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1.
Xenobiotica ; 51(4): 413-426, 2021 Apr.
Article in English | MEDLINE | ID: mdl-33413022

ABSTRACT

Absorption, metabolism, and excretion (AME) of licogliflozin, a sodium-glucose co-transporters (SGLTs) 1 and 2 inhibitor, were studied in male rats, dogs, and healthy male volunteers and reported.Oral absorption of licogliflozin was rapid (tmax < 1 h) with absorption estimated at 87%, 100% and 77% in rats, dogs and humans, respectively.Excretion of licogliflozin-related radioactivity was rapid and nearly complete following oral administration with total radioactivity recovery ranging from 73% in dogs, 92.5% in humans, to 100% in rats. Dose-related radioactivity was excreted in both urine and faeces with urinary excretion playing a slightly more important role in humans (∼56%) than in animal species (∼19-41%).Elimination of licogliflozin was predominantly via metabolism with the majority of the radioactivity dose (∼54-74%) excreted as metabolites across species.The principal biotransformation pathways involved direct glucuronidation and oxidation across all species. In humans, direct glucuronidation to M17 and M27 was the major pathway observed, accounting for ∼38% of the dose in excreta while oxidative metabolism also contributed to >29% of the dose in excreta. Oxidative pathways were predominant in animal species.


Subject(s)
Body Fluids , Sodium-Glucose Transporter 2 Inhibitors , Administration, Oral , Anhydrides , Animals , Biotransformation , Dogs , Feces , Humans , Male , Rats , Sorbitol/analogs & derivatives
2.
J Clin Pharmacol ; 60 Suppl 2: S49-S62, 2020 12.
Article in English | MEDLINE | ID: mdl-33274510

ABSTRACT

Oral contraceptives (OCs) are the most widely used form of birth control among women of childbearing potential. Knowledge of potential drug-drug interactions (DDIs) with OCs becomes imperative to provide information on the medication to women of childbearing potential and enable their inclusion in clinical trials, especially if the new molecular entity is a teratogen. Although a number of DDI guidance documents are available, they do not provide recommendations for the design and conduct of OC DDI studies. The evaluation of DDI potential of a new molecular entity and OCs is particularly challenging because of the availability of a wide variety of combinations of hormonal contraceptives, different doses of the ethinyl estradiol, and different metabolic profiles of the progestin component. The aim of this review is to comprehensively discuss factors to be considered such as pharmacokinetics (PK), pharmacodynamics (PD), choice of OC, and study population for the conduct of in vivo OC DDI studies. In this context, metabolic pathways of OCs, the effect of enzyme inhibitors and inducers, the role of sex hormone-binding globulin in the PK of progestins, current evidence on OC DDIs, and the interpretation of PD end points are reviewed. With the emergence of new tools like physiologically based PK modeling, the decision to conduct an in vivo study can be made with much more confidence. This review provides a comprehensive overview of various factors that need to be considered in designing OC DDI studies and recommends PK-based DDI studies with PK end points as adequate measures to establish clinical drug interaction and measurement of PD end points when there is basis for PD interaction.


Subject(s)
Contraceptives, Oral/pharmacology , Drug Interactions , Contraceptives, Oral/metabolism , Contraceptives, Oral/pharmacokinetics , Cytochrome P-450 CYP3A Inducers/pharmacokinetics , Cytochrome P-450 CYP3A Inhibitors/pharmacokinetics , Female , Humans , Models, Biological , Sex Hormone-Binding Globulin/pharmacokinetics
4.
J Pharm Sci ; 106(5): 1439-1451, 2017 05.
Article in English | MEDLINE | ID: mdl-28089685

ABSTRACT

Sacubitril/valsartan (LCZ696) has been approved for the treatment of heart failure. Sacubitril is an in vitro inhibitor of organic anion-transporting polypeptides (OATPs). In clinical studies, LCZ696 increased atorvastatin Cmax by 1.7-fold and area under the plasma concentration-time curve by 1.3-fold, but had little or no effect on simvastatin or simvastatin acid exposure. A physiologically based pharmacokinetics modeling approach was applied to explore the underlying mechanisms behind the statin-specific LCZ696 drug interaction observations. The model incorporated OATP-mediated clearance (CLint,T) for simvastatin and simvastatin acid to successfully describe the pharmacokinetic profiles of either analyte in the absence or presence of LCZ696. Moreover, the model successfully described the clinically observed drug effect with atorvastatin. The simulations clarified the critical parameters responsible for the observation of a low, yet clinically relevant, drug-drug interaction DDI between sacubitril and atorvastatin and the lack of effect with simvastatin acid. Atorvastatin is administered in its active form and rapidly achieves Cmax that coincide with the low Cmax of sacubitril. In contrast, simvastatin requires a hydrolysis step to the acid form and therefore is not present at the site of interactions at sacubitril concentrations that are inhibitory. Similar models were used to evaluate the drug-drug interaction risk for additional OATP-transported statins which predicted to maximally result in a 1.5-fold exposure increase.


Subject(s)
Aminobutyrates/pharmacokinetics , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacokinetics , Models, Biological , Tetrazoles/pharmacokinetics , Angiotensin II Type 1 Receptor Blockers/pharmacokinetics , Angiotensin Receptor Antagonists/pharmacokinetics , Biphenyl Compounds , Drug Combinations , Drug Evaluation, Preclinical/methods , Drug Interactions/physiology , Humans , Valsartan
5.
Clin Pharmacol Drug Dev ; 6(1): 19-26, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27138546

ABSTRACT

The objectives of this analysis were to establish the exposure-response relationship between plasma rifampicin and 4ß-hydroxycholesterol (4ßHC) concentration and to estimate the effect of weak, moderate, and potent CYP3A induction. Plasma rifampicin and 4ßHC concentration-time data from a drug-drug interaction study with rifampicin 600 mg were used for model development. An indirect response model with an effect compartment described the relationship between rifampicin and 4ßHC concentrations. The model predicted that the equilibration t1/2 and 4ßHC t1/2 were 72.8 and 142 hours, respectively. EM50 and Emax of rifampicin induction were 32.6 µg and 8.39-fold, respectively. The population PK-PD model was then used to simulate the effects of rifampicin 10, 20, and 100 mg on plasma 4ßHC for up to 21 days, in which rifampicin 10, 20, and 100 mg were used to represent weak, moderate, and strong inducers, respectively. The model-predicted median (5th, 95th percentiles) 1.13 (1.04, 1.44)-, 1.28 (1.10, 1.71)-, and 2.10 (1.45, 3.49)-fold increases in plasma 4ßHC after 14-day treatment with rifampicin 10, 20, and 100 mg, respectively. A new drug candidate can likely be classified as a weak, moderate, or strong inducer if baseline-normalized plasma 4ßHC increases by <1.13-, 1.13- to 2.10-, or >2.10-fold, respectively, after 14 days of dosing.


Subject(s)
Cytochrome P-450 CYP3A Inducers/administration & dosage , Hydroxycholesterols/blood , Rifampin/administration & dosage , Adult , Cytochrome P-450 CYP3A Inducers/blood , Cytochrome P-450 CYP3A Inducers/pharmacokinetics , Drug Interactions , Female , Healthy Volunteers , Humans , Hydroxycholesterols/administration & dosage , Hydroxycholesterols/pharmacology , Male , Middle Aged , Models, Theoretical , Rifampin/blood , Rifampin/pharmacokinetics , Young Adult
6.
Clin Pharmacol Drug Dev ; 3(2): 132-8, 2014 Mar.
Article in English | MEDLINE | ID: mdl-27128457

ABSTRACT

The oral bioavailability of valsartan from extemporaneous suspension and solution formulations were evaluated relative to tablet formulation in two separate open-label, randomized crossover studies in healthy adults. In both studies, the plasma concentrations of valsartan after oral administration were analyzed using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods, and the corresponding pharmacokinetic parameters were estimated using noncompartmental analysis. The peak plasma concentration (Cmax ) and area under the concentration time-curves (AUC(0-∞) ) of valsartan from the extemporaneous suspension were higher by 1.93- and 1.56-fold, respectively, relative to the tablet formulation (P < .001). The Cmax and AUC(0-∞) of valsartan from the oral solution were higher by 2.21- and 1.74-fold, respectively, relative to the tablet formulation (P < .001). These results indicate that both rate and extent of absorption of valsartan are higher in the two liquid dosage forms (extemporaneous suspension and solution formulations) relative to the solid oral dosage form (tablet formulation).

