Validated method for the determination of piroxicam by capillary zone electrophoresis and its application to tablets.

Simple and rapid capillary zone electrophoretic method was developed and validated in this study for the determination of piroxicam in tablets. The separation of piroxicam was conducted in a fused-silica capillary by using 10 mM borate buffer (pH 9.0) containing 10% (v/v) methanol as background electrolyte. The optimum conditions determined were 25 kV for separation voltage and 1 s for injection time. Analysis was carried out with UV detection at 204 nm. Naproxen sodium was used as an internal standard. The method was linear over the range of 0.23-28.79 µg/mL. The accuracy and precision were found to be satisfied within the acceptable limits (<2%). The LOD and LOQ were found to be 0.07 and 0.19 µg/mL, respectively. The method described here was applied to tablet dosage forms and the content of a tablet was found in the limits of USP-24 suggestions. To compare the results of capillary electrophoretic method, UV spectrophotometric method was developed and the difference between two methods was found to be insignificant. The capillary zone electrophoretic method developed in this study is rapid, simple, and suitable for routine analysis of piroxicam in pharmaceutical tablets.

Development of a CD-MEKC method for investigating the metabolism of tamoxifen by flavin-containing monooxygenases and the inhibitory effects of methimazole, nicotine and DMXAA.

A selective and low-cost CD-MEKC method under acidic conditions was developed for investigating the N-oxygenation of tamoxifen (TAM) by flavin-containing monooxygenases (FMOs). The inhibitory effects of methimazole (MMI), nicotine and 5,6-dimethylxanthenone-4-acetic acid (DMXAA) on the given FMO reaction were also evaluated; 100 mM phosphate buffer (pH 8.6) was used for performing the enzymatic reaction and the separation of TAM and its metabolite tamoxifen N-oxide (TNO) was obtained with a BGE consisting of 100 mM phosphoric acid solution adjusted to pH 2.5 with triethanolamine containing 50 mM sodium taurodeoxycholate, 20 mM carboxymethyl ß-CD and 20% ACN. The proposed method was applied for the kinetics study of FMO1 using TAM as a substrate probe. A Michaelis-Menten constant (K(m)) of 164.1 µM was estimated from the corrected peak area of the product, TNO. The calculated value of the maximum reaction velocity (V(max)) was 3.61 µmol/min/µmol FMO1; 50% inhibitory concentration and inhibition constant (K(i)) of MMI, the most common alternate substrate FMO inhibitor, were evaluated and the inhibitory effects of two other important FMO substrates, nicotine and DMXAA, a novel anti-tumour agent, were investigated.

Effect of dose and duration of micronized progesterone treatment during the first trimester on incidence of glucose intolerance and on birth weight.

OBJECTIVE: The aim was to investigate the potential effect of oral progesterone therapy during the first trimester on glucose metabolism and on birth weight, and to assess the existence of dose-related differences. METHODS: One hundred and fifty women with a history of imminent abortion and who used micronized progesterone (MicP) (200-600 µg/day for 4-6 weeks), and 150 healthy pregnant women as a control group, were included in the study. Fasting blood glucose (FBG), hemoglobin A1c (HbA1c) and OGL were measured between 24 and 28 weeks of gestation. Patients were followed up to term and birth weight was recorded. RESULTS: Risk of abnormal FBG and OGL was increased by 4.5- and 9.4-fold, respectively, in patients receiving MicP (p < 0.001). Median birth weight and gestational age were 3,599 g (500) and 39.0 weeks (1.3) for the MicP exposed group and 3,120 g (210) and 39.4 weeks (1.5) for the control group, respectively. Median birth weight was significantly higher in the MicP-exposed group for a similar gestational age (p < 0.001). There were no dose-related differences between groups. CONCLUSION: MicP therapy during the first trimester of pregnancy might have undesirable effects on glucose metabolism, which stresses the need of larger studies to confirm this association.

The impact of birth weight and maternal history on acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent girls.

The aim of the study was to determine the association between birthweight, maternal medical history and acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent population. Self-administered questionnaires were distributed to all volunteer female students at 15 secondary schools. The subjects' body mass index, birthweight, age at menarche, pattern of menstrual cycle, and presence of acne or hirsutism problems were recorded. Maternal obstetric parameters, menstrual cycle, presence of acne or hirsutism at present and at adolescent period were also asked. The impact of birthweight and maternal history on acne, hirsutism, and menstrual disorder symptoms was evaluated. The results of the study showed that after exclusion of subjects born prematurely, total of 1,309 students filled the questionnaires properly and included in the study. Of these students, 174 had low birthweight (LBW) (<2,500 g), 925 had appropriate (2,500-4,000 g), and 210 had high birthweight (>4,000 g). LBW students had higher incidence of menstrual disorder and acne problems (P = 0.032 and P = 0.011, respectively). Maternal acne and hirsutism problems were significantly often in LBW group. Multivariate analysis showed that LBW was a predictor of acne, hirsutism, and menstrual disorder at adolescent period (P = 0.001; P = 0.01, and 0.02, respectively). In addition, maternal menstrual disorder was also a predictor of menstrual disorder (P = 0.035). We concluded that LBW is a good predictor of acne, hirsutism, and menstrual disorder problems in Turkish adolescent population.

A simple and sensitive LC-ESI-MS (ion trap) method for the determination of bupropion and its major metabolite, hydroxybupropion in rat plasma and brain microdialysates.

A specific and highly sensitive liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) method for the direct determination of bupropion (BUP) and its main metabolite hydroxybupropion (HBUP) in rat plasma and brain microdialysate has been developed and validated. The analysis was performed on a Bonus RP C18 (100 mm × 2.1mm i.d., 3.5 µm particles) column using gradient elution with the mobile phase consisting of acetonitrile and ammonium formate buffer (10mM, pH 4). Plasma samples were analyzed after a simple, one-step protein precipitation clean-up with trichloroacetic acid (TCA), however clean-up for microdialysis samples was not necessary, enabling direct injection of the samples into the LC-ESI-MS system. Signals of the compounds were monitored under the multiple reaction monitoring (MRM) mode of the LC-ESI-MS (ion trap) for quantification. The precursor to product ion transitions of m/z 240-184 and m/z 256-238 were used to measure BUP and HBUP, respectively. The method was validated in both plasma and microdialysate samples, and the obtained lower limit of quantification (LLOQ) was 1.5 ng mL(-1) for BUP and HBUP in both matrices. The intra- and inter-day assay variability was less than 15% for both analytes. This LC-ESI-MS method provided simple sampling, rapid clean-up and short analysis time (<9 min), applicable to the routine therapeutic monitoring and pharmacokinetic studies of BUP and HBUP.

The effects of vasoactive intestinal peptide on dura mater nitric oxide levels and vessel-contraction responses in sympathectomized rats.

Nitric oxide (NO) and neurogenic inflammation in dura mater due to nociceptor activation has been implicated for pathophysiology of primary headache disorders. Development of migraine has also been observed in patients treated with ganglion blockage for sympathetic reflex dystrophy. Vasoactive intestinal peptide (VIP) is an antioxidant, anti-inflammatory, and neuroprotective neuropeptide. This study is intended to investigate the effects of VIP on dura mater NO levels and vessel-contraction responses in sympathectomized rats. In the experiments, 30 male rats in five groups were used. Group 1 sympathectomized: under anesthesia, superior cervical sympathetic ganglion was removed via incision at the center line in the neck area. Group 2 sympathectomized + VIP: postoperative VIP of 25 ng/kg/day (0.2 ml) intraperitoneally administered to the rats exposed to the same operations for 5 days. Group 3 sham: ganglia and nerves were exposed but not dissected. Group 4 control: no treatment was done. Group 5 VIP: only VIP was administered for 5 days. Sympathectomy induced a significant increase in dura mater NO levels and VIP decreased NO to control levels and increased the norepinephrine vessel-contraction responses of sympathectomized rats. VIP is an efficient NO modulator in superior cervical ganglionectomized rats.

Isolation of peptide transport system-6 from brain endothelial cells: therapeutic effects with antisense inhibition in Alzheimer and stroke models.

By isolating for the first time ever a peptide transporter from the blood-brain barrier (BBB) and developing an antisense that selectively targets the brain-to-blood efflux component, we were able to deliver a therapeutic concentration of the neurotrophic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) 27 to brain in animal models of Alzheimer's and stroke. Efflux pumps at the BBB are major causes of BBB impermeability to peptides. PACAP is neuroprotective in vitro in femtomole amounts, but brain uptake of PACAP27 is limited by an efflux component of peptide transport system-6 (PTS-6). Here, we characterized, isolated, and sequenced this component of PTS-6, identifying it as beta-F1 ATPase, and colocalized it with PACAP27 on BBB endothelial cells. Antisenses targeting the BBB inhibited PACAP27 efflux, thus increasing brain uptake of PACAP27. Treatment with antisense+PACAP27 improved cognition in a mouse model of Alzheimer's disease and reduced infarct size after cerebral ischemia. This represents the first isolation from BBB tissue of a peptide transporter and shows that inhibition of peptide efflux pumps is a potential strategy for drug delivery to brain.

Prevalence and predictors of mental disorders among women in Sanliurfa, Southeastern Turkey.

BACKGROUND: Mental health is one of the most important public health issues because of major contributor to the global burden of disease. In this study, we examined the prevalence and predictors of mental disorders among married women from 15 to 49 years of age and the need for mental health services in the primary health care settings. METHODS: In this cross-sectional study, 270 women were selected using probability cluster sampling method at 95% confidence interval (91.5% response rate). The Structured Clinical Interview for DSM-IV (SCID-I) and women socio-demographic information form were used to collect data. RESULTS: Although the prevalence of mental disorder was 25.9% (8.5% with one diagnosis; 17.4% were two or more diagnoses), 4.7% of these women had contacted a carer in the last year for psychological reasons. According to the SCID-I assessment, the most prevalent diagnoses were major depressive disorder (7.3%), phobic disorder (4.8%) and posttraumatic stress disorder (3.6%). In this study, comorbid diagnoses were present in 67.2% of patients. Logistic regression analyses revealed that domestic violence, history of previous trauma, anemia and cutaneous leishmaniasis were significant predictors of any mental disorders (P < 0.05). CONCLUSIONS: These findings highlight the need for systematic development of community-based mental health services in conjunction with primary health care services for the screening, early identification and treatment of women suffering from mental disorders, and the improvement of anemia and cutaneous leishmaniasis control programme.

Determination of leflunomide in tablets by high performance liquid chromatography.

In the present study, a reverse phase high performance liquid chromatography (HPLC) method was validated and applied for the determination of leflunomide in tablets. Chromatographic separation of leflunomide and oxazepam as an internal standard was carried out on a C(18) column (50 mm, 3 mm i.d.) using a mobile phase, consisting of methanol and water (60:40, v/v), at a flow rate of 0.5 ml min(-1) and UV detection at 260 nm. The retention times for oxazepam and leflunomide were 2.6 and 5.2 min, respectively. The validated quantification range of the method was 2.7 x 10(-6) to 5.5 x 10(-5) M for leflunomide. The results of the developed procedure in tablets were compared with those of UV spectrophotometry to assess active leflunomide content.

Brain mast cells and therapeutic potential of vasoactive intestinal peptide in a Parkinson's disease model in rats: brain microdialysis, behavior, and microscopy.

