Predicted values for human total clearance of a variety of typical compounds with differently humanized-liver mouse plasma data.

Prediction of human pharmacokinetics is important in the preclinical stage. Values for total clearance of compounds from plasma should be one of the most important pharmacokinetic parameters for predictions. Although several physiological and empirical methods including single-species allometry for prediction of values for human clearance of compounds using humanized-liver mice have been reported, further improvement of prediction accuracies would be still expected. To optimize these approaches, we proposed methods for unbound intrinsic clearance in virtually 100% humanized-liver mouse by incorporating unbound plasma fractions of compounds in differently humanized-liver mice. Comparisons of prediction accuracies of values for human clearance of 15 model compounds were performed among our current physiological and previously reported models and single-species allometry using humanized-liver mice. Incorporation of the actual unbound plasma fractions of compounds and correction of residual mice hepatocyte in humanized-liver mice showed comparable prediction accuracy to that by single-species allometry. After exclusion of 3 compounds with large species differences in values of clearance and unbound plasma fractions between mice and humans out of 15 compounds, prediction accuracies were improved in the methods investigated. The previously and present reported physiological methods could show the good prediction accuracy of values for clearance of drugs from plasma.

Biofluid sampler: A new gateway for mail-in-analysis of whole blood samples.

The current study reports the development of a novel biofluid sampler (BFS) which is capable of sampling and sample preparation of whole blood without converting it into plasma or serum. The sampler can retain a whole blood sample from 10 to 1000 µL. Although the device shares the same working principle of dried blood spot (DBS) cards, it eliminates most of the technological shortcomings of DBS cards such as low maximum sample volume (~50 µL), sample inhomogeneity due to haematocrit, and poor physical adsorption driven analyte retention by incorporating sol-gel derived high efficiency, multi-functional sorbents on cellulose fabric substrate. The performance of BFS was tested via "Mail-in-Analysis" using three non-steroidal anti-inflammatory drugs (NSAIDs, ketoprofen, carprofen and diclofenac) as the test compounds. Human whole blood samples were fortified with the test compounds and sampled on conventional DBS cards and biofluid samplers (BFSs) in the USA. After drying the blood samples at room temperature, the samples were shipped to Italy for chromatographic analysis. The analytes were back-extracted from the DBS cards and BFSs using methanol and subsequently analysed using a short Symmetry C18 column (75 × 4.6 mm, 3.5 µm). Acetonitrile (ACN) and PBS (30 mM; pH = 2.5) were used as the mobile phases and the elution was performed under isocratic conditions. Compared to the classical dried blood spot cards (DBS), BFSs offer better performance in retaining the selected NSAIDs under conventional postal shipment. By substantially expanding the sampling capacity, eliminating most of the shortcomings of classical DBS cards and exploiting the better materials properties of sol-gel based functional sorbents, BFSs offer a new and profoundly simplified approach for whole blood sampling and analysis and is expected to change the current practice of blood analysis, allowing accurate quantitative analyses either in a local laboratory (on site) or using mail-in-analysis (off site) without compromising the quality of bioanalytical data.

Facile synthesis of magnetic carbon nanotubes derived from ZIF-67 and application to magnetic solid-phase extraction of profens from human serum.

Magnetic carbon nanotubes (CNTs) with encapsulated Co nanoparticles (Co@CNTs), was synthesized by exploiting the one-step pyrolysis strategy using ZIF-67 as template. The as-synthesized Co@CNTs is provided with the nanopores, a large specific surface area, and strong magnetic response. The obtained Co@CNTs was used as magnetic solid-phase extraction adsorbents to extract two profens including flurbiprofen and ketoprofen. The parameters of extraction efficiency, involving extraction time, sample solution volume, ionic strength, pH and the conditions of desorption efficiency, were optimized in detail. After determined by high-performance liquid chromatography-ultraviolet (HPLC-UV), the results evinced that Co@CNTs showed a high extraction efficiency with high enrichment factors of 832 and 672. The good linear range of both flurbiprofen and ketoprofen were all 5.0-1000 ng L-1, with the limit of detection were 0.60 ng L-1 and 0.70 ng L-1, respectively. Furthermore, a valid method for the extraction of flurbiprofen and ketoprofen from human serum was established. The spiking recoveries of two profens were between 86.74% and 97.22%, and the relative standard deviation was less than 6.55%. Co@CNTs can be repeatedly used at least 10 times, indicating its excellent regeneration and reusability. The results demonstrated that the Co@CNTs materials exhibits high enrichment ability and extraction efficiency, playing great promise in MSPE.

