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Integration of mitochondria with cytosolic ATP-consuming/ATP-sensing and substrate supply processes is critical for muscle bioenergetics and electrical activity. Whether age-dependent muscle weakness and increased electrical instability depends on perturbations in cellular energetic circuits is unknown. To define energetic remodeling of aged atrial myocardium we tracked dynamics of ATP synthesis-utilization, substrate supply, and phosphotransfer circuits through adenylate kinase (AK), creatine kinase (CK), and glycolytic/glycogenolytic pathways using 18O stable isotope-based phosphometabolomic technology. Samples of intact atrial myocardium from adult and aged rats were subjected to 18O-labeling procedure at resting basal state, and analyzed using the 18O-assisted HPLC-GC/MS technique. Characteristics for aging atria were lower inorganic phosphate Pi[18O], γ-ATP[18O], β-ADP[18O], and creatine phosphate CrP[18O] 18O-labeling rates indicating diminished ATP utilization-synthesis and AK and CK phosphotransfer fluxes. Shift in dynamics of glycolytic phosphotransfer was reflected in the diminished G6P[18O] turnover with relatively constant glycogenolytic flux or G1P[18O] 18O-labeling. Labeling of G3P[18O], an indicator of G3P-shuttle activity and substrate supply to mitochondria, was depressed in aged myocardium. Aged atrial myocardium displayed reduced incorporation of 18O into second (18O2), third (18O3), and fourth (18O4) positions of Pi[18O] and a lower Pi[18O]/γ-ATP[18 O]-labeling ratio, indicating delayed energetic communication and ATP cycling between mitochondria and cellular ATPases. Adrenergic stress alleviated diminished CK flux, AK catalyzed β-ATP turnover and energetic communication in aging atria. Thus, 18O-assisted phosphometabolomics uncovered simultaneous phosphotransfer through AK, CK, and glycolytic pathways and G3P substrate shuttle deficits hindering energetic communication and ATP cycling, which may underlie energetic vulnerability of aging atrial myocardium.

Background: Heart failure (HF) is associated with ventricular dyssynchrony and energetic inefficiency, which can be alleviated by cardiac resynchronization therapy (CRT). The aim of this study was to determine the metabolomic signature in HF and its prognostic value regarding the response to CRT., Methods and Results: This prospective study consisted of 24 patients undergoing CRT for advanced HF and 10 control patients who underwent catheter ablation for supraventricular arrhythmia but not CRT. Blood samples were collected before and 3 months after CRT. Metabolomic profiling of plasma samples was performed with the use of gas chromatography-mass spectrometry and nuclear magnetic resonance. The plasma metabolomic profile was altered in the HF patients, with a distinct panel of metabolites, including Krebs cycle and lipid, amino acid, and nucleotide metabolism. CRT improved the metabolomic profile. The succinate-glutamate ratio, an index of Krebs cycle activity, improved from 0.58 ± 0.13 to 2.84 ± 0.60 (P < .05). The glucose-palmitate ratio, an indicator of the balance between glycolytic and fatty acid metabolism, increased from 0.96 ± 0.05 to 1.54 ± 0.09 (P < .01). Compared with nonresponders to CRT, responders had a distinct baseline plasma metabolomic profile, including higher isoleucine, phenylalanine, leucine, glucose, and valine levels and lower glutamate levels at baseline (P < .05)., Conclusions: CRT improves the plasma metabolomic profile of HF patients, indicating harmonization of myocardial energy substrate metabolism. CRT responders may have a favorable metabolomic profile as a potential biomarker for predicting CRT outcome., (Published by Elsevier Inc.)

Development of therapeutic strategies to prevent Alzheimer's Disease (AD) is of great importance. We show that mild inhibition of mitochondrial complex I with small molecule CP2 reduces levels of amyloid beta and phospho-Tau and averts cognitive decline in three animal models of familial AD. Low-mass molecular dynamics simulations and biochemical studies confirmed that CP2 competes with flavin mononucleotide for binding to the redox center of complex I leading to elevated AMP/ATP ratio and activation of AMP-activated protein kinase in neurons and mouse brain without inducing oxidative damage or inflammation. Furthermore, modulation of complex I activity augmented mitochondrial bioenergetics increasing coupling efficiency of respiratory chain and neuronal resistance to stress. Concomitant reduction of glycogen synthase kinase 3β activity and restoration of axonal trafficking resulted in elevated levels of neurotrophic factors and synaptic proteins in adult AD mice. Our results suggest metabolic reprogramming induced by modulation of mitochondrial complex I activity represents promising therapeutic strategy for AD.

