Chaotropic chromatography method development for the determination of aripiprazole and its impurities following analytical quality by design principles

In this paper, development of robust and reliable chaotropic chromatography method for the determination of aripiprazole and its impurities, following Analytical Quality by Design principles is presented. The efficient baseline separation and accurate determination of aripiprazole and its four impurities from tablets were set as Analytical Target Profile. In line with it, the influence of Critical Method Parameters (acetonitrile content, concentration of perchloric acid in water phase, and column temperature) on predefined Critical Method Attributes (separation of the critical pair of peaks, retention of the first and last eluting peak) was investigated with aid of the Central Composite Design. Further on Design Space, where Critical Method Parameters meet predefined acceptance limits with a high level of probability (π ≥ 85%), was computed as a result of performed Monte Carlo simulations. A normal operating conditions corresponding to 34% of acetonitrile, 66% of 42.5 mM perchloric acid, and column temperature at 35°C were selected from created Design Space. Robustness testing of the quantitative performances of the developed method was conducted combining Plackett-Burman design with alias matrix approach. Through the additional validation testing, reliability of the developed method for the use in the routine practice was completely confirmed.

Simultaneous HPLC determination of 22 components of essential oils; method robustness with experimental design

The aim of the present study was the development and validation of a simple, precise and specific reversed phase HPLC method for the simultaneous determination of 22 components present in different essential oils namely cinnamon bark oil, caraway oil and cardamom fruit oil. The chromatographic separation of all the components was achieved on Wakosil-II C18 column with mixture of 30 mM ammonium acetate buffer (pH 4.7), methanol and acetonitrile in different ratio as mobile phase in a ternary linear gradient mode. The calibration graphs plotted with five different concentrations of each component were linear with a regression coefficient R(2) >0.999. The limit of detection and limit of quantitation were estimated for all the components. Effect on analytical responses by small and deliberate variation of critical factors was examined by robustness testing with Design of Experiment employing Central Composite Design and established that this method was robust. The method was then validated for linearity, precision, accuracy, specificity and demonstrated to be applicable to the determination of the ingredients in commercial sample of essential oil.

Stability-indicating Reversed-phase Liquid Chromatographic Method for Simultaneous Determination of Losartan Potassium and Ramipril in Tablets

A stability-indicating reversed-phase liquid chromatographic method has been developed and validated for simultaneous determination of losartan potassium and ramipril. Separations were achieved using a C(18) column with mobile phase consisting of acetonitrile and (0.2% v/v, pH 2.5) aqueous trifluoroacetic acid (45:55, v/v) in isocratic mode at 1 ml/min flow rate. Column effluent was monitored at 210 nm using a UV detector. The method was validated for selectivity, linearity, accuracy, precision, sensitivity and robustness. Novel microwave-assisted forced degradation technique was employed for evaluation of selectivity. The method demonstrated excellent linearity for losartan potassium and ramipril with regression coefficients of 0.9999 and 0.9998, respectively. The linearity range was found to be 62.5-5000 ng/ml and 125-10,000 ng/ml with the mean percentage recoveries of 100.36% (±2.27) and 100.16% (±3.33) for losartan potassium and ramipril, respectively. In a robustness study, a full factorial design revealed that the analytical response remains unaffected by small variations in the critical chromatographic factors. The method was found to be sensitive with quantification limits of 44.30 and 79.93 ng/ml for losartan potassium and ramipril. The method was successfully employed for the determination of losartan potassium and ramipril in commercially available and in-house prepared tablets.