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Monoclonal antibodies of both the IgG and the IgM type were purified by hydroxylapatite HPLC (HA-HPLC) under very mild conditions. The IgM type antibodies, which were isolated from ascites fluid and separated from other proteins also by means of size exclusion HPLC.It was shown that the most frequently observed disadvantage of HA-HPLC, that is the relative short life of the columns (P. Steifen (1989) GIT Fachz. Lab., Suppl. 3/89 (Chromatogr.}, 50-90), is due to microbial contamination rather than lower mechanical stability. In order to monitor column performance, a test was developed based on the use of standard proteins under isocratic separation conditions. This allows a direct comparison between the respective performances of columns made from different materials, hydroxylapatite or fluoroapatite, from different sources and with different particle sizes. A problem which often occurs with HA-HPLC in the case of IgM antibody isolation, namely precipitation of the antibodies at low salt concentrations at the beginning of a Chromatographie run, was avoided by adding sodium chloride to both separation buffers. Reinigung monoklonaler Antikörper durch HPLC an Hydroxylapatit und durch Size-Exclusions-HPLC

An ion-pair reversed-phase high-performance liquid chromatographic (HPLC) method for the separation and simultaneous determination of thiamine HCI (vitamin B1), riboflavin (vitamin B2), nicotinamide, pyridoxine HCI (vitamin B6), cyanocobalamin (vitamin BI2), ascorbic acid (vitamin C) and folic acid in capsule preparations is described. The above seven active substances were extracted from the preparations within 5 min using an electronically controlled extraction apparatus. Ion-pair reversed-phase HPLC was carried out on LiChrosorb RP-18 using methanol -waterconcentrated phosphoric acidoctanesulphonic acid as the eluent.All seven active ingredients were separated in less than 4 min. The detection limits were 1-2 ng for all vitamins; however, amounts of 5-10 ng were required for the quantitative HPLC determination of the vitamins. The proposed HPLC method is suitable for the determination of these active ingredients in pharmaceutical preparations such as multivitamin capsules and has a coefficient of variation between 1 .I and 3.2%. The ease of extraction, accuracy and sensitivity of the method and the time required for analysis are emphasised.