Combustion fabrication of magnetic porous carbon as a novel magnetic solid-phase extraction adsorbent for the determination of non-steroidal anti-inflammatory drugs.

Based on a one-step combustion fabrication approach, a novel magnetic porous carbon (MPC) was fabricated using filter paper as porous carbon source and iron salts as magnetic precursors. The textural properties of the MPC were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), vibration sample magnetometer (VSM) and nitrogen absorption-desorption isotherms. The as-prepared MPC possessed a high specific surface area, a microstructure comprised of mesopores and strong magnetic response. It was employed as a magnetic solid-phase extraction (MSPE) adsorbent for the determination of three non-steroidal anti-inflammatory drugs (NSAIDs) in environmental water and biological samples coupled with high performance liquid chromatography (HPLC). The main parameters affecting extraction efficiency were investigated in detail and a satisfactory performance was obtained under the optimal conditions. The calibration curves were linear over the concentration ranging from 1 to 1200 µg L-1 for ketoprofen (KET) and 2-1200 µg L-1 for naproxen (NAP) and diclofenac (DCF) with determination coefficients (R2) between 0.9995 and 0.9997. The limits of detection (LODs) were in the range of 0.2-0.4 µg L-1. The intra- and inter-day relative standard deviations (RSDs) were less than 4.03% and 8.72%, respectively. The recoveries ranged from 84.67% to 113.73% with RSDs less than 7.76%. The satisfactory results confirmed the great potential of the novel MPC adsorbent for the extraction of NSAIDs from complex sample matrices.

Ketoprofen and tramadol pharmacokinetics in patients with chronic pancreatitis.

OBJECTIVE: Chronic pancreatitis (CP) is a disease leading to irreversible pancreas dysfunction. One of the main symptoms is pain. Many patients require pharmacological therapy which should be started with paracetamol or, in selected groups of patients, ketoprofen. If the effect of ketoprofen is irrelevant, patients receive tramadol. The aim of this study is the evaluation of ketoprofen and tramadol pharmacokinetics (PK) in CP patients. PATIENTS AND METHODS: 36 patients were divided into two groups: I - receiving ketoprofen (n=18; mean [SD] age, 48.61 [13.32] years; weight, 73.28 [20.48] kg), II - receiving tramadol (n=18; mean [SD] age, 46.78 [10.28] years; weight, 74.22 [14.04] kg, and BMI (Body Mass Index), 24.61 [4.51] kg/m2). The plasma concentrations of ketoprofen and tramadol with its active metabolite M1 (0-desmethyltramadol) were measured with the validated high-performance liquid chromatography method. RESULTS: The main PK parameters for ketoprofen were as follows: Cmax (maximum plasma concentration), 3.41 [2.32] mg/L; AUC0-inf (area under the plasma concentration-time curve from time zero to infinity), 10.45 [5.57] mg⋅h/L; tmax (time to first occurrence of Cmax), 1.94 [1.25] h; Cl (clearance), 0.199 [0.165] L/kg·h, and Vd/kg (volume of distribution per kilogram of body weight), 0.71 [0.58] L/kg. The main PK parameters for TRM and M1 were as follows: Cmax, 226.4 [80.5] and 55.6 [23] ng/mL; AUC0-inf, 1903.3 [874.8] and 790.4 [512.4] ng⋅h/mL; tmax, 1.78 [0.73] and 2.67 [1.19] h, respectively. CONCLUSIONS: Chronic pancreatitis led to a decrease in the total amount of absorbed ketoprofen. Consequently, the analgesic effect of the drug may be weaker. Cmax of tramadol for most CP patients was within the therapeutic range associated with its analgesic activity. M1/TRM ratios for Cmax and AUC were unchanged.

