High-pressure Liquid Chromatographic Method Research Articles

H2S, Endoplasmic Reticulum Stress, and Apoptosis of Insulin-secreting Beta Cells

Cystathionine gamma-lyase (CSE) is a key enzyme in the trans-sulfuration pathway, which uses L-cysteine to produce hydrogen sulfide (H2S). Functional changes of pancreatic beta cells induced by endogenous H2S have been reported, but the effect of the CSE/H2S system on pancreatic beta cell survival has not been known. In this study, we demonstrate that H2Sat physiologically relevant concentrations induced apoptosis of INS-1E cells, an insulin-secreting beta cell line. Transfection of INS-1E cells with a recombinant defective adenovirus containing the CSE gene (Ad-CSE) resulted in a significant increase in CSE expression and H2S production. Ad-CSE transfection also stimulated apoptosis. The other two end products of CSE-catalyzed enzymatic reaction, ammonium and pyruvate, had no effects on INS-1E cell apoptosis, indicating that overexpression of CSE may stimulate INS-1E cell apoptosis via increased endogenous production of H2S. Both exogenous H2S (100 microM) and Ad-CSE transfection inhibited ERK1/2 but activated p38 MAPK. Interestingly, BiP and CHOP, two indicators of endoplasmic reticulum (ER) stress, were up-regulated in H2S-and CSE-mediated apoptosis in INS-1E cells. After suppressing CHOP mRNA expression, H2S-induced apoptosis of INS-1E cells was significantly decreased. Inhibition of p38 MAPK, but not of ERK1/2, inhibited the expression of BiP and CHOP and decreased H2S-stimulated apoptosis, suggesting that p38 MAPK activation functions upstream of ER stress to initiate H2S-induced apoptosis. It is concluded that H2S induces apoptosis of insulin-secreting beta cells by enhancing ER stress via p38 MAPK activation. Our findings may help unmask a novel role of CSE/H2S system in regulating pancreatic functions under physiological condition and in diabetes.

Manganese Induces Oxidative Impairment in Cultured Rat Astrocytes

Excessive free radical formation has been implicated as a causative factor in neurotoxic damage associated with exposures to a variety of metals, including manganese (Mn). It is well established that Mn accumulates in astrocytes, affecting their ability to indirectly induce and/or exacerbate neuronal dysfunction. The present study examined the effects of Mn treatment on the following endpoints in primary astrocyte cultures: (1) oxidative injury, (2) alterations in high-energy phosphate (adenosine 5'-triphosphate, ATP) levels, (3) mitochondrial inner membrane potential, and (4) glutamine uptake and the expression of glutamine transporters. We quantified astrocyte cerebral oxidative damage by measuring F(2)-isoprostanes (F(2)-IsoPs) using stable isotope dilution methods followed by gas chromatography-mass spectrometry with selective ion monitoring. Our data showed a significant (p < 0.01) elevation in F(2)-IsoPs levels at 2 h following exposure to Mn (100 microM, 500 microM, or 1 mM). Consistent with this observation, Mn induced a concentration-dependent reduction in ATP and the inner mitochondrial membrane potential (DeltaPsi(m)), measured by the high pressure liquid chromatography method and the potentiometric dye, tetramethyl rhodamine ethyl ester, respectively. Moreover, 30 min of pretreatment with Mn (100 microM, 500 microM, or 1 mM) inhibited the net uptake of glutamine (GLN) ((3)H-glutamine) measured at 1 and 5 min. Expression of the messenger RNA coding the GLN transporters, SNAT3/SN1 and SNAT1, was inhibited after 100 and 500 microM Mn treatment for 24 h. Our results demonstrate that induction of oxidative stress, associated mitochondrial dysfunction, and alterations in GLN/glutamate cycling in astrocytes represent key mechanisms by which Mn exerts its neurotoxicity.

