Stereospecific high-performance liquid chromatographic assay of ketoprofen in human plasma and urine

A new liquid phase microextraction method-based reverse micelle for analysis of dexketoprofen in human plasma by HPLC-DAD

A new liquid phase microextraction method was developed by used reverse micelle-based coacervates as microextraction agents for the separation of dexketoprofen (DKT) from human plasma before its determination by high-performance liquid chromatography with photodiode-array detection (HPLC-DAD). The change in the concentration of dexketoprofen in the plasma of the male and female patients was successfully monitored by using this method. The proposed method involves the use of reverse micelles of decanoic acid (DA) are dispersed in tetrahydrofuran (THF) and aqueous system. After addition of the DA and THF to the aqueous sample phase, the formation of micelles of nano and molecular size was observed in an ultrasonic bath. The solution was centrifuged, and the DKT extracted into the DA phase was analyzed by HPLC-DAD. Some analytical parameters that important in the developed procedure were examined in detail. The limit of detection (LOD), the limit of quantification (LOQ), the intraday, and inter day relative standard deviation (RSD, %) of the developed method in the plasma sample were found to be 12.8 ng mL−1, 38.8 ng mL−1, 1.7 and 3.9%, respectively. Additional/recovery studies were performed in plasma samples with proposed method, and quantitative recoveries were obtained in the range of 97–100%. The developed microextraction method was applied to human plasma that taken from volunteer patients for the determination of DKT.

Graphical abstract

High-performance liquid chromatography method development and validation for simultaneous determination of five model compounds, antipyrine, metoprolol, ketoprofen, furosemide and phenol red, as a tool for the standardization of rat in situ intestinal permeability studies using timed wavelength detection

A simple, precise, accurate and rugged reversed-phase high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of five permeability model compounds, viz. antipyrine, metoprolol, ketoprofen, furosemide and phenol red. The method was intended to standardize rat in situ single-pass intestinal perfusion studies to assess the intestinal permeability of drugs in the market as well as new chemical entities. Optimum resolution was achieved by gradient elution on a Symmetry Shield C-18 analytical column with the mobile phase consisting of a mixture of aqueous potassium dihydrogen orthophosphate (pH 5.5; 0.01 m) and methanol at a flow rate of 1.5 mL/min. The retention times of antipyrine, metoprolol, ketoprofen, phenol red and furosemide were about 9, 12, 13, 16 and 17 min, respectively. Data acquisition was carried out using a photo diode array detector in the wavelength range 210-600 nm. Extraction of chromatograms was carried out by timed wavelength. Data obtained in all studies indicated that the method was suitable for the intended purpose. The validated method was found to be linear and precise in the working range. Suitability of storage under various conditions and freeze/thaw impact at cold temperature were established to ensure complete sample recovery without any stability issues. Recovery very close to the spiked amounts indicated that the method was highly accurate and suitable for use on routine basis.

Analytical and semipreparative resolution of enatiomers of albendazole sulfoxide by HPLC on amylose tris (3,5-dimethylphenylcarbamate) chiral stationary phases

Broad spectrum anthelmintic agent-albendazole sulfoxide (ABZSO) have been separated and semiprepared on amylose tris (3,5-dimethylphenylcarbamate) chiral stationary phases by HPLC using mobile phases contained with n-hexane and different alcohols. For analytical separation the influence of the nature and content of alcoholic modifiers on separation were systemically studied. Then, the analytical methods were scaled up to semipreparative loading to obtain small quantities (about 1 g) of both ABZSO enantiomers. Especially, different loading amounts were investigated for their effect on various parameters of semipreparative HPLC. In addition, optical rotation and circular dichroism (CD) of both ABZSO enantiomers collected were determined and single enantiomers were found stable in configuration for 1 year.

