Matrix elimination ion chromatography method for trace level azide determination in irbesartan drug.

Ultra-trace analysis of azide in complicated Irbesartan sample matrix is achieved by the in-line sample preparation technique. Sodium azide is the precursor of Irbesartan, which is used as an anti-hypertensive drug. Due to the toxic nature of sodium azide, reliable determination of azide in Irbesartan is necessary. Irbesartan when analyzed for sodium azide, as per the USP 31-NF26 method, gets adsorbed to the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h for each sample analysis. The new method developed overcomes the limitations of the USP 31-NF26 method. This method is validated for specificity, linearity, accuracy, precision, sample solution stability, and robustness as per International Conference on Harmonization guidelines. The relationship between peak response and concentration is found to be linear between 5 to 80 ng/mL of sodium azide, with the correlation coefficient (r(2)) of 0.9995. The limits of detection and quantification for sodium azide are 0.532 and 1.61 microg/gm with respect to the sample weight.

Ion chromatographic determination of residual phase transfer catalyst in active pharmaceutical ingredient.

A new ion chromatography method with non-suppressed conductivity detection has been developed for the quantification of residual phase transfer catalyst-tetrabutylammonium bromide (TBAB) in an active pharmaceutical drug, Levetiracetam. Separation conditions are optimized to get a clear separation of TBAB from drug impurities using a Metrosep Cation C2-150 column. Conditions are also optimized to separate tetramethylammonium bromide, tetraethylammonium bromide, and tetrapropylammonium bromide, which are also used as phase transfer catalysts in several syntheses. Method performance was checked for selectivity, linearity, limit of quantification, limit of detection, accuracy, and precision. The method has superior performance with linearity r(2) > or = 0.9999, recovery from 94.7% to 96.5%, precision < or = 0.74%. In-line preconcentration is used to achieve limits of detection and quantification of 39 ng and 118 ng of TBAB, which corresponds to 1.56 and 4.72 microg/g of TBAB with respect to sample weight. The proposed method can be used for routine quality assurance analysis in the pharmaceutical industry.

An improved ion chromatographic method for fast and sensitive determination of N-methylpyrrolidine in cefepime hydrochloride.

An alternative ion chromatographic method to the existing USP method for the determination of N-methylpyrrolidine (NMP) in cefepime hydrochloride is developed. The cefepime in solution behaves as a strong cation and gets retained in the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with a special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h time for sample analysis. We used a silica-based cation exchange column with poly-butadiene-maleic acid functional group attached with an optimized mobile phase composition. The characteristic feature of this method is the short analysis time with a clear separation of NMP and the cationic drug molecule within a run-time of 30 min. The developed method overcomes the limitations of the USP method. This method describes the matrix elimination by choosing appropriate column and eluent condition. The method is tested for selectivity, linearity, limits of detection and quantification, accuracy, and precision and is suitable for continuous sample analysis.