Radiochemical stability of fluconazole in the solid state

The effect of ionizing radiation in doses between 20 and 200 kGy on physicochemical properties of fluconazole (α-(2,4-diflurophenyl)-α-(1 H-triazol-1-methyl)-1 H-1,2,4-triazole-1-ethanol) in the solid state was examined. A number of qualitative and quantitative methods such as scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), ultraviolet (UV) and infrared (IR) spectroscopy, thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC) and organoleptic analysis were used to determine and analyse any changes resulting from irradiation. A change in colour from white to cream was observed at even smallest dose (20 kGy) and as the dose increased the colour deepened from salmon pink to orange at the highest dose of 200 kGy. The UV method showed an increase in absorbance at λ max and an appearance of an additional band in the range 280–310 nm for irradiated samples. These changes were associated with the appearance of one to two decomposition products observed by TLC. Depending on the dose of radiation, the HPLC method detected between 2 and 3 radiolysis products and the decreasing fluconazole content from 0.48 to 7.12%. The remaining analytical methods (SEM, IR and NMR) did not provide any conclusive information in respect of radiological stability of fluconazole. The results indicate that fluconazole is a compound of low radiological stability and should not be sterilized using gamma, beta or E-beam radiation.

Mice Lacking Neutrophil Elastase Are Resistant to Bleomycin-Induced Pulmonary Fibrosis

Neutrophil elastase is a serine protease stored in the azurophilic granules of leukocytes. It has been implicated in the pathology of several lung diseases and is generally presumed to contribute to the tissue destruction and extracellular matrix damage associated with these conditions. To delineate the role of neutrophil elastase in pulmonary inflammation and fibrosis, neutrophil elastase-null mice were intratracheally instilled with bleomycin. In neutrophil elastase-null mice, biochemical and morphological characteristics of pulmonary fibrosis were attenuated for at least 60 days after bleomycin administration despite a typical response to bleomycin as evidenced by assessment of indices of DNA and cell damage. Neutrophil burden of bleomycin-treated wild-type and neutrophil elastase-null mice was comparable, and marked neutrophilic alveolitis was manifest in bleomycin-treated neutrophil elastase-null mice. An absence of immunostaining for active transforming growth factor (TGF)-beta in lung tissue from bleomycin-treated neutrophil elastase-null mice suggested a defect in TGF-beta activation, which was confirmed by biochemical assessment of TGF-beta levels in bronchoalveolar lavage fluid and lung tissue. These data point to novel and unexpected fibrogenic consequences of neutrophil elastase activity in the inflamed lung.

Simultaneous Determination of Plasma Cortisol by High Pressure Liquid Chromatography and Radioimmunoassay Methods in Fish

The aim of the study was to compare the sensitivity of High Performance Liquid Chromatography (HPLC) and Radioimmunoassay (RIA) analytical methods in the determination of blood plasma cortisol level of common carp (Cyprinus carpio L.). Cortisol, the most potent glucocorticoid, is widely used as an indicator of stress. The monitoring of plasma cortisol concentration was performed during the test focused on stress response caused by handling and long-distance transport of common carp. The samples were collected before, during and after transport. The correlation between blood cortisol level in fish measured by HPLC and RIA was determined using 66 samples. The correlation was HPLC = 0.9454 RIA + 0.40676 and correlation coefficient was 0.815. From the presented results it can be concluded that both methods (RIA and HPLC) can be used for the determination of plasma (serum) cortisol level.

Hypoglycemic and Antilipidperoxidative Effects of a Polyherbal Formulation, Diakyur, in Experimental Animal Models

