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This descriptive study aimed to investigate the prevalence of hypertension and its risk factors among undergraduate students in Lubango-Angola. The results obtained according to the health field model were: a) human biology: 61.3% were between 18 and 29 years old; prevalence of hypertension from 20.3 to 26.7%; 17.1% were overweight; 3.2% were obese; b) environment: 36.1% were exclusively students; 33.1% gained a family income of up to 250 dollars; c) life style: 86.2% practiced physical activity; 60.6% preferred salty food; 4.0% were smokers; 40.6% drank alcohol; d) health care: 82.8% already had their arterial pressure verified sometime in their life, and 65.4% did not remember the obtained value. [ABSTRACT FROM AUTHOR]

Background: To determine the effectiveness of low-dose diuretic therapy to achieve an optimal level of blood pressure (BP) in adults with prehypertension., Methods: The PREVER-prevention trial was a randomized, parallel, double-blinded, placebo-controlled trial, with 18 months of follow-up, conducted at 21 academic medical centers in Brazil. Of 1772 individuals evaluated for eligibility, 730 volunteers with prehypertension who were aged 30-70 years, and who did not reach optimal blood pressure after 3 months of lifestyle intervention, were randomized to a fixed association of chlorthalidone 12.5 mg and amiloride 2.5 mg or placebo once a day. The main outcomes were the percentage of participants who achieved an optimal level of BP., Results: A total of 372 participants were randomly allocated to diuretics and 358 to placebo. After 18 months of treatment, optimal BP was noted in 25.6% of the diuretic group and 19.3% in the placebo group (P < 0.05). The mean net reduction in SBP and DBP for the diuretic group compared with placebo was 2.8 mmHg (95% CI 1.1 to 4.5) and 1.1 mmHg (95% CI -0.09 to 2.4), respectively. Most participants in the active treatment group (74.5%) and in the placebo group (80.7%) continued to have BP in the prehypertension range or progressed to hypertension., Conclusion: Low-dose diuretic therapy increased the probability of individuals with prehypertension to achieve optimal BP but most of those treated continued to have a BP in the prehypertension range or progressed to having overt hypertension.

Nebivolol is a racemate of the d-isomer responsible for β 1 adrenergic receptor antagonism and the l-isomer responsible for the release of nitric oxide from endothelial cells. Nebivolol is mainly metabolized to nebivolol glucuronide, which also contribute to the nebivolol β 1 adrenoreceptor antagonism. This study reports the development and validation of an indirect stereoselective method of analysis of nebivolol glucuronides in plasma by LC-MS/MS. The method was applied to the investigation of stereoselectivity in the glucuronidation of nebivolol in elderly hypertensive patients (n=11) CYP2D6 phenotyped as EM and treated with a single oral dose of the racemate. One-milliliter plasma aliquots spiked with internal standard (S)-(-)-metoprolol were incubated with 25μL of β-glucuronidase (final concentration 2500unit/mL) at pH 5.0 for 16h at 37°C. Linearity for total nebivolol was 0.2-125ng of each isomer per mL plasma and permitted analysis of nebivolol glucuronide isomers up to 48h after administration of a single oral dose of 10mg racemate. Regarding to the nebivolol glucuronide isomers, higher plasma concentrations of the d-isomer were observed compared to the l-isomer (d/l AUC=5.4), explaining at least in part the plasma accumulation of unchanged l-nebivolol (l/d AUC=1.8). This study also showed metabolic glucuronide nebivolol/unchanged nebivolol ratios of approximately 6.5 for the l-isomer (AUC 65.3 vs 10.1ngh/mL) and approximately 62.1 (335.2 vs 5.4ngh/mL) for the d-isomer. Considering that d-nebivolol glucuronide also contributes for β 1 adrenergic receptor antagonism, future studies regarding PK-PD of nebivolol should evaluate not only plasma concentrations of unchanged nebivolol isomers but also glucuronide nebivolol isomers., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Prehypertension is associated with higher cardiovascular risk, target organ damage, and incidence of hypertension. The Prevention of Hypertension in Patients with PreHypertension (PREVER-Prevention) trial aimed to evaluate the efficacy and safety of a low-dose diuretic for the prevention of hypertension and end-organ damage., Methods and Results: This randomized, parallel, double-blind, placebo-controlled trial was conducted in 21 Brazilian academic medical centers. Participants with prehypertension who were aged 30 to 70 years and who did not reach optimal blood pressure after 3 months of lifestyle intervention were randomized to a chlorthalidone/amiloride combination pill or placebo and were evaluated every 3 months during 18 months of treatment. The primary outcome was incidence of hypertension. Development or worsening of microalbuminuria, new-onset diabetes mellitus, and reduction of left ventricular mass were secondary outcomes. Participant characteristics were evenly distributed by trial arms. The incidence of hypertension was significantly lower in 372 study participants allocated to diuretics compared with 358 allocated to placebo (hazard ratio 0.56, 95% CI 0.38-0.82), resulting in a cumulative incidence of 11.7% in the diuretic arm versus 19.5% in the placebo arm (P=0.004). Adverse events; levels of blood glucose, glycosylated hemoglobin, creatinine, and microalbuminuria; and incidence of diabetes mellitus were no different between the 2 arms. Left ventricular mass assessed through Sokolow-Lyon voltage and voltage-duration product decreased to a greater extent in participants allocated to diuretic therapy compared with placebo (P=0.02)., Conclusions: A combination of low-dose chlorthalidone and amiloride effectively reduces the risk of incident hypertension and beneficially affects left ventricular mass in patients with prehypertension., Clinical Trial Registration: URL: http://www.ClinicalTrials.gov, www.ensaiosclinicos.gov. Unique identifiers: NCT00970931, RBR-74rr6s., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Objectives: To compare the blood pressure (BP)-lowering efficacy of a chlorthalidone/amiloride combination pill with losartan, during initial management of stage I hypertension., Methods: In a randomized, double-blind, controlled trial, 655 participants were followed for 18 months in 21 Brazilian academic centers. Trial participants were adult volunteers aged 30-70 years with stage I hypertension (BP 140-159 or 90-99 mmHg) following 3 months of a lifestyle intervention. Participants were randomized to 12.5/2.5 mg of chlorthalidone/amiloride (N = 333) or 50 mg of losartan (N = 322). If BP remained uncontrolled after 3 months, study medication dose was doubled, and if uncontrolled after 6 months, amlodipine (5 and 10 mg) and propranolol (40 and 80 mg twice daily) were added as open-label drugs in a progressive fashion. At the end of follow-up, 609 (93%) participants were evaluated., Results: The difference in SBP during 18 months of follow-up was 2.3 (95% confidence interval: 1.2 to 3.3) mmHg favoring chlorthalidone/amiloride. Compared with those randomized to diuretic, more participants allocated to losartan had their initial dose doubled and more of them used add-on antihypertensive medication. Levels of blood glucose, glycosilated hemoglobin, and incidence of diabetes were no different between the two treatment groups. Serum potassium was lower and serum cholesterol was higher in the diuretic arm. Microalbuminuria tended to be higher in patients with diabetes allocated to losartan (28.5 ± 40.4 versus 16.2 ± 26.7 mg, P = 0.09)., Conclusion: Treatment with a combination of chlorthalidone and amiloride compared with losartan yielded a greater reduction in BP., Clinical Trials Registration Number: NCT00971165.

The aim in this study was to identify the cardiovascular risk in patients suffering from white coat hypertension (WCH) by determining the ankle brachial index (ABI) with an automatic oscillometric sphygmomanometer. The study was undertaken in a Brazilian city between August 2010 and June 2011. The study variables were age, ethnic origin, marital status, education level, profession, weight, height, waist circumference, arm and ankle blood pressure (BP), and ABI. Analysis of variance was used for repeated measures and Tukey's test for multiple comparisons of means. The linear relationship between systolic BP levels and ankle brachial indices was verified using Pearson's correlation coefficient. Results were expressed as mean values ± standard errors of means, and differences were considered statistically significant when P < .05. Study participants were 135 subjects, including 37% normotensive, 37% hypertensive (HT), and 26% WCH patients. WCH individuals revealed intermediate risk in the analysis of the clinical variables. Alterations compatible with peripheral obstructive arterial disease and arterial calcification were observed only in the HT and WCH groups. These findings lead to the premise that WCH should not be viewed as a benign condition. The measurement of the ABI should be considered in the clinical approach of patients and professionals should use it as an instrument for cardiovascular risk assessment in routine health care delivery., (Copyright © 2014 Society for Vascular Nursing, Inc. Published by Mosby, Inc. All rights reserved.)

Objectives: The purpose of this study was to phenotype the CYP2D6 in elderly with heart disease classified as extensive metabolizer or poor metabolizers (PM) of metoprolol, develop and validate the method of analysis of metoprolol tartrate and its metabolite in urine using HPLC, and identify potential correlations between anthropometric factors with metabolic ratios of metoprolol/α-OH metoprolol in urine., Methods: The sample was composed of 130 elderly individuals with a previously identified type of heart condition, with normal renal and hepatic functions. The urine of all the patients were collected 0-8 h after the administration of a pill of 100 mg of metoprolol to determine concentrations of metoprolol and α-hydroxymetoprolol. Those patients presenting a metabolic ratio greater than 12.6 were phenotyped as PM., Key Findings: The median age of patients was 71.0 years, with a minimum of 60 and maximum of 93 years old. Three patients (2.3%) were phenotyped as PM of metoprolol different from the rate (7-10%) of PM existing in the Caucasian population., Conclusions: Most of the studied individuals were women, and the proportion of elderly with heart disease classified as PM was smaller than what is usually found among Caucasian populations., (© 2013 University of Sao Paulo. JPP © 2013 Royal Pharmaceutical Society.)

We investigated the influence of angiotensin-converting enzyme inhibitor (ACEi) treatment and physical exercise on arterial pressure (AP) and heart rate variability (HRV) in volunteer patients with hypertension. A total of 54 sedentary volunteers were divided into three groups: normotensive (NT Group), hypertensive (HT Group) and HT volunteers treated with ACEi (ACEi Group). All volunteers underwent an aerobic physical-training protocol for 15 weeks. HRV was investigated using a spectral analysis of a time series of R-R interval (RRi) that was obtained in a supine position and during a tilt test. Physical training promoted a significant reduction in the mean arterial pressure of the HT group (113±3 vs. 106±1 mm Hg) and the ACEi group (104±2 vs. 98±2 mm Hg). Spectral analysis of RRi in the supine position before physical training demonstrated that the NT and ACEi groups had similar values at low frequency (LF; 0.04-0.15 Hz) and high frequency (HF; 0.15-0.5 Hz) oscillations. The HT group had an increase in LF oscillations in absolute and normalized units and a decrease in HF oscillations in normalized units compared with the other groups. The HT group had the lowest responses to the tilt test during LF oscillations in normalized units. Physical training improved the autonomic modulation of the heart rate in the supine position only in the HT group. Physical training promoted a similar increase in autonomic modulation responses in the tilt test in all groups. Our findings show that aerobic physical training improves cardiac autonomic modulation in HT volunteers independently of ACEi treatment.

Objective: To assess the cardiovascular risk, using the Framingham risk score, in a sample of hypertensive individuals coming from a public primary care unit., Methods: The caseload comprised hypertensive individuals according to criteria established by the JNC VII, 2003, of 2003, among 1601 patients followed up in 1999, at the Cardiology and Arterial Hypertension Outpatients Clinic of the Teaching Primary Care Unit, at the Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo. The patients were selected by draw, aged over 20 years, both genders, excluding pregnant women. It was a descriptive, cross-sectional, observational study. The Framingham risk score was used to stratify cardiovascular risk of developing coronary artery disease (death or non-fatal acute myocardial infarction)., Results: Age range of 27-79 years (x = 63.2 +/- 9.58). Out of 382 individuals studied, 270 (70.7%) were female and 139 (36.4%) were characterized as high cardiovascular risk for presenting diabetes mellitus, atherosclerosis documented by event or procedure. Out of 243 stratified patients, 127 (52.3%) had HDL-C < 50 mg/dL; 210 (86.4%) had systolic blood pressure > or = 120 mmHg; 46 (18.9%) were smokers; 33 (13.6%) had a high cardiovascular risk. Those added to 139 enrolled directly as high cardiovascular risk, totaled up 172 (45%); 77 (20.2%) of medium cardiovascular risk and 133 (34.8%) of low risk. The highest percentage of high cardiovascular risk individuals was aged over 70 years; those of medium risk were aged over 60 years; and the low risk patients were aged 50 to 69 years., Conclusion: The significant number of high and medium cardiovascular risk individuals indicates the need to closely follow them up.

Background: Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage., Methods: This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution., Discussion: The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil., Trial Registration: Clinical Trials NCT00970931.

Background: Cardiovascular disease is the leading cause of death in Brazil, and hypertension is its major risk factor. The benefit of its drug treatment to prevent major cardiovascular events was consistently demonstrated. Angiotensin-receptor blockers (ARB) have been the preferential drugs in the management of hypertension worldwide, despite the absence of any consistent evidence of advantage over older agents, and the concern that they may be associated with lower renal protection and risk for cancer. Diuretics are as efficacious as other agents, are well tolerated, have longer duration of action and low cost, but have been scarcely compared with ARBs. A study comparing diuretic and ARB is therefore warranted., Methods/design: This is a randomized, double-blind, clinical trial, comparing the association of chlorthalidone and amiloride with losartan as first drug option in patients aged 30 to 70 years, with stage I hypertension. The primary outcomes will be variation of blood pressure by time, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new subclinical atherosclerosis and sudden death. The study will last 18 months. The sample size will be of 1200 participants for group in order to confer enough power to test for all primary outcomes. The project was approved by the Ethics committee of each participating institution., Discussion: The putative pleiotropic effects of ARB agents, particularly renal protection, have been disputed, and they have been scarcely compared with diuretics in large clinical trials, despite that they have been at least as efficacious as newer agents in managing hypertension. Even if the null hypothesis is not rejected, the information will be useful for health care policy to treat hypertension in Brazil., Clinical Trials Registration Number: ClinicalTrials.gov: NCT00971165.

Background: Very few studies have investigated, in the elderly, the effect of rheumatic inflammatory states on phagocyte function and free radical production. The objective of this article is to evaluate phagocytosis by neutrophils and the production of nitric oxide (·NO) by monocytes in elderly women recruited among patients of the Brazilian Public Health System., Methods: Forty patients aged more than 60 years with rheumatic inflammatory diseases were studied. Phagocytosis was measured by flow cytometry. ·NO production was measured by the total nitrite assay and conventional inflammation markers were determined. Data were analyzed with the Mann-Whitney nonparametric test and P<0.05 was considered significant., Results: C-reactive protein levels and white blood cell counts were significantly higher in inflammation than in the control group (P<0.05). The phagocytosis fluorescence intensity per neutrophil and the percentual of neutrophils expressing phagocytosis were significantly higher (P<0.05) in the test than in the control group. Furthermore, there was significant ·NO overproduction by monocytes, (P<0.05)., Conclusion: Phagocytosis and ·NO production are affected by rheumatic states. This suggests that the increased ·NO levels may play a part in the increased oxidative stress in rheumatic diseases in elderly women., (© 2011 Wiley-Liss, Inc.)

A selective and reproducible off-line solid-phase microextraction procedure was developed for the simultaneous enantioselective determination of mirtazapine (MRT), demethylmirtazapine and 8-hydroxymirtazapine in human urine. CE was used for optimization of the extraction procedure whereas LC-MS was used for method validation and application. The influence of important factors in the solid-phase microextraction efficiency is discussed, such as the fiber coatings, extraction time, pH, ionic strength, temperature and desorption time. Before extraction, human urine samples were submitted to enzymatic hydrolysis at 37 degrees C for 16 h. Then, the enzyme was precipitated with trichloroacetic acid and the pH was adjusted to 8 with 1 mol/L pH 11 phosphate buffer solution. In the extraction, the analytes were transferred from the aqueous solution to the polydimethylsiloxane-divinylbenzene fiber coating and then desorbed in methanol. The mean recoveries were 5.4, 1.7 and 1.0% for MRT, demethylmirtazapine and 8-hydroxymirtazapine enantiomers, respectively. The method was linear over the concentration range of 62-1250 ng/mL. The within-day and between-day assay precision and accuracy were lower than 15%. The method was successfully employed in a preliminary cumulative urinary excretion study after administration of racemic MRT to a healthy volunteer.

Iron and oxidative stress have a regulatory interplay. During the oxidative burst, phagocytic cells produce free radicals such as hypochlorous acid (HOCl). Nevertheless, scarce studies evaluated the effect of either iron deficiency anemia (IDA) or anemia of chronic disease (ACD) on phagocyte function in the elderly. The aim of the present study was to determine the oxidative burst, phagocytosis, and nitric oxide (*NO) and HOCl, reactive species produced by monocytes and neutrophils in elderly with ACD or IDA. Soluble transferrin receptor, serum ferritin, and soluble transferrin receptor/log ferritin (TfR-F) index determined the iron status. The study was constituted of 39 patients aged over 60 (28 women and 11 men) recruited from the Brazilian Public Health System. Oxidative burst fluorescence intensity per neutrophil in IDA group and HOCl generation in both ACD and IDA groups were found to be lower (p < 0.05). The percentages of neutrophils and monocytes expressing phagocytosis in ACD group were found to be higher (p < 0.05). There was an overproduction of *NO from monocytes, whereas the fundamental generation of HOCl appeared to be lower. Phagocytosis, oxidative burst, and *NO and HOCl production are involved in iron metabolism regulation in elderly patients with ACD and IDA.

Background: The nitric oxide (NO) synthesis blockade is characterized by an increase in the cardiac sympathetic activity and the physical training promotes the decrease in the sympathetic activity., Objective: We investigated the effect of the NO synthesis blockade on the autonomic cardiovascular control in rats submitted to aerobic exercises during a 10-week period., Methods: Male Wistar rats were divided in four groups: control rats, treated with chow food and water ad libitum for 10 weeks (CR); control rats, treated with N G-nitro-L-arginine methyl ester (L-NAME) during the last week (CRL); rats trained during 10 weeks on an electrical treadmill (TR); rats trained for 10 weeks and treated with L-NAME during the last week (TRL). The autonomic cardiovascular control was investigated in all groups with the use of a double blockade with methylatropine and propranolol and analysis of variability., Results: The CRL and TRL groups presented hypertension. The CRL group presented tachycardia and predominance of the sympathetic tonus in heat rate (HR) measurement after the pharmacological autonomic blockade. The TR group presented bradycardia and lower intrinsic HR when compared to the others. The evaluation of the HR variability showed lower absolute and normalized values in the low frequency (LF) band in the CRL group. On the other hand, the TRL presented an increase in the LF band in absolute values. The analysis of variability of the systemic arterial pressure (SAP) showed that the CRL and TRL groups presented higher values in the LF band., Conclusion: The previous physical exercise prevented the deficit in the autonomic cardiac control induced by the treatment with L-NAME, but did not prevent the increase in the SAP variability.

An enantioselective high-performance liquid chromatographic method for the analysis of carvedilol in plasma and urine was developed and validated using (-)-menthyl chloroformate (MCF) as a derivatizing reagent. Chloroform was used for extraction, and analysis was performed by HPLC on a C18 column with a fluorescence detector. The quantitation limit was 0.25 ng/ml for S(-)-carvedilol in plasma and 0.5 ng/ml for R(+)-carvedilol in plasma and for both enantiomers in urine. The method was applied to the study of enantioselectivity in the pharmacokinetics of carvedilol administered in a multiple dose regimen (25 mg/12 h) to a hypertensive elderly female patient. The data obtained demonstrated highest plasma levels for the R(+)-carvedilol (AUC(SS) (0-12) 75.64 vs 37.29 ng/ml). The enantiomeric ratio R(+)/S(-) was 2.03 for plasma and 1.49 for urine (Ae(0-12) 17.4 vs 11.7 microg).

A new high-performance liquid chromatography method is presented for the determination of 10 frequently prescribed tricyclic and nontricyclic antidepressants: imipramine, amitriptyline, clomipramine, fluoxetine, sertraline, paroxetine, citalopram, mirtazapine, moclobemide and duloxetine. The simple and accurate sample preparation step, consisted of liquid:liquid extraction with recoveries ranging between 72% and 86%, except for moclobemide (59%). Separation was obtained using a reverse phase Select B column under isocratic conditions with UV detection (230 nm). The mobile phase consisted of 35% of a mixture of acetonitrile/methanol (92:8, v/v) and 65% of 0.25 mol L(-1) sodium acetate buffer, pH 4.5. The standard curves were linear over a working range of 2.5-1000 ng mL(-1) for moclobemide, 5-2000 ng mL(-1) for citalopram, duloxetine, fluoxetine, 10-2000 ng mL(-1) for sertraline, imipramine, paroxetine, mirtazapine and clomipramine. The intra-assay and inter-assay precision and accuracy were studied at three concentrations (50, 200, and 500 ng mL(-1)). The intra-assay coefficients of variation (CVs) for all compounds were less than 8.8%, and all inter-CVs were less than 10%. Limits of quantification were 2.5 ng mL(-1) for moclobemide, 5 ng mL(-1) for citalopram, duloxetine and amitriptyline, and 10 ng mL(-1) for mirtazapine, paroxetine, imipramine, fluoxetine, sertraline, and clomipramine. No interference of the drugs normally associated with antidepressants was observed. The method has been successfully applied to the analysis of real samples, for the drug monitoring of ten frequently prescribed tricyclic and non-tricyclic antidepressant drugs.

The aim of this study is to assess the effects of sibutramine (S) 15 mg/day, fluoxetine (F) 60 mg/day, and metformin (M) 1,700 mg/day, as an adjunct therapy to a 1,500 kcal/day diet, in reducing anthropometric and metabolic parameters. S (n= 8), F (n= 9), and M (n= 8) were compared to placebo (n= 10) in 35 obese patients in a 90-day trial. Side effects were also studied during the treatment. The data demonstrated that F therapy resulted in a greater average reduction in BMI (11.0%), weight (10.0%), abdominal circumference (11.0%) and %fatty-tissue (12.8). An elevation in HDL-cholesterol (25.8%) and a reduction in average triglyceride levels (28.3%) were also shown. S presented a 7.91% reduction in the abdominal circumference and a 9.65 reduction in %fatty-tissue was also found. M group presented reductions in BMI (4.03%), waist circumference (6.92%), HOMA (23.5%) and blood pressure (6.08% in systolic and 2.08% in diastolic). In general, the three drugs can be considered well tolerated. We concluded that F and S demonstrated a greater mean reduction in anthropometric and metabolic parameters when compared to M, however all of them are useful for that purpose, when the subjects characteristics are considered.

A simple and rapid solid-phase microextraction method was developed for the enantioselective analysis of ibuprofen in urine. The sampling was made with a polydimethylsiloxane-divinylbenzene coated fiber immersed in the liquid sample. After desorptioning from the fiber, ibuprofen enantiomers were analyzed by HPLC using a Chiralpak AD-RH column and UV detection. The mobile phase was made of methanol-pH 3.0 phosphoric acid solution (75:25, v/v), at a flow rate of 0.45 mL/min. The mean recoveries of SPME were 19.8 and 19.1% for (-)-R-ibuprofen and (+)-(S)-ibuprofen, respectively. The method was linear at the range of 0.25-25 microg/mL. Within-day and between-day assay precision and accuracy were below 15% for both ibuprofen enantiomers at concentrations of 0.75, 7.5 and 20 microg/mL. The method was tested with urine quality control samples and human urine fractions after administration of 200 mg rac-ibuprofen.

A simple, rapid and sensitive high-performance liquid chromatography (HPLC) method was developed for the enantioselective analysis of the new antidepressant drug mirtazapine in human plasma. The procedure involved liquid-liquid extraction using toluene, followed by liquid chromatography coupled to UV detection at 292 nm. The chromatographic separation of the (+)-(S)- and (-)-(R)-enantiomers of mirtazapine was achieved on a Chiralpak AD column (250 mm x 4.6 mm, 10 microm particle size) protected with a CN guard column, using hexane-ethanol (98:2, v/v) plus 0.1% diethylamine as the isocratic mobile phase, at a flow rate of 1.2 ml/min. The total analysis time was less than 12 min per sample. The recoveries of (+)-(S)- and (-)-(R)-mirtazapine were in the 88-111% range with a linear response over the 6.25-625 ng/ml concentration range for both enantiomers. The quantification limit (LOQ) was 5 ng/ml. Within-day and between-day assay precision and accuracy were studied at three concentration levels (10, 50 and 250 ng/ml). For both mirtazapine enantiomers, the coefficients of variation (CV) and deviation from the theoretical value were lower than 15% at all concentration levels. The method proved to be suitable for pharmacokinetic studies., (Copyright 2004 Elsevier B.V.)

Direct stereoselective separation on chiral stationary phase was developed for HPLC analysis of the four stereoisomers of alpha-hydroxymetoprolol in human plasma and urine. Plasma samples were prepared using solid-phase extraction columns and urine samples were prepared by liquid-liquid extraction. The stereoisomers were separated on a Chiralpak AD column at 24 degrees C with fluorescence detection and a mobile phase consisting of a mixture of hexane:ethanol:isopropanol:diethylamine (88:10.2:1.8:0.2) for plasma samples and hexane:ethanol:diethylamine (88:12:0.2) for urine samples. Calibration curves for the individual stereoisomers were linear within the concentration range of 2.0-200 ng/ml plasma or 0.125-25 microg/ml urine. The methods were validated with intra- and interday variations less than 15%. The absolute configuration of the pure stereoisomers were assigned by circular dichroism spectra. The methods were employed to determine the concentrations of alpha-hydroxymetoprolol stereoisomers in a metabolism study of multiple-dose administration of racemic metoprolol to hypertensive patients phenotyped as extensive metabolizers of debrisoquine. We observed stereo-selectivity in the alpha-hydroxymetoprolol formation favoring the new 1'R chiral center from both metoprolol enantiomers (AUC(0-24) (1'R1'S) = 3.02). The similar renal clearances (Cl(R)) of the four stereoisomers demonstrated absence of stereoselectivity in their renal excretion. (-)-(S)-metoprolol was slightly more alpha-hydroxylated than its antipode (AUC(0-24) (2S/2R) = 1.19), suggesting that this pathway is not responsible for plasma accumulation of this enantiomer in humans., (Copyright 2003 Wiley-Liss, Inc.)

Debrisoquine (D), an antihypertensive drug metabolized to 4-hydroxydebrisoquine (4-OHD) by CYP2D6, is commonly used as an in vivo probe of CYP2D6 activity and can be used to phenotype individuals as either extensive (EMs) or poor metabolizers (PMs) of such drugs as beta-adrenergic blockers, tricyclic antidepressants, and class 1C antiarrhythmics. This report describes reversed-phase HPLC systems by which D and 4-OHD or S-(+) and R-(-)-4-OHD in urine are more selectively quantified without the need for derivatization techniques. We also studied the urinary excretion of R-(-)- and S-(+)-4-hydroxydebrisoquine in EM hypertensive patients in order to determine weather 4-OHD formation exhibits enantioselectivity. Twelve patients with mild to severe essential hypertension were admitted to the study. They received a single tablet of Declinax containing 10 mg debrisoquine sulfate. All the urine excreted during the following 8 h was collected. The debrisoquine metabolic ratio (DMR) was calculated as % of dose excreted as D/% of dose excreted as 4-OHD and the debrisoquine recovery ratio (DRR) was calculated as % of dose excreted as 4-OHD/% of dose excreted as D+4-OHD. Debrisoquine and its metabolite were determined in urine by HPLC using a reversed-phase Select B LiChrospher column, a mobile phase of 0.25 N acetate buffer, pH 5-acetonitrile (9:1, v/v) and a fluorescence detector. The limit of quantitation was determined to be 25.0 ng/ml for D and 18.75 ng/ml for 4-OHD. Intra- and inter-day relative standard deviations (RSDs) were less than 10%. All hypertensive patients studied showed a DMR of less than 12.6 or a DRR higher than 0.12 and were classified as EMs. Direct enantioselective separation on chiral stationary phase involved resolution of S-(+)-4-OHD and R-(-)-4-OHD on a Chiralcel OD-R column with a mobile phase of 0.125 N sodium perchlorate, pH 5-acetonitrile-methanol (85:12:3, v/v/v). The quantitation limit of each enantiomer was 3.75 ng/ml of urine. Intra- and inter-day RSDs were less than 10% for each enantiomer. A high degree of enantioselectivity in the 4-hydroxylation of D favouring the S-(+) enantiomer was observed, resulting in R-(-)-4-OHD not detected in the urine of the EM hypertensive patients studied.

An enantioselective high-performance liquid chromatography method was developed for the simultaneous determination of disopyramide (DP) and mono-N-dealkyldisopyramide (MND) enantiomers in plasma and urine. The drugs were extracted from plasma samples by liquid-liquid extraction with dichloromethane after protein precipitation with trichloroacetic acid; the urine samples were processed by liquid-liquid extraction with dichloromethane. The enantiomers were resolved on a Chiralpak AD column using hexane-ethanol (91:9, v/v) plus 0.1% diethylamine as the mobile phase and monitored at 270 nm. Under these conditions the enantiomeric fractions of the drug and of its metabolite were analyzed within 20 min. The extraction procedure was efficient in removing endogenous interferents and low values for the relative standard deviations were demonstrated for both within-day and between-day assays. The method described in this paper allows the determination of DP and MND enantiomers at plasma levels as low as 12.5 ng/ml and can be used in clinical pharmacokinetic studies.

Direct enantioselective separation on chiral stationary phases and indirect separation based on the formation of diastereomeric derivatives were developed and compared for the HPLC analysis of R(+) and S(-)-metoprolol in human plasma. Plasma samples prepared using solid-phase extraction columns or liquid-liquid extraction were directly analyzed on a Chiralpack AD or on a Chiralcel OD-H columns, respectively. S-(-)-menthyl choroformate was also used to yield diastereomeric derivatives resolved on a RP-8 column. The methods were employed to determine plasma concentrations of metoprolol enantiomers in a pharmacokinetic study of single dose administration of racemic metoprolol to a healthy Caucasian volunteer phenotyped as extensive metabolizer of debrisoquine. The correlation coefficients among enantioselective metoprolol plasma concentrations (5-223 ng/ml) obtained by the three methods were equal or higher than 0.99. The direct method that employed the chiral column Chiralpak AD may be considered the most sensitive, although the three methods demonstrated interchangeable use in the pharmacokinetic investigation.

An enantioselective liquid chromatography method was developed for the simultaneous determination of propafenone (PPF) and 5-hydroxypropafenone (PPF-5OH) enantiomers in plasma. After liquid liquid extraction with dichloromethane, the enantiomers were resolved on a Chiralpak AD column using hexane-ethanol (88:12, v/v) plus 0.1% diethylamine as the mobile phase and monitored at 315 nm. Under these conditions the enantiomeric fractions of the drug and of its metabolite were analysed within 20 min. The extraction procedure resulted in absolute recoveries of 62.9 and 61.3% for (R)- and (S)-PPF, respectively, and of 57.6 and 56.5% for (R)- and (S)-PPF-5OH, respectively. This procedure was efficient in removing endogenous interferents as well the interference of an other PPF metabolite, N-despropylpropafenone (PPF-NOR). The calibration curves were linear over the concentration range 25-1250 ng/ml. Low values of the coefficients of variation were demonstrated for both within-day and between day assays. The method described in this paper allows the determination of PPF and PPF-5OH enantiomers at plasma levels as low as 25 ng/ml and can be used in clinical pharmacokinetic studies.

In the present study we investigated the enantioselectivity in the pharmacokinetics of metoprolol administered in a multiple-dose regimen as the racemate. The study was conducted on 10 patients of both sexes with mild to severe essential hypertension, aged 28 to 76 years, with normal hepatic and renal function and phenotyped as extensive metabolizers of debrisoquine (urine debrisoquine to 4-hydroxydebrisoquine ratios of 0.28 to 6.56). The patients were treated with racemic metoprolol (two 100 mg tablets every 24 h) for 7 days. Serial blood samples were collected at times zero, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 16, 20, 22, and 24 h and urine at each 6 h period until 24 h after metoprolol administration. The plasma concentrations of the (-)-(S)- and (+)-(R)-metoprolol enantiomers were determined by HPLC using a chiral stationary phase (Chiralpak AD, 4.6 x 250 mm) and fluorescence detection. The enantiomeric ratios differing from one were evaluated by the paired t test and the results are reported as means (95% CI). No differences were observed between metoprolol enantiomers in half-lives and absorption, distribution and elimination rate constants. However, the following differences (p < 0.05) were observed between the (-)-(S) and (+)-(R) enantiomers: maximum plasma concentration, C(max), 179.99 (123. 33-236.64) versus 151.30 (95.04-207.57) ng/mL; area under the plasma concentration versus time curve, AUC(0-24)(SS), 929.85 (458.02-1401. 70) versus 782.11 (329.80-1234.40) ng h/mL; apparent total clearance, Cl(T)/f, 1.70 (0.79-2.61) versus 2.21 (1.06-3.36) L/h/kg, apparent distribution volume, Vd/f, 10.51 (6.35-14.68) versus 13.80 (6.93-20. 68) L/kg, and renal clearance, Cl(R), 0.06 (0.05-0.08) versus 0.07 (0.05-0.09) L/kg. The enantiomeric ratios AUC((-)-(S))/AUC((+)-(R)) ranged from 1.14 to 1.44, with a mean of 1.29. The data obtained demonstrate enantioselectivity in the kinetic disposition of metoprolol, with plasma accumulation of the pharmacologically more active (-)-(S)-metoprolol enantiomer in hypertensive patients phenotyped as extensive metabolizers of debrisoquine., (Copyright 1999 Wiley-Liss, Inc.)

Enzymatic hydrolysis with beta-glucuronidase/sulfatase was used for the enantioselective determination of N-hydroxymexiletine glucuronide in plasma for pharmacokinetic studies. N-Hydroxymexiletine glucuronide was determined as the quantity of mexiletine released by hydrolysis (difference between the enantiomeric concentrations of mexiletine obtained with and without hydrolysis). Plasma samples (100 microliters) were treated at pH 5.0 with 10 mg of the enzyme (Limpet Acetone Powder type I) for 16 hr at 37 degrees C and extracted at pH 10.4 with diisopropyl ether. Chiral mexiletine discrimination was obtained by reaction with o-phthalaldehyde/N-acetyl-L-cysteine, separation of the resulting diastereomers on a C-18 reversed-phase column with a mobile phase of methanol-0.05 N acetate buffer, pH 5.5 (6.5:3.5, v/v), and fluorescence detection (lambda ex 350 nm, lambda em 455 nm). The performance characteristics for the enantioselective analysis of mexiletine preceded by enzymatic hydrolysis were recovery approximately 90%, quantification limit 1 ng/ml, and linearity up to 1000 ng/ml plasma for both enantiomers. The coefficients of variation obtained in the study of intra- and inter-day precision were respectively 5% and 7% for both enantiomers. The assay was shown to be suitable for a pharmacokinetic study performed in a patient with the arrhythmic form of chronic Chagas' heart disease treated with 200 mg t.i.d. of racemic mexiletine hydrochloride. The high sensitivity of the method allows analysis of only 100 microliters plasma.

