Based on a new generation of silica and bonding technologies, Bonna-Agela technologies has developed new Durashell C18-AM columns. Firstly, silica gel made by inert processing techniques can be kept stable in alkaline mobile phase, significantly improving column lifetime compared with conventional silica; Secondly, the strong ability to identify stereoisomeric compounds, applicable to separation of structurally similar compounds, especially for analysis of a variety of impurities simultaneously in drug.
● Excellent stability in extreme pH range (1.5-12.0);
● Double polar end-capped, strong separation ability for polar compounds;
● Special bonding, strong ability to identify stereoisomeric compounds;
● Hydrophilic stationary phase, compatible with 100% aqueous mobile phase.
The determination of cefradine content and related substance
Analysis result for cefradine content and the inspection of related substance
1. The retention time of Cefradine is 6.7 mins. Column efficiency is 9501. Tailing factor is 0.939. The resolutions of
Cephalexin, Cefradine and Arginine peaks all meet the requirements of Pharmacopoeia;
2. During the inspection of related substances, two main impurities were detected , while the resolutions of each
chromatographic peak all meet the requirements of Pharmacopoeia.
Good batch reproducibility
To inspect the lifetime of Durashell C18-AM, the method of cefradine content determination was applied.
The sample spiked with arginine was injected consecutively into Durashell C18-AM which was washed
once per 80 injections. At the same time, the changes should be observed in cefradine peak’s retention time,
column efficiency and peak shape, as well as the resolution of arginine and the 4th unknown impurity, and if
any of the changes was significant, then the test should be stopped. In this way, totally 280 injections
were processed successfully. The above figure shows, after 280 injections, there is no significant change
in retention time, column efficiency, tailing factor. During the analysis of cefradine, due to the use of
higher concentration of ion-pair reagents and buffer solution (total concentration of 54 mM) and alkaline
mobile phase (pH 8.0), decline of a lot of other C18 column was observed in peak retention and efficiency
and impurity resolution in less than 50 injections. Although a certain C18 alkali tolerant column has good stability
in the first 80 injections, decrease was gradually appeared in retention, efficiency and resolution in the more injections,
even it was unable to separate impurities near arginine in 4th 80 injections (totally about 240 injection).
While Durashell C18-AM showed excellent durability, and still remained a stable retention, good separation and high
column efficiency after the 1100 injections.