Ethnopharmacological Relevance: Trifolium species are used in Turkish folk medicine as a wound healing agent, expectorant, antiseptic, sedative and to alleviate pain in rheumatism. In the present study, the aqueous methanolic extracts (80%) of 13 Trifolium species (Trifolium ambigum, Trifolium arvense var. arvense, Trifolium campestre, Trifolium canescens, Trifolium hybridum var. anatolicum, Trifolium hybridum var. hybridum, Trifolium pannonicum, Trifolium pratense var. pratense, Trifolium purpureum var. purpureum, Trifolium repens var. repens, Trifolium resupinatum var. microcephalum, Trifolium spadiceum and Trifolium trichocephalum) collected from different regions of Anatolia were evaluated for their in vivo wound healing effects., Materials and Methods: In vivo wound healing activities of the plant aqueous methanolic extracts were evaluated by linear incision and circular excision wound models subsequent to histopathological analysis. Active constituents were determined by a validated high performance liquid chromatographic method. Precision of the method was performed by the evaluation of intra-day and inter-day variations of the each standard at limits of quantification (LOQ) levels., Results: The aqueous methanolic extracts of Trifolium canescens and Trifolium pretense var. pratense possessed better wound healing activity compared to the other extracts and control groups. The animal groups treated with the Trifolium canescens extract demonstrated increased contraction (48.96%) on excision and a significant increase in wound tensile strength (35.6%) on incision models. The main compounds were detected as genistein and biochanin A for Trifolium canescens., Conclusion: The results of the present study revealed the wound healing potential of Trifolium canescens. This might be due to the combined effect of the isoflavones genistein, formononetin, daidzein, and biochanin A present in the extract., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the CNS. Although, MS is well characterized in terms of the role played by immune cells, cytokines and CNS pathology, nothing is known about the metabolic alterations that occur during the disease process in circulation. Recently, metabolic aberrations have been defined in various disease processes either as contributing to the disease, as potential biomarkers, or as therapeutic targets. Thus in an attempt to define the metabolic alterations that may be associated with MS disease progression, we profiled the plasma metabolites at the chronic phase of disease utilizing relapsing remitting-experimental autoimmune encephalomyelitis (RR-EAE) model in SJL mice. At the chronic phase of the disease (day 45), untargeted global metabolomic profiling of plasma collected from EAE diseased SJL and healthy mice was performed, using a combination of high-throughput liquid-and-gas chromatography with mass spectrometry. A total of 282 metabolites were identified, with significant changes observed in 44 metabolites (32 up-regulated and 12 down-regulated), that mapped to lipid, amino acid, nucleotide and xenobiotic metabolism and distinguished EAE from healthy group (p<0.05, false discovery rate (FDR)<0.23). Mapping the differential metabolite signature to their respective biochemical pathways using the Kyoto Encyclopedia of Genes and Genomics (KEGG) database, we found six major pathways that were significantly altered (containing concerted alterations) or impacted (containing alteration in key junctions). These included bile acid biosynthesis, taurine metabolism, tryptophan and histidine metabolism, linoleic acid and D-arginine metabolism pathways. Overall, this study identified a 44 metabolite signature drawn from various metabolic pathways which correlated well with severity of the EAE disease, suggesting that these metabolic changes could be exploited as (1) biomarkers for EAE/MS progression and (2) to design new treatment paradigms where metabolic interventions could be combined with present and experimental therapeutics to achieve better treatment of MS.