The phenomenon of enantioselectivity in the metabolism of mexiletine (MEX) conjugation was investigated in eight female patients with the arrhythmic form of chronic Chagas' heart disease treated with racemic mexiletine hydrochloride (two 100 mg capsules every 8 hr). Blood samples were collected up to 24 hr after the administration of the morning dose, with discontinuation of the subsequent doses during the study period. Plasma concentrations of N-hydroxymexiletine glucuronide were calculated as the difference between the concentrations of unchanged and total (unchanged + conjugated) MEX enantiomers. Total plasma MEX concentrations were analyzed by HPLC after enzymatic hydrolysis with beta-glucuronidase, the formation of diastereomeric derivatives with the chiral reagent N-acetyl-L-cysteine/o-phthalaldehyde, and fluorescence detection. The differences in the pharmacokinetic parameters of the enantiomers were evaluated by the paired t-test. The plasma concentrations of the (+)-(S)-MEX did not differ before and after enzymatic hydrolysis. The pharmacokinetic parameters calculated for (-)-(R)-N-hydroxymexiletine glucuronide are presented as means (95% confidence interval): maximum plasma concentration Cmax = 194.0 ng.ml-1 (154.3-233.7), time to maximum plasma concentration tmax = 1.4 hr (0.3-2.5), area under the plasma concentration versus time curve AUC0-24 = 2099.2 ng.h.ml-1 (1585.6-2612.6), elimination half-life t1/2 beta = 12.8 hr (9.9-15.6) and extent of conjugation of 31.6% (24.3-38.9%). The present data indicate stereospecific conjugation of (-)-(R)-N-hydroxymexiletine in the female patients with the arrhythmic form of Chagas' heart disease.

Following a week of racemic mexiletine HCl at 200 mg tid (2x100 mg capsules), stereoselective aliphatic hydroxylation was studied in eight Chagasic women with chronic ventricular arrhythmias (52-67 yrs) with no history of renal or hepatic diseases. Blood samples were collected at dose interval up to 24 h of drug administration. Plasma concentrations of R(-) and S(+) mexiletine (MEX) and its metabolite hydroxymethylmexiletine (HMM) were determined by HPLC after derivatization with chiral reagent. The differences between R(-) and S(+) enantiomers were compared by paired t-test. Results are mean (95% CI). The following differences (p < 0.05) between R(-) and S(+) enantiomers, respectively, were found: MEX AUCss(0-8) 2.34 (1.84-2.85) vs 2.55 (1.97-3.13) microg.ml(-1) x h(-1); MEX CL/f 11.27 (7.77-14.77) vs 10.46 (7.18-13.74)ml.min(-1).Kg(-1); HMM Cmax 38.26 (24.3-52.22) vs 16.73 (10.1-23.29)ng.ml(-1); HMM Tmax 4.71 (2.67-6.76) vs 3.29 (1.24-5.33) h and HMM AUCss(0-8) 253.50 (165.39-341.61) vs 103.70 (69.51-137.90)ng.ml(-1).h(-1). The AUCss(0-8) ratio R(-)/S(+) for MEX was 0.93 (0.87-0.98) while for HMM was 2.50 (2.16-2.85). Distribution of MEX and HMM enantiomers were not significantly different. In this study we demonstrate that kinetic disposition of mexiletine exhibits stereoselectivity in vivo and that aliphatic hydroxylation is favored for R(-) mexiletine in Chagasic women with ventricular arrhythmias.

Pre-column derivatization with o-phthaldialdehyde and N-acetyl-l-cysteine was used for liquid-chromatographic diastereomeric resolution of p-hydroxymexiletine (PHM) and hydroxymethylmexiletine (HMM), metabolites of mexiletine formed by aromatic and aliphatic hydroxylation, respectively. The resulting diastereomeric derivatives were resolved on a C18 column and monitored by fluorescence detection. The diastereomeric elution order for both metabolites was determined on the basis of the circular dichroism spectra of each eluted fraction. Plasma samples (500 microliters) showed recoveries greater than 75% for both the metabolites. Calibration curves in plasma samples were linear over the concentration ranges 10-500 and 20-1,000 ng/ml for each enantiomer of PHM and HMM, respectively. The limits of quantitation were found to be 10.0 and 5.0 ng/ml for both enantiomers of PHM and HMM. The within-day and between-day coefficients of variation were less than 10%. The assay was shown to be suitable for a pharmacokinetic study performed in a patient with ventricular arrhythmias following the short-term oral treatment of 200 mg t.i.d. of racemic mexiletine hydrochloride.

Two methods were developed for the determination of mexiletine enantiomers in plasma samples suitable for studies on the stereoselective disposition of this drug. Both methods used fluorescence detection to improve sensitivity and selectivity. The direct enantioselective separation was based on the chiral resolution of mexiletine-2-naphthamide derivatives on a Chiralcel OJ column. The calibration curves were linear over the concentration range 50-500 ng/ml for each enantiomer; therefore the method can be used only for therapeutic monitoring, drug interaction and multiple dose pharmacokinetic studies. The indirect method was based on the formation of diastereomers using o-phthaldialdehyde and N-acetyl-L-cysteine reagents. The diastereomers were resolved on a reversed-phase RP-18 column. The method proved to be suitable for single or multiple dose pharmacokinetic studies based on the low quantification limit (1 ng/ml) and the broader linear range (1-1000 ng/ml) obtained.

We describe a boy with bilateral lid agenesis and total keratinization of cornea and conjunctiva, macrostomia, psychomotor retardation, forehead hypertrichosis, ocular hypertelorism, thin lips, abnormal auricles and nose, skin alterations, and other findings. Differential diagnosis with ablepharon-macrostomia syndrome is presented. Cause is unknown.