Dried blood spots and parallel artificial liquid membrane extraction-A simple combination of microsampling and microextraction.

In this paper, parallel artificial liquid membrane extraction (PALME) was used for the first time to clean-up dried blood spots (DBS) prior to ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Fundamental studies exploring amongst others desorption from the DBS in alkaline or acidic aqueous conditions, total extraction time and absolute recoveries were executed. Desorption and PALME were performed using a set of two 96-well plates, one of them housing the sample and the other comprising the supported liquid membrane (SLM) and the acceptor solution. In one procedure, amitriptyline and quetiapine (basic model analytes) were desorbed from the DBS using 250 µL of 10 mM sodium hydroxide solution (aqueous), and subsequently extracted through the SLM consisting of 4 µL of 1% trioctylamine in dodecyl acetate, and further into an acceptor solution consisting of 50 µL of 20 mM formic acid. In a second procedure, ketoprofen, fenoprofen, flurbiprofen, and ibuprofen (acidic model analytes) were desorbed from the DBS into 20 mM formic acid, extracted through an SLM with dihexyl ether, and further into an acceptor solution of 25 mM ammonia. Within 60 min of PALME, both basic and acidic model analytes were effectively desorbed from the DBS and extracted into the acceptor solution, which was injected directly into the analytical instrument. Recoveries between 63 and 85% for the six model analytes were obtained. PALME provided excellent clean-up from the DBS samples, and acceptor solutions were free from phospholipids. Linearity was obtained with r2 > 0.99 for five of the six analytes. Accuracy, precision and UHPLC-MS/MS matrix effects were in accordance with the European Medicines Agency (EMA) guideline. Based on these experiments, PALME shows great potential for future processing of DBS in a short and simple way, and with the presented setup, up to 96 DBS can be processed within a total extraction time of 60 min.

From concept to in vivo testing: Microcontainers for oral drug delivery.

This work explores the potential of polymeric micrometer sized devices (microcontainers) as oral drug delivery systems (DDS). Arrays of detachable microcontainers (D-MCs) were fabricated on a sacrificial layer to improve the handling and facilitate the collection of individual D-MCs. A model drug, ketoprofen, was loaded into the microcontainers using supercritical CO2 impregnation, followed by deposition of an enteric coating to protect the drug from the harsh gastric environment and to provide a fast release in the intestine. In vitro, in vivo and ex vivo studies were performed to assess the viability of the D-MCs as oral DDS. D-MCs improved the relative oral bioavailability by 180% within 4h, and increased the absorption rate by 2.4 times compared to the control. This work represents a significant step forward in the translation of these devices from laboratory to clinic.

Pharmacokinetic and bioequivalence studies of fast dispersible ketoprofen tablets in healthy volunteers.

In the present study the pharmacokinetic and bioequivalence parameter of Ketoprofen 100 mg fast dispersible tablets (test) were measured with marketed (reference) product. This study was accomplished following FDA guidance. A single dose, open labeled, cross over (two way), randomized study design was used to conduct investigation on 12 Pakistani healthy volunteers. At various time points blood samples (10mL) were drawn i.e. at 0.25, 0.5, 1, 1.5, 2, 3, 4, 8, 12 and 13hr. Plasma was then separated and ketoprofen concentrations were estimated by validated HPLC technique using LC 20A pump (Shimadzu Corp, Japan) and Spectrophotometric SPD-20Adetector (Shimadzu Corp, Japan). Ketoprofen concentrations were then analyzed by KineticaTM 4.4.1 (Thermo electron corp, USA) to estimate various compartmental and noncompartmental pharmacokinetic parameters. Various parameters of bioequivalence including AUCtot, AUC0-oo, AUClast, Tmaxcalc and Cmaxcalcw ere compared using ANOVA method (two way). For log and non-log transformed data the 90% confidence interval values for AUC oo0-oo, (1.0087-1.0704; 1.0099-1.0714), AUC tot , (0.95482- 1.0093; 0.95486-1.0098), AUClast (0.93373-0.98605; 0.93404-0.98603), Cmaxcalc (0.92978-0.9955; 0.92962-0.99663) and Tmaxcalc (0.89019-0.94116; 0.89095-0.94288) for test and reference products respectively. Results were found to be within the FDA satisfactory range. For the results verification, Schuirman's one sided t test was used. SPSS 17.0 (SPSS Inc.) was utilized for the determination of wilcoxon sign rank test. Results showed no carry over effect after first study period. Also test product met the regulatory criteria for bioequivalence with the reference product. Both the formulations were well tolerated.

Stereoselective Pharmacokinetics of Ketoprofen After Oral Administration of Modified-Release Formulations in Caucasian Healthy Subjects.

BACKGROUND AND OBJECTIVES: Ketoprofen, a potent nonsteroidal anti-inflammatory drug, is clinically administered as a racemic mixture. One of the possible metabolism routes of ketoprofen is the inversion of the R- to S-enantiomer in the gastrointestinal tract. Ketoprofen, as a weak acid drug, might undergo recirculation through pancreatic/intestinal juices. The aim of the work was to investigate if a plasma-gastrointestinal tract recirculation of ketoprofen could explain its R-to-S chiral inversion after the oral administration of two modified-release formulations: a gastro-resistant delayed-release tablet (Reference) and an extended-release-plus-immediate-release bilayer tablet (Test). METHODS: Sixteen healthy Caucasian volunteers (eight women and eight men) participated in a ketoprofen bioequivalence study. Both formulations were administered with and without food. In both cases, standard meals were given throughout the experiment. R- and S-enantiomers were measured separately using a validated HPLC-UV chiral method. Mean concentration-time profiles of ketoprofen enantiomers in plasma were obtained for men and women. Area under the plasma concentration-time curve, maximum ketoprofen plasma concentration, and time-to-peak were also computed for both isomers, both modes of administration, and both sexes. S/R concentration ratio was assessed as an indicator of enantiomer chiral inversion rate. RESULTS: Differences in the pharmacokinetics of S- and R-ketoprofen enantiomers were found after the Test administration. S-Ketoprofen presented a lower plasma exposure compared to R-enantiomer. However, the S/R concentration ratio increased 1 h (in men) and 2 h (in women) after meal intakes. This was related to pancreatic and/or intestinal and/or biliary secretions of the drug, followed by reabsorption and conversion of the R- to the S-isomer. The lower intestinal pH reported for men would lead to a higher oral bioavailability of the Test formulation and a higher reabsorption of both ketoprofen isomers in this sex. Hence, a higher rise of the S/R concentration ratio could be observed in men. No significant differences between isomers exposure were detected in both sexes after the Reference administration. Different lag times were observed after fed and fasting administration of this formulation; however, drug absorption coincided with food ingestion. Then, drug recirculation affected the S/R ratio from the beginning of drug exposure, minimizing the difference between isomers disposition. CONCLUSIONS: R-to-S conversion rate could be mainly associated with several passages of the drug through the intestinal mucosa. The concentration-time profiles of ketoprofen in plasma after the administration of both formulations evidenced R-to-S conversion of recirculating drug following meal intakes.

A Dose-Finding Study of Dexketoprofen in Patients Undergoing Laparoscopic Cholecystectomy: A Randomized Clinical Trial on Effects on the Analgesic Concentration of Oxycodone.

