Applications of shun shell column and nanocomposite sorbent for analysis of eleven anti-hypertensive in human plasma.

High-performance liquid chromatography (HPLC) and solid phase micro membrane tip extraction (SPMMTE) methods are developed for the simultaneous analysis of eleven cardiovascular drugs in human plasma. Iron nanoparticles were obtained by the green method, characterized by XRD, FT-IR, TEM, and EDS and utilized in SPMMTE for sample preparation. The mobile phase used was ammonium acetate buffer-methanol-acetonitrile (65:18:17) with a 1.0 mL/min flow rate at 260 nm detection. Column used was Sunshell C18 150 × 4.6 mm, 2.6 µm. The values of k, α, and Rs were ranged from 040 to109.22, 1.20 to 2.67 and 1.0 to 26.18. SPMMTE and HPLC methods were fast, reproducible, precise, robust, economic and rugged for analysis of methyldopa, hydrochlorothiazide, prazosin hydrochloride, furosemide, labetalol, propranolol, valsartan, losartan potassium, diltiazem, irbesartan and spironolactone in human plasma. The recoveries (%) of methyldopa, hydrochlorothiazide, prazosin hydrochloride, furosemide, labetalol, propranolol, valsartan, losartan potassium, diltiazem, irbesartan, and spironolactone were 91.0, 85.2, 92.3, 90.4, 90.1, 85.6, 86.6, 86.2, 85.1, 86.6, and 85.7, respectively. These results showed that SPMMTE and HPLC methods can be applied to test the described drugs in several matrices.

Regulation of magnesium sulfate combined with nifedipine and labetalol on disease-related molecules in serum and placenta in the treatment of preeclampsia.

OBJECTIVE: To explore the regulatory effect of magnesium sulfate combined with nifedipine and labetalol on disease-related molecules in serum and placenta in the treatment of preeclampsia. PATIENTS AND METHODS: Altogether 100 patients with preeclampsia admitted to the Children & Women's Healthcare of Laiwu City were selected. They were divided into control group and experimental group according to different treatment methods. Among them, 51 patients in the control group were treated with magnesium sulfate combined with nifedipine, and 49 patients in the experimental group were treated with labetalol on the basis of the treatment in the control group. The therapeutic effects of the two methods were compared. The levels of the following factors in the two groups were compared: kallikrein expression, pregnancy-associated plasma protein A (PAPP-A), pregnancy-specific ß1 glycoprotein (SPI), placental growth factor (PLGF), human placental prolactin (HPL), transforming growth factor ß1(TGF-ß1), vascular cell adhesion molecule 1 (VCAM-1) and E-selectin in serum and placenta tissues. RESULTS: After treatment, the blood pressure in the experimental group was lower than that in the control group (p<0.05). The expression of kallikrein in serum and placental tissue of the patients in the experimental group was higher than that of the patients in the control group (p<0.05); PAPP-A level was lower than that in the control group (p<0.05); TGF-ß1 level was higher than that in the control group (p<0.05); VCAM-1 and E-selectin were lower than those in the control group (p<0.05), and kallikrein and TGF-ß1 in serum and placenta in the non-occurrence group were higher than those in the occurrence group (p<0.05). The serum and placenta PAPP-A, VCAM-1, and E-selectin in the non-occurrence group were lower than those in the occurrence group (p<0.05). CONCLUSIONS: Magnesium sulfate combined with nifedipine and labetalol has good efficacy in the treatment of preeclampsia. They can promote the expression of endogenous kallikrein, reduce the level of pregnancy-related hypertension predictors, and weaken the infiltration ability of cytotrophoblasts.

Electrochemical Quantitative Assessment of Labetalol Hydrochloride in Pure Form and Combined Pharmaceutical Formulations.

This work describes how to utilize the electrochemical technique to determine labetalol hydrochloride (Lab) in pure form and combined pharmaceutical formulation for quality control purposes. Four membrane sensors were developed using two plasticizers, dioctyl phthalate with 2-hydroxypropyl-?-cyclodextrin and ammonium reineckate (RNC) for sensors 1a and 2a, and tributyl phthalate with 2-hydroxypropyl-?-cyclodextrin and ammonium reineckate for sensors 1b and 2b as ionophores in polyvinyl chloride (PVC) matrix. Fast response and stable Nernstian slopes of 59.60, 57.58, 53.00 and 55.00 mV/decade for sensors 1a, 2a, 1b, and 2b, respectively, were obtained by developed sensors within a concentration range 10-4 M-10-2 M over pH range 2.00-5.10. Developed sensors showed good selectivity for Lab in pure form, in the presence of co-administered drugs, many of interfering ions, and excipients present in pharmaceutical formulation. No remarkable difference was detected upon the statistical comparison between the results of proposed sensors and the official method.