7.
Clin Pharmacol Drug Dev ; 3(6): 487-92, 2014 11.
Article in English | MEDLINE | ID: mdl-27129123

ABSTRACT

A double fixed dose combination of amlodipine/valsartan and triple fixed dose combination of amlodipine/valsartan/HCTZ tablets have been developed to treat patients with moderate-to-severe hypertension. Here, we present the effect of food on the oral bioavailability of these two fixed dose combination tablets from two separate clinical studies in healthy subjects. Single oral doses of amlodipine/valsartan (10/160 mg) and amlodipine/valsartan/HCTZ (10/320/25 mg were administered under fasted or fed conditions. Blood samples were collected in both studies to determine the pharmacokinetic parameters of amlodipine, valsartan, and/or HCTZ using non-compartmental analysis. Following amlodipine/valsartan administration, the geometric mean ratios (GMRs, 90% CI) of AUC0-∞ and Cmax were 1.09 (1.05-1.13) and 1.03 (0.97-1.09) for amlodipine, and 0.94 (0.81-1.10) and 0.86 (0.73-1.02) for valsartan, respectively. Following amlodipine/valsartan/HCTZ administration, the GMRs (90%CI) of AUC0-∞ and Cmax were 1.09 (1.04-1.15) and 1.11 (1.05-1.08) for amlodipine, 1.14 (0.99-1.31) and 1.12 (0.98-1.29) for valsartan, and 1.09 (1.02-1.16) and 0.86 (0.79-0.93) for HCTZ, respectively. Considering the sample size and pharmacokinetic variability associated with analytes, these study results indicate that food effect is minimal or none when fixed dose combination tablets are administered with food. In conclusion, both fixed dose combination tablets can be administered without regards to meals.


Subject(s)
Amlodipine, Valsartan Drug Combination/administration & dosage , Amlodipine, Valsartan Drug Combination/pharmacokinetics , Angiotensin II Type 1 Receptor Blockers/administration & dosage , Angiotensin II Type 1 Receptor Blockers/pharmacokinetics , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/pharmacokinetics , Calcium Channel Blockers/administration & dosage , Calcium Channel Blockers/pharmacokinetics , Food-Drug Interactions , Hydrochlorothiazide/administration & dosage , Hydrochlorothiazide/pharmacokinetics , Administration, Oral , Adolescent , Adult , Amlodipine, Valsartan Drug Combination/adverse effects , Amlodipine, Valsartan Drug Combination/blood , Angiotensin II Type 1 Receptor Blockers/adverse effects , Angiotensin II Type 1 Receptor Blockers/blood , Antihypertensive Agents/adverse effects , Antihypertensive Agents/blood , Area Under Curve , Biological Availability , Calcium Channel Blockers/adverse effects , Calcium Channel Blockers/blood , Cross-Over Studies , Dietary Fats/administration & dosage , Drug Combinations , Drug Monitoring , Female , Healthy Volunteers , Humans , Hydrochlorothiazide/adverse effects , Hydrochlorothiazide/blood , Male , Metabolic Clearance Rate , Middle Aged , Tablets , Young Adult
8.
Ann Noninvasive Electrocardiol ; 19(1): 70-81, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24372708

ABSTRACT

A collaboration between the Consortium for Innovation and Quality in Pharmaceutical Development and the Cardiac Safety Research Consortium has been formed to design a clinical study in healthy subjects demonstrating that the thorough QT (TQT) study can be replaced by robust ECG monitoring and exposure-response (ER) analysis of data generated from First-in-Man single ascending dose (SAD) studies. Six marketed drugs with well-characterized QTc effects were identified in discussions with FDA; five have caused QT prolongation above the threshold of regulatory concern. Twenty healthy subjects will be enrolled in a randomized, placebo-controlled study designed with the intent to have similar power to exclude small QTc effects as a SAD study. Two doses (low and high) of each drug will be given on separate, consecutive days to 9 subjects. Six subjects will receive placebo. