Polymer/lipid interplay in altering in vitro supersaturation and plasma concentration of a model poorly soluble drug.

Supersaturation drug delivery system (SDDS) based on amorphous solid dispersion (ASD) is a widely used strategy to improve oral absorption of poorly water-soluble drugs by achieving a supersaturated state where drug concentration is significantly higher than drug solubility. However, dissolved drugs tend to recrystallize in gastrointestinal (GI) tract if without effective stabilizing excipients. In this paper, well-recognized polymer (polyvinylpyrrolidone, PVP) and lipid (phosphatidylcholine, PC) excipients are combined as ASD carrier, aiming at investigating the effects on evolution of in vitro supersaturation and in vivo plasma concentration of a model poorly soluble drug indomethacin (IND). Fundamental aspects including polymer/lipid composition ratio, drug loading (DL) degree and administration dose were investigated. The in vitro dissolution profiles of ASDs were assessed by supersaturation degree, duration, maximum achievable drug concentration and dose-normalized efficiency, and correlated with in vivo pharmacokinetic data. Results showed that both in vitro and in vivo concentration-time profiles of IND were significantly varying with abovementioned factors. Solution viscosity, solid-state properties and morphology of ASDs were related to the results. This study revealed fundamental mechanisms of PVP/PC mixture effect on IND supersaturation and oral bioavailability, demonstrating that polymer/lipid mixture could be used as a promising carrier to alter supersaturation profile and oral bioavailability of SDDS products.

Pharmacokinetics-based analysis of indomethacin's anti-tumor effect and drug efficacy.

Non-steroidal anti-inflammatory drugs are commonly used anti-inflammatory analgesics in clinic. Indomethacin is a kind of NSAIDs and has anti-tumor effect. It can significantly change the growth cycle of cancer cells, inhibit their proliferation. In this paper, the antineoplastic effect of indomethacin and its pharmacokinetic effect were analysed. The result showed that indomethacin had more metabolic distribution in tumor tissues and reached its peak at 4 hours, after that, the clearance rate was slower than that in the blood, with the clearance rate slowest at 6-12 hours. At the same time, the expression of Bcl-2 protein in cancer cells was significantly reduced and weakened, while the expression of Bax protein did not change significantly. Pharmacodynamic studies have proved that IN (Indomethacin) has a strong anti-tumor effect. It can enter into tumor cells through cell membrane and nuclear membrane to have an anti-tumor effect.

Active Micropump-Mixer for Rapid Antiplatelet Drug Screening in Whole Blood.

There is a need for scalable automated lab-on-chip systems incorporating precise hemodynamic control that can be applied to high-content screening of new more efficacious antiplatelet therapies. This paper reports on the development and characterization of a novel active micropump-mixer microfluidic to address this need. Using a novel reciprocating elastomeric micropump design, we take advantage of the flexible structural and actuation properties of this framework to manage the hemodynamics for on-chip platelet thrombosis assay on type 1 fibrillar collagen, using whole blood. By characterizing and harnessing the complex three-dimensional hemodynamics of the micropump operation in conjunction with a microvalve controlled reagent injection system we demonstrate that this prototype can act as a real-time assay of antiplatelet drug pharmacokinetics. In a proof-of-concept preclinical application, we utilize this system to investigate the way in which rapid dosing of human whole blood with isoform selective inhibitors of phosphatidylinositol 3-kinase dose dependently modulate platelet thrombus dynamics. This modular system exhibits utility as an automated multiplexable assay system with applications to high-content chemical library screening of new antiplatelet therapies.

Carboxylesterase catalyzed 18O-labeling of carboxylic acid and its potential application in LC-MS/MS based quantification of drug metabolites.

LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel 18O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H218O in the presence of the enzyme, generating singly- and doubly-18O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds - indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery.

Concentrations of indomethacin and its metabolite desmethylindomethacin in plasma and urine after repeated indomethacin topical application to Thoroughbreds.