Role of biological matrices during the analysis of chiral drugs by liquid chromatography

The review article covers advances of chiral drugs analysis by high-performance liquid chromatography (HPLC) methods achieved during last 10 years. Emphasis is given to various aspects of influence of biological matrix in pharmacodynamics, pharmacokinetics, HPLC analysis. Discussed is composition of main biological matrices from the point of view of potential interferences to above-mentioned fields of study. Beside typical analytical approaches to chiral recognition in HPLC, sample pretreatment and/or clean-up by conventional extraction procedures, column switching (CSW) techniques using restricted access materials (RAMs), microdialysis (MCD) is discussed. Measurement of unbound drug concentration and discussion of column maintenance and remedy is an additional source of information and field where knowledge on complex properties and interactions of biological matrix is usefully applicable.

Voltammetric studies and assay of the anti-inflammatory drug ketoprofen in pharmaceutical formulation and human plasma at a mercury electrode

The electrochemical reduction of the anti-inflammatory drug ketoprofen was studied in a Britton-Robinson (B-R.) buffer series of pH 2–11 using dc-polarography, cyclic voltammetry, and coulometry techniques. The electrode reaction pathway of the drug at the dropping mercury electrode was proposed and discussed. A new adsorptive cathodic stripping square-wave voltammetric procedure was optimized for the assay of bulk drug in a B-R. buffer of pH 2.0. The peak current was linear with the drug concentration over the ranges 2 × 10–9 to 2 × 10–7 M of the bulk drug, using a 60 s accumulation time period at –0.6 V (vs. Ag/AgCl/KCls). The percentage recovery of the bulk drug was 99.57 ± 0.54 and a detection limit of 0.10 ng mL–1 was achieved. The proposed procedure was successfully applied for the assay of ketoprofen in pharmaceutical formulation (Ketofan®) and human plasma. The percentage recoveries were 99.66 ± 0.47 and 101.76 ± 0.64 in pharmaceutical formulation and human plasma, respectively. A detection limit of 0.14 ng mL–1 plasma was achieved which was below that reported in literature using the different analytical techniques.Key words: ketoprofen (Ketofan®) determination, polarography, cyclic voltammetry, adsorptive cathodic stripping square-wave voltammetry, human plasma.

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.

Clinical Pharmacokinetics of Dexketoprofen

Dexketoprofen trometamol is a water-soluble salt of the dextrorotatory enantiomer of the nonsteroidal anti-inflammatory drug (NSAID) ketoprofen. Racemic ketoprofen is used as an analgesic and an anti-inflammatory agent, and is one of the most potent in vitro inhibitors of prostaglandin synthesis. This effect is due to the (S)-(+)-enantiomer (dexketoprofen), while the (R)-(-)-enantiomer is devoid of such activity. The racemic ketoprofen exhibits little stereoselectivity in its pharmacokinetics. Relative bioavailability of oral dexketoprofen (12.5 and 25mg, respectively) is similar to that of oral racemic ketoprofen (25 and 50mg, respectively), as measured in all cases by the area under the concentration-time curve values for (S)-(+)-ketoprofen. Dexketoprofen trometamol, given as a tablet, is rapidly absorbed, with a time to maximum plasma concentration (tmax) of between 0.25 and 0.75 hours, whereas the tmax for the (S)-(+)-enantiomer after the racemic drug, administered as tablets or capsules prepared with the free acid, is between 0.5 and 3 hours. The drug does not accumulate significantly when administered as 25mg of free acid 3 times daily. The profile of absorption is changed when dexketoprofen is ingested with food, reducing both the rate of absorption (tmax) and the maximal plasma concentration. Dexketoprofen is strongly bound to plasma proteins, particularly albumin. The disposition of ketoprofen in synovial fluid does not appear to be stereoselective. Dexketoprofen trometamol is not involved in the accumulation of xenobiotics in fat tissues. It is eliminated following extensive biotransformation to inactive glucuroconjugated metabolites. No (R)-(-)-ketoprofen is found in the urine after administration of dexketoprofen, confirming the absence of bioinversion of the (S)-(+)-enantiomer in humans. Conjugates are excreted in urine, and virtually no drug is eliminated unchanged. The analgesic efficacy of the oral pure (S)-(+)-enantiomer is roughly similar to that observed after double dosages of the racemic compound. At doses above 7mg, dexketoprofen was significantly superior to placebo in patients with moderate to severe pain. A dose-response relationship between 12.5 and 25mg could be seen in the time-effects curves, the superiority of the 25mg dose being more a result of an extended duration of action than of an increase in peak analgesic effect. A plateau in the analgesic activity of dexketoprofen trometamol at the 25mg dose is suggested. The time to onset of pain relief appeared to be shorter in patients treated with dexketoprofen trometamol. The drug was well tolerated.