Technological innovations and translation of basic discoveries to clinical practice drive advances in medicine. Today's innovative technologies enable comprehensive screening of the genome, transcriptome, proteome, and metabolome. The detailed knowledge, converged in the integrated "omics" (genomics, transcriptomics, proteomics, and metabolomics), holds an immense potential for understanding mechanism of diseases, facilitating their early diagnostics, selecting personalized therapeutic strategies, and assessing their effectiveness. Metabolomics is the newest "omics" approach aimed to analyze large metabolite pools. The next generation of metabolomic screening requires technologies for high throughput and robust monitoring of metabolite levels and their fluxes. In this regard, stable isotope 18O-based metabolite tagging technology expands quantitative measurements of metabolite levels and turnover rates to all metabolites that include water as a reactant, most notably phosphometabolites. The obtained profiles and turnover rates are sensitive indicators of energy and metabolic imbalances like the ones created by genetic deficiencies, myocardial ischemia, heart failure, neurodegenerative disorders, etc. Here we describe and discuss briefly the potential use of dynamic phosphometabolomic platform for disease diagnostics currently under development at Mayo Clinic.

A new method was here developed for the determination of (18)O-labeling ratios in metabolic oligophosphates, such as ATP, at different phosphoryl moieties (α-, β-, and γ-ATP) using sensitive and rapid electrospray ionization mass spectrometry (ESI-MS). The ESI-MS-based method for monitoring of (18)O/(16)O exchange was validated with gas chromatography-mass spectrometry and 2D (31)P NMR correlation spectroscopy, the current standard methods in labeling studies. Significant correlation was found between isotopomer selective 2D (31)P NMR spectroscopy and isotopomer less selective ESI-MS method. Results demonstrate that ESI-MS provides a robust analytical platform for simultaneous determination of levels, (18)O-labeling kinetics and turnover rates of α-, β-, and γ-phosphoryls in ATP molecule. Such method is advantageous for large scale dynamic phosphometabolomic profiling of metabolic networks and acquiring information on the status of probed cellular energetic system.

Next-generation screening of disease-related metabolomic phenotypes requires monitoring of both metabolite levels and turnover rates. Stable isotope (18)O-assisted (31)P nuclear magnetic resonance (NMR) and mass spectrometry uniquely allows simultaneous measurement of phosphometabolite levels and turnover rates in tissue and blood samples. The (18)O labeling procedure is based on the incorporation of one (18)O into P(i) from [(18)O]H(2)O with each act of ATP hydrolysis and the distribution of (18)O-labeled phosphoryls among phosphate-carrying molecules. This enables simultaneous recording of ATP synthesis and utilization, phosphotransfer fluxes through adenylate kinase, creatine kinase, and glycolytic pathways, as well as mitochondrial substrate shuttle, urea and Krebs cycle activity, glycogen turnover, and intracellular energetic communication. Application of expanded (18)O-labeling procedures has revealed significant differences in the dynamics of G-6-P[(18)O] (glycolysis), G-3-P[(18)O] (substrate shuttle), and G-1-P[(18)O] (glycogenolysis) between human and rat atrial myocardium. In human atria, the turnover of G-3-P[(18)O], which defects are associated with the sudden death syndrome, was significantly higher indicating a greater importance of substrate shuttling to mitochondria. Phosphometabolomic profiling of transgenic hearts deficient in adenylate kinase (AK1-/-), which altered levels and mutations are associated to human diseases, revealed a stress-induced shift in metabolomic profile with increased CrP[(18)O] and decreased G-1-P[(18)O] metabolic dynamics. The metabolomic profile of creatine kinase M-CK/ScCKmit-/--deficient hearts is characterized by a higher G-6-[(18)O]P turnover rate, G-6-P levels, glycolytic capacity, γ/β-phosphoryl of GTP[(18)O] turnover, as well as β-[(18)O]ATP and β-[(18)O]ADP turnover, indicating altered glycolytic, guanine nucleotide, and adenylate kinase metabolic flux. Thus, (18)O-assisted gas chromatography-mass spectrometry and (31)P NMR provide a suitable platform for dynamic phosphometabolomic profiling of the cellular energetic system enabling prediction and diagnosis of metabolic diseases states.

Background: The identification of early mechanisms underlying Alzheimer's Disease (AD) and associated biomarkers could advance development of new therapies and improve monitoring and predicting of AD progression. Mitochondrial dysfunction has been suggested to underlie AD pathophysiology, however, no comprehensive study exists that evaluates the effect of different familial AD (FAD) mutations on mitochondrial function, dynamics, and brain energetics., Methods and Findings: We characterized early mitochondrial dysfunction and metabolomic signatures of energetic stress in three commonly used transgenic mouse models of FAD. Assessment of mitochondrial motility, distribution, dynamics, morphology, and metabolomic profiling revealed the specific effect of each FAD mutation on the development of mitochondrial stress and dysfunction. Inhibition of mitochondrial trafficking was characteristic for embryonic neurons from mice expressing mutant human presenilin 1, PS1(M146L) and the double mutation of human amyloid precursor protein APP(Tg2576) and PS1(M146L) contributing to the increased susceptibility of neurons to excitotoxic cell death. Significant changes in mitochondrial morphology were detected in APP and APP/PS1 mice. All three FAD models demonstrated a loss of the integrity of synaptic mitochondria and energy production. Metabolomic profiling revealed mutation-specific changes in the levels of metabolites reflecting altered energy metabolism and mitochondrial dysfunction in brains of FAD mice. Metabolic biomarkers adequately reflected gender differences similar to that reported for AD patients and correlated well with the biomarkers currently used for diagnosis in humans., Conclusions: Mutation-specific alterations in mitochondrial dynamics, morphology and function in FAD mice occurred prior to the onset of memory and neurological phenotype and before the formation of amyloid deposits. Metabolomic signatures of mitochondrial stress and altered energy metabolism indicated alterations in nucleotide, Krebs cycle, energy transfer, carbohydrate, neurotransmitter, and amino acid metabolic pathways. Mitochondrial dysfunction, therefore, is an underlying event in AD progression, and FAD mouse models provide valuable tools to study early molecular mechanisms implicated in AD.

Plasticity of the cellular bioenergetic system is fundamental to every organ function, stress adaptation and disease tolerance. Here, remodelling of phosphotransfer and substrate utilization networks in response to chronic creatine kinase (CK) deficiency, a hallmark of cardiovascular disease, has been revealed in transgenic mouse models lacking either cytosolic M-CK (M-CK(-/-)) or both M-CK and sarcomeric mitochondrial CK (M-CK/ScCKmit(-/-)) isoforms. The dynamic metabolomic signatures of these adaptations have also been defined. Tracking perturbations in metabolic dynamics with (18)O and (13)C isotopes and (31)P NMR and mass spectrometry demonstrate that hearts lacking M-CK have lower phosphocreatine (PCr) turnover but increased glucose-6-phosphate (G-6-P) turnover, glucose utilization and inorganic phosphate compartmentation with normal ATP γ-phosphoryl dynamics. Hearts lacking both M-CK and sarcomeric mitochondrial CK have diminished PCr turnover, total phosphotransfer capacity and intracellular energetic communication but increased dynamics of β-phosphoryls of ADP/ATP, G-6-P and γ-/β-phosphoryls of GTP, indicating redistribution of flux through adenylate kinase (AK), glycolytic and guanine nucleotide phosphotransfer circuits. Higher glycolytic and mitochondrial capacities and increased glucose tolerance contributed to metabolic resilience of M-CK/ScCKmit(-/-) mice. Multivariate analysis revealed unique metabolomic signatures for M-CK(-/-) and M-CK/ScCKmit(-/-) hearts suggesting that rearrangements in phosphotransfer and substrate utilization networks provide compensation for genetic CK deficiency. This new information highlights the significance of integrated CK-, AK-, guanine nucleotide- and glycolytic enzyme-catalysed phosphotransfer networks in supporting the adaptivity and robustness of the cellular energetic system.

Intramolecular correlations among the (18)O-labels of metabolic oligophosphates, mapped by J-decoupled (31)P NMR 2D chemical shift correlation spectroscopy, impart stringent constraints to the (18)O-isotope distributions over the whole oligophosphate moiety. The multiple deduced correlations of isotopic labels enable determination of site-specific fractional isotope enrichments and unravel the isotopologue statistics. This approach ensures accurate determination of (18)O-labeling rates of phosphometabolites, critical in biochemical energy conversion and metabolic flux transmission. The biological usefulness of the J-decoupled (31)P NMR 2D chemical shift correlation maps was validated on adenosine tri-phosphate fractionally (18)O labeled in perfused mammalian hearts.

Atorvastatin is commonly used as a cholesterol lowering agent in patients. Recently, the neuroprotective effects of atorvastatin became the focus of many research studies. In this study, we have formulated chitosan microspheres containing atorvastatin calcium. In-vitro characterization of chitosan microspheres and quantification of atorvastatin calcium from formulations were also evaluated. The neuroprotective efficiency of atorvastatin calcium was investigated by an experimental spinal cord injury model. Atorvastatin calcium microspheres were implanted at the laminectomy area (1 mg/kg) immediately after trauma. Twenty-four hours after injury, motor functions of animals were scored according to modified Tarlov Scale. In spinal cord tissues tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and lipid peroxidation levels were quantified and ultrastructural changes have been investigated. The results of all parameters indicate that microspheres containing atorvastatin calcium were capable of improving functional outcome, attenuating the expression of TNF-alpha, IL-1beta and IL-6; lowering lipid peroxidation levels and maintaining the preservation of the cellular uniformity.

Wide-spectrum quinolones such as moxifloxacin and levofloxacin as well as high-order cephalosporins such as cefoperazone and cefepime have increased antimicrobial activity. However, little is known about their distribution in fetal blood. Therefore, the aim of this study was to measure and compare maternal and fetal blood levels of these agents. For the measurement of blood levels, 9 pregnant women received cefepime hydrochloride, 10 received cefoperazone, 10 received moxifloxacin and 12 received levofloxacin intravenously. Maternal and umbilical cord blood samples were drawn during delivery. Antibiotic levels were analysed by high-performance liquid chromatography. Mean transplacental passage rates of moxifloxacin, levofloxacin, cefepime and cefoperazone were 74.84%, 66.53%, 23.21% and 12.68%, respectively, and mean transfetal passage rates were 90.78%, 84.22%, 79.17% and 79.78%, respectively. The transplacental passage rate for either quinolone was significantly higher than that of either cephalosporin, and the transplacental passage rate of cefoperazone was lower than that of cefepime. In conclusion, both quinolones have high transplacental passage rates. Cefepime and cefoperazone have a lower transplacental passage rate and thus may be used as prophylaxis in situations where transplacental passage is undesirable., (Copyright (c) 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)

In this study, a simple, rapid, cost-effective, and sensitive reversed-phase high-performance liquid chromatographic method has been developed and validated for the analysis of moxifloxacin in plasma. The chromatographic separation was achieved on a Zorbax Eclipse XDB-C18 column (150 mm x 4.6 mm i.d.) connected to a Phenomenex C(18) column (4 mm x 3.0 mm i.d.) using a mixture of acetonitrile: 15 mM citrate buffer (pH 3) (23:77, v/v) as the mobile phase with isocratic system at a flow rate of 1 mL/min. Fluorescence detection was employed with excitation at 290 nm and emission at 500 nm. Lomefloxacin was used as internal standard. Plasma samples were prepared with addition of acetonitrile only. The method was fully validated according to the International Conference on Harmonization (ICH) guidelines. The results of the validation parameters were: linearity range, 3-6000 ng/mL (R(2) = 0.9994); mean recovery, 100.48 %; limit of quantification, 5 ng/mL; limit of detection, 1 ng/mL; and intra- and inter-day precision less than 3.2% and 5.1%, respectively. The robustness of the method was evaluated and confirmed with fractional factorial design. After validation studies, the method was applied in order to conclude the effects of pregnancy on postoperative pharmacokinetic profiles of moxifloxacin. For this aim, moxifloxacin was given to non-pregnant women (n=9) and caesarean-sectioned women (n=6) as a single intravenous dose (400 mg Avelox(R) infusion). Plasma samples were analyzed in order to compare pharmacokinetic profiles of pregnants and non-pregnants. Peak serum concentrations of non-pregnant and caesarean-sectioned women at the arterial port after the infusion were 4.95 +/- 1.50 and 1.56 +/- 0.16 microg/mL, respectively. The mean elimination half-life, volume of distribution and calculated area under the concentration-time curve (AUC)(0-infinity) were 5.54 +/- 0.73 h, 65.58 +/- 6.30 L and 49.95 +/- 6.30 microg.h/mL for non-pregnant women and 3.50 +/- 0.37 h, 215.85 +/- 24.87 L and 10.53 +/- 0.66 microg.h/mL for caesarean-sectioned women, respectively. These results indicated that pregnancy has a significant effect on the pharmacokinetics of moxifloxacin.

