Kiran R. Patil

VALIDATED CHIRAL LC METHOD FOR DEXRABEPRAZOLE ON REVERSE PHASE AMYLOSE BASED STATIONARY PHASE

A simple, rapid and robust LC method was developed and validated for the enantiomeric separation of dexrabeprazole in bulk drug and formulation. The enantiomers of dexrabeprazole were resolved on a Chiralpak AD-RH (amylose based stationary phase) column using a mobile phase consisting of water: acetonitrile (50:50, v/v) at a flow rate of 0.5 ml min -1. The resolution between the enantiomers was found to be more than 1.5 in optimized method. The developed method was extensively validated and proved to be robust. The calibration curve for (S)-enantiomer showed excellent linearity over the concentration range of 0.05 µg ml-1 (LOQ) to 1 µg ml-1. The limit of detection and limit of quantification for (S)-enantiomer were 0.015 µg ml -1 and 0.05 µg ml-1, respectively. The percentage recovery of the (S)-enantiomer ranged between 97 to 101 % in bulk drug samples of dexrabeprazole. The proposed method was found to be suitable and accurate for quantitative determination of (S)-enantiomer in bulk drug substance.

Simultaneous determination of zidebactam and cefepime in dog plasma by LC-MS/MS and its application to pre-clinical pharmacokinetic study

A precise and accurate liquid chromatography-tandem mass spectrometric (LC-MS/MS) bioanalytical method has been developed and validated for the simultaneous quantification of zidebactam (ZID) and cefepime (FEP) in dog plasma. Ceftazidime was used as an internal standard. Protein precipitation method was used as sample preparation approach. The calibration curve obtained was linear (r ≥ 0.99) over the concentration range 0.156-80 μg/mL for ZID and 0.312-160 μg/mL for FEP. The method was validated as per US Food and Drug Administration guidelines and the results met the acceptance criteria. A run time of 3.5 min for each sample made it possible to analyze the maximum number of samples per day. The proposed method was successfully applied for pharmacokinetic study in beagle dogs.

STABILITY - INDICATING LC METHOD FOR THE SIMULTANEOUS DETERMINATION OF TELMISARTAN AND HYDROCHLOROTHIAZIDE IN DOSAGE FORM

ABSTRACT A simple, rapid, and precise method is developed for the quantitative simultaneous estimation of telmisartan and hydrochlorothiazide in combined pharmaceutical dosage form. A chromatographic separation of the two drugs was achieved with an ACE 5 C 18 (250 x 4.6 mm) analytical column using buffer-acetonitrile (55:45 v/v ). The buffer used in mobile phase contains 0.1M sodium perchlorate monohydrate in double distilled water pH adjusted 3.0 with trifluoroacetic acid. The instrumental settings are flow rate of 1.5 ml min -1 , column temperature at 30 o C, and detector wavelength of 215 nm using a photodiode array detector. The resolution between hydrochlorothiazide and telmisartan founds to be more than 5. Theoretical plates for hydrochlorothiazide and telmisartan were 13022 and 6629 respectively. Tailing factor for hydrochlorothiazide and telmisartan was 0.94 and 0.98 respectively. Telmisartan, hydrochlorothiazide and their combination drug products stressed samples were analysed by the proposed method. The described method shows excellent linearity over a range of 70 to 130% of target analyte concentration. The correlation coefficient for telmisartan and hydrochlorothiazide are 0.9999. The relative standard deviation for six measurements in two sets of each drug in tablets is always less than 2%. The proposed method was found to be suitable and accurate for quantitative determination and stability study of telmisartan and hydrochlorothiazide in pharmaceutical preparations.

Development and Validation of the Chiral Liquid Chromatography Method for Separation of Enantiomeric Impurity in Novel Oxazolidinone Antibacterial Agent WCK 4086

A highly stereo-specific liquid chromatographic method was developed and validated for the quantification of enantiomeric impurity (R-enantiomer) in novel oxazolidinone antibacterial agent (WCK 4086), a drug substance. The separation was achieved on Chiralpak AD-H (amylose-based chiral stationary phase) using a mobile phase consisting of n-hexane:2-propanol:methanol:trifluoroacetic acid (80:10:10:0.4, v/v/v/v) at a flow rate of 1.0 mL min-1. Chromatographic resolution between two enantiomers was found to be more than 2.0. Method was extensively validated for the quantification of R-enantiomer in WCK 4086 and proved to be robust. Method was found to be highly specific as all other related impurities were separated from the enantiomers. The calibration curve for R-enantiomer showed an excellent linearity over the concentration range of 1-5 μg mL-1. Limit of quantitation (LOQ) and limit of detection (LOD) for R-enantiomer were 0.009 μg and 0.003 μg, respectively. Average recovery of the R-enantiomer was in the range of 94.55-109.67%. Analytical solutions were found to be stable up to 70 h at room temperature. Developed method was found to be specific, sensitive, precise and accurate for quantitative determination of R-enantiomer in WCK 4086 and useful for controlling the enantiomeric impurity in drug substance used for preclinical studies.