Several HPLC methods with UV detection were developed for qualitative and quantitative analysis of chlorin e(6) and photosensitizer Photolon either in the free form or upon pre-derivatization (methylation) under reversed- and normal-phase conditions. Optimum analysis conditions providing the best resolution of analytes were found at acidic pH where polar groups are completely protonated. The separation was performed by gradient elution with mobile phases of 0.08% trifluoroacetic acid and acetonitrile on an XTerra RP(18) column. The method was specific, accurate and precise, allowing the analysis of chlorin e(6) in the presence of numerous degradation products useful in the manufacturing process and quality control of chlorin e(6) and Photolon.

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We have used luminescence and absorption spectroscopy to study the dynamics of photosensitized singlet oxygen generation and the photophysical characteristics of chlorin e 6 in Photolon ointment. We have shown that dimethylsulfoxide and polyethylene glycol 400, in concentrations comparable with their content in the ointment form of the drug Photolon, do not lead to appreciable changes in the spectral characteristics of chlorin e 6 . Substantial changes in the photophysical characteristics of the photosensitizer are observed at significantly higher concentrations of the excipients in the ointment. We have shown that in buffer solution, chlorin e 6 forms a complex with polyethylene glycol 1500. For the first time, we have detected luminescence of singlet oxygen from the surface of biological tissue treated with Photolon ointment.

A method for the synthesis of bioactive hydroxyapatite (HA) adapted for industrial production is described. It is established that a nanocrystalline HA gel more effectively stimulates osteogenic activity than does HA powder. In addition, the HA gel is suitable as injection for direct introduction into bone wounds and can be used for the impregnation of porous ceramic implants in order to improve their bioactivity and biocompatibility. It is shown that thermal and gamma-ray sterilization of HA-based preparations does not influence their properties as well as their stability during 3-year storage.