Teicoplan is a mixture of six major components (A 2-1 to A 2-5 and A 3-1).The aim of this study was to develop a method for evaluating variations in composition between the branded teicoplanin product and the 7 generic versions of it on the market.The branded product was designated as product A and it was compared with 3 generics-product B,C and D.
The results of an assay by HPLC showed that product B was very similar to product A regarding percentage contents and ranking order of the 6 major components while product C and D differed from product A in these respects.The percentage contents of the A 3-1 component in product C and D were relatively high.Further,analysis by FPIA indicated that percentage contents of the 6 main components affected plasma concentration sensitivity and protein binding.Total plasma concentrations were measured and observed concentration to theoretical concentration ratios were calculated for each sample as an indicator of sensitivity.In terms of plasma concentration sensitivity,there was no significant difference between product A and B,but sensitivity was significantly lower in product C and D than in product A.As regards unbound concentrations,there was no significant difference between product A and B,but they were significantly higher in product C and D than in product A.
Our results showed that variations in sensitivity and protein binding were connected with percentage contents,and that of A 3-1 was negatively correlated with sensitivity and protein binding.
In conclusion,these findings suggest that differences in percentage contents of teicoplanin mixtures would affect pharmacokinetics and pharmacodynamics and we consider that the method we developed for evaluating such differences would be useful.
