Development and validation of a high-throughput radiometric cyp2c9 inhibition assay using tritiated diclofenac.

Development and validation of a high throughput radiometric CYP3A4 inhibition assay using tritiated testosterone

Development and validation of a high-throughput radiometric CYP3A4/5 inhibition assay using tritiated testosterone.

A rapid and sensitive radiometric assay for assessing the potential of drugs to inhibit cytochrome P450 (P450) 3A4/5 in human liver microsomes is described. In contrast to the conventional testosterone 6beta-hydroxylation assay, the new method does not require high-performance liquid chromatography (HPLC) separation and mass spectrometry. The assay is based on the release of tritium as tritiate...

Cytochrome P450 inhibition using recombinant proteins and mass spectrometry/multiple reaction monitoring technology in a cassette incubation.

Detailed cytochrome P450 (P450) inhibition profiles are now required for the registration of novel molecular entities. This method uses combined substrates (phenacetin, diclofenac, S-mephenytoin, bufuralol, and midazolam) with combined recombinant P450 enzymes (CYP1A2, 2C9, 2C19, 2D6, and 3A4) in an attempt to limit interactions with other more minor P450s and associated reductases. Kinetic ana...

Comparison of "high throughput" micromethods for determination of cytochrome P450 activities with classical methods using HPLC for product identification.

Enzyme activities of the CYP enzymes (CYP3A4, CYP2C9 and CYP2A6) were determined using classical substrates (testosterone, diclofenac and coumarin, respectively) as well as with luminogenic or fluorogenic substrates in micromethod arrangement. The luciferin-based luminogenic substrates for CYP3A4 and CYP2C9 as well as coumarin in micromethod for assay of CYP2A6 activity gave results well compar...

Development and Validation of RP-HPLC-UV Method for Determination of Diclofenac Sodium Residues on Surfaces for Cleaning Validation

In recent years, cleaning validation has achieved a position of increasing in the pharmaceutical industry. It provides assurance to the cleaning procedure that ensures equipment is consistently cleaned from the product, detergent and microbial residues to an acceptable level to avoid cross-contamination and adulteration of drug product with other active ingredients. The aim of this study was to...