BACKGROUND: Repeated topical application of indomethacin is common in Japanese racehorses, despite the lack of pharmacokinetic data. OBJECTIVES: To determine the concentrations of indomethacin and its metabolite, desmethylindomethacin, in plasma and urine of Thoroughbreds topically treated repeatedly with indomethacin. STUDY DESIGN: In vivo experimental. METHODS: Seven female Thoroughbreds were topically treated with 50 g of 1% indomethacin cream per horse to the back and hips (500 mg of indomethacin/head/2400 cm2 , 0.21 g/cm2 ) for 3 consecutive days. Samples were pretreated by protein precipitation for plasma and liquid-liquid extraction with ethyl acetate after hydrolysis with hydrochloric acid for urine. The concentrations of indomethacin and desmethylindomethacin in plasma and urine were measured by liquid chromatography-mass spectrometry. RESULTS: Indomethacin was quantifiable in plasma up to 48-72 h and in urine up to 96 h after the final application. Desmethylindomethacin was quantifiable in plasma up to 48 h and in urine up to 72-96 h after the final application. MAIN LIMITATIONS: The relationship between the local and systemic indomethacin concentrations after the topical application was not clarified. CONCLUSIONS: Pharmacokinetic data were acquired for repeated topical administration of 1% indomethacin cream to Thoroughbreds. Hydrolysing urine samples with hydrochloric acid was effective for the analysis of indomethacin and its metabolite, and indomethacin may be an excellent marker analyte for doping tests. The estimated withdrawal time based on the limit of detection was 342 h.

Effect of CYP2C9 Polymorphisms on the Pharmacokinetics of Indomethacin During Pregnancy.

BACKGROUND AND OBJECTIVE: Cytochrome P450 (CYP) 2C9 catalyzes the biotransformation of indomethacin to its inactive metabolite O-desmethylindomethacin (DMI). The aim of this work was to determine the effect of CYP2C9 polymorphisms on indomethacin metabolism in pregnant women. METHODS: Plasma concentrations of indomethacin and DMI at steady state were analyzed with a validated LC-MS/MS method. DNA was isolated from subject blood and buccal smear samples. Subjects were grouped by genotype for comparisons of pharmacokinetic parameters. RESULTS: For subjects with the *1/*2 genotype, the mean steady-state apparent oral clearance (CL/Fss) of indomethacin was 13.5 ± 7.7 L/h (n = 4) and the mean metabolic ratio (AUCDMI/AUCindomethacin) was 0.291 ± 0.133. For subjects with the *1/*1 genotype, these values were 12.4 ± 2.7 L/h and 0.221 ± 0.078, respectively (n = 14). Of note, we identified one subject who was a carrier of both the *3 and *4 alleles, resulting in an amino acid change (I359P) which has not been reported previously. This subject had a metabolic ratio of 0.390 and a CL/Fss of indomethacin (24.3 L/h) that was nearly double the wild-type clearance. CONCLUSION: Although our results are limited by sample size and are not statistically significant, these data suggest that certain genetic polymorphisms of CYP2C9 may lead to an increased metabolic ratio and an increase in the clearance of indomethacin. More data are needed to assess the impact of CYP2C9 genotype on the effectiveness of indomethacin as a tocolytic agent.

Voltammetric analysis of dantrolene and its active metabolite with indomethacin in rat plasma.

AIM: Differential pulse polarography was used for the concurrent analysis of the coadministered dantrolene (DAN) and indomethacin (IND) in plasma. MATERIALS & METHODS: DAN and IND, Hanging mercury drop electrode and Britton-Robinson buffer at pH 5 were used. In plasma, cathodic reduction of DAN nitro group and its active metabolite at -0.2 V was done. IND was analyzed after carbonyl group reduction at -1.1 V. RESULTS: Drugs determination in rat plasma with good recoveries and low limit of quantitation was done. Application to trace analysis of drugs in rat plasma was done with Cmax and Tmax determination. CONCLUSION: This technique shows high sensitivity, simplicity and low cost. The method is US FDA validated and it is applicable to human level.

A novel chemiluminescence sensor for the determination of indomethacin based on sulfur and nitrogen co-doped carbon quantum dot-KMnO4 reaction.

We report on a simple and sensitive sulfur and nitrogen co-doped carbon quantum dot (S,N-CQD)-based chemiluminescence (CL) sensor for the determination of indomethacin. S,N-CQDs were prepared by a hydrothermal method and characterized by fluorescence spectra, Fourier transform infrared spectroscopy and transmission electron microscopy. To obtain the best CL system for determination of indomethacin, the reaction of S,N-CQDs with some common oxidants was studied. Among the tested systems, the S,N-CQD-KMnO4 reaction showed the highest sensitivity for the detection of indomethacin. Under optimum conditions, the calibration plot was linear over a concentration range of 0.1-1.5 mg L-1 , with a limit of detection (3σ) of 65 µg L-1 . The method was applied to the determination of indomethacin in environmental and biological samples with satisfactory results.

