Application of ultra-sensitive GC-QqQ-MS/MS (MRM) method for the determination of diclofenac in whole blood samples without derivatization.

Diclofenac is one of the most frequently prescribed nonsteroidal anti-inflammatory drugs (NSAID) worldwide. Although it is considered a relatively safe drug, it exhibits high toxicity to some animal populations (e.g., raptors). An ultra-sensitive gas chromatography method, coupled with tandem mass spectrometry (GC-QqQ-MS/MS) with an electron impact (EI) ionization source for diclofenac determination in whole blood samples without a derivatization procedure, was developed and fully validated. Diclofenac-d4 was used as an internal standard. The determination of analytes was performed in the multiple-reaction monitoring (MRM) mode. The method was linear in the range from 0.1 to 200 ng/mL, with a coefficient of determination of 0.999 (R2). The lower limit of quantification was 0.1 ng/mL, and the detection limit was 0.05 ng/mL. The blood samples (200 µL) were prepared by liquid-liquid extraction (pH3) with ethyl acetate. The intra- and interday accuracies and precisions did not exceed 15%. Recovery and matrix effect values were in the range of 92.2-105.9% and -7.8 to 5.9%, respectively. The developed method was applied in authentic blood samples. A simple and precise GC-QqQ-MS/MS method can be potentially applied for routine clinical, toxicological and environmental analysis.

Physiologically-based pharmacokinetic modeling to support bioequivalence and approval of generic products: A case for diclofenac sodium topical gel, 1.

Establishing bioequivalence (BE) for dermatological drug products by conducting comparative clinical end point studies can be costly and the studies may not be sufficiently sensitive to detect certain formulation differences. Quantitative methods and modeling, such as physiologically-based pharmacokinetic (PBPK) modeling, can support alternative BE approaches with reduced or no human testing. To enable PBPK modeling for regulatory decision making, models should be sufficiently verified and validated (V&V) for the intended purpose. This report illustrates the US Food and Drug Administration (FDA) approval of a generic diclofenac sodium topical gel that was based on a totality of evidence, including qualitative and quantitative sameness and physical and structural similarity to the reference product, an in vivo BE study with PK end points, and, more importantly, for the purposes of this report, a virtual BE assessment leveraging dermal PBPK modeling and simulation instead of a comparative clinical end point study in patients. The modeling approach characterized the relationship between systemic (plasma) and local (skin and synovial fluid) diclofenac exposure and demonstrated BE between the generic and reference products at the presumed site of action. Based on the fit-for-purpose modeling principle, the V&V process involved assessing observed data of diclofenac concentrations in skin tissues and plasma, and the overall performance of the modeling platform for relevant products. Using this case as an example, this report provides current scientific considerations on good practices for model V&V and the establishment of BE for dermatological drug products when leveraging PBPK modeling and simulation for regulatory decision making.

Formulation of Aceclofenac Tablets Using Nanosuspension as Granulating Agent: An Attempt to Enhance Dissolution Rate and Oral Bioavailability.

PURPOSE: The aim of the studies was to fabricate aceclofenac (AC) tablets using nanosuspension as granulating fluid to boost its rate of in vitro dissolution and eventually its oral bioavailability. METHODS: The optimized nanosuspension with particle size of 112±2.01 nm was fabricated using HPMC 1% (w/v), PVP-K30 1% (w/v) and SLS 0.12% (w/v) at 400 watts of ultrasonication energy for 15 min duration and 3 sec pause. Then, the optimized aceclofenac nanosuspension was used as granulating fluid for aceclofenac tablets formulation. The characterization was performed using Malvern zetasizer, SEM, TEM, DSC and P-XRD. The granules were evaluated for the bulk and tapped densities, Hausner's ratio, angle of repose and their resulted values were found within limit. The prepared tablets were tested for average weight, hardness, friability, disintegration, dissolution and in vivo bioavailability in rabbits. RESULTS: The in vitro dissolution data showed the boosted rate of nanosuspension-based tablets compared to the microsuspension-based tablets. The in vivo bioavailability (in rabbits model) of aceclofenac nanosuspension-based tablets (ACN-1, ACN-2) proved an improved absorption as in comparison to the marketed formulation. The Cmax and AUC0→24 of ACN-1 and ACN-2 were 1.53-fold, 1.48-fold and 2.23-fold, 2.0-fold greater than that of the marketed drug, and were 1.74-fold, 1.68-fold and 2.3-fold, 2.21-fold greater in comparison to raw drug. CONCLUSION: This boosted in vitro and in vivo bioavailability may be attributed to reduced particle size of aceclofenac nanoformulations used in tablets. Finally, this will result in faster absorption of these fabricated tablets.

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.

Liquid chromatographic method for simultaneous determination of alprazolam with NSAIDs in bulk drug, pharmaceutical formulation and human serum.

High performance liquid chromatography with UV/vis detection was optimized and validated for simultaneous quantification of alprazolam with celecoxib and diclofenac sodium in pharmaceutical formulation and human serum. Chromatographic separation was achieved at detection wavelength of 230 nm on Shimadzu Shim-pack CLC-ODS (M) 25M column employing 80:20 (v/v) methanol: water (pH 3.5) as mobile phase with elution rate 1.0mL min-1. Analytes were quantified in the ranges 0.2-15, 0.3-20 and 0.6-40 µg mL-1 with detection limits 19.76, 17.29 and 11.83ng mL-1 respectively. Recoveries were in the range 98.15-101.15, 99.24-99.90 and 98.87-101.19% in pharmaceutical formulation and 98.05-101.01, 98.72-99.49 and 98.25-99.47% in human serum respectively and precision ranged from 0.19-1.84%. The analytes were successfully detected without any observable interference commonly present in pharmaceutical formulation and human serum demonstrating applicability of method.

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.

Electrospun NiFe layered double hydroxide/Nylon 6 composite nanofibers as a sorbent for micro solid phase extraction by packed sorbent of non-steroidal anti-inflammatory drugs in human blood.

In the present work, NiFe layered double hydroxide (LDH)/Nylon 6 composite nanofibers were prepared by electrospinning method and used as a new sorbent for the extraction and measurement of non-steroidal anti-inflammatory drugs (naproxen, mefenamic acid, and diclofenac) in whole blood samples. The method is based on micro solid phase extraction (µSPE) by packed sorbent followed by HPLC-UV analysis. Effective parameters on the extraction efficiency were optimized using a central composite design (CCD). In order to characterize the sorbent, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and elemental mapping were applied. The method was fully validated based on linearity, limits of detection (LOD) and quantification (LOQ), precision, and recovery. Under the optimal conditions, LOD values were found to be 25 ng mL-1 for naproxen and diclofenac and 15 ng mL-1 for mefenamic acid. A seven-point calibration curve was obtained in the range of 75-2000 ng mL-1 for naproxen and diclofenac and 50-2000 for mefenamic acid. The method showed good linearity with coefficients of determination, r2> 0.9962, for the three drugs. In the entire analytical range, the relative standard deviations (RSD%) were less than 8.1%. Finally, the efficiency of the method was investigated for the analysis of the target analytes in human blood samples, and the recoveries were obtained in the range of 90.7-109.8%.

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.

Pharmacokinetics of diclofenac sodium injection in swine.

The pharmacokinetics of a diclofenac sodium was investigated in swine. A single intravenous (i.v.) or intramuscular (i.m.) injection of 5% diclofenac sodium (concentration = 2.5 mg · kg-1) was administered to 8 healthy pigs according to a two-period crossover design. The pharmacokinetic parameters were calculated by non-compartmental analysis with DAS2.1.1 software. After a single i.v. administration, the main pharmacokinetic parameters of diclofenac sodium injection in swine were as follows: the elimination half-time (T1/2ß) was 1.32±0.34 h; the area under the curve (AUC) was (55.50±5.50 µg · mL-1 h; the mean residence time (MRT) was 1.60±0.28 h; the apparent volume of distribution (Vd) was 0.50±0.05 L · kg-1; and the body clearance (CLB) was 0.26±0.04 L · (h · kg)-1. After the single i.m. administration, the pharmacokinetic parameters were as follows: peak time (Tmax) was 1.19±0.26 h; and peak concentration (Cmax) was 11.61±5.99 µg mL-1. The diclofenac sodium has the following pharmacokinetic characteristics in swine: rapid absorption and elimination; high peak concentration; and bioavailability.