BACKGROUND: Dexketoprofen has been shown to provide efficient analgesia and an opioid-sparing effect after orthopedic surgery. In this dose-finding study, we evaluated the analgesic efficacy and opioid-sparing effect of dexketoprofen administered intravenously (i.v.) after laparoscopic cholecystectomy (LCC). METHODS: Twenty-four patients undergoing LCC were randomized to receive dexketoprofen 10 or 50 mg i.v. 15 min before the end of the surgery. Subjects were provided with 0.2 mg/kg of oxycodone at anesthesia induction. In the recovery room, pain was assessed with an 11-point numerical rating scale (NRS; score of 0 = no pain, score of 10 = most severe pain) every 10 min. When the NRS score was ≥3/10 at rest or ≥5/10 at wound compression, a plasma sample was taken for analysis of oxycodone [to determine the minimum effective concentration (MEC)], its metabolites, and dexketoprofen. After that, subjects were titrated with oxycodone 2 or 3 mg i.v. every 10 min until the NRS score was <3/10 at rest and <5/10 at wound compression. At this point, a second plasma sample was taken for analysis of oxycodone [minimum effective analgesic concentration (MEAC)], its metabolites, and dexketoprofen. RESULTS: At the onset of pain, the plasma oxycodone concentrations (MEC) were similar in the two groups: median 60 ng/mL (range 37-73) in the 10 mg group and median 52 ng/mL (range 24-79) in the 50 mg group. At the time of pain relief, the MEACs were 98 ng/mL (range 59-150) in the 10 mg group and 80 ng/mL (range 45-128) in the 50 mg group. The total doses of oxycodone needed to achieve pain relief were similar: 0.11 mg/kg (range 0-0.33) in the 10 mg group and 0.08 mg/kg (range 0-0.24) in the 50 mg group. Eleven subjects developed mild desaturation or a decreased respiratory rate after oxycodone titration. CONCLUSION: In the present double-blinded, randomized clinical trial, the need for a rescue opioid analgesic, oxycodone, was similar with the two dose levels of dexketoprofen-10 and 50 mg i.v.-after LCC.

Randomised trial of the bioavailability and efficacy of orally administered flunixin, carprofen and ketoprofen in a pain model in sheep.

OBJECTIVE: To determine the efficacy and bioavailability of non-steroidal anti-inflammatory drugs (NSAIDs) when administered orally to sheep. DESIGN: Randomised experimental design with four treatment groups: three NSAID groups and one control group (n = 10/group). The study animals were 40 18-month-old Merino ewes with an average weight of 31.4 ± 0.5 kg. METHODS: Treatment was given orally at 24 h intervals for 6 days at dose rates expected to achieve therapeutic levels in sheep: carprofen (8.0 mg/kg), ketoprofen (8.0 mg/kg) and flunixin (4.0 mg/kg). Oil of turpentine (0.1 mL) was injected into a forelimb of each sheep to induce inflammation and pain; responses (force plate pressure, skin temperature, limb circumference, haematology and plasma cortisol) were measured at 0, 3, 6, 9, 12, 24, 36, 48, 72 and 96 h post-injection. NSAID concentrations were determined by ultra-high-pressure liquid chromatography. RESULTS: The NSAIDs were detectable in ovine plasma 2 h after oral administration, with average concentrations of 4.5-8.4 µg/mL for ketoprofen, 2.6-4.1 µg/mL for flunixin and 30-80 µg/mL for carprofen. NSAID concentrations dropped 24 h after administration. Pain response to an oil of turpentine injection was assessed using the measures applied but no effect of the NSAIDs was observed. Although this pain model has been previously validated, the responses observed in this study differed from those in the previous study. CONCLUSIONS AND CLINICAL RELEVANCE: The three NSAIDs reached inferred therapeutic concentrations in blood at 2 h after oral administration. The oil of turpentine lameness model may need further validation.

Fast ibuprofen, ketoprofen and naproxen simultaneous determination in human serum for clinical toxicology by GC-FID.

OBJECTIVES: The aim of this study was to develop and validate a gas chromatographic method with flame ionization detection (GC-FID) for the measurement of ibuprofen, naproxen and ketoprofen for clinical toxicology purposes. DESIGN AND METHODS: 100µL of plasma was treated with methyl chloroformate and derivatized analytes were extracted with hexane. Optimal conditions of the derivatization procedure have been found using the experimental chemometric design (face-centered central composite design). The selectivity and efficiency of the procedure was confirmed by GC-MS. RESULTS: The assay was linear in the concentration range of 10-400µgmL(-1), with adequate accuracy and precision for GC-FID (98-106.7%, CV≤9.1%, respectively) and for GC-MS (99.3-105.5%, CV≤9.2%, respectively). CONCLUSION: The entire sample preparation procedure is completed within 5 min and the quantitative results are available within 35 min. The method was successfully applied to quantify the selected compounds in serum of patients from emergency units.