Pharmacokinetics and safety of low-dose submicron indomethacin 20 and 40 mg compared with indomethacin 50 mg.

INTRODUCTION: Indomethacin is a potent analgesic that, similar to other nonsteroidal anti-inflammatory drugs, is associated with serious dose-related adverse events. There is a need for newer nonsteroidal anti-inflammatory drug products with improved tolerability. Low-dose submicron indomethacin was developed using SoluMatrix Fine Particle Technology™ to enable treatment at lower doses than commercially available indomethacin drug products. This study evaluated the pharmacokinetics and safety of submicron indomethacin 20 and 40 mg compared with indomethacin 50-mg capsules. METHODS: This was a phase 1, randomized, open-label, 4-period, 4-sequence, single-dose crossover study. Forty healthy volunteers received low-dose submicron indomethacin 20- or 40-mg capsules, or indomethacin 50-mg capsules under fasting or fed conditions. Pharmacokinetic parameters and safety were assessed. RESULTS: Comparable fasting peak plasma levels (mean ± standard deviation) were demonstrated for submicron indomethacin 40 mg (2368.79 ± 631.38 ng/ml) and indomethacin 50 mg (2369.40 ± 969.06 ng/ml). The overall systemic exposure (geometric least squares mean; 95% CI) was > 21% lower for submicron indomethacin 40 mg (6007.71 ng·h/mL; 5585.73-6461.58) compared with indomethacin 50 mg (7646.23 ng·h/ml; 7110.44-8222.40) under fasting conditions. Food delayed the rate but did not affect the extent of indomethacin absorption from submicron indomethacin 40 mg. Submicron indomethacin 40 mg administration resulted in earlier time to peak plasma levels (median 1.67; min-max 0.5-3.5 hours) under fasting conditions compared with indomethacin 50 mg (2.02; 0.5-5.0 hours). Submicron indomethacin 20 and 40 mg were dose proportional and generally well tolerated. CONCLUSION: Compared with indomethacin 50 mg, submicron indomethacin 40 mg achieved similar peak plasma concentrations, lower systemic exposure, and a faster time to peak plasma concentration, indicating rapid absorption. The current formulation of low-dose submicron indomethacin has recently demonstrated efficacy in 2 phase 3 studies in patients with acute pain following bunionectomy and represents a new, low-dose treatment option for patients with acute pain.

An in situ crosslinked compression coat comprised of pectin and calcium chloride for colon-specific delivery of indomethacin.

The use of pectin for colon-specific drug delivery has been extensively investigated; however, when used alone, pectin is often compromised due to its high solubility. This study explored the feasibility of using an in situ compression-coated crosslinking system, composed of pectin and calcium chloride, for colon-specific drug delivery. A pectin/calcium chloride (P/Ca) coating was compressed onto a core tablet. The colon specificity of the compression-coated tablet was verified by dissolution, pharmacokinetics and scintigraphy with (99m)Tc labeling. The in situ pectin and calcium chloride gel slowed the release of indomethacin. The lag time varied between 3 h and 7 h depending on the amount of calcium chloride and the coating weight. Pectinase triggered the release of indomethacin from the compression-coated tablet, which was then accelerated by the calcium chloride in the coating layer. The compression-coated tablet had a prolonged tmax and apparent t1/2, as well as a decreased Cmax and AUC0-t, compared with the core tablet counterpart. Evaluation with γ-scintigraphy verified colon-specific delivery of the compression-coated tablet. In conclusion, the P/Ca in situ crosslinking system worked well for colon-specific drug delivery.

Development of a novel 96-well format for liquid-liquid microextraction and its application in the HPLC analysis of biological samples.

A novel 96-well liquid-liquid microextraction system combined with modern HPLC was developed and used for the simultaneous analysis of 96 biological samples. The system made use of hollow fibers, a 96-well plate, and a plastic base with a center hole and a side hole. One end of the hollow fiber was sealed, while the other end was attached to one of the holes positioned at the center for the plastic base. The needle was inserted into the liquid from inside or outside of the hollow fiber through the center or the side holes, respectively. The system was tested with plasma samples containing three compounds, acidic indomethacin, neutral dexamethasone, and basic propafenone. Some parameters, such as the kind and dimension of hollow fiber, pH and salt concentration of the donor phase, the selection of organic solvent for the acceptor phase, and the extraction time were investigated. Under the optimization conditions, the Log D and drug concentration of indomethacin, dexamethasone, and propafenone in plasma and urine samples were analyzed. Then, the methodology was validated. The results demonstrated that ng/mL levels could be exactly and rapidly analyzed by our system, which was equipped with an auto-injection sampler, making sample analysis more convenient.

A liquid chromatography method with single quadrupole mass spectrometry for quantitative determination of indomethacin in maternal plasma and urine of pregnant patients.

A liquid chromatography with single quadrupole mass spectrometry method was developed for the quantitative determination of indomethacin in the maternal plasma and urine of pregnant patients under treatment. A deuterium-labeled isotope of indomethacin (d4-indomethacin) was used as an internal standard. The maternal plasma and urine samples were acidified with 1.0M HCl then extracted with chloroform to achieve the extraction recovery range of 94-104% with variation less than 11%. Chromatographic separation was achieved by a Waters Symmetry C18 column with isocratic elution of 0.05% (v/v) formic acid aqueous solution and acetonitrile (47:53, v/v). An in-source fragmentation was applied on the single quadrupole mass spectrometer equipped with an electrospray ionization source at positive mode. The LC-ESI-MS quantification was performed in the selected ion monitoring mode targeting ions at m/z 139 for indomethacin and m/z 143 for its internal standard. The calibration curves were linear in the concentration ranges between 14.8 and 2.97 × 10(3) ng/mL for plasma samples and between 10.5 and 4.21 × 10(3) ng/mL for urine samples. The relative standard deviation of this method was less than 8% for intra- and inter-day assays, and the accuracy ranged between 90% and 108%.

The anticancer effect of phospho-tyrosol-indomethacin (MPI-621), a novel phosphoderivative of indomethacin: in vitro and in vivo studies.

We have synthesized a novel derivative of indomethacin, phospho-tyrosol-indomethacin (PTI; MPI-621), and evaluated its anticancer efficacy in vitro and in vivo. PTI inhibited the growth of human colon, breast and lung cancer cell lines 6-30-fold more potently than indomethacin. In vivo, in contrast to indomethacin that was unable to inhibit colon cancer xenograft growth, PTI inhibited the growth of colon (69% at 10mg/kg/day, P < 0.01) and lung (91% at 15mg/kg/day, P < 0.01) subcutaneous cancer xenografts in immunodeficient mice, suppressing cell proliferation by 33% and inducing apoptosis by 75% (P < 0.05, for both). Regarding its pharmacokinetics in mice, after a single intraperitoneal injection of PTI, its plasma levels reached the maximum concentration (Cmax = 46 µM) at 2h (Tmax) and became undetectable at 4h. Indomethacin is the major metabolite of PTI, with plasma Cmax = 378 µM and Tmax = 2.5h; it became undetectable 24h postadministration. The cellular uptake of PTI (50-200 µM) at 6h was about 200-fold greater than that of indomethacin. Regarding its safety, PTI had no significant genotoxicity, showed less gastrointestinal toxicity than indomethacin and presented no cardiac toxicity. Mechanistically, PTI suppressed prostaglandin E2 production in A549 human lung cancer cells and strongly inhibited nuclear factor-κB activation in A549 xenografts. These findings indicate that PTI merits further evaluation as an anticancer agent.

Development and validation of a liquid chromatography-tandem mass spectrometry method for quantitation of indomethacin in rat plasma and its application to a pharmacokinetic study in rats.

A highly sensitive and rapid bioanalytical method has been developed and validated for the estimation of indomethacin in rat plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves a simple liquid-liquid extraction of indomethacin and phenacetin (internal standard, IS) from rat plasma with acetonitrile. Chromatographic separation was achieved with 0.2% formic acid-acetonitrile (25:75, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 3.0 min. The MS/MS ion transitions monitored were 357.7 → 139.1 for indomethacin and 180.20 → 110.10 for IS. Method validation and pharmacokinetic study plasma analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.51 ng/mL and the linearity was observed from 0.51 to 25.5 ng/mL. The intra- and inter-day precisions were in the range of 1.00-10.2 and 5.88-9.80%, respectively. This novel method has been applied to an oral pharmacokinetic study in rats.

Indomethacin but not a selective cyclooxygenase-2 inhibitor inhibits esophageal adenocarcinogenesis in rats.