Determination of (R)- and (S)-ketoprofen in human plasma by liquid chromatography/tandem mass spectrometry following automated solid-phase extraction in the 96-well format

A sensitive and selective method was developed for the determination of (R)-ketoprofen ((R)-kt) and (S)-ketoprofen ((S)-kt) in human plasma using chiral liquid chromatography/tandem mass spectrometry (LC/MS/MS). Plasma samples spiked with stable-isotope-labeled [(13)C(1), (2)H(3)]-(R and S)-ketoprofen, for use as the internal standards, were prepared for analysis using automated solid-phase extraction (SPE) in the 96-well microtiter format. The enantiomers were separated on an (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid (Chirex 3005) 250x2.0 mm i.d. analytical column, equipped with a 30x2.0 mm i.d. guard column using isocratic mobile phase conditions. The (R)- and (S)-kt levels were quantifiable from 0.05 to 2500 ng ml(-1) by constructing two separate curves from calibration standards covering the same range. The first curve ranged from 0.05 to 100 and the second from 100 to 2500 ng ml(-1). A concentration of 0.05 ng ml(-1) of either enantiomer was easily detected using a 1 ml plasma sample volume. The average method accuracy, evaluated at four levels over an extended period, was better than +/-3% over the entire range. The precision for the same set of quality control samples ranged from 4.0 to 7.0 % RSD (n = 24). The method was applied to the evaluation of pharmacokinetic parameters in human plasma obtained from volunteers who received 25 mg of kt by peroral administration of Actron caplets or by topical administration of Oruvail gel.

HPLC determination of ketoprofen enantiomers in human serum using a nonporous octadecylsilane 1.5 microns column with hydroxypropyl beta-cyclodextrin as mobile phase additive

A sensitive and stereospecific high-performance liquid chromatography (HPLC) method for the quantitation of ketoprofen enantiomers in human serum was developed. The assay involves the use of an octadecylsilane solid-phase extraction for serum sample clean-up prior to HPLC analysis. Chromatographic resolution of the ketoprofen enantiomers was performed on a nonporous octyldecylsilane column with hydroxypropyl beta-cyclodextrin as the mobile phase additive. The composition of the mobile phase was 98:2 v/v aqueous 0.1% trifluoroacetic acid (TFA), pH 4.00 (adjusted with triethylamine (TEA))/acetonitrile containing 10 mM hydroxypropyl beta-cyclodextrin (beta-CD) at a flow rate of 0.8 ml min-1. Recoveries of R(-)-ketoprofen was 95.4 +/- 2.16% and for S(+)-ketoprofen 96.2 +/- 1.31%. Linear calibration curves were obtained in the range 0.025-15 micrograms ml-1 range for each enantiomer in serum. The detection limit based on a S/N = 3 ratio was 10 ng ml-1 for each enantiomer in serum with ultraviolet detection at 220 nm. The limit of quantitation for each enantiomer was 25 ng ml-1. Precision calculated as % relative standard deviation (%R.S.D.) and accuracy calculated as % error were in the range 0.2-5.2% and 0.3-2.2%, respectively, for the R enantiomer and 0.3-6.2 and 0.2-3.2%, respectively, for the S enantiomer.

Enantiospecific inhibition of ligature-induced periodontitis in beagles with topical (S)-ketoprofen

Systemic and topical administration of non-steroidal anti-inflammatory drugs (NSAIDs) has been shown to reduce periodontal disease progression in both animal models and human subjects. Our present research focuses on single enantiomers of these agents to examine whether enantiospecific therapy will be efficacious in slowing periodontitis. The purpose of this study was to evaluate the inhibitory effects of (S)-ketoprofen on experimentally induced alveolar bone loss in beagle dogs. 16, 18-month-old, female beagles were brought to optimal periodontal health over a 2-week pretreatment period. Experimental periodontitis was then induced by placing silk ligatures around premolar and molar teeth and by instituting a soft, plaque-promoting diet. At baseline, animals were randomized to 1 of 4 groups, consisting of 2x daily administration of (1) placebo dentifrice, (2) 0.3% (S)-ketoprofen dentifrice, (3) 3.0% (S)-ketoprofen dentifrice, or (4) 10.0 mg (S)-ketoprofen capsules (p.o.) over a 60 day treatment period. Standardized, periapical radiographs exposed at days 1 and 60 were analyzed by computer-assisted digital radiography in order to assess the rate of alveolar bone loss. Secondary outcomes included technetium 99m-tin-diphosphonate (99mTc-Sn-MDP) uptake and the gingival index. At baseline, no differences were observed among the groups for linear bone height or 99mTc-Sn-MDP uptake ratios. From days 1 to 60, cohorts differed significantly in terms of bone loss rates (p < 0.001). In particular, beagles treated with systemic or topical (S)-ketoprofen (0.3% or 3.0% dentifrices) exhibited significantly lower mean rates of bone loss compared to placebo treated beagles (p < 0.05). Group differences in mean radiopharmaceutical uptake ratio changes approached significance (ANOVA, p = 0.07), where animals treated with topical 0.3% (S)-ketoprofen demonstrated a reduction and other groups demonstrated elevations over the 60-day dosing period. Treatment cohorts did differ significantly with respect to changes in mean gingival indices (p < 0.05). Animals treated with 0.3% or 3.0% (S)-ketoprofen dentifrice exhibited significantly reduced elevations in gingival index scores as compared to placebo treated animals. These data provide evidence that enantiospecific therapy with (S)-ketoprofen, topically or systemically delivered, may alter the progression of periodontal disease in the beagle dog model.

Methods of analysis of chiral non-steroidal anti-inflammatory drugs

Although the analysis of the enantiomers of chiral non-steroidal anti-inflammatory drugs (NSAIDs) has been carried out for over 20 years, there often remains a deficit within the pharmaceutical and medical sciences to address this issue. Hence, despite world-wide therapeutic use of chiral NSAIDs the importance of stereoselectivity in pharmacokinetic, pharmacodynamic and pharmacological activity and disposition has often been ignored. This review presents both the general principles that allow separation of chiral NSAID enantiomers, and discusses both the advantages and disadvantages of the available chromatographic assay methods and procedures used to separately quantify NSAID enantiomers in biological matrices.

Quantification of ketoprofen enantiomers in human plasma based on solid-phase extraction and enantioselective column chromatography

An HPLC method for the quantification of ketoprofen enantiomers in human plasma is described. Following extraction with a disposable C18 solid-phase extraction column, separation of ketoprofen enantiomers and I.S. (3,4-dimethoxy benzoic acid) was achieved using a chiral column [Chirex 3005; (R)-1-naphthylglycine 3,5-dinitrobenzoic acid] with the mobile phase, 0.02 M ammonium acetate in methanol, set at a flow-rate of 1.2 ml/min. Baseline separation of ketoprofen enantiomers and I.S., free from interferences, was achieved in less than 20 min. The calibration curves (n = 14) were linear over the concentration range of 0.16 to 5.00 micrograms/ml per enantiomer [mean r2 of 0.999 for both enantiomers, root mean square error were 0.015 for R(-) and 0.013 for S(+)]. The inter-day coefficient of variation for duplicate analysis of spiked samples was less than 7% and the accuracy was more than 93% over the over the concentration range of 0.2 to 4.0 micrograms/ml for individual enantiomer using 1 ml of plasma sample. This method has been applied to a pharmacokinetic study from healthy human volunteers following the administration of a ketoprofen extended release product (200 mg). This method is simple, fast and should find wide application in monitoring pharmacokinetic studies of ketoprofen.

Recent applications of chromatographic resolution of enantiomers in pharmaceutical analysis

The principles and applications of chromatographic separation of enantiomers in pharmaceutical analysis have been reviewed. Several of recently reported enantioselective analysis of various racemic drugs using both the 'indirect' and 'direct' methods have been presented.