Derivatization of labetalol hydrochloride for its spectrofluorimetric and spectrophotometric determination inhuman plasma: Application to stability study.

Two simple, selective and accurate methods were developed for the determination of Labetalol hydrochloride in pure form and pharmaceutical tablets. Both methods are based on derivatization of the studied drug with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBDCl) in alkaline medium (pH7.5).The reaction product was measured spectrofluorimetrically at 540nm after excitation at 476nm (method I) or spectrophotometrically at 480nm (method II). The calibration graphs were rectilinear over the concentration ranges of 0.10-2.0 and 1.0-11.0µgmL-1 for methods I and II, respectively. The proposed methods were successfully applied to the analysis of commercial tablets without interference from common excipients. Furthermore, the spectrofluorimetric method was utilized for the in vitro determination of labetalol in spiked human plasma, with a percent mean recovery (n=3) of 97.80±1.29%. Moreover, the spectrofluorimetric method was extended to examine the stability study of LBT under different stress conditions such as alkaline, acidic, oxidative, photolytic and a thermal degradation.

CYP2C19 genotype has a major influence on labetalol pharmacokinetics in healthy male Chinese subjects.

PURPOSE: The pharmacokinetics (PK) of labetalol show wide inter-subject variability, but the genetic causes for this are largely undetermined. This study was performed to examine whether common polymorphisms in UGT1A1, UGT2B7, CYP2C19 and ABCB1 affect the PK of labetalol. METHODS: The PK of labetalol were determined in 37 Chinese healthy male subjects who took a single oral dose of 200 mg labetalol. Plasma concentrations of labetalol were determined by a high-performance liquid chromatographic method. Subjects were genotyped for the CYP2C19 2 and 3, UGT1A1 6, 28 and 60, UGT2B7 2 and ABCB1 1236C>T, 2677G>T/A and 3435C>T polymorphisms. RESULTS: Subjects with the CYP2C19 2/ 2 genotype had a higher peak concentration (255.5 ± 80.1 vs. 156.0 ± 66.3 ng/mL; P < 0.05) and area under the concentration-time curve (AUC0-∞; 1,473.7 ± 493.6 vs. 502.8 ± 176.1 ng[Symbol: see text]h/mL; P < 0.001) than subjects with 60 or 28, and UGT2B7 2 did not result in a significant effect. Subjects with ABCB1 2677TA or TT or ABCB1 3435TT genotypes had higher AUC0-∞ and lower total clearance than the wild-types (P < 0.05), but this appeared to be related to the distribution of CYP2C19 genotypes. The CYP2C19 genotype appeared to be the only predictor of labetalol concentrations, accounting for approximately 60 % of the total variance in the AUC0-∞. CONCLUSION: Our results suggest that the PK of labetalol are significantly affected by the common CYP2C19 polymorphisms in individuals of Chinese ethnicity. Future larger studies are needed to evaluate the effect of CYP2C19 and UGT1A1 polymorphisms on the PK of labetalol stereoisomers and the pharmacodynamic effects.

Influence of gestational diabetes mellitus on the stereoselective kinetic disposition and metabolism of labetalol in hypertensive patients.

PURPOSE: This study investigated the influence of gestational diabetes mellitus on the kinetic disposition and stereoselective metabolism of labetalol administered intravenously or orally. METHODS: Thirty hypertensive women during the last trimester of pregnancy were divided into four groups: non-diabetic and diabetic women treated with intravenous or oral labetalol. RESULTS: The pharmacokinetics of labetalol was not stereoselective in diabetic or non-diabetic pregnant women receiving the drug intravenously. However, oral administration of labetalol resulted in lower values of the area under the plasma concentration versus time curve (AUC) for the ß-blocker (RR) than for the other enantiomers in both diabetic and non-diabetic women. Gestational diabetes mellitus caused changes in the kinetic disposition of the labetalol stereoisomers when administered orally. The AUC values for the less potent adrenoceptor antagonist (SS) and for the α-blocking (SR) isomers were higher in diabetic than in non-diabetic pregnant women. CONCLUSIONS: The approximately 100% higher AUC values obtained for the (SR) isomer in diabetic pregnant women treated with oral labetalol may be of clinical relevance in terms of the α-blocking activity of this isomer.

Stereoselective analysis of labetalol in human plasma by LC-MS/MS: application to pharmacokinetics.

Labetalol is clinically available as a mixture of two racemates (four stereoisomers). The stereoisomer (R,R) has as main activity the beta1-antagonism and the stereoisomer (S,R) is highly selective for the alpha1 adrenoceptor and is responsible for most of the alpha-blocker activity. In the present investigation, a method for the analysis of labetalol stereoisomers in human plasma was developed and applied to pharmacokinetic studies. Plasma samples (0.5 ml) were extracted with methyl tert-butyl ether at pH 9.5. The four labetalol stereoisomers were analyzed by LC-MS/MS on a Chirobiotic V column using a mobile phase consisting of methanol, acetic acid, and diethylamine, with a recovery of more than 90% for all four. The quantitation limit was 0.5 ng/ml and linearity was observed at 250 ng/ml plasma for each stereoisomer. Studies of precision and accuracy presented coefficients of variation and percentage inaccuracy of less than 15%, indicating that the method is precise and accurate. The method was applied to the study of the kinetic disposition of labetalol over a period of 12 h after oral administration of a single 100 mg dose to a hypertensive pregnant woman. The clinical study revealed stereoselectivity in the pharmacokinetics of labetalol, with a lower plasma proportion for the active stereoisomers (R,R)-labetalol and (S,R)-labetalol. The stereoselectivity observed after oral administration is due to the hepatic metabolism and the first pass effect, with an AUC(R,R)/AUC(S,S) ratio of 0.5.

Simultaneous determination of beta-blockers in human plasma using liquid chromatography-tandem mass spectrometry.

A detailed procedure for the analysis of four beta-blockers, acebutolol, labetalol, metoprolol and propranolol, in human plasma by high-performance liquid chromatography (LC)-tandem mass spectrometry (MS-MS) using an MSpak GF column, which enables direct injection of crude plasma samples, is presented. Protein and/or macromolecule matrix compounds were eluted first from the column, while the drugs were retained on the polymer stationary phase of the MSpak GF column. The analytes retained on the column were then eluted into an acetonitrile-rich mobile phase using a gradient separation technique. All drugs showed base peak ions due to [M + H]+ ions by LC-MS with positive ion electrospray ionization, and the product ions were produced from each [M + H]+ ion by LC-MS-MS. Quantification was performed by selected reaction monitoring. The recoveries of the four beta-blockers spiked into plasma were 73.5-89.9%. The regression equations for all compounds showed excellent linearity in the range 10-1000 ng/mL of plasma, with the exception of propranolol (10-800 ng/mL). The limits of detection and quantification for each drug were 1-3 and 10 ng/mL, respectively, of plasma. The intra- and inter-day coefficients of variation for all drugs in plasma were not greater than 10.9%.

Chiral separation of labetalol stereoisomers in human plasma by capillary electrophoresis.

A newly derivatized cyclodextrin [octakis-(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin] was investigated as a chiral selector in capillary zone electrophoresis in a study of the chiral separation of labetalol stereoisomers. Heptakis(2,3-diacetyl-6-sulfato)-beta-cyclodextrin (HDAS-beta-CD) and octakis(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin (ODAS-gamma-CD) were shown to be effective in separating labetalol stereoisomers. Optimal separating conditions of the four stereoisomers of labetalol were achieved with 10 mM HDAS-beta-CD and 10 mM ODAS-gamma-CD in an acidic pH buffer of low molarity. Data illustrating the effects of capillary length and cyclodextrin concentration on the separation are presented. The longer capillary length and high voltage enabled the baseline separation of all isomers in less than 15 min. The optimized method was applied to the analysis of human control plasma containing labetalol utilizing solid-phase extraction (SPE) in the 96-well format.

[Toxicologic analysis of some adrenergic-beta blockers in the diagnosis of intoxications]. / Analiza toksykologiczna wybranych beta-adrenolityków w diagnostyce zatruc.

The study aimed at finding effective techniques of qualitative and quantitative analysis of selected beta-adrenergic blockers, useful both for monitoring of therapy and for thanatological diagnosis of intoxications. The studies took advantage of gas chromatography (GLC) and high performance liquid chromatography (HPLC). For isolation of studied compounds from biological material, classical and solid phase extraction procedures (SPE) Extrelut-20 (Merck), Abselut Nexus (Varian), STRATA C--18 E (Phenomenex) were used. The program included the analysis of most frequently applied derivatives: Acebutolol, Atenolol, Bunitrolol, Bupranolol, Labetolol, Metipranolol, Metoprolol, Oxprenolol, Practolol, Propranolol.

Phenoxybenzamine placental transfer during the third trimester.

OBJECTIVE: To report phenoxybenzamine placental transfer in the treatment of maternal hypertension secondary to pheochromocytoma. CASE SUMMARY: A 22-year-old woman diagnosed with pheochromocytoma was medically managed at 33 weeks gestation with oral phenoxybenzamine and labetalol until delivery 26 days later. To determine phenoxybenzamine placental passage, at the time of cesarean section simultaneous samples were obtained from the cord blood, maternal blood, and amniotic fluid. Additional blood samples were obtained from the newborn at 32 and 80 hours of life. Mean concentrations of phenoxybenzamine from cord and maternal plasma and in amniotic fluid were 103.3, 66, and 79.3 ng/mL, respectively; the newborn's plasma concentration at 32 hours of life was 22.3 ng/mL. At the time of delivery, the 2475-g male infant exhibited perinatal depression; mild transient hypotension was also noted for the first few days of life. DISCUSSION: The fetal-maternal plasma accumulation ratio of 1.6:1 indicates that at this gestational age after 26 days of therapy, the placental transfer of phenoxybenzamine occurs and is accompanied by accumulation in the fetal blood. CONCLUSIONS: Because of the placental transfer of phenoxybenzamine, mild perinatal depression and transient hypotension may occur in newborns of mothers receiving this medication. These newborns must be closely monitored during the first few days of life for respiratory depression and hypotension.

Determination of some cardiovascular drugs in serum and urine by capillary isotachophoresis.

The separation and determination of amiloride, metoprolol, deacetylmetipranolol, labetalol and furosemide in human serum and urine by capillary isotachophoresis were investigated. Amiloride and beta-blockers were separated by cationic isotachophoresis in the electrolyte system sodium morpholinoethanesulfonate buffer (pH 5.5) (cL = 10 mM)-glutamic acid. Furosemide was separated using the anionic electrolyte system histidine hydrochloride buffer (pH 6.2) (cL = 10 mM)-morpholinopropanesulfonic acid. Endogenous and the possible exogenous compounds were almost totally removed from serum and urine by solid-phase extraction using a Separon SGX C18 cartridge. The recovery of compounds varied from 98.2 to 103.2%. The linearity range for the compounds was 50-1000 ng/ml. The relative standard deviations varied from 0.1 to 5.6%. The overall limits of determination ranged from 32 to 46 ng/ml of urine and from 39 to 46 ng/ml of serum, depending of the type of drugs.

Neonatal adrenergic blockade following single dose maternal labetalol administration.

A single 30 mg intravenous dose of labetalol given 20 minutes prior to cesarean delivery at 35 weeks of gestation for severe pregnancy-induced hypertension was associated with symptoms of beta-adrenergic blockade (hypoglycemia, bradycardia, hypotension) in preterm twins. The infants were subsequently found to have therapeutic labetalol concentrations (180 and 150 ng/mL) in umbilical cord blood. The pharmacology of transplacental labetalol is reviewed and potential mechanisms for neonatal beta-adrenergic blockade are discussed.

Sensitive high-performance liquid chromatographic method for the determination of labetalol diastereoisomers in plasma samples without derivatization.

A direct high-performance liquid chromatographic assay for the determination of labetalol diastereoisomers in plasma without derivatization was developed. Baseline resolution of diastereoisomers was accomplished on a C18 bonded reversed-phase polymeric column with a basic (pH 11.5) mobile phase and isocratic elution. Sample treatment was optimized in order to achieve a complete extraction of labetalol diastereoisomers and to avoid racemization during extraction. Fluorimetric detection improved the selectivity and afforded a detection limit of 3 ng/ml for each diastereoisomer. This method is suitable for routine quantification of labetalol diastereoisomers and has been applied to a pharmacokinetic study in small laboratory animals.

Pharmacokinetics of dilevalol and its conjugates in man. Assay method for plasma, blood, urine and bile samples and preliminary pharmacokinetic studies.

The renal and biliary excretion of the beta-adrenoceptor blocking agent dilevalol (CAS 75659-07-3) and its conjugates was examined in a preliminary pharmacokinetic study. Plasma, urine and bile dilevalol concentrations were determined with a simplified procedure that is based on alkaline liquid-liquid extraction using diethyl ether and subsequent reversed-phase HPLC separation of the reconstituted samples (on a PRP-1 stationary phase using a mixture of methanol and pH 9.8 carbonate buffer as mobile phase). Triamterene was used as internal standard. The quantification of the conjugates was accomplished indirectly via enzymatic hydrolysis (glusulase) with and without addition of the beta-glucuronidase inhibitor 1,4-saccharolactone (at a final concentration of 5.5 mmol/l). In the pharmacokinetic study healthy volunteers and cholecystectomised patients with a T-drain received a single oral dose of 200 mg dilevalol. Furthermore, to healthy volunteers an i.v. dose of 60 mg dilevalol was given in order to estimate the absolute bioavailability. From the obtained data the systemic plasma clearance was calculated to be 1708 ml/min. The oral bioavailability was calculated to be 16%. The log concentration-time curves of the metabolites paralleled those of dilevalol in the terminal section with average terminal half-lives of approx. 5 h. In volunteers the fractions of the dose excreted renally were 0.5% for parent drug, 23% for the glucuronide(s) and 8% for the sulfate. The corresponding values found for the patients were not significantly different. In the patients' bile only 1.2% of the total dose were found (0.03% dilevalol, 1.1% dilevalol glucuronide(s), 0.1% dilevalol sulfate).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute hemodynamic and neurohumoral profile of dilevalol in hypertensive patients with ischemic heart disease.

Acute systemic and, possibly, coronary vasoconstriction may limit the usefulness of i.v. beta-blockade for the management of hypertension in ischemic patients. The acute hemodynamic and neurohumoral profile of i.v. dilevalol (50 mg/5 min), a nonselective beta-antagonist and selective partial beta 2-agonist, was evaluated for 1 h in nine patients with stable angina, significant (> 50%) coronary artery disease, and mild hypertension. Immediately after administration, arterial pressures fell significantly by 13% and remained lowered for the entire study period. Concomitantly, heart rate slowed from 76 +/- 2 (mean +/- SEM; control) to 67 +/- 2 beats/min (60 min postadministration, p < 0.05), and cardiac index and stroke work decreased significantly by 15 and 21%, respectively. Isovolumetric contractility indices (measured at fixed heart rates) fell progressively by 9-12%, whereas relaxation (Tau1 and Tau2) slowed by 10% (all p < 0.05 vs. control). Consequently, left ventricular end-diastolic and right atrial pressures increased significantly from 17 +/- 3 and 9 +/- 1.2 mm Hg at baseline to 21 +/- 2.5 and 12 +/- 2.1 mm Hg, respectively. Dilevalol did not affect systemic or coronary resistance. However, coronary flow decreased by 24% (p < 0.05 vs. control), accompanied by significant reductions in myocardial oxygen demand and consumption of 23 and 14%, respectively. Levels of circulating norepinephrine and dopamine increased by 35 and 71%, whereas those of renin and angiotensin II decreased by 26 and 33%, respectively (all p < 0.05 vs. control). Adverse side effects did not occur. None of the patients became ischemic. Thus, at the dose level used, dilevalol has predominant beta-blocking effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypersensitivity immune reaction as a mechanism for dilevalol-associated hepatitis.

OBJECTIVE: To assess lymphocyte reactivity to dilevalol and to serum containing putative ex vivo dilevalol antigens or metabolites in a case of dilevalol-induced liver injury. PATIENT: A 58-year-old woman with a clinical diagnosis of dilevalol-induced liver injury. METHODS: Peripheral blood mononuclear cells collected from the patient were cultured in the presence of a solution of dilevalol and also with sera collected from a volunteer before and after dilevalol intake. A similar protocol was performed with lymphocytes from a healthy subject. RESULTS: No lymphocyte proliferation was observed either in the patient or in the healthy volunteer in the presence of dilevalol solutions. A significant proliferative response to serum collected after dilevalol intake was observed in the case of the patient compared with the proliferative response to the serum collected before the drug intake. No reactivity was found when lymphocytes from the healthy subject were tested under similar conditions. CONCLUSIONS: The methodology used allowed the detection of lymphocyte sensitization to sera containing ex vivo-prepared dilevalol antigens, suggesting the involvement of an immunologic mechanism in dilevalol-induced liver injury.

Dilevalol: a dose-response study in normal volunteers.

Dilevalol, 100 mg, 200 mg and 400 mg, and placebo were given to eight normal volunteers and the effect on blood pressure and heart rate studied at rest and on exercise. There was a dose-dependent fall in exercising heart rate and in the increased heart rate on exercise with dilevalol, while exercising systolic blood pressure and the rise in systolic blood pressure on exercise fell dose-dependently up to 200 mg, but the effect of 400 mg was similar. Diastolic blood pressure was not affected. Supine heart rate and blood pressure changes were not different from placebo. Tilt heart rate fell most constantly from 200 mg. Some fall in tilt systolic blood pressure was seen but this was not dose-dependent, diastolic blood pressure was not affected. There was wide variation in plasma concentration of dilevalol, as might be expected from a liver metabolised drug, with a relatively larger amount absorbed of the 400 mg dose compared to the 100 or 200 mg doses.