AIM: To evaluate the effects of indomethacin [dual cyclooxygenase (COX)-1/COX-2 inhibitor] and 3-(3,4-difluorophenyl)-4-(4-(methylsulfonyl) phenyl)-2-(5H)-furanone (MF-tricyclic) (COX-2 selective inhibitor) in a rat experimental model of Barrett's esophagus and esophageal adenocarcinoma. METHODS: A total of 112 surviving post-surgery rats were randomly divided into three groups: the control group (n = 48), which did not receive any treatment; the indomethacin group (n = 32), which were given 2 mg/kg per day of the COX-1/COX-2 inhibitor; and the MF-tricyclic group (n = 32), which received 10 mg/kg per day of the selective COX-2 inhibitor. Randomly selected rats were killed either 8 wk or 16 wk after surgery. The timing of the deaths was in accordance with a previous study performed in our group. Only rats that were killed at the times designated by the protocol were included in the study. We then assessed the histology and prostaglandin E2 (PGE2) expression levels in the rat esophagi. An additional group of eight animals that did not undergo esophagojejunostomy were included in order to obtain normal esophageal tissue as a control. RESULTS: Compared to a control group with no treatment (vehicle-treated rats), indomethacin treatment was associated with decreases in ulcerated esophageal mucosa (16% vs 35% and 14% vs 17%, 2 mo and 4 mo after surgery, respectively; P = 0.021), length of intestinal metaplasia in continuity with anastomosis (2 ± 1.17 mm vs 2.29 ± 0.75 mm and 1.25 ± 0.42 mm vs 3.5 ± 1.54 mm, 2 mo and 4 mo after surgery, respectively; P = 0.007), presence of intestinal metaplasia beyond anastomosis (20% vs 71.4% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P = 0.009), severity of dysplasia (0% vs 71.4% and 20% vs 85.7% high-grade dysplasia, 2 mo and 4 mo after surgery, respectively; P = 0.002), and adenocarcinoma incidence (0% vs 57.1% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P < 0.0001). Treatment with the selective COX-2 inhibitor, MF-tricyclic, did not prevent development of intestinal metaplasia or adenocarcinoma. In parallel, we observed a significant decrease in PGE2 levels in indomethacin-treated rats, but not in those treated with MF-tricyclic, at both 2 mo and 4 mo. Compared to control rats that did not undergo surgery (68 ± 8 ng/g, P = 0.0022 Kruskal-Wallis test) there was a significant increase in PGE2 levels in the esophageal tissue of the rats that underwent surgery either 2 mo (1332 ± 656 ng/g) or 4 mo (1121 ± 1015 ng/g) after esophagojejunostomy. However, no differences were found when esophageal PGE2 levels were compared 2 mo vs 4 mo post-esophagojejunostomy. At both the 2- and 4-mo timepoints, we observed a significant decrease in PGE2 levels in indomethacin-treated rat esophagi compared to those in either the control or MF-tricyclic groups (P = 0.049 and P = 0.017, respectively). No differences in PGE2 levels were found when we compared levels in rats treated with MF-tricyclic to not-treated rats. CONCLUSION: In this rat model of gastrointestinal reflux, indomethacin was associated with a decrease in the severity of esophagitis and reduced development of esophageal intestinal metaplasia and adenocarcinoma.

Effectiveness of submicronized chitosan-coated liposomes in oral absorption of indomethacin.

The plasma profile of indomethacin (IMC) after oral administration of IMC-loaded submicronized chitosan-coated liposomes (ssCS-Lip) was evaluated to reveal the effectiveness of the mucoadhesive function for improving the absorption of this poorly absorbable drug. The stomach and small intestine were removed from rats after 1, 2, and 4 hours of oral administration of submicron-sized liposomes (ssLip) or ssCS-Lip containing fluorescent dye, and the retentive properties were confirmed by measuring the amount of dye in each part of the gastrointestinal (GI) tract. Results showed that ssCS-Lip tended to be better retained in the upper part of the GI tract, compared with ssLip, at 1, 2, and 4 hours after administration, and was significantly better retained in the small intestine at 4 hours. The plasma profile and bioavailability of IMC after oral administration of both types of liposomes were improved, compared with oral administration of IMC solution. The maximum residence time of ssCS-Lip was significantly longer than those of ssLip. The extended plasma profile of ssCS-Lip was attributed to its prolonged retention in the upper region of the GI tract, and its delayed migration to the lower part of the intestine, the neutral pH of which is more soluble for IMC, an acidic drug. Therefore, the chitosan-coated ssLip, with its higher retention in the GI tract, is a promising drug carrier for the oral administration of poorly absorbed compounds.

Monitoring of the non-steroid anti-inflammatory drug indomethacin: development of immunochemical methods for its purification and detection.

