Simultaneous HPLC Determination Of The Content Of Ampicillin And Probenecid In Ampicillin And Probenecid Capsules

Ampicillin and Probenecid Capsules is an antibiotic medicine that is imitated from USP(ⅩⅩⅡ)[]in 1998 by Chinese pharmaceutical company. In the quality standard,we determinate ampicillin and probenecid by UV spectrophotometry according to USP(ⅩⅩⅡ)[].After several year's producing and determinating,we find that the result of determination of probenecid can not conform to the feeding quantity. So there are many risks for the management in the pharmaceutical company. The purpose of the study is to establish a method more simple, convenient and accurate to determinate the content of ampicillin and probenecid simultaneously.HPLC technology is a very important analysis way, which is used to separation and analysis in the experiment. Different matters have different sorption in two phases. When the two phases move convectively, the matters will separate from each other one by one as time goes. As a simple,convenient,scientific and accurate analysis way,HPLC method has been applied to more and more experience in different fields.The study is as ampicillin and probenecid as the research aims.The method of determinating content of ampicillin is HPLC,but the method of probenecid is titration. The method of determinating ampicillin can not determinate probenecid. But according to this method,we can determinate both ampicillin and probenecid simultaneously. Separation was achieved on a AichromBond-AQ C18(4.6mm*250mm,5μm) column at indoor temperature(10～30℃);and detected at 254nm. The mobile phase consisted of acetonitrile-0.05mol·L-1potassium dihydrogen phosphate[400∶600(adjusted PH to 6.6 with 20% NaOH solution)] at a flow rate of 0.5ml·min-1. The linear ranges(n=7) for the determination of ampicillin and probenecid were 7.434～29.73μg(injection quantity,r=0.9998),2.522～10.09μg(injection quantity,r=0.9997),respectively. The method recovery were 99.21%～101.3% and 98.84%～101.7%,respectively;intra-day RSD were less than 1%. Exclusive test to the method were made,and found that the impurity didn't influence the analysis of the main components. The test of tolerance was made and found that the slight change to the range of the chromatographic parameter didn't influence the analysis. According to the method we determinated the contents of ampicillin and probenecid of 3 batches of production. The relative errors were less than 3%. This method is accurate,simple and convenient,and is suitable for determination of ampicillin and probenecid in experience. This study has solved a difficult technical problem for the manufacturing company. This has provided the technical materials to revise the quanlity standard of this kind of medicine.