The present study investigates the effect of Diakyur, a polyherbal formulation composed of powder of Cassia javanica and dried, standardised aqueous extracts of Cassia auriculata, Salacia reticulata, Gymnema sylvestre, Mucuna pruriens, Syzygium jambolanum, Terminalia arjuna on blood glucose level of normal and diabetic animals as well as lipid peroxide level in normal and 28 day drug treated diabetic rats. The raw materials and the formulation were standardised by high performance thin layer chromatography (HPTLC) and high pressure liquid chromatography (HPLC) method of analysis. The hypoglycemic activity and glucose tolerance test were studied in normal and alloxan (150 mg/kg, i.p) induced diabetic rats and rabbits after administration of Diakyur at the dose of 1600 mg/kg, p.o. Blood glucose level was determined by O-toluidine method. Lipid peroxide levels of plasma, erythrocyte membrane, liver and kidney tissues were studied in alloxan induced diabetic rats after 28 days drug treatment. At the dose of 1600 mg/kg, p.o Diakyur showed a hypoglycemic effect at varying degree of significance (p < 0.05‐ 0.001) in normal as well as alloxan induced diabetic rats and rabbits in comparison with respective control groups. Diakyur treatment in the glucose tolerance test showed the maximum effect at 180th min of glucose administration in both normal and alloxan diabetic animals. The drug treated alloxan diabetic rats showed significant (p < 0.001) reduction in plasma, erythrocyte membrane, liver and kidney lipid per

Vitamin B2 content determination in liver paste by using acid and acid-enzyme hydrolysis

Vitamin B2 is available in foodstuff in the form of coenzyme and in free form. For its content determination a few procedures should be performed (deliberation from a complex, extraction of free and deliberated form) and detection, identification and quantification. There is a particular problem in determination of vitamin B2 in the meat products. For a determination of total vitamin B2 content in liver paste two preparation procedures are compared: acid and acid-enzymatic hydrolysis. The aim of this study thus, was to compare the effectivenes of these two different procedures for vitamin B2 content determination in liver paste. High pressure liquid chromatography (HPLC) method with fluorescence detector, as specific and adequately sensitive for the foodstuff of a complex composition with a natural vitamin content, was used for determination of vitamin B2 in liver paste. Acid hydrolysis was performed with the application 0.1 M hydrochloric acid in a pressure cooker, and enzymatic hydrolysis was performed with the 10% takadiastase on 45 degrees C within four hours. Ten samples of liver paste from the supply of the Serbian Army were examined. Separation was performed on the analytical column Nucleosil 50-5 C18 with mobile phase 450 ml CH3OH + 20 ml 5 mM CH3COONH4, and detection on the fluorescent detector with the variable wave length. Both methods were validated: examining a detection limit, quantification limit, specificity (because of a possible B2 vitamin interference with reagents), linearity of a peak area and standard concentration of B2 vitamin ratio in the range from 0.05 microg/ml to 2 microg/ml, precision for the 0.05 microg/ml concentration and recovery. All the previously examined parameters validated both methods as specific, precise and reproductive, with a high recovery (98.5% for acid and 98.2% for acid-enzymatic hydrolysis), as well as linearity in a range that significantly superseded the expected content in the samples (r = 0.9994, and r = 0.99987). Hydrolysis procedures make a sample suitable for vitamin B2 determination. In the liver paste samples a high content of vitamin B2 was determined: 0.83 mg/100 g after acid hydrolysis, and 0.909 mg/100 g after acid-enzyme hydrolysis. There were statistically significantly higher values determined after the acid-enzyme hydrolysis (p < 0.05). Using acid-enzyme hydrolysis and separation instrument technique (liquid chromatography) with a fluorescent detector as detection system, statistically significantly greater vitamin B2 quantities were determined than after using acid hydrolysis procedure. Vitamin B2 content determined in ten liver paste samples was high (0.881-0.936 mg/100 g) indicating that this meat product is a good vitamin B2 source.

Vitamin D fortification of milk products does not resolve hypovitaminosis D in young Finnish men

To study if vitamin D fortification of milk products started in February 2003 has improved vitamin D status of young Finnish men, which has been poor before. A longitudinal study of one cohort. Helsinki University Central Hospital. Sixty-five healthy men, studied for the first time in January 2001, were re-examined in January 2004. They were aged 18-21 years in 2001. Blood was sampled for determination of serum 25-hydroxyvitamin D (25-OHD) and intact parathyroid hormone (iPTH). 25-OHD was measured by both radioimmunoassay (RIA) and high-pressure liquid chromatography (HPLC). Consumption of milk, sour milk and fish and use of vitamin D supplements were assessed using a questionnaire. In January 2004, vitamin D fortification had raised serum 25-OHD level, with the mean of individual percent changes being 20.4% measured with RIA (P=0.0015). The correlation between the RIA and HPLC methods was high (r=0.85). Nineteen men (29.2%) had vitamin D deficiency (25-OHD<or=20 nmol/l) and 48 men (73.8%) had hypovitaminosis D (25-OHD<or=37.5 nmol/l). Serum 25-OHD and iPTH levels correlated inversely (r=-0.30; P=0.017). Serum 25-OHD levels were 52.0% higher for 13 vitamin D supplement users than for 51 non-users (P=0.0001). After exclusion of supplement users, an association between 25-OHD level and consumption of milk products was found (P=0.011), with the median vitamin D level being 6.5 nmol/l higher for those consuming four glasses of milk products or more daily than for those consuming one or less. Likewise, the higher the milk consumption, the higher the difference in 25-OHD between years 2004 and 2001 (P=0.0025). Vitamin D fortification of milk products slightly but insufficiently improved the poor vitamin D status of young Finnish men during winter. Further supplementation is warranted in order to normalize vitamin D levels and to support achievement of maximum peak bone mass. Supported by Paulo Foundation, Juho Vainio Foundation, Emil Aaltonen Foundation and Research Funding from Helsinki University Central Hospital (Erityisvaltionosuus).

Effects of water extract of Hibiscus sabdariffa, Linn (Malvaceae) ‘Roselle’ on excretion of a diclofenac formulation

The effect of beverages prepared from the dried calyx of the flowers of Hibiscus sabdariffa on the excretion of diclofenac was investigated using a controlled study in healthy human volunteers. A high pressure liquid chromatographic method was used to analyse the 8 h urine samples collected after the administration of diclofenac with 300 mL (equivalent to 8.18 mg anthocyanins) of the beverage administered daily for 3 days. An unpaired two-tailed t-test was used to analyse for significant difference observed in the amount of diclofenac excreted before and after administration of the beverage. There was a reduction in the amount of diclofenac excreted and the wide variability observed in the control with the water beverage of Hibiscus sabdariffa (p < 0.05). There is an increasing need to counsel patients against the use of plant beverages with drugs.

The disposition of lidocaine during a 12‐hour intravenous infusion to postoperative horses

Lidocaine is administered as an intravenous infusion to horses for a variety of reasons, but no study has assessed plasma lidocaine concentrations during a 12-h infusion to horses. The purpose of this study was to evaluate the plasma concentrations and pharmacokinetics of lidocaine during a 12-h infusion to postoperative horses. A second purpose of the study was to evaluate the in vitro plasma protein binding of lidocaine in equine plasma. Lidocaine hydrochloride was administered as a loading dose, 1.3 mg/kg over 15 min, then by a constant rate IV infusion, 50 microg/kg/min to six postoperative horses. Lidocaine plasma concentrations were measured by a validated high-pressure liquid chromatography method. One horse experienced tremors and collapsed 5.5 h into the study. The range of plasma concentrations during the infusion was 1.21-3.13 microg/mL. Lidocaine plasma concentrations were significantly increased at 0.5, 4, 6, 8, 10 and 12 h compared with 1, 2 and 3 h. The in vitro protein binding of lidocaine in equine plasma at 2 microg/mL was 53.06+/-10.28% and decreased to 27.33+/-9.72% and 29.52+/-6.44% when in combination with ceftiofur or the combination of ceftiofur and flunixin, respectively. In conclusion, a lower lidocaine infusion rate may need to be administered to horses on long-term lidocaine infusions. The in vitro protein binding of lidocaine is moderate in equine plasma, but highly protein bound drugs may displace lidocaine increasing unbound concentrations and the risk of lidocaine toxicity.

Treatment of post-dialytic orthostatic hypotension with an inflatable abdominal band in hemodialysis patients

The purpose of this study was to ascertain whether abdominal compression with an inflatable abdominal band, a device we developed, improved post-dialytic orthostatic hypotension (OH) in hemodialysis (HD) patients. Twenty-five chronic HD patients with intractable post-dialytic OH were recruited. Post-HD changes in systolic blood pressure (DeltaSBP) in the supine and standing positions were compared in the patients, measured with or without the use of the band. The study showed DeltaSBP after HD without the band was significantly greater than that measured before HD (-36.1+/-18.2 vs -13.1+/-16.8 mm Hg; P<0.0001). DeltaSBP after HD with the band was reduced significantly in comparison to DeltaSBP after HD without the band (-19.4+/-21.2 vs -36.1+/-18.2 mm Hg; P<0.002). Use of the band did not cause an elevation in SBP in the supine position (149.0+/-29.6 vs 155.4+/-25.7 mm Hg); however, it did increase SBP upon standing (129.6+/-27.3 vs 117.2+/-22.6 mm Hg; P<0.05). Eight patients in whom an increase in SBP of 25 mm Hg or more was achieved with the band were classified as responders. Ejection fraction was significantly higher (76.4+/-11.1 vs 61.9+/-13.6%; P<0.02) and atrial natriuretic peptide concentration significantly lower (27.9+/-22.0 vs 68.9+/-47.5 pg/ml; P<0.02) in responders than in non-responders. We conclude that the abdominal band was effective for overcoming post-dialytic OH, without elevating supine SBP in some patients.

New Validated Methods for the Simultaneous Determination of Two Multicomponent Mixtures Containing Guaiphenesin in Syrup by HPLC and Chemometrics‐Assisted UV‐Spectroscopy

High pressure liquid chromatographic (HPLC) and spectrophotometric methods are developed for the determination of two multicomponent mixtures containing guaiphenesin, dextromethorphane hydrobromide, and sodium benzoate together with either phenylephrine hydrochloride, chlorpheniramine maleate, and butylparaben (mixture 1) or ephedrine hydrochloride and diphenhydramine hydrochloride (mixture 2). The HPLC method depended on using an ODS column with mobile phase consisting of acetonitrile −10 mM potassium dihydrogen phosphate, pH 2.7 (40∶60 v/v) containing 5 mM heptane sulfonic acid sodium salt (for mix 1) and a cyanopropyl column with mobile phase consisting of acetonitrile −12 mM ammonium acetate, pH 5 (40∶60 v/v) (for mix 2) and UV detection at 214 nm. The cyanopropyl column is much less hydrophobic, less sterically restricted to the penetration of bulky solute molecules into the stationary phase, and has weaker hydrogen‐bond acidity than the ODS column. So the cyanopropyl column is more suitable for separation of components of mix 2. The chemometric‐assisted spectrophotometric method with, principal component regression (PCR) and partial least squares (PLS‐1) was used. For the chemometric method a calibration set of the mixture consisting of each compound in each mixture was prepared in distilled water. The absorbance data in the UV spectra were measured in the spectral region (210–240 or 210–224 nm for mix 1 and mix 2, respectively, as this range provided the greatest amount of information about the two mixture components). The spectrophotometric method does not require a separation step. The proposed methods were successfully applied for the analysis of the two multicomponents combinations in laboratory‐prepared mixtures and in commercial syrups, and the results were compared with each other.

Optimization of a Fluorescence Polarization Immunoassay for Rapid Quantification of Deoxynivalenol in Durum Wheat–Based Products

A fluorescence polarization immunoassay previously described for deoxynivalenol (DON) screening in wheat was optimized for the rapid quantification of DON in durum wheat kernels, semolina, and pasta. A background signal was observed in both spiked and naturally contaminated samples, strictly depending on the testing matrix. After subtracting the background DON level for durum wheat (0.27 μg of DON per g), semolina (0.08 μg of DON per g), and pasta (0.04 μg of DON per g), an accurate quantification of DON was possible at levels greater than 0.10 μg/g for all matrices. Average recoveries from spiked samples (0.25 to 1.75 μg/g) were 98, 102, and 101% for wheat, semolina, and pasta, respectively. Comparative analyses of 35 naturally contaminated durum wheat samples, 22 semolina samples, and 26 pasta samples performed by both the fluorescence polarization method and high-pressure liquid chromatography/immunoaffinity cleanup showed a good correlation (r > 0.995). The fluorescence polarization method showed better accuracy and precision with respect to the high-pressure liquid chromatography method and is suitable for the rapid and quantitative determination of DON in durum wheat–based products at levels foreseen by existing or coming international regulations.

Determination of creatinine in human serum and urine by reversed-phase high pressure liquid chromatography

目的 评价以5-氟尿嘧啶(5-Fluorouracil,5-Fu)作内标的反相高压液相色谱(high pressure liquid chromatography ,HPLC)测定血清和尿中肌酐(creatinine)的方法,拟初步推荐其作为肌酐测定的候选参考方法,同时对3种常规肌酐测定试剂进行评定.方法 首先对以5-Fu作内标的反相HPLC测定血清和尿中肌酐的方法进行了方法学评价.进一步以该方法为对比方法,分别采用Jaffe动力学法、酶法、干化学法测定试剂对85份新鲜血清和94份新鲜尿液标本进行测定,对测定结果进行相关和偏差分析.结果 以5-Fu作内标的反相HPLC,其线性范围达2 210 μmol/L,批内变异系数(n=5)＜2.5%,日间变异系数(n=10)＜4.5%,回收率96.3%～102.4%.血清肌酐含量＜150 μmol/L时(n=53),HPLC与各种方法间的相关系数分别为0.931 4、0.942 1、0.928 4.血清肌酐含量＞150 μmol/L时(n=32),HPLC与各种方法间的相关系数分别为0.987 7、0.984 1、0.993 4. 结论 拟推荐以5-Fu作内标的反相HPLC作为肌酐测定的候选参考方法;肌酐酶偶联肌氨酸氧化酶法可作为常规测定方法。

Pharmacokinetics of the citrus flavanone aglycones hesperetin and naringenin after single oral administration in human subjects

Hesperetin and naringenin, the aglycones of the flavanone glycosides hesperidin and naringin, occur naturally in citrus fruits. They exert interesting pharmacological properties such as antioxidant, anti-inflammatory, blood lipid and cholesterol lowering and are considered to contribute to health benefits in humans. However, no information is available on the pharmacokinetics of the citrus flavanones hesperetin and naringenin after their oral administration to humans as pure aglycones. Therefore, the objective of the present investigation was the evaluation of the pharmacokinetic parameters of hesperetin and naringenin in plasma and urine, after their single oral administration in humans in the form of solid dispersion capsules, and also to improve the absorption rate of flavanones by using aglycones rather than the naturally occurring glycosides. Six healthy volunteers received orally 135 mg of each compound, hesperetin and naringenin, under fasting conditions. Blood samples were collected at 14 different time points over a 12 h period. Urine was collected over 24 h, in five sequential timed intervals. Plasma and urine hesperetin and naringenin concentrations, after enzymatic hydrolysis of their conjugated forms, were measured using validated high-pressure liquid chromatography methods. Pharmacokinetic parameters for hesperetin and naringenin, such as C(max), T(max), AUC(0-t), AUC(0-infinity), CL/F, V/F, t(1/2), MRT, A(e), A(e)((0-24)), and R(max) were calculated from their plasma or urine concentrations. Pharmacokinetic analysis showed that both hesperetin and naringenin were rapidly absorbed and their concentrations in plasma observed 20 min after dosing and reached a peak in 4.0 and 3.5 h, respectively. The mean peak plasma concentration (C(max)) for hesperetin and naringenin were 825.78+/-410.63 ng/ml (2731.8+/-1358.4 nmol/l) and 2009.51+/-770.82 ng/ml (7386.6+/-2833.4 nmol/l), respectively and the mean AUC(0-infinity) values were 4846.20+/-1675.99 ng h/ml and 9424.52+/-2960.52 ng h/ml for hesperetin and naringenin, respectively. The elimination half-life for hesperetin was found to be 3.05+/-0.91 h and for naringenin 2.31+/-0.40 h, respectively. The mean values of the relative cumulative urinary excretion, as percentage of the administered dose, for hesperetin and naringenin, were found to be 3.26+/-0.44 and 5.81+/-0.81%, respectively. Oral administration of the flavanone aglycones, hesperetin and naringenin, lead to their rapid absorption as their conjugated forms. The cumulative urinary recovery data indicated low bioavailability for both flavanone aglycones, owing to extensive first-pass metabolism partly by cleavage of the C-ring by the enzymes of intestinal bacteria leading to degradation products such as phenolic acids.