An LC-MS/MS method for the quantification of diclofenac sodium in dairy cow plasma and its application in pharmacokinetics studies.

An LC-MS/MS method with internal standard tolfenamic acid for determining diclofenac sodium (DCF) in dairy cow plasma was developed and validated. Samples were processed with protein precipitation by cold formic acid-acetonitrile. Determination of DCF was performed using LC-ESI+ -MS/MS with the matrix-matched calibration curve. The results showed that the method was sensitive (LOD 2 ng mL-1 , LOQ 5 ng mL-1 ), accurate (97.60 ± 5.64%), precise (<10%) and linear in the range of 5-10,000 ng mL-1 . A single intravenous (i.v.) or intramuscular (i.m.) administration of 5% diclofenac sodium injection at a dose of 2.2 mg kg-1 was performed in six healthy dairy cows according to a two-period crossover design. The main pharmacokinetic (PK) parameters after a single i.v. administration were as follows: t1/2ß , 4.52 ± 1.71 h; AUC, 77.79 ± 16.76 h µg mL-1 ; mean residence time, 5.16 ± 1.11 h. The main PK parameters after a single i.m. administration were as follows: Tmax , 2.38 ± 1.19 h; Cmax , 7.46 ± 1.85 µg mL-1 ; t1/2ß , 9.46 ± 2.86 h; AUC 67.57 ± 13.07 h µg mL-1 . The absolute bioavailability was 87.37 ± 5.96%. The results showed that the diclofenac sodium injection had PK characteristics of rapid absorption and slow elimination, and high peak concentration and bioavailability in dairy cows, and that the recommended clinical dosage of diclofenac sodium injection is 2.2 mg kg-1 .

A novel HPLC-DAD method for simultaneous determination of febuxostat and diclofenac in biological samples: pharmacokinetic outcomes.

AIM: To develop a simple HPLC-DAD method for simultaneous determination of febuxostat (FEB) and diclofenac (DIC) in biological samples to assess pharmacokinetic outcomes of their coadministration. Methodology & results: Sample preparation was performed by liquid-liquid extraction. Drugs analysis was done on C18 column using methanol-formic acid pH 2.1 (76:24, v/v) as mobile phase and time-programmed UV detection. Lower limits of quantitation for FEB and DIC were 10 and 20 ng/ml, respectively. Baseline pharmacokinetics were similar to published data on either drug alone. Coadministration led to more than twofold increase in FEB Cmax and AUC together with a reduced hepatic uptake in rats. CONCLUSION: DIC interfered with initial distribution and terminal clearance of FEB potentially due to reduced FEB hepatic uptake.

The Influence of Simulated Fasted Gastrointestinal pH Profiles on Diclofenac Sodium Dissolution in a Glass-Bead Flow-Through System.

High inter- and intra-individual variability in the pH of fluids in the human gastrointestinal (GI) tract has been described in the literature. The aim of this study was to assess the influence of physiological variability in fasted pH profiles of media along the GI tract on diclofenac sodium (DF-Na) dissolution from matrix tablets. Four individual in vivo fasted pH profiles were selected from the literature that differed in pH values and transit times from the stomach to the proximal colon. Using a glass-bead device flow-through dissolution system, these pH profiles were simulated in vitro using a specific media sequence and considering simulated intestinal buffer capacities corresponding to in vivo literature data. Dissolution experiments were then performed in the same system with media sequence following individual pH profiles. In dissolution experiments, where influences of simulated gastric emptying time (GET), gastric pH value, small intestinal transit time, and colonic pH were studied; high influence of gastric pH value and GET on DF-Na dissolution was observed. The effect of variability in pH profiles in the range of individual in vivo data on DF-Na dissolution was also clearly observed in experiments, where dissolution studies were performed following three simulated in vivo individual pH profiles. The differences in DF-Na release between three individual pH profiles were substantial; they also reflected in simulated plasma concentration profiles and can be attributed to pH dependent diclofenac solubility.