Pharmacokinetics of the individual enantiomer S-(+)-ketoprofen after intravenous and oral administration in dogs at two dose levels.

The pharmacokinetic of the individual S-(+)-enantiomer of ketoprofen, S-(+)-ketoprofen, after intravenous (IV) and oral (PO) administration was determined in six dogs at 1 and 3 mg/kg. Plasma concentrations were determined by high performance liquid chromatography with ultraviolet detection. The concentration-time curves were analyzed by non-compartmental methods. Steady-state volume of distribution (Vss) and clearance (Cl) of S-(+)-ketoprofen after IV administration were 0.22 ± 0.07 and 0.19 ± 0.03 L/kg, and 0.10 ± 0.02 and 0.09 ± 0.01 L/h/kg, at 1 and 3 mg/kg, respectively. Following PO administration, S-(+)-ketoprofen achieved maximum plasma concentrations of 4.91 ± 0.76 and 12.47 ± 0.62 µg/ml, at two dose levels, respectively. The absolute bioavailability after PO route was 88.66 ± 12.95% and 85.36 ± 13.90%, respectively.

Relationship between blood levels and the anti-hyperalgesic effect of ketoprofen in the rat.

The relationship between blood levels of ketoprofen and its anti-hyperalgesic effects was examined in rat using the carrageenan-evoked thermal hyperalgesia model. Female adult Wistar rats were injected with carrageenan into the plantar surface of the right hind paw. Immediately after, rats were administered with ketoprofen po and hindpaw withdrawal latency measured and micro-whole blood samples were obtained over six hours via a cannula inserted in the caudal artery. Ketoprofen levels were measured by HPLC. Ketoprofen concentration increased in a dose-dependent manner and was reflected in dose-dependent anti-hyperalgesic effect. The pharmacokinetic and pharmacodynamic parameters expressed as mean ± s.e.m. following administration of 1, 3.2, and 10 mg/kg ketoprofen were: Cmax 1.27 ± 0.08, 3.44 ± 0.20 and 11.76 ± 0.81 µg/mL; AUClast 4.16 ± 0.17, 11.63 ± 0.65 and 28.15 ± 1.32 µg h/mL; and Emax observed (AUCE ): 65.41 ± 7.79, 92.06 ± 6.46 and 98.42 ± 7.53%. A direct relationship between blood concentrations and the anti-hyperalgesic effect of ketoprofen followed a maximum effect model equation. The results indicate that the anti-hyperalgesic effect of ketoprofen in the carrageenan pain model can be predicted by the pharmacokinetic properties of ketoprofen.

Differential pharmacokinetics and pharmacokinetic/pharmacodynamic modelling of robenacoxib and ketoprofen in a feline model of inflammation.

Robenacoxib and ketoprofen are acidic nonsteroidal anti-inflammatory drugs (NSAIDs). Both are licensed for once daily administration in the cat, despite having short blood half-lives. This study reports the pharmacokinetic/pharmacodynamic (PK/PD) modelling of each drug in a feline model of inflammation. Eight cats were enrolled in a randomized, controlled, three-period cross-over study. In each period, sterile inflammation was induced by the injection of carrageenan into a subcutaneously implanted tissue cage, immediately before the subcutaneous injection of robenacoxib (2 mg/kg), ketoprofen (2 mg/kg) or placebo. Blood samples were taken for the determination of drug and serum thromboxane (Tx)B2 concentrations (measuring COX-1 activity). Tissue cage exudate samples were obtained for drug and prostaglandin (PG)E2 concentrations (measuring COX-2 activity). Individual animal pharmacokinetic and pharmacodynamic parameters for COX-1 and COX-2 inhibition were generated by PK/PD modelling. S(+) ketoprofen clearance scaled by bioavailability (CL/F) was 0.114 L/kg/h (elimination half-life = 1.62 h). For robenacoxib, blood CL/F was 0.684 L/kg/h (elimination half-life = 1.13 h). Exudate elimination half-lives were 25.9 and 41.5 h for S(+) ketoprofen and robenacoxib, respectively. Both drugs reduced exudate PGE2 concentration significantly between 6 and 36 h. Ketoprofen significantly suppressed (>97%) serum TxB2 between 4 min and 24 h, whereas suppression was mild and transient with robenacoxib. In vivo IC50 COX-1/IC50 COX-2 ratios were 66.9:1 for robenacoxib and 1:107 for S(+) ketoprofen. The carboxylic acid nature of both drugs may contribute to the prolonged COX-2 inhibition in exudate, despite short half-lives in blood.

