Determination of Benzylpenicillin In Pharmaceuticals By Capillary Zone Electrophoresis

Abstract

A rapid and direct method is described for the determination of benzylpenicillin (penicillin G) in pharmaceutical preparations. the method involves very little sample preparation and total analysis time for duplicate results is less than 30 minutes per sample. The method takes advantage of the speed and separating power of capillary zone electrophoresis (CZE). Detection of penicillin is by absorption at 228 nm. an internal standard is employed to reduce sample injection error. the method was applied successfully to both tablets and injectable preparations. larger on longer aging. It was the authors' hypothesis that this peak was due to formation of penicilloate. When this degradation product was synthesized according to an established procedure¹⁴, CZE retention time of the synthesized product was the same as that final peak in the aged penicillin samples. UV spectra on both solutions was further evidence we had properly identified the degradation product. Thus the relative amount of active and degraded compound in a sample can be estimated readily. Also, this indicates fresh solutions should be used for analytical work. In conclusion, CZE of penicillin G was shown to not only be possible, but useful in a practical, rapid assay for the level of the antibiotic in pharmaceutical samples. Extension of this work to other types of penicillin and to the variety of samples in which the antibiotic is found in the next logical step.