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A selective, repeatable, and robust isocratic liquid chromatographic method has been developed for the analysis of bulk samples of roxithromycin, a semi-synthetic macrolide antibiotic. The method involves the use of XTerra RP18 as stationary phase and acetonitrile-2.0 m (NH4)2HPO4, pH 6.4-water, 25∶30∶45, (v/v) as mobile phase, delivered at a flow rate of 1.0 mL min−1. Detection was by UV absorbance at 215 nm. Sufficient separation of roxithromycin from its homolog containing one more methyleneoxy group (roxithromycin G) and from other related substances was achieved. The robustness of the method was evaluated by means of a full-factorial experimental design. [ABSTRACT FROM AUTHOR]

A simple, robust, sensitive isocratic liquid chromatographic (LC) method suitable for the analysis of spiramycin is described. This method utilizes XTerra RP18 as the stationary phase and acetonitrile-0.2 m K2HPO4 (pH 6.5)-water, 39.5:5:55.5 (v/v), as mobile phase. The mobile phase flow rate is 1.0 mL min−1; the column is maintained at 70°C by immersion in a waterbath; and UV detection is performed at 232 nm. The method has good selectivity towards the major components (spiramycins I, II, and III), other related substances, and many impurities. The robustness of the method was evaluated by means of full-factorial experimental design. [ABSTRACT FROM AUTHOR]

A simple, sensitive, selective and robust isocratic LC method is described for the analysis of erythromycin on XTerra RP18. The main component, erythromycin A, is separated from all known related substances and degradation products. Several unknown impurities are also separated. Acetonitrile-0.2 MK2HPO4pH7.0-water, (35∶5∶60, v/v) was used as a mobile phase at 1.0 mL min−1. UV detection was at 215 nm. The robustness of the method was evaluated by a full-factorial experimental design. [ABSTRACT FROM AUTHOR]

A simple and sensitive isocratic LC method is described for the determination of erythromycins in fermentation broths. A simple technique utilizing acetone-methyl ethyl ketone, 1∶1, as extraction solvent was coupled with suitable chromatographic conditions—compounds were separated on a 250 mm×4.6 mm i.d., 5 μm, reversed-phase column at 65°C with acetonitrile-0.2 m K2HPO4 pH7.0-water, 35:5:60 ( v/v), as mobile phase at a flow rate of 1.0 mL min−1. UV detection was performed at 215 nm. Separation of erythromycin F from polar components of the fermentation liquid was sufficient. Erythromycins A, B, C, D, and E, and N-desmethylerythromycin A were also separated, as were known decomposition products of erythromycin A and several unknown components. The method is suitable for monitoring the progress of erythromycin fermentation. [ABSTRACT FROM AUTHOR]