HPLC method with solid-phase extraction for determination of (R)- and (S)-ketoprofen in plasma without caffeine interference: application to pharmacokinetic studies in rats.

A fast and reproducible high-performance liquid chromatography method has been developed for the determination of (R)- and (S)-ketoprofen. Ketoprofen enantiomers were determined in plasma samples (50 µL), after solid-phase extraction, using diclofenac as internal standard. Analyses were performed on a (S, S)-Whelk-O 1 stainless steel column (5 µm, 250 × 4.6 mm) using hexane-ethanol-acetic acid (93:7:0.5, v/v/v) as the mobile phase and detection at 254 nm. The method was selective for ketoprofen enantiomers in the presence of caffeine and endogenous plasma compounds. Standard curves were linear (R(2) > 0.999) over the concentration range of 0.25-12.50 and 0.25 µg/mL was taken as the limit of quantification. The intra- and interday precision (relative standard deviation) values were <15.0% and the accuracy (relative error) was within ±12.0% at 1.0, 5.0 and 10.0 µg/mL. Enantiomer recoveries yielded 100.0 ± 15%. No significant differences were determined in plasma samples stored at room temperature for 24.0 h, after two freeze-thaw cycles, and between 0 and 4 weeks at -20°C (P > 0.05). The validated method was successfully applied in determination of (S)-ketoprofen in Wistar rats after oral administration of 3.2 mg/kg of (S)-ketoprofen alone or 3.2 mg/kg of (S)-ketoprofen + 17.8 mg/kg of caffeine.

Enantiospecific ketoprofen concentrations in plasma after oral and intramuscular administration in growing pigs.

BACKGROUND: Ketoprofen is a non-steroidal anti-inflammatory drug which has been widely used for domestic animals. Orally administered racemic ketoprofen has been reported to be absorbed well in pigs, and bioavailability was almost complete. The objectives of this study were to analyze R- and S-ketoprofen concentrations in plasma after oral (PO) and intra muscular (IM) routes of administration, and to assess the relative bioavailability of racemic ketoprofen for both enantiomers between those routes of administration in growing pigs. METHODS: Eleven pigs received racemic ketoprofen at dose rates of 4 mg/kg PO and 3 mg/kg IM in a randomized, crossover design with a 6-day washout period. Enantiomers were separated on a chiral column and their concentrations were determined by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated and relative bioavailability (Frel) was determined for S and R -ketoprofen. RESULTS: S-ketoprofen was the predominant enantiomer in pig plasma after administration of the racemic mixture via both routes. The mean (± SD) maximum S-ketoprofen concentration in plasma (7.42 mg/L ± 2.35 in PO and 7.32 mg/L ± 0.75 in IM) was more than twice as high as that of R-ketoprofen (2.55 mg/L ± 0.99 in PO and 3.23 mg/L ± 0.70 in IM), and the terminal half-life was three times longer for S-ketoprofen (3.40 h ± 0.91 in PO and 2.89 h ± 0.85 in IM) than R-ketoprofen (1.1 h ± 0.90 in PO and 0.75 h ± 0.48 in IM). The mean (± SD) relative bioavailability (PO compared to IM) was 83 ± 20% and 63 ± 23% for S-ketoprofen and R-ketoprofen, respectively. CONCLUSIONS: Although some minor differences were detected in the ketoprofen enantiomer concentrations in plasma after PO and IM administration, they are probably not relevant in clinical use. Thus, the pharmacological effects of racemic ketoprofen should be comparable after intramuscular and oral routes of administration in growing pigs.

Does ketoprofen or diclofenac pose the lowest risk to fish?

Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 µg/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 µg/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6 ‰ of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar.