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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Pyrimidine derivatives are widely used for the treatment of viral diseases and cancer. The analysis of pyrimidine derivatives is typically performed using various chromatographic techniques, in particular, reversed-phase high performance liquid chromatography (HPLC). The separation is typically carried out with (7 -30)-cm-long C 8 and C 18 silica gel columns, mainly at room temperature, and a 1 -1.5 ml/min eluent flow rate. The column is eluted in an isocratic or gradient system, and a variety of mobile phases have been proposed. The detection is based on optical absorption or fluorescence measurements, or makes use of mass spectrometry. Various methods of extraction of pyrimidine derivatives from biological samples are discussed, and the corresponding detection limits are presented.

An HPLC-based method for determining cytarabine (1-b-D-arabinofuranosylcytosine, Ara-C) and uracil arabinoside (Ara-U, a product of the hydrolytic deamination of Ara-C), as well other related compounds (cytidine, cyclocytidine, uridine), in aqueous solutions has been developed. The proposed method is characterized by good reproducibility and is capable of quantitatively determining all compounds simultaneously present in solution.