No abstract

Omeprazole (OMP), which is given for treatment in conjunction with a number of medications, is drawing increased attention for its capacity to reduce gastric acid formation. Commonly administered OMP-loaded dose forms include aspirin (ASN), diclofenac (DCF) and domperidone (DMP). As a result, a single liquid chromatographic approach, which can simultaneously determine OMP-ASN, OMP-DCF or OMP-DMP in commercial formulations was developed. On a reverse-phase Agilent Eclipse XBD C18 analytical column (4.6 × 150 mm; 3.5 (m), the requisite separation was accomplished utilizing a gradient flow of the mobile phase made up of a mixture of solvents A and B (50:50 v/v) and diode array detection at 272 nm. Where solvent A is acetonitrile:buffer-A:buffer-B (10:90:50 v/v/v) and solvent B is acetonitrile:buffer-A:buffer-B (90:10:50 v/v/v). The buffer-B is made up of an equal mixture of 100 mM acetic acid and 100 mM triethyl-amine with a final attained pH of 5.2, whereas the buffer-A is made up of 10 mM trifluoroacetic acid (pH adjusted to 2.2). According to ICH Q2(R1) criteria, the method had been validated and verified the senstivity of the proposed method with a linearity range of 0.5-20 mcg/mL for all the analytes. The established technique for concurrently quantifying OMP with DCF, ASN or DMP in commercial formulations can be regularly employed in the quality control laboratory in accordance with the validation conditions.

A simple and sensitive liquid chromatographic method along with tandem mass detection has been developed for the determination of levodopa and carbidopa in mice plasma. Owing the hydrophilic nature of both the analytes, a hydrophilic interaction liquid chromatography (HILIC) setup was used for their separation by a Merck (Germany) HILIC column (4.6 × 250 mm, 5 μm; 200 Å). The mobile phase composed equal proportion of water and acetonitrile both containing 0.1% formic acid at a flow rate of 1.4 mL/min to achieve rapid separation of the compounds. The column was coupled with a triple quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source using multi reaction monitoring (MRM) analysis. Since, recovery of both analytes in mice plasma posed significant challenge, a customized extraction procedure based on protein precipitation was adopted with best recovery. The optimized HILIC-MS/MS condition led to yield lower limit of quantification (LLOQ) of 9.9 ng/mL and 2.47 ng/mL for levodopa and carbidopa, respectively. The method was validated with suitable determination of correlation coefficient (R2: 0.997), precision (1.6-17.2%), accuracy (84.7-120%). Successful application of this validated method was accomplished for analytes in biological samples.