Chiral inversion of (R)-ketoprofen: influence of age and differing physiological status in dairy cattle

Chiral inversion of R(-) to S(+) ketoprofen in pigs

The S(+) enantiomer of ketoprofen is predominant in the plasma of pigs after administration of racemic ketoprofen, although the occurrence and extent of R(-)-to-S(+) inversion is uncertain. Plasma concentrations of both enantiomers were measured and percentages of S(+) ketoprofen were calculated at different time points after intravenous and oral dosing of pigs with 1.5mg/kg R(-) ketoprofen. S(+) ketoprofen was formed immediately after administration and concentrations exceeded R(-) concentrations after 1h. Absence of pre-systemic inversion was deduced from the lower S(+) percentages after oral administration. A rapid and increasing inversion, reaching a maximum of about 70%, occurred and appeared to be responsible for the predominance of S(+) ketoprofen in pig plasma after administration of the racemate.

Patient variation in veterinary medicine--part II--influence of physiological variables

In veterinary medicine, the characterization of a drug's pharmacokinetic properties is generally based upon data that are derived from studies that employ small groups of young healthy animals, often of a single breed. In Part I of the series, we focused on the potential influence of disease processes, stress, pregnancy and lactation on drug pharmacokinetics. In this Part II of the series, we consider other covariates, such as gender, heritable traits, age, body composition, and circadian rhythms. The impact of these factors with respect to predicting the relationship between dose and drug exposure characteristics within an animal population is illustrated through the use of Monte Carlo simulations. Ultimately, an appreciation of these potential influences will improve the prediction of situations when dose adjustments may be appropriate.

Chiral separation of ketoprofen on an achiral C8 column by HPLC using norvancomycin as chiral mobile phase additives

A high-performance liquid chromatographic method for chiral separation of ketoprofen racemate was developed. (R)- and (S)-ketoprofen enantiomers were separated on a Hypersil BDS C8 column (150 mm x 4.6 mm i.d., 5 microm) at 25 degrees C, using acetonitrile-triethylamine acetate (TEAA) buffer (pH 5.2, 20 mM) (35:65, v/v) containing 2.0 mM norvancomycin as the mobile phase. Effects of norvancomycin concentration, content of acetonitrile and TEAA buffer pH on the enantioseparation were investigated. The method was validated for linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). Calibration curves (r2 = 0.999) were constructed in the range of 2.01-200.8 microg ml(-1) for (S)-ketoprofen and 2.04-152.4 microg ml(-1) for (R)-ketoprofen, respectively. Repeatability (n = 5) showed less than 2% relative standard deviation (R.S.D.). LOD and LOQ for the two enantiomers were found to be 0.20 and 0.78 ng for (S)-ketoprofen, 0.20 and 0.86 ng for (R)-ketoprofen, respectively. Norvancomycin and vancomycin as chiral mobile phase additives (CMPAs) in the chiral separation showed similar abilities of enantioseparation. However, to obtain the optimum enantioseparation, a lower concentration of norvancomycin than that of vancomycin is required.

Pharmacokinetics and synovial fluid concentrations of flurbiprofen enantiomers in horses: chiral inversion

Flurbirpofen (FBP), a member of the 2-aryl propionate nonsteroidal anti-inflammatory drug class, has potent anti-inflammatory and analgesic properties. The commercial preparation is a racemic mixture of the R(-) and S(+) enantiomers of FBP. In this study, R(-) and S(+) FBP were used to investigate the metabolic chiral inversion. Each enantiomer was administered separately (0.25 mg/kg) and in a racemic mixture (0.5 mg/kg) intravenously to horses. Plasma and synovial concentration of each enantiomer was determined and the disposition of each was analyzed. After intravenous administration of R(-) FBP and S(+) FBP to horses no chiral inversion was detected. After the administration of the FBP racemate and individual enantiomers no differences were observed between pharmacokinetic parameters [t(1/2beta) (h), Cl (L/h.kg), AUC (microg.h/mL), Vss (L/kg) and MRT (h)] for R(-) and S(+) FBF. Synovial fluid concentrations of both FBP enantiomers were lower than plasma concentrations and no stereoselective differences were detected. These data indicate that the disposition of FBF in horses is not enantioselective and demonstrate a difference in the pharmacokinetic behavior of the enantiomers as compared with other 2-aryl-propionic acids, such as carprofen, ketoprofen and vedaprofen in the horse.

Resolution of enantiomers of ketoprofen by HPLC: a review

Today, a heightened awareness of the applicability of enantiomers in medicine and clinical practice has been gene-rated due to the continuous evolvement of the field of chirality. In this context, this article provides a review of separation of ketoprofen, an important drug, in a popular class of non-steroidal anti-inflammatory drugs (i.e. profens). This review highlights various methodologies, logistical considerations for separation and provides an exhaustive list of applications mainly focusing on the pharmacokinetic aspects. Clearly, the application of enantioselective methods for drug racemates paves the way to understand the in vivo behavior of individual enantiomer and hence an opportunity for an alternate and/or better option for treating the disease.