Aim: Moxifloxacin and levofloxacin are wide spectrum quinolones and cefixime is a third-generation cephalosporin with a wider spectrum of activity against gram-positive and gram-negative bacteria and anaerobics. Although they are widely used, little is known about the amniotic fluid levels of these antibiotics. The aim of the present investigation was to study and compare the maternal blood and amniotic fluid levels of these antibiotics in second trimester pregnancy., Methods: To assess the amniotic fluid levels of these antibiotics, 10 pregnant women were given moxifloxacin, 10 were given levofloxacin and 6 were given cefixime orally 2 h before amniocentesis as a single dose for prophylaxis. During amniocentesis, an extra 2 mL amniotic fluid sample and 2 mL maternal venous blood were drawn. The levels of these agents in samples were analyzed using high performance liquid chromatography., Results: The amniotic fluid levels of moxifloxacin and levofloxacin were 0.27 +/- 0.21 microg/mL and 0.60 +/- 0.41 microg/mL, respectively. The maternal blood levels were 3.53 +/- 0.65 microg/mL and 3.95 +/- 0.77 microg/mL in the moxifloxacin and levofloxacin groups, respectively. The maternal blood level of cefixime was 2.59 +/- 1.10 microg/mL and the amniotic fluid level was 0.85 +/- 0.42 microg/mL. The amniotic fluid passage rates were 7.83% for moxifloxacin, 15.67% for levofloxacin and 37.55% for cefixime., Conclusion: Of these three antibiotics, cefixime has the highest transplacental passage rate and, therefore, can be used as a therapeutic agent in infectious conditions in which membranes and the placenta are involved. Moxifloxacin and levofloxacin have low passage rates, which should be considered when using as a therapeutic agent.

An HPLC method for the separation of seven cephalosporins [Cefepime (CEP), ceftazidime (CTA), ceftizaxime (CTI), ceftriaxone (CTR), cefotaxime (COT), cefixime (CIX) and cefoperazone (COP)] in human plasma and amniotic fluid has been developed. Optimization of the chromatographic method was performed in three steps: a series of initial experiments followed by two sets of experiments based on different experimental designs. The initial experiments were performed to decide the basic analytical requirements of the method. Then screening experiment fractional factorial design was used in order to decrease the number of parameters by eliminating parameters which having insignificant effect on responses. The parameters having significant effect were further optimized through a full factorial design. Having studied two responses (retention times and resolutions), a desirability function that assess the responses together, was used to find experimental conditions where the system generated desirable results. The desirable results were obtained with XTerra C18 (250 mm x 4.6mm, 5 microm i.d.) column, 40 mM phosphate buffer, pH 3.2, 18% MeOH, 0.85 mL min(-1) flow rate and 32 degrees C column temperature. Gradient elution with MeOH was applied. A simple and efficient solid-phase extraction was applied for the preparation of plasma and amniotic fluid samples. The validation parameters of the method were evaluated in accordance with ICH guideline. The method validated was applied to the analysis of CEP and COP in maternal venous, fetal venous and fetal arterial plasma, and to the analysis of CIX in maternal venous plasma and amniotic fluid.

A capillary zone electrophoretic assay has been developed and validated for analysis of magnesium, calcium, sodium, and potassium in blood plasma samples. Optimum results were obtained with 20 mmol L(-1) imidazole (pH 2.8) and 0.5 mmol L(-1) oxalic acid containing 5% methanol, capillary temperature 25 degrees C, applied voltage 30 kV, hydrodynamic injection time 3 s, and a poly(vinyl alcohol)-coated capillary (i.d. 50 microm, total length 64.5 cm and effective length 56 cm). Indirect detection was performed at 214 nm. Cadmium was used as internal standard. The migration times of magnesium, calcium, sodium, and potassium were 4.25, 3.79, 3.96, and 2.79 min, respectively. The method was applied to the determination of magnesium, calcium, sodium, and potassium in blood plasma samples. The results were compared with those from atomic absorption spectrophotometry and no statistically significant difference was found (P > 0.05).

