Peculiarities of Pharmacokinetics and Bioavailability of Some Cardiovascular Drugs under Conditions of Antiorthostatic Hypokinesia.

We studied pharmacokinetics and bioavailability of verapamil, propranolol, and ethacizine in healthy volunteers after single oral administration under normal conditions and on the second day of simulated antiorthostatic hypokinesia modeling some effects of microgravity. Under conditions of antiorthostatic hypokinesia, a tendency to a decrease in half-elimination period, mean retention time, and volume of distribution and an increase in the rate of absorption, ratio of maximum concentrations, and relative rate of absorption of verapamil and propranolol were revealed. For ethacizine, a statistically significant increase in the time of attaining maximum concentration and volume of distribution and a decrease in the maximum concentration, rate of absorption, ratio of maximum concentrations, and relative rate of absorption under conditions of antiorthostatic hypokinesia were found.

Experimental and Clinical Pharmacokinetics of Fluoxetine and Amitriptyline: Comparative Analysis and Possible Methods of Extrapolation.

The pharmacokinetics of two fluoxetine capsulated dosage forms and two amitriptyline tablet forms after a single oral intake was studied in dogs and healthy volunteers. High significant correlations were detected between plasma concentrations of fluoxetine (r=0.96, p<0.00001, n=11) and amitriptyline (r=0.78, p<0.0224, n=8) in dogs and volunteers. A correlation of medium strength (though insignificant) was detected between nortriptyline concentrations in the plasma of dogs and volunteers (r=0.69, p<0.199, n=5). The bioavailability parameters of the test drugs in dogs and volunteers did not differ. Similar trends of fluoxetine and amitriptyline pharmacokinetic parameters were revealed in volunteers and animals. Methods for extrapolation of experimental pharmacokinetics parameters of fluoxetine and amitriptyline obtained on dogs for humans are proposed and validated.

PROPRANOLOL PHARMACOKINETICS AND HEMODYNAMIC INDICES IN ANTIORTHOSTATIC HYPOKINESIA.

Purpose of the work was to study pharmacokinetics of beta adrenoblocker propranolol, and hemodynamic indices in volunteers for simulation of some effects of microgravity The study involved 8 essentially healthy subjects and the head-down tilt (-80) bedrest model reproducing the effects of microgravity (BD). This was designed as three series of investigations, i.e. before BD, on BD day-2 and on the first day of BD completion. Propranolol concentration in blood plasma was determined using high performance liquid chromatography with fluorescence detection. Hemodynamic indices including heart rate (HR), stroke volume, cardiac output, cardiac index and total peripheric resistance were measured using integral rheography; average blood pressure (BPav) Was assessed by Korotkovs method. Statistical deviations in propranolol pharmacokinetics were found in none of the three series. The most characteristic reactions to propranolol were BPav reductions in all series and HR decreases 2 hours after intake in the first and second series. These deviations were not pathologic but physiological variations typical of healthy people. Therefore, propranolol can be advised for rational pharmacotherapy of acute cardiovascular diseases in piloted space missions.

[TESTING STABILITY OF TABLETED ACETAMINOPHEN AND FUROSEMIDE AFTER 6-MONTH STORAGE IN SPACE FLIGHT].

It was shown that multiple spaceflight factors (i.e., acceleration, overvibration, microgravity etc.) do not impact stability of acetaminophen and furosemide tablets stored onboard the International space station over 6 months. Acetaminophen dose in a tablet was 496.44 ± 6.88 mg (99.29 ± 1.38%) before spaceflight (SF) and 481.77 ± 1 2.40 mg (96.35 ± 0.48%) after 6 mos. of storage; furosemide dose in a tablet was 40.19 ± 0.28 mg (100.47 ± 0.71%) before and 39.24 ± 0.72 mg (98.105 ± 1.80%) after SF remaining within the established limits.

The Influence of Atorvastatin, Amlodipine and Ethoxidol on Ubiquinol and Ubiquinone Endogenous Plasma Concentrations in Patients with Chronic Heart Failure.