Lack of Formation of Heteroyclic Amines in Fumes from Frying French Fries

The formation of heterocyclic amines (HAs) in the fumes from frying French fries in soybean oil or lard was studied. A high-pressure liquid chromatography method was used to determine the various HAs in fumes. Results showed that the yields of fumes produced from soybean oil when heated alone for 2 or 4 h were higher than from lard; however, a reversed trend was found when frying French fries in soybean oil and lard. Most fumes from soybean oil and lard while frying French fries were adsorbed onto the condensation apparatus, while the other portions were adsorbed onto the wool and glass beads, which were incorporated in our experimental design for collecting the fumes. The fumes from soybean oil when heated alone were found to contain three HAs, namely, 2-amino-3-methylimidazo[4,5-f ]quinoxaline (IQx), 2-amino-3-methylimidazo[4,5-f ]quinoline (IQ), and 1-methyl-9H-pyrido[4,3-b ]indole (Harman), whereas two more HAs, 2-amino-3,4-dimethylimidazo[4,5-f ]quinoline (MeIQ) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b ]indole (Trp-P-1), were generated in lard. Lard was more susceptible to the formation of HAs than soybean oil when both were heated alone. No HAs were detected in the fumes from French fries fried in soybean oil and lard.

The effect of gender on the pharmacokinetics of verapamil and norverapamil in human

The effects of gender on the pharmacokinetics of verapamil and its active metabolite, norverapamil, following single oral dose (80 mg, Isoptin) to 12 healthy male (mean age: 25.75+/-2.42 years, mean body weight: 70.59+/-9.94 kg) and 12 healthy female subjects (mean age: 24.08+/-2.84 years, mean body weight: 56.67+/-5.23 kg) were investigated in the present study. Plasma concentrations of verapamil and norverapamil were analysed using a modified high-pressure liquid chromatography method. Pharmacokinetic parameters were calculated by non-compartmental analysis for each subject. For verapamil the half-life (t1/2) and mean residence time (MRT) were significantly shorter in women than men (p<0.01 and p<0.05, respectively). For other pharmacokinetic parameters of verapamil there were no significant differences between males and females. For norverapamil, t1/2, MRT and time to reach to the maximum plasma concentration (Tmax) showed statistically significant differences between the two genders. The AUC(0-24) and AUC(0-infinity) ratios of norverapamil to verapamil were also calculated. The ratios were significantly higher in women compared with men. These observations indicate that the elimination rate of verapamil is faster in women than men which may be attributed to the higher activity of CYP3A4 or lower activity of P-glycoprotein in women compared with men. A contribution of both factors in the appearance of gender differences in verapamil pharmacokinetics is also possible.

Comparative analysis of lamivudine in two commercially available brands using HPLC and UV-VIS spectroscopy

One of the components of care for people living with HIV/AIDS is the use of antiretroviral drugs (ART) and the successful outcome of these drugs requires proven quality, safety and efficacy. The quality of these drugs can be assessed by qualitative and quantitative analysis using different analytical techniques. The objective of this study is to compare the analytical results of two brands of ART drug, Lamivox-150 and Lamidine using high pressure liquid chromatography (HPLC) and UV spectroscopy in order to select a validated, simple, cost-effective and affordable analytical technique. The two brands of a lamivudine tablets were quantified against a reference standard, lamivudine with HPLC and UV spectroscopy and the results were compared. The HPLC method involves the use of methanol:acetonitrile (5:95) as a mobile phase, and octadecylsilane (C18) as a stationary phase. For UV spectroscopic analysis, complete release of the active ingredient from the tablets was achieved with 0.01N HCl using ultrasonic bath for 10 min. This is followed by subsequent quantitative determination of the released drug at maximum absorbance wavelength of 280 nm. Concentrations of lamivudine ranging from 0.2-2 mg/ml and 1.6-16 µg/m were used to construct calibration curves for HPLC and UV spectroscopic analyses, respectively. The content of lamivudine per tablet in Lamivox-150 and Lamidine was found to be in agreement with the labelled amount when analysed by both techniques (p

PHARMACOKINETICS OF FLORFENICOL AFTER A SINGLE INTRAMUSCULAR DOSE IN WHITE-SPOTTED BAMBOO SHARKS (CHILOSCYLLIUM PLAGIOSUM)

This study evaluated the pharmacokinetics of florfenicol in the white-spotted bamboo shark (Chiloscyllium plagiosum). In addition to the pharmacokinetics, the potential application for treatment of bacterial meningitis was explored. A pilot study was used to compare doses of 30, 40, and 50 mg/kg i.m. Following that study, 10 adult sharks were administered a single i.m. dose of florfenicol at 40 mg/kg. Plasma and cerebrospinal fluid were collected and analyzed for florfenicol by a sensitive and specific high-pressure liquid chromatographic method. Pharmacokinetic analysis was performed using both non-compartmental and compartmental techniques. The absorption produced an average peak at 54 (+/-19) hr from the i.m. site of administration, and the half-life was prolonged, averaging 269.79 hr (+/-135.87). Florfenicol plasma concentrations peaked at an average of 11.85 microg/ml (+/-1.45) and were maintained above our target minimum inhibitory concentration of 4-8 microg/ml for at least 120 hr. Cerebrospinal fluid concentrations peaked at an estimated 9 microg/ml around 48 hr, surpassing the target minimum inhibitory concentration for at least 72 hr.

Yersiniabactin Production by Pseudomonas syringae and Escherichia coli , and Description of a Second Yersiniabactin Locus Evolutionary Group

The siderophore and virulence factor yersiniabactin is produced by Pseudomonas syringae. Yersiniabactin was originally detected by high-pressure liquid chromatography (HPLC); commonly used PCR tests proved ineffective. Yersiniabactin production in P. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. Three similarly divergent yersiniabactin locus groups were determined: the Yersinia pestis group, the P. syringae group, and the Photorhabdus luminescens group; yersiniabactin locus organization is similar in P. syringae and P. luminescens. In P. syringae pv. tomato DC3000, the locus has a high GC content (63.4% compared with 58.4% for the chromosome and 60.1% and 60.7% for adjacent regions) but it lacks high-pathogenicity-island features, such as the insertion in a tRNA locus, the integrase, and insertion sequence elements. In P. syringae pv. tomato DC3000 and pv. phaseolicola 1448A, the locus lies between homologues of Psyr_2284 and Psyr_2285 of P. syringae pv. syringae B728a, which lacks the locus. Among tested pseudomonads, a PCR test specific to two yersiniabactin locus groups detected a locus in genospecies 3, 7, and 8 of P. syringae, and DNA hybridization within P. syringae also detected a locus in the pathovars phaseolicola and glycinea. The PCR and HPLC methods enabled analysis of nonpathogenic Escherichia coli. HPLC-proven yersiniabactin-producing E. coli lacked modifications found in irp1 and irp2 in the human pathogen CFT073, and it is not clear whether CFT073 produces yersiniabactin. The study provides clues about the evolution and dispersion of yersiniabactin genes. It describes methods to detect and study yersiniabactin producers, even where genes have evolved.