Zero and first order derivative UV spectrophotometric methods were developed for the analysis of lornoxicam (LOR). The solutions of the standards and pharmaceutical samples were prepared in 0.05 N NaOH. Absorbances of LOR were measured at 376 nm for the zero order by measuring height of peak from zero and at 281 and 302 nm for the first order derivative spectrophotometric method by measuring peak to peak height. The linearity ranges were found to be 0.5-35 microg/mL for the zero order and 0.2-75 microg/mL for the first order derivative UV spectrophotometric method. The methods were validated and applied to the determination of LOR in pharmaceutical preparations (tablet and injectable, both containing 8 mg LOR). It was concluded that the methods developed were accurate, sensitive, precise, robust, rugged and useful for the quality control of LOR in pharmaceutical preparations.

A simple and rapid micellar electrokinetic capillary chromatographic (MEKC) method for analysis of rofecoxib (ROF) and its photodegradation product (PDP) in pharmaceutical preparations has been developed and validated. Analyses were conducted in a fused silica capillary (72 cm effective length, 50 microm i.d.) with a background electrolyte consisting of 25 mmol L(-1) borate buffer at pH 7.0 containing 15 mmol L(-1) sodium dodecyl sulfate (SDS) and 10% acetonitrile (ACN). The separation was performed by voltage-controlled system, applying 30 kV at 30 degrees C, detecting at 225 nm; injection was hydrodynamic at 50 mbar for 2 s. Nifedipine was used as internal standard (IS). Under the optimum conditions ROF, PDP, and IS were well separated with in 10 min. The method was validated with regard to linearity, limit of detection and quantitation, precision, accuracy, specificity, and robustness. The detection limit of the method was low, 0.8 microg mL(-1), and the linearity range was wide, 2.5 to 125 microg mL(-1). The method was highly efficient-5x10(5) plates m(-1) for ROF. The method was applied to the tablet form of ROF-containing pharmaceutical preparations. The data were compared with those from the voltammetric method described in literature. No statistically significant difference was found.

A capillary zone electrophoresis assay for the analysis of meloxicam has been developed and validated. The influence of buffer concentration, buffer pH, methanol as organic modifier, capillary temperature, applied voltage and injection time was systemically investigated in a fused silica capillary (i.d. 50 microm, total length 44 cm and effective length 35.5 cm). Optimum results were obtained with a 100 mM borate buffer (pH 8.5) containing 5% methanol, capillary temperature 25 degrees C, applied voltage 20 kV and injection time 3 s hydrodynamic injection. The detection wavelength was set to 205 nm. Diflunisal was used as internal standard. The method showed good selectivity, accuracy, precision, linearity and sensitivity according to the evaluation of the validation parameters. The method was applied to the determination of six pharmaceutical preparations including two dosage forms. The relative standard deviation of 7 replicate analyses for each sample was less than 0.66%. The results were compared with a spectrophotometric method reported in literature and no significant difference was found statistically.

Meloxicam is a new non-steroidal anti-inflammatory drug (NSAID), which has a higher activity cyclooxygenase-2 (COX-2) than against cyclooxygenase-1 (COX-1), with potentially high anti-inflammatory and analgesic action. The voltammetric behaviour of meloxicam was studied using direct current (DC), differential pulse polarography (DPP) and cyclic voltammetry (CV). The influence of several variables (including nature of the buffer, pH, concentration, modulation amplitude, scan rate, drop size, etc.) was examined in DPP method for meloxicam. The best DPP response was obtained in acetate buffer pH 4.88. The peak currents were measured with a static mercury drop electrode at -1.49 V versus Ag/AgCl. Calibration curve for meloxicam was linear at a concentration range from 0.38 to 15.0 microg ml(-1). The method was validated and applied to the determination of meloxicam in tablets, which were in two different dosage forms. A spectrophotometric method reported in the literature was utilized as a comparison method. There were no significant differences between the results obtained by two methods. DPP method is also available and applicable for the determination of mentioned substance in plasma. Mean recovery was 99.20+/-0.37%. It was concluded that the developed method was accurate, sensitive, precise, reproducible and useful for the quality control of meloxicam in pharmaceuticals and spiked plasma.