In the present study, the effect of systemically administered vasoactive intestinal peptide (VIP) (25 ng/kg i.p.) was investigated on drug-induced rotational behavior, extra-cellular dopamine levels and histology of corpus striatum in a 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. After 15 days of 6-OHDA lesion, apomorphine-induced (0.05 mg/kg s.c.) rotational behavior of the animals significantly increased and extra-cellular dopamine levels of corpus striatum were significantly reduced. VIP reversed the rotational deficits but did not alter the decrease in striatal dopamine levels. On the other hand, histological data indicate that VIP significantly reduced neuronal death and demyelination. Electron microscopic appearance of mast cells showed ultra-structural variety between VIP-treated and 6-OHDA lesioned groups. VIP activates mast cells without any evidence of typical exocytosis, and possibly mast cells could participate in neuroprotection. Our results suggest that systemically administered VIP can attenuate the motor response changes, neuronal cell death, and myelin sheet loss characteristically associated with 12 microg 6-OHDA administration into the rat striatum. Brain mast cells seem to participate in neuronal protection. Possibly, protective cues could be produced by brain mast cells.

Determination of lansoprazole in pharmaceutical capsules by flow injection analysis using UV-detection.

The direct determination of lansoprazole by using a flow injection analysis (FIA) with UV-detection and its application to the pharmaceutical capsules is described, in this study. The best carrier solvent was found to be 0.01 M NaOH and it was determined at optimum conditions such as flow rate of 1 ml min(-1) and wavelength of 292 nm. Examining the repeatability of the method that was found to be 1.72% for intra-day and 2.13% for inter-day precision using the 8.01 x 10(-6) M lansoprazole concentration has validated the method. The linear range of the method was 5.4 x 10(-6) to 5.4 x 10(-5) M. The limit of detection and quantification was found to be 5.8 x 10(-7) and 1.7 x 10(-6) M, respectively. The proposed method was applied to the pharmaceutical capsules and very good results obtained. Thus, the FIA method for the quantification of lansoprazole can be proposed as a cheap, rapid, easy, accurate, and precise method for the routine determination in pharmaceutical preparations.

Passage of VIP/PACAP/secretin family across the blood-brain barrier: therapeutic effects.

In recent years, VIP/PACAP/secretin family has special interest. Family members are vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP), secretin, glucagon, glucagon like peptide-1 (GLP(1)), GLP(2), gastric inhibitory peptide (GIP), growth hormone releasing hormone (GHRH or GRF), and peptide histidine methionine (PHM). Most of the family members present both in central nervous system (CNS) and in various peripheral tissues. The family members that are released into blood from periphery, especially gut, circulate the brain and they can cross the blood brain barrier. On the other hand, some of the members of this family that present in the brain, can cross from brain to blood and reach the peripheral targets. VIP, secretin, GLP(1), and PACAP 27 are transported into the brain by transmembrane diffusion, a non-saturable mechanism. However, uptake of PACAP 38 into the brain is saturable mechanism. While there is no report for the passage of GIP, GLP(2), and PHM, there is only one report that shows, glucagon and GHRH can cross the BBB. The passage of VIP/PACAP/secretin family members opens up new horizon for understanding of CNS effects of peripherally administrated peptides. There is much hope that those peptides may prove to be useful in the treatment of serious neurological diseases such as Alzheimer's disease, amyotropic lateral sclerosis, Parkinson's disease, AIDS related neuropathy, diabetic neuropathy, autism, stroke and nerve injury. Their benefits in various pathophysiologic conditions undoubtly motivate the development of a novel drug design for future therapeutics.

Protective effect of vasoactive intestinal peptide on testicular torsion-detorsion injury: association with heparin-containing mast cells.

OBJECTIVES: To elucidate the action of vasoactive intestinal peptide (VIP) on detorsion injury and the heterogeneity of mast cells in the testes of rats. METHODS: Prepubertal male Sprague-Dawley rats were used in six groups. Group 1 was the control group (sham operation); group 2 had 2 hours of torsion; group 3, 2 hours of torsion and 1 hour of detorsion after administration of saline; group 4 had 2 hours of torsion and 4 hours of detorsion after administration of saline; group 5, 2 hours of torsion and 1 hour of detorsion after administration of intraperitoneal VIP (25 ng/kg); and group 6, 2 hours of torsion and 4 hours of detorsion after intraperitoneal VIP. The 2 hours of torsion was created by rotating the right testis 720 degrees in a clockwise direction. VIP (25 ng/kg) was injected intraperitoneally 1 minute before the 1 and 4 hours of detorsion. At the end of the experiment, catalase enzyme activity was measured polarographically, and superoxide dismutase, malondialdehyde, and protein were measured spectrophotometrically. Nitric oxide was measured by capillary electrophoresis in the testicular tissue. Routine histologic examination of testicular mast cells was done under light microscopy; the histochemistry was also analyzed. RESULTS: Torsion significantly induced oxidative stress, mast cell degranulation, and tissue damage. Detorsion attenuated oxidative stress without any diminution of the histologic damage to the tissue. VIP significantly protected the testicular tissue from detorsion injury. It also inhibited mast cell activity while increasing the heparin content. CONCLUSIONS: VIP can protect testicular tissue from detorsion injury. Heparin-containing mast cells seem to be important mediator cells for this protection.

Quantitative evaluation of the vasculature and fibronectin localization in gingival connective tissue of smokers and non-smokers.

BACKGROUND: It has been shown that tobacco is a significant risk factor for periodontal disease. The reason for decreased gingival bleeding in smokers is not known. The aim of the present study was to demonstrate the localization of fibronectin in the extracellular matrix of the inflamed gingiva of smokers and non-smokers and to evaluate the chronic effect of smoking on the gingival microvessel number (NVES) and vascular surface density (VSD). METHODS: Seventy-four (74) adult patients with periodontitis were included in this investigation. Of these patients, 38 were smokers and 36 were non-smokers. Probing depths (PD), papillary bleeding index (PBI) of both groups, and the smoking habits of the smokers were recorded. Biopsy specimens obtained during periodontal surgery were prepared to evaluate fibronectin distribution and to quantitate the vasculature. RESULTS: The mean VSD values of smokers and non-smokers were 6.721 +/- 1.845 and 5.721 +/- 3.118 (mean +/- SD), and the mean NVES of smokers and non-smokers was 31.582 +/- 11.810 and 30.145 +/- 15.442, respectively. The difference between the mean PD and PBI values of the 2 groups was not statistically significant. The location of the biopsy specimen, whether in the anterior or posterior area of the mouth, did not lead to any statistically significant differences between the groups. In addition, the number of years smoked and the tobacco brand used did not result in statistically significant differences. The most intense staining of fibronectin was observed beneath the epithelium around the blood vessels of the uppermost region of the connective tissue, showing a fibrillar and diffuse distribution; however, there was no significant difference between smokers and non-smokers. CONCLUSION: The results of the present study indicate that smoking does not affect the vascular surface density, number of vessels per mm2 stroma, or fibronectin distribution in subepithelial gingival connective tissue.

Passage of vasoactive intestinal peptide across the blood-brain barrier.

We investigated the ability of vasoactive intestinal peptide (VIP) to cross the blood-brain barrier (BBB), the interface between the peripheral circulation and central nervous system (CNS). VIP labeled with 131I (I-VIP) and injected intravenously into mice was taken up by brain as determined by multiple-time regression analysis. Excess unlabeled VIP was unable to impede the entry of I-VIP, indicating that passage is by nonsaturable transmembrane diffusion. High pressure liquid chromatography (HPLC) showed the radioactivity entering the brain to be intact I-VIP. After intracerebroventricular (i.c.v.) injection, I-VIP was sequestered by brain, slowing its efflux from the CNS. In summary, VIP crosses the BBB unidirectionally from blood to brain by transmembrane diffusion.

