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PubMed1985

Determination of ibuprofen in human plasma by solid phase extraction and reversed-phase high-performance liquid chromatography.

A new, sensitive and simple method for the rapid quantitative determination of ibuprofen in human plasma has been developed. This method involves the use of a solid phase extraction on "Baker" C-18 disposable extraction columns for sample clean-up and uses mefenamic acid as an internal standard. Separation and quantitation are performed by reversed-phase liquid chromatography using a Nucleosil C18 column and methanol-0.04 M phosphoric acid (80:20, v/v), as the mobile phase. Detection was achieved by UV-absorbance measurements at 229 nm.

Journal Article↗
PubMed1990

Prostanoids and hypothermic renal preservation injury.

The effect of 48 hours of hypothermic renal ischemia utilizing Euro-Collins flush and short term reperfusion on renal prostaglandin synthesis was studied in dogs. Hypothermic ischemia followed by 60 minutes of reperfusion in-vivo resulted in significant elevations in renal Thromboxane B2 (TXB2) production in the outer cortex, inner cortex, and medulla, relative to non-ischemic kidneys. Prostaglandin E2 (PGE2) and 6-keto Prostaglandin F1 alpha (6-K PGF1 alpha) production were not significantly affected by ischemia and reperfusion. Enhanced TXB2 production was not seen with ischemia alone (without reperfusion) or with reperfusion with O2 saturated buffer, indicating a blood born source or stimuli. Early postreperfusion renal blood flow after hypothermic ischemia followed a biphasic pattern; blood flow increased for the first 10 minutes of reperfusion to achieve normal values, and then steadily declined over the next 20 minutes. This pattern was not altered by the cyclooxygenase inhibitors Idomethacin (5 mg/kg, P.O.) or Mefenamic acid (10 mg/kg, I.V.). Administration of the TXA2 synthesis inhibitor CGS-12970 (3 mg/kg, I.V.) or the TXA2/endoperoxide receptor antagonist SQ-29548 (80 micrograms/min, I.A.) significantly increased renal blood flow during reperfusion but neither agent altered the basic time dependent pattern observed in the control group. These data indicate that 48 hours of hypothermic renal ischemia results in dramatic changes in intrarenal TXA2 synthesis at the time of reperfusion. Enhanced TXA2 production is not dependent on reoxygenation per se, but rather requires reperfusion with blood suggesting a circulatory source.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Modulation of functional properties of KCNQ1 channel by association of KCNE1 and KCNE2.

The KCNE proteins (KCNE1 through KCNE5) function as beta-subunits of several voltage-gated K(+) channels. Assembly of KCNQ1 K(+) channel alpha-subunits and KCNE1 underlies cardiac I(Ks), while KCNQ1 interacts with all other members of KCNE forming complexes with different properties. Here we investigated synergic actions of KCNE1 and KCNE2 on functional properties of KCNQ1 heterologously expressed in COS7 cells. Patch-clamp recordings from cells expressing KCNQ1 and KCNE1 exhibited the slowly activating current, while co-expression of KCNQ1 with KCNE2 produced a practically time-independent current. When KCNQ1 was co-expressed with both of KCNE1 and KCNE2, the membrane current exhibited a voltage- and time-dependent current whose characteristics differed substantially from those of the KCNQ1/KCNE1 current. The KCNQ1/KCNE1/KCNE2 current had a more depolarized activation voltage, a faster deactivation kinetics, and a less sensitivity to activation by mefenamic acid. These results suggest that KCNE2 can functionally couple to KCNQ1 even in the presence of KCNE1.

Animals↗
PubMed2006

Determination of pharmaceuticals of various therapeutic classes by solid-phase extraction and liquid chromatography-tandem mass spectrometry analysis in hospital effluent wastewaters.

A multi-residue analytical method has been developed and validated for determining a selection of 16 pharmaceuticals: the anti-epileptic carbamazepine, seven analgesic/anti-inflammatory drugs (mefenamic acid, indomethacine, ibuprofen, naproxen, diclofenac, ketorolac and acetaminophen), the analgesic opiate codeine, two antidepressants (fluoxetine and paroxetine), beta-blockers (atenolol and propranolol), antibiotic (trimethoprim, metronidazole, and erythromycin) and the anti-ulcer ranitidine in hospital effluent wastewaters. The method allows simultaneous extraction of the pharmaceuticals compounds by solid-phase extraction (SPE) using the Waters Oasis HLB at pH 7. The analytes were then identified and quantitatively determined by liquid chromatography-tandem mass spectrometry (LC-MS-MS) using multiple reaction monitoring (MRM). Recoveries of the pharmaceuticals were higher than 75%, with the exception of ranitidine (45%) and the overall variability of the method was below 9%. The instrumental detection limit (IDL) varied between 2 and 31 pg injected, the method detection limit (LOD) was between 7 and 47 ng/L in spiked hospital effluent. The precision of the method, calculated as relative standard deviation (RSD), ranged from 0.3 to 4.9%. A detail study off matrix effect is included in this work, regarding to signal suppression in these effluent wastewaters from a hospital complex samples. The developed analytical method was applied for preliminary data results in effluent wastewaters from a hospital.

Adrenergic beta-Antagonists↗
PubMed2005

Determination of glabridin in human plasma by solid-phase extraction and LC-MS/MS.

Glabridin is a major flavonoid included specifically in licorice (Glycyrrhiza glabra L.), and has various physiological activities including antioxidant and anti-inflammatory effects. We have developed and validated an analytical method for determination of glabridin in human plasma by solid-phase extraction (SPE) and LC-MS/MS. Glabridin was extracted from plasma by SPE using a C8 cartridge and analyzed by LC-MS/MS using mefenamic acid as an internal standard (IS). The analyte were separated by a C18 column on LC, and monitored with a fragment ion of m/z 201 formed from a molecular ion of m/z 323 for glabridin and that of m/z 196 from m/z 240 for IS during negative ion mode with tandem MS detection. The lower limit of quantitation (LLOQ) of glabridin was 0.1 ng/mL in plasma, corresponding to 1.25 pg injected on-column. The calibration curves exhibited excellent linearity (r>0.997) between 0.1 and 50 ng/mL. Precision and accuracy were <17 and <+/-7% at LLOQ, and <11 and <+/-5% at other concentrations. Glabridin was recovered >90%, and was stable when kept at 10 degrees C for 72 h, at -20 degrees C until 12 weeks, and after three freeze-thaw cycles. This is the first report on determination of glabridin in body fluids by the selective, sensitive, and reproducible method.

Chromatography, Liquid↗
PubMed2004

Biological activity of five antibacterial flavonoids from Combretum erythrophyllum (Combretaceae).

Preliminary studies with Combretum erythrophyllum showed antimicrobial activity against Gram-positive and Gram-negative bacteria. Seven antibacterial flavonoids were subsequently isolated by bioassay-guided fractionation, i.e. apigenin; genkwanin; 5-hydroxy-7,4'-dimethoxyflavone, rhamnocitrin; kaempferol; quercetin-5,3'-dimethylether; rhamnazin. All compounds had good activity against Vibrio cholerae and Enterococcus faecalis, with MIC values in the range of 25-50 microg/ml. Rhamnocitrin and quercetin-5,3'-dimethylether also inhibited Micrococcus luteus and Shigella sonei at 25 microg/ml. With the exception of 5-hydroxy-7,4'-dimethoxy-flavone the flavonoids were not toxic towards human lymphocytes. This compound is potentially toxic to human cells and exhibited the poorest antioxidant activity whereas rhamnocitrin and rhamnazin exhibited strong antioxidant activity. Genkwanin; rhamnocitrin; quercetin-5,3'-dimethylether; rhamnazin had a higher anti-inflammatory activity than the positive control mefenamic acid. Although these flavonoids are known, this is the first report of biological activity with several of these compounds.

Anti-Bacterial Agents↗
PubMedDate not supplied

Hysteroscopic endometrial ablation using the Hydro ThermAblator in an outpatient hysteroscopy clinic: feasibility and acceptability.

STUDY OBJECTIVE: To assess the feasibility and patient acceptability of global endometrial ablation using the Hydro ThermAblator (HTA) in an outpatient hysteroscopy clinic setting under local anaesthesia. DESIGN: A prospective cohort study (Canadian Task Force classification II-2). SETTING: University hospital in the United Kingdom. PATIENTS: Forty patients with medication-resistant menorrhagia. INTERVENTION: Oral mefenamic acid was administered 8 hours before the procedure. A combined cervical/paracervical block using lignocaine 1% adrenaline 1:200,000 was used before hysteroscopic endometrial ablation using the HTA device. MEASUREMENTS AND MAIN RESULTS: A successful procedure was defined as a completed HTA treatment cycle. Failure was defined as premature termination or inability to carry out the HTA procedure after scheduling the patient. Pain scores were estimated at three stages during and after the procedure using a visual-analog scale. A questionnaire was used before discharge to assess acceptability. Forty patients were successfully treated. The median pain score during the ablation was 6.4 (range 4.0-8.9). Eighty-eight percent of patients found the procedure acceptable. No serious complications occurred. All patients were discharged home within 2 hours of the procedure. CONCLUSION: Selected patients suffering from menorrhagia may be treated with the HTA device using local anesthesia in an outpatient setting.

Adult↗
PubMed1998

Cyclooxygenase-1 and cyclooxygenase-2 selectivity of widely used nonsteroidal anti-inflammatory drugs.

PURPOSE: Both isoforms of cyclo-oxygenase, COX-1 and COX-2, are inhibited to varying degrees by all of the available nonsteroidal anti-inflammatory drugs (NSAIDs). Because inhibition of COX-1 by NSAIDs is linked to gastrointestinal ulcer formation, those drugs that selectively inhibit COX-2 may have less gastrointestinal toxicity. We measured the extent to which NSAIDs and other anti-inflammatory or analgesic drugs inhibit COX-1 and COX-2 in humans. SUBJECTS AND METHODS: Aliquots of whole blood from 16 healthy volunteers were incubated ex vivo with 25 antiinflammatory or analgesic drugs at six concentrations ranging from 0 (control) to 100 microM (n = 5 for each). Blood was assayed for serum-generated thromboxane B2 synthesis (COX-1 assay) and for lipopolysaccharide-stimulated prostaglandin E2 synthesis (COX-2 assay). In addition, gastric biopsies from the same volunteers were incubated with each drug ex vivo and mucosal prostaglandin E2 synthesis measured. RESULTS: Inhibitory potency and selectivity of NSAIDs for COX-1 and COX-2 activity in blood varied greatly. Some NSAIDs (eg, flurbiprofen, ketoprofen) were COX-1 selective, some (eg, ibuprofen, naproxen) were essentially nonselective, while others (eg, diclofenac, mefenamic acid) were COX-2 selective. Inhibitory effects of NSAIDs on gastric prostaglandin E2 synthesis correlated with COX-1 inhibitory potency in blood (P < 0.001) and with COX-1 selectivity (P < 0.01), but not with COX-2 inhibitory potency. Even COX-2 "selective" NSAIDs still had sufficient COX-1 activity to cause potent inhibitory effects on gastric prostaglandin E2 synthesis at concentrations achieved in vivo. CONCLUSION: No currently marketed NSAID, even those that are COX-2 selective, spare gastric COX activity at therapeutic concentrations. Thus, all NSAIDs should be used cautiously until safer agents are developed.

Adult↗
PubMed2000

Beta(3)-adrenergic stimulation and insulin inhibition of non-selective cation channels in white adipocytes of the rat.

Single-channel currents were recorded from the plasma membrane of white adipocytes of 6-8-week-old male Sprague-Dawley rats. In outside-out patches (high K(+), no Ca(2+) in pipette), a voltage-dependent K-channel (delayed rectifier) with a single-channel conductance (gamma) of 16 pS (24 degrees C) in modified Ringer's was active at a density of 0.5/microm(2). It was blocked by TEA (IC(50)=1.5 mM). A Ca(2+)-activated non-selective cation channel (NSC-channel) appeared at a mean density of 1/microm(2) in inside-out patches ([Ca(2+)](i)=1.2 mM). gamma was 28 pS (24 degrees C). The NSC showed weak voltage dependence and was blocked by mefenamic acid and by internal ATP. In the cell-attached mode spontaneous activity could be blocked reversibly by 100 nM insulin. Noradrenaline (NA, 100 nM) induced a flickering activity of the NSC-channels. Isoproterenol (100 nM) caused activity of the NSC-channel as well. After 1 microM propranolol even 1 microM NA did not induce any activity. The alpha-antagonist phentolamine had no effect on isoproterenol- or on NA-induced currents. The beta(3)-agonists BRL 37344 and BRL 35135A induced activity of the NSC-channel at 100 nM as well. We conclude that white adipocytes express ion channels which are comparable to those in brown adipocytes and that beta-receptor activation opens NSC-channels thus allowing for Na(+) entry into white adipocytes.

Adenosine Triphosphate↗
PubMed1999

Medical treatment of a grossly enlarged adenomyotic uterus with the levonorgestrel-releasing intrauterine system.

Adenomyosis is an important cause of menorrhagia. Besides hysterectomy, the treatment options for adenomyosis have been limited. Presented here is the successful treatment of adenomyosis in a woman presenting with menorrhagia, dysmenorrhea, and an enlarging uterus, for whom conservative therapy initiated with mefenamic acid was unsatisfactory. The patient had insertion of the levonorgestrel-releasing intrauterine system (LNG-IUS). A marked decrease in uterine size occurred within 12 months of insertion accompanied by resolution of the menorrhagia and dysmenorrhea. Thus, the LNG-IUS is a viable option and represents a real advance in the treatment of adenomyosis.

Adult↗
PubMed1998

Vasoconstriction induced by zooxanthellatoxin-B, a polyoxygenated long-chain product from a marine alga.

We found that zooxanthellatoxin-B from a symbiotic marine alga, Symbiodinium sp., caused a concentration-dependent contraction of the rabbit isolated aorta at concentrations of 10(-7)-10(-5) M. Verapamil (10(-6) M) and mefenamic acid (10(-5) M) significantly attenuated the contractile response to zooxanthellatoxin-B at lower concentrations (10(-7)-10(-6) M) but not at higher concentrations (3 X 10(-6)-10(-5) M). The response to zooxanthellatoxin-B was partly inhibited by phentolamine (10(-6) M), whereas it was potentiated by ouabain (10(-5) M). Tetrodotoxin (10(-6) M), methysergide (10(-6) M), chlorpheniramine (10(-6) M) or indomethacin (3 X 10(-6) M), however, did not affect it. The zooxanthellatoxin-B-induced contraction was abolished by incubation in Ca2+-free solution. The contractile response increased in a concentration-dependent fashion with Ca2+ (0.03 and 10 mM) or Sr2 + (0.10 and 10 mM). After treatment with verapamil (10(-6) or 5 X 10(-6) M), the concentration-contractile response curves for Ca2+ and Sr2+ in the presence of zooxanthellatoxin-B were shifted to the right in parallel. MgCl2 (10 mM) shifted the concentration-response curve for Ca2+ more markedly than did verapamil. Zooxanthellatoxin-B increased tissue Na+ and reduced tissue K+ contents in the aorta, suggesting that zooxanthellatoxin-B increases Na+ and K+ permeability across the plasma membrane. These results suggest that the zooxanthellatoxin-B-induced contraction of the aorta is caused mainly by a direct action on smooth muscle, i.e., an increase in Ca2+ permeability that occurs at least partly through voltage-sensitive Ca2+ channels as well as through nonselective cation channels in the cell membrane of smooth muscle.

Animals↗
PubMed1985

Analysis of antipyretics by semimicro liquid chromatography.

Using semimicro columns (150 X 1 mm I.D.) of octadecyl silica and styrene-divinylbenzene porous polymer, antipyretic drugs were analyzed by means of high-performance liquid chromatography. The antipyretics studied were sulpyrin, caffeine, guaiacol glycerol ether, acetaminophen, 3-hydroxy-p-butyrophenetidine, methyl p-hydroxybenzoate, phenacetin, mefenamic acid, aspirin, salicylamide, salicylic acid, o-ethoxybenzamide, theobromine, theophylline and their preparations. The semimicro columns are economical in solvents in chromatographic analysis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Sepsis alters vessel contraction by adrenoceptor-induced nitric oxide and prostanoid.

BACKGROUND: Alpha-adrenergic agents contract vascular smooth muscle (VSM) and stimulate endothelial release of secondary factors which modulate VSM contraction. Our study examined constrictor prostanoid (cPN) and nitric oxide (NO) as secondary factors which could alter alpha-1 adrenoceptor-mediated contraction during sepsis. METHODS: Sepsis was induced in rats by inoculation of an implanted sponge with Escherichia coli and Bacteroides fragilis. Aortic rings at 24 h from septic (n = 21) and control (n = 21) rats were suspended in physiological salt solution (PSS) with or without blockers to NO (N(G)-monomethylarginine), cPN (mefenamic acid, MFA), or thromboxane A2 (SQ29548). Contraction dose-response curves were generated to determine maximal contraction force (F(max)) and pD2 (sensitivity) to phenylephrine in each experimental group. RESULTS: Sepsis increased F(max) to phenylephrine (PHE) (1.18 vs 0.90 g, SEM 0.0703). COX inhibition reduced the F(max) in control (0.63 vs 0.90 g, SEM 0.0675) but not in septic animals (1.19 vs 1.18 g, SEM 0.0433). TXA2 receptor inhibition did not alter F(max) in control (1.017 vs 0.973 g, SEM 0.0959) or septic animals (1.28 vs 1.12 g, SEM 0.0823). NOS inhibition enhanced the F(max) in both nonseptic (2.03 vs 0.83 g, SEM 0.0523) and septic rats (1.96 vs 1.15 g, SEM 0.0526), but did less so in the septic animals. CONCLUSIONS: PHE-induced F(max) is determined by a balance between PHE-stimulated VSM alpha-adrenoceptor activity, and PHE-stimulated endothelial release of cPN and NO. Sepsis enhances total PHE-induced F(max) by increasing VSM alpha-adrenoceptor activity and reducing PHE-stimulated endothelial release of dilator NO. Sepsis abolishes the PHE-stimulated endothelial release of cPN. PHE-stimulated cPN is not thromboxane A2, but could be a nonprostanoid dilator in the lipoxygenase (HETE) or cytochrome P450 (EET) pathways.

Animals↗
PubMed1983

Relationships between prostaglandins and estrogens on the motility of isolated rings from the rat urinary bladder.

We studied the spontaneous contractile activity and the effect of inhibitors of prostaglandin synthesis on the motility of the detrusor muscle isolated from estrous and ovariectomized rats. The constancy with time of the isometric developed tension and of the frequency of contractions of preparations obtained from estrous and spayed rats were not significantly different. In addition, the basal tone was in both cases stable and comparable during the whole experiment. Indomethacin (10(-5) M) or mefenamic acid (10(-5) M) abolished the phasic spontaneous motility whereas the basal tone was significantly diminished with time, the decrement being stabilized after 30 or 40 minutes. The action of inhibitors of prostaglandin synthesis was similar in isolated rings from estrous or ovariectomized animals. Cumulative dose-response curves of PGE2, PGE1 and PGF2 alpha demonstrated that PGF2 alpha evoked contractions with less efficacy and potency than PGs of the E series in both experimental groups. The most important finding was that the dose-response curves of PGE2 and PGE1 were shifted to the right in preparations obtained from ovariectomized rats, whereas the reactivity to PGF2 alpha was similar in estrus or after ovariectomy. In spayed rats injected with 17-beta-estradiol the contractile response of the isolated detrusor to PGE1 had greater efficacy and potency than in preparations from untreated ovariectomized animals. The present findings suggest the possibility that micturition problems commonly found in menopause could be due to a diminished sensitivity to PGE associated to low estrogen levels.

Animals↗
PubMed2002

Aquatic environmental assessment of the top 25 English prescription pharmaceuticals.

An environmental assessment is presented for the 25 most used pharmaceuticals in the National Health Service (NHS) in England in 2000. Predicted environmental concentrations (PECs) for the aquatic environment were calculated using conservative assumptions and all PECs exceeded 1 ng 1 (-1). The calculation of predicted no-effect concentration (PNEC) based on aquatic toxicity data from the literature was possible for eleven of the pharmaceuticals. PNECs were predicted with ECOSAR for 12 of the remaining 14 but no data was available for two of the compounds. The PEC/ PNEC ratio exceeded one for Paracetamol, Amoxycillin, Oxytetracycline and Mefenamic acid. Comparisons of the predicted concentrations of the compounds in sewage sludge based on either calculated sludge-water coefficients (Kd), octanol water coefficients (K(ow)), acid base constants (pKa) or environmental modelling revealed large variations. No toxicity data was available for the terrestrial environment and no assessment was made.

England↗
PubMed1988

Effect of fenamates on prostaglandin E receptor binding.

The effect of fenamates on prostaglandin E receptor binding was examined in myometrial samples collected at hysterectomy. Sodium meclofenamate and mefenamic acid inhibited binding of PGE2 to its specific receptor in a dose-dependent manner, with an ED50 of 20 mumol/l and 200 mumol/l, respectively.

Dinoprostone↗
PubMed1989

Rapid high-performance liquid chromatographic methods for the determination of overdose concentrations of some non-steroidal anti-inflammatory drugs in plasma or serum.

Separate methods are described for the determination of the non-steroidal anti-inflammatory drugs diflunisal, indomethacin, fenoprofen, ibuprofen, ketoprofen, naproxen, mefenamic acid and piroxicam at overdose concentrations in human plasma or serum, using high-performance liquid chromatography and ultraviolet detection. A common extraction, involving protein precipitation with acetonitrile, is employed for all methods. A 25 cm Hypersil ODS (5 mu particle size) analytical column is used for all chromatographic separations, with a mobile phase of acetonitrile-acetate buffer (pH 4.2 or 4.8). The methods are all reproducible and can also determine concentrations that fall within the normal therapeutic range for each drug.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

Simple, rapid and sensitive method for the determination of indomethacin in plasma by high-performance liquid chromatography with ultraviolet detection.

A micro method for determination of indomethacin in plasma was developed. Following deproteinization of plasma with acetonitrile containing internal standard (mefenamic acid), the separation of indomethacin and internal standard was achieved by high-performance liquid chromatography using a 7 microm LiChrosorb-RP18 column (250x4 mm I.D.) at 50 degrees C. The mobile phase was 6 mM phosphoric acid-acetonitrile (50:50). The flow-rate was kept at 2.0 ml/min and the column effluent was monitored at 205 nm. The coefficients of variation of the method estimated at 0.2 and 1.0 microg/ml were 4.2 and 2.3%, and the detection limit of the drug was about 0.05 microg/ml (S/N=5). The method requires minimum pretreatment of the plasma with a small sample volume (25 microl), and is very suitable for therapeutic drug monitoring of indomethacin in premature infants with symptomatic patent ductus arteriosus.

Chromatography, High Pressure Liquid↗