Development of electrochemically controlled packed-in-tube solid phase microextraction method for sensitive analysis of acidic drugs in biological samples.

In the present research, for the first time, a novel "packed-in-tube" configuration has been applied to electrochemically controlled in-tube solid phase microextraction, followed by high performance liquid chromatography. In order to prepare a mini packed column, small beads of stainless steel were first placed into the stainless steel column. Then, a nanostructured polypyrrole film was prepared on the internal surface of a stainless steel tube and the surface of stainless steel particles through a facile in-situ electrodeposition method. Filling the column with tiny particles of stainless steel effectively reduces the dead volume of the extraction tube and increases the extraction phase volume. The column was used for separation and preconcentration of diclofenac and mefenamic acid as model analytes from biological samples. Several important factors affecting extraction efficiency, such as extraction and desorption times, flow rates of the sample solution and eluent, and extraction and desorption voltages were investigated and optimized. This method showed good linearity for the drugs in the range of 0.3-200.0 µg L-1, 1.1-200.0 µg L-1, and 1.8-200.0 µg L-1 with coefficients of determination better than 0.9986, 0.9973, and 0.9973 in water, urine, and plasma samples, respectively. Intra- and inter-assay precisions (RSD%, n = 3) were in the range of 2.6-4.8% and 2.9-5.1, respectively, at three concentration levels of 10, 25, and 75 µg L-1. In addition, the limits of detection were in the range of 0.02-0.04 µg L-1. The validated method was successfully applied to the analysis of diclofenac and mefenamic acid in some biological samples. Finally, it is concluded that this method can be a general and reliable alternative to the analysis of ionic compounds in biological matrices.

The pharmacokinetics and metabolism of diclofenac in chimeric humanized and murinized FRG mice.

The pharmacokinetics of diclofenac were investigated following single oral doses of 10 mg/kg to chimeric liver humanized and murinized FRG and C57BL/6 mice. In addition, the metabolism and excretion were investigated in chimeric liver humanized and murinized FRG mice. Diclofenac reached maximum blood concentrations of 2.43 ± 0.9 µg/mL (n = 3) at 0.25 h post-dose with an AUCinf of 3.67 µg h/mL and an effective half-life of 0.86 h (n = 2). In the murinized animals, maximum blood concentrations were determined as 3.86 ± 2.31 µg/mL at 0.25 h post-dose with an AUCinf of 4.94 ± 2.93 µg h/mL and a half-life of 0.52 ± 0.03 h (n = 3). In C57BL/6J mice, mean peak blood concentrations of 2.31 ± 0.53 µg/mL were seen 0.25 h post-dose with a mean AUCinf of 2.10 ± 0.49 µg h/mL and a half-life of 0.51 ± 0.49 h (n = 3). Analysis of blood indicated only trace quantities of drug-related material in chimeric humanized and murinized FRG mice. Metabolic profiling of urine, bile and faecal extracts revealed a complex pattern of metabolites for both humanized and murinized animals with, in addition to unchanged parent drug, a variety of hydroxylated and conjugated metabolites detected. The profiles in humanized mice were different to those of both murinized and wild-type animals, e.g., a higher proportion of the dose was detected in the form of acyl glucuronide metabolites and much reduced amounts as taurine conjugates. Comparison of the metabolic profiles obtained from the present study with previously published data from C57BL/6J mice and humans revealed a greater, though not complete, match between chimeric humanized mice and humans, such that the liver humanized FRG model may represent a model for assessing the biotransformation of such compounds in humans.

High-performance thin-layer chromatographic methods for the determination of febuxostat and febuxostat/diclofenac combination in human plasma.

