-modified MBG, which led to the pores' closing with cyclobutane dimers and trapping of the guest phenanthrene in the mesopores. However, irradiating the dimerized-coumarin-modified MBG with shorter wavelength UV light (approximately 250 nm) regenerates the coumarin monomer derivative by the photo-cleavage of cyclobutane dimers, such that trapped guest molecules are released from the mesopores. The structural, morphological, textural and optical properties are well characterized by X-ray diffraction, transmission electron microscopy, N(2) adsorption/desorption, and UV-visible spectroscopy. The results reveal that the MBG exhibits the typical ordered characteristics of the hexagonal mesostructure. The system demonstrates great potential in light-sensitive intelligent drug delivery systems and disease therapy fields.

Polycomplexes of poly(acrylic acid) with streptomycin sulfate and their antibacterial activity

Complex formation between streptomycin sulfate and poly(acrylic acid) has been studied in aqueous solutions by turbidimetric, potentiometric and viscometric methods as well as by FTIR spectroscopy. It was shown that these polycomplexes are stabilized by electrostatic interactions. The solubility of polycomplexes was examined as a function of pH and it was found that at pH values below 3.1 the polycomplexes undergo complete dissociation or dissolution. The antimicrobial activity of the drug and its polycomplex was evaluated using Sarcina sp. as a model organism. It was demonstrated that the polycomplexes have an antimicrobial activity on the same level as the free drug.