The antioxidants alpha-lipoic acid and N-acetylcysteine reverse memory impairment and brain oxidative stress in aged SAMP8 mice.

Oxidative stress may play a crucial role in age-related neurodegenerative disorders. Here, we examined the ability of two antioxidants, alpha-lipoic acid (LA) and N-acetylcysteine (NAC), to reverse the cognitive deficits found in the SAMP8 mouse. By 12 months of age, this strain develops elevated levels of Abeta and severe deficits in learning and memory. We found that 12-month-old SAMP8 mice, in comparison with 4-month-old mice, had increased levels of protein carbonyls (an index of protein oxidation), increased TBARS (an index of lipid peroxidation) and a decrease in the weakly immobilized/strongly immobilized (W/S) ratio of the protein-specific spin label MAL-6 (an index of oxidation-induced conformational changes in synaptosomal membrane proteins). Chronic administration of either LA or NAC improved cognition of 12-month-old SAMP8 mice in both the T-maze footshock avoidance paradigm and the lever press appetitive task without inducing non-specific effects on motor activity, motivation to avoid shock, or body weight. These effects probably occurred directly within the brain, as NAC crossed the blood-brain barrier and accumulated in the brain. Furthermore, treatment of 12-month-old SAMP8 mice with LA reversed all three indexes of oxidative stress. These results support the hypothesis that oxidative stress can lead to cognitive dysfunction and provide evidence for a therapeutic role for antioxidants.

Determination of amlodipine in pharmaceutical formulations by differential-pulse voltammetry with a glassy carbon electrode.

A differential-pulse voltammetric method was developed for the determination of amlodipine based on the oxidation of the dihydropyridine group on the surface of glassy carbon electrode under stationary and rotating conditions. The experiments were conducted in a supporting electrolyte consisting of 0.2 M KCl, 0.1 M phosphate buffer, and 10% (v/v) methanol during investigation of initial potential and pH effects. No adsorption effect was observed on using an initial potential of 0 mV and the supporting electrolyte solution at pH 5.5 under both stationary and rotating conditions. The factor affecting the voltammetric current was diffusional in the range of 200-1000 rpm for rotating, and 2-40 mV s-1 for stationary conditions up to a concentration of 0.04 mg mL-1 amlodipine. The limit of detection (LOD) and the limit of quantitative (LOQ) for the rotating and stationary techniques were found to be 0.004 and 0.0072 mg mL-1 (for S/N = 3.3) and LOQ 0.012 and 0.022 mg mL-1 (for S/N = 10), respectively. The proposed method was applied to the tablets containing amlodipine and according to the statistical evaluations acceptable results were obtained at the 95% probability level.

Determination of Amlodipine in Pharmaceutical Formulations by Differential-Pulse Voltammetry with a Glassy Carbon Electrode.

A differential-pulse voltammetric method was developed for the determination of amlodipine based on the oxidation of the dihydropyridine group on the surface of glassy carbon electrode under stationary and rotating conditions. The experiments were conducted in a supporting electrolyte consisting of 0.2 MKCl, 0.1 Mphosphate buffer, and 10 % (v/v) methanol during investigation of initial potential and pH effects. No adsorption effect was observed on using an initial potential of 0 mVand the supporting electrolyte solution at pH 5.5 under both stationary and rotating conditions. The factor affecting the voltammetric current was diffusional in the range of 200-1000 rpm for rotating, and 2-40 mV s(-1) for stationary conditions up to a concentration of 0.04 mg mL(-1) amlodipine. The limit of detection (LOD) and the limit of quantitative (LOQ) for the rotating and stationary techniques were found to be 0.004 and 0.0072 mg mL(-1) (for S/N = 3.3) and LOQ 0.012 and 0.022 mg mL(-1) (for S/N = 10), respectively. The proposed method was applied to the tablets containing amlodipine and according to the statistical evaluations acceptable results were obtained at the 95 % probability level.