Two simple, sensitive and specific high-performance thin-layer chromatographic (HPTLC) methods were developed for the determination of febuxostat (FEB) individually, and simultaneously with diclofenac (DIC) in human plasma. Method A presents the first HPTLC-ultraviolet attempt for FEB determination in human plasma. FEB was separated from endogenous plasma components (at hRF = 70) with ethyl acetate-methanol-water (9:2:1, v/v) mixture as mobile phase and quantified by densitometry at its λmax (315 nm). Method B is considered the first attempt for the simultaneous determination of FEB and DIC in human plasma. A mixture of petroleum ether-chloroform-ethyl acetate-formic acid (7.5:1:2.5:0.25, v/v) was used as the mobile phase. The two drugs were separated at hRF of 39 and 60 for FEB and DIC, respectively. FEB and DIC were quantified by densitometry at their isoabsorptive point (289 nm). FEB calibration plots were linear between 0.1 and 7 µg mL-1 in both methods A and B. In method B, DIC showed linear response in the range of 0.08-8 µg mL-1. Sample preparation was performed by liquid-liquid extraction using diethyl ether. Both methods did not record any interference from plasma matrix, the studied drugs' metabolites or their decomposition products. They were successfully applied for the determination of the studied drugs in healthy male volunteers after oral administration of FEB or FEB/DIC dosage forms. FEB plasma concentration increased significantly when given with DIC. The proposed methods provided very simple, rapid and cheap approaches that might be attractive for the future pharmacokinetic and bioavailability studies of FEB and/or DIC.

Liquid chromatography-tandem MS/MS method for simultaneous quantification of paracetamol, chlorzoxazone and aceclofenac in human plasma: An application to a clinical pharmacokinetic study.

A facile, fast and specific method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous quantitation of paracetamol, chlorzoxazone and aceclofenac in human plasma was developed and validated. Sample preparation was achieved by liquid-liquid extraction. The analysis was performed on a reversed-phase C18 HPLC column (5 µm, 4.6 × 50 mm) using acetonitrile-10 mM ammonium formate pH 3.0 (65:35, v/v) as the mobile phase where atrovastatin was used as an internal standard. A very small injection volume (3 µL) was applied and the run time was 2.0 min. The detection was carried out by electrospray positive and negative ionization mass spectrometry in the multiple-reaction monitoring mode. The developed method was capable of determining the analytes over the concentration ranges of 0.03-30.0, 0.015-15.00 and 0.15-15.00 µg/mL for paracetamol, chlorzoxazone and aceclofenac, respectively. Intraday and interday precisions (as coefficient of variation) were found to be ≤12.3% with an accuracy (as relative error) of ±5.0%. The method was successfully applied to a pharmacokinetic study of the three analytes after being orally administered to six healthy volunteers.

[Metabolism of Sesamin and Drug-Sesamin Interaction].

　Sesamin, derived from sesame seeds, is known to have various biological effects. Since some of these effects appear to be derived from its metabolites, the elucidation of sesamin metabolism is essential to understanding the molecular mechanism of its effects. In addition, it is important to clarify drug-sesamin interactions in order to address safety concerns, as some food factors are known to affect drug metabolism. Our previous studies revealed that sesamin was sequentially metabolized by cytochrome P450 (CYP) and UDP-glucuronosyltransferase or sulfotransferase. Whereas sesamin metabolism is mainly mediated by CYP2C9 in human liver, sesamin causes a mechanism-based inhibition (MBI) of CYP2C9. However, we found that the metabolite-intermediate complex between CYP2C9 and sesamin was unstable, and the effects of sesamin appeared to be minimal. To confirm this assumption, in vivo studies using rats were conducted. After the administration of sesamin to rats for 3 d, diclofenac (an NSAID) was administered to measure the time course of plasma concentration of diclofenac. No significant differences were observed in the diclofenac Cmax, Tmax, and AUC0-24 h between the group that was administered sesamin and the group that was not. Based on these results, it could be concluded that no significant interaction occurs in people who take sesamin supplements at a standard dose.

Simultaneous extraction and determination of trace amounts of diclofenac from whole blood using supported liquid membrane microextraction and fast Fourier transform voltammetry.

A novel, simple, and inexpensive analytical technique based on flat sheet supported liquid membrane microextraction coupled with fast Fourier transform stripping cyclic voltammetry on a reduced graphene oxide carbon paste electrode was used for the extraction and online determination of diclofenac in whole blood. First, diclofenac was extracted from blood samples using a polytetrafluoroethylene membrane impregnated with 1-octanol and then into an acceptor solution, subsequently it was oxidized on a carbon paste electrode modified with reduced graphene oxide nanosheets. The optimal values of the key parameters influencing the method were as follows: scan rate, 6 V/s; stripping potential, 200 mV; stripping time, 5 s; pH of the sample solution, 5; pH of the acceptor solution,7; and extraction time, 240 min. The calibration curves were plotted for the whole blood samples and the method was found to have a good linearity within the range of 1-25 µg/mL with a determination coefficient of 0.99. The limits of detection and quantification were 0.1 and 1.0 µg/mL, respectively. Using this coupled method, the extraction and determination were merged into one step. Accordingly, the speed of detection for sensitive determination of diclofenac in complex samples, such as blood, increased considerably.