BACKGROUND: Coenzyme Q10 is a key component of the mitochondrial respiratory chain and a fat-soluble endogenous antioxidant performing many vital functions in the human body. Many researchers studied the plasma concentrations of ubiquinol, ubiquinone, total CoQ10 and the redox state (ubiquinol/ubiquinone ratio) of CoQ10 in healthy volunteers. However, these parameters in the plasma of patients with chronic heart failure (CHF) remain almost uninvestigated. OBJECTIVE: The aim of this case-control study was to investigate the effect of atorvastatin, amlodipine and ethoxidol on endogenous plasma concentrations of ubiquinol, ubiquinone, total CoQ10 and its redox state in patients with CHF. METHODS: The study included 62 patients with CHF divided into four groups depending on the prescribed therapy. For the quantitative determination of ubiquinol, ubiquinone, and total CoQ10 in the plasma of patients, HPLCMS/ MS was used. RESULTS: It was established that the endogenous plasma concentration of total CoQ10 in patients with CHF is significantly lower than in healthy volunteers, and the ratio of reduced and oxidized forms of CoQ10 is shifted towards ubiquinone. It was a statistically significant effect of drugs with different physicochemical structures and pharmacological action on the plasma concentrations of ubiquinol, ubiquinone and total CoQ10: atorvastatin administration led to a decrease in the concentration of ubiquinol (-33.3Δ%), and total CoQ10 (-15Δ%), administration of amlodipine contributed to an increase in the levels of ubiquinol (+27.7Δ%) and total CoQ10 (+18.2Δ%), and the administration of ethoxidol caused an increase in the concentration of ubiquinol (+25Δ%), ubiquinone (+17.7Δ%) and total CoQ10 (+20.2Δ%). CONCLUSION: Amlodipine is able to neutralize the negative effect of atorvastin on the redox balance of CoQ10 in patients with CHF. An additional prescription of the antioxidant ethoxidol to standard therapy for patients with CHF was substantiated. Determination of the redox state of CoQ10 in plasma can be used to diagnose and assess the degree of oxidative stress in patients with cardiovascular diseases, as well as to assess the efficacy and safety of ongoing pharmacotherapy.

The effect of coenzyme Q10 as a part of standard therapy on plasma concentrations of ubiquinol, ubiquinone, total CoQ10 and its redox state in patients with ischemic heart disease.

BACKGROUND: Despite CoQ10 being a powerful antioxidant and its redox state that may characterize the body's antioxidant system, the latter remains unstudied in patients with cardiovascular diseases. OBJECTIVE: This prospective case-control study aimed to investigate the concentrations of ubiquinol, ubiquinone, total CoQ10 and its redox state in patients with ischemic heart disease (IHD) and arterial hypertension (AH) during standard therapy and with the additional prescription of CoQ10. METHODS: The study included 54 healthy individuals and 26 patients, who were divided into a control group receiving standard therapy and a test group receiving CoQ10 in addition to standard therapy. Quantitative determination of COQ10, ubiquinone and ubiquinol was carried out by HPLC-MS/MS. RESULTS: It was found that the CoQ10 level in patients was significantly lower than in healthy individuals (on average -32Δ%). In the test group, after treatment, the concentrations of ubiquinol (+53 Δ%), ubiquinone (-28 Δ%), total CoQ10 (+27 Δ%) and redox state (+112 Δ%) were significantly different from the baseline, while in the control group no significant differences were noticed. In the test group after treatment, the levels of total CoQ10 (+25 Δ%), ubiquinol (+43 Δ%), and redox state (+86 Δ%) were statistically significantly higher than in the control group and total CoQ10 concentration did not significantly differ from that in healthy individuals (-12 Δ%). CONCLUSION: The additional prescription of CoQ10 for patients with IHD significantly increases the level of total CoQ10, which leads to the increase of body antioxidant potential .

Experimental and clinical pharmacokinetics of amitryptiline: comparative analysis.

Pharmacokinetics of two amitriptyline tablets, Amitryptiline Nycomed and Amitryptiline, was investigated clinically and experimentally after a single oral dose of 50 mg. A statistically significant correlation between amitryptiline serum concentrations in dogs and healthy humans (r=0.683, p<0.006) was established. In humans, standartized values of peak concentration and area under the concentration curve were significantly higher, specific volume of distribution and total clearance were lower, and half-life and mean retention time were significantly higher than in dogs. Characteristics of apparent bioavailability in dogs and healthy people did not statistically differ.

[Omeprazol and ezomeprazol pharmacokinetics, duration of antisecretory effect, and reasons for their probable changes in duodenal ulcer].

There were authentic distinctions between the groups of healthy volunteers and patients with a peptic ulcer disease in Cmax, Tmax, AUC(0-t), AUC(0-infinity), CIt, Vd of omeprazole and Cmax of esomeprazole (Nexium, AstraZeneca). When the pharmacokinetics of omeprazole and ezomeprazole were compared in both groups, there were authentic distinctions in Cmax, AU(0-t), AUC(0-infinity), CIt, T1/2. The patients who had taken omeprazole the time of hypoacide condition was much shorter than in other groups. Disintegration test modeling pHmax for pH oscillation with large amplitude, that is typical for ulcer disease, demonstrated a possibility of early partial release of omeprazole, its acid-depended degradation and reduction of its bioavailability.