The present research focused on the development of an immunoassay and an immunochemical sol-gel-based immunoaffinity purification (IAP) method for purification and detection of the non-steroid anti-inflammatory drug (NSAID) indomethacin (IMT). A polyclonal antibody (Ab) for IMT was generated, and two sensitive microplate assays for the detection of IMT were developed (termed OV and HRP formats), based on the enzyme-linked immunosorbent assay (ELISA) method. The limits of detection of the assays were 15 ± 1.25 ng mL(-1) (n = 50) and 12 ± 0.17 ng mL(-1) (n = 4) for the OVA and HRP formats, respectively. The Abs exhibited slight cross-reactivity with other NSAIDs. The Abs were also used to develop a sol-gel-based IAP method for clean-up and concentration of IMT. Several sol-gel formats with various amounts of antibodies were examined; the best and most reproducible format was at a TMOS:HCl molar ratio of 1:6 in which 120 µL of IMT Abs was entrapped. The binding capacity under these conditions was ca. 100 to 250 ng of IMT with very low non-specific binding (less than 5% of the applied amount). The sol-gel IAP method, combined with solid-phase extraction, successfully eliminated serum interference to a degree that enabled analysis of spiked serum samples by ELISA. The method was also found to be fully compatible with subsequent chemical analytical methods, such as liquid chromatography followed by mass spectrometry. The approaches developed in this study form a basis for analysis of IMT in biological samples in order to monitor their pharmacokinetic properties, and may be further used to study population exposure to IMT, and to monitor the occurrence of IMT contamination in water samples.

[The increase of bioavailability and anti-inflammatory effect of indomethacin loaded into phospholipid nanoparticles].

The ultrafine formulation on the base of plant phosphatidylcholine and antiinflammatory remedy indomethacin with nanoparticles less than 50 nm was obtained. Drug bioavailability after its peroral administration to rats was more than 2 fold higher as compared with free indomethacin. Increased antiinflammatory activity of indomethacin in phospholipids nanoparticles as compared with its free form was shown in two models of inflammation - adjuvant arthritis in rats and conconavalin A induced edema in mice. The increased bioavailability of indomethacin after administration of its phospholipid formulation allows to decrease a dose for achievement of therapeutic effect, that reduces risks of occurrence of collateral displays.

A new open tubular capillary microextraction and sweeping for the analysis of super low concentration of hydrophobic compounds.

A sample pre-concentration method based on the in-line coupling of in-tube solid-phase microextraction and electrophoretic sweeping was developed for the analysis of hydrophobic compounds. The sample pre-concentration and electrophoretic separation processes were simply and sequentially carried out with a (35%-phenyl)-methylpolysiloxane-coated capillary. The developed method was validated and applied to enrich and separate several pharmaceuticals including loratadine, indomethacin, ibuprofen and doxazosin. Several parameters of microextration were investigated such as temperature, pH and eluant. And the concentration of microemulsion that influences separation efficiency and microextraction efficiency were also studied. Central composite design was applied for the optimization of sampling flow rate and sampling time that interact in a very complex way with each other. The precision, sensitivity and recovery of the method were investigated. Under the optimal conditions, the maximum enrichment factors for loratadine, indomethacin, ibuprofen and doxazosin in aqueous solutions are 1355, 571, 523 and 318, respectively. In addition, the developed method was applied to determine loratadine in rabbit blood sample.

Quantitation of indomethacin in serum and plasma using gas chromatography-mass spectrometry (GC-MS).

Indomethacin is a non-narcotic and non-steroidal anti-inflammatory drug used in the treatment of various inflammatory diseases such as rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. In neonates, it is also used for induction of closure of patent ductus arteriosus (PDA). Its mechanism of action is believed to be through the inhibition of cyclooxygenase. Due to narrow therapeutic window and number of side effects, it's monitoring, particularly in neonates, is recommended. In the gas chromatography method described here, the drug is extracted from serum or plasma using methylene chloride and phosphate buffer (pH 6). The methylene chloride phase containing drug is separated and dried under stream of nitrogen. The drug is derivatized using Bis-(Trimethylsilyl)trifluoroacetamide (BSTFA) with 1% TMCS (trimethylchlorosilane). The derivatized drug is analyzed using gas chromatography-mass spectrometry. Quantitation of the drug in a sample is achieved by comparing responses of the unknown sample to the responses of the calibrators using selected ion monitoring. Meclofenamic acid is used as an internal standard.