Pharmacokinetics of Diclofenac and Hydroxypropyl-ß-Cyclodextrin (HPßCD) Following Administration of Injectable HPßCD-Diclofenac in Subjects With Mild to Moderate Renal Insufficiency or Mild Hepatic Impairment.

Given their established analgesic properties, nonsteroidal anti-inflammatory drugs (NSAIDs) represent an important postoperative pain management option. This study investigated: (1) the effects of mild or moderate renal insufficiency and mild hepatic impairment on the pharmacokinetics (PK) of diclofenac and hydroxypropyl-ß-cyclodextrin (HPßCD) following administration of the injectable NSAID HPßCD-diclofenac; and (2) the PK of HPßCD following administration of HPßCD-diclofenac and intravenous itraconazole formulated with HPßCD in healthy adults. Diclofenac clearance (CL) and volume of distribution (Vz ) tended to increase with decreasing renal function (moderate insufficiency versus mild insufficiency or healthy controls). Regression analysis demonstrated a significant relationship between Vz (but not CL or elimination half-life, t½ ) and renal function. HPßCD CL was significantly decreased in subjects with renal insufficiency, with a corresponding increase in t½ . There were no significant differences in diclofenac or HPßCD PK in subjects with mild hepatic impairment versus healthy subjects. Exposure to HPßCD in healthy subjects following HPßCD-diclofenac administration was ∼12% of that with intravenous itraconazole, after adjusting for dosing schedule and predicted accumulation (<5% without adjustment). With respect to PK properties, these results suggest that HPßCD-diclofenac might be administered to patients with mild or moderate renal insufficiency or mild hepatic impairment without dose adjustment (NCT00805090).

Coupling of two centrifugeless ultrasound-assisted dispersive solid/liquid phase microextractions as a highly selective, clean, and efficient method for determination of ultra-trace amounts of non-steroidal anti-inflammatory drugs in complicated matrices.

In this work, a new, simple, rapid, and environmentally friendly method with a high sample clean-up capability termed as centrifugeless ultrasound-assisted dispersive micro solid-phase extraction coupled with salting-out ultrasound-assisted liquid-liquid microextraction based on solidification of a floating organic droplet followed by high performance liquid chromatography is introduced for the first time. In this method, the three non-steroidal anti-inflammatory drugs diclofenac, ibuprofen, and mefenamic acid are first extracted based on an effective nanoadsorbent named as the layered double hydroxide-carbon nanotube nanohybrid. The first step provides a rapid and convenient way to separate the adsorbent from the sample matrix by a syringe nanofilter without additional centrifugation. In the next step, which is based upon the salting-out effect, after emulsification in the presence of ultrasonic irradiation, the phase separation is simply achieved through the salting-out phenomenon, and the extracting solvent is suspended on top of the sample solution. Under the optimal experimental conditions including the initial pH value of 6.0, 8.0 mg of the nanohybrid, 3 min ultrasonic time, 100 µL elution solvent (first step), secondary pH value of 3.0, 60 µL of 1-undecanol, 60 s ultrasonic time, and flow rate of 3 mL min-1 (second step), good responses were obtained for diclofenac, ibuprofen, and mefenamic acid in the concentration ranges of 0.8-2000, 0.8-2500, and 0.5-2000 ng mL-1, respectively, with low limits of detection ranging from 0.1 to 0.2 ng mL-1. The intra-day and inter-day precisions for the target analytes at the three concentration levels were in the ranges of 6.1-7.8% and 6.3-8.1%, respectively. The proposed method was also successfully applied to the biological and waste water samples, and excellent recoveries were obtained in the range of 92.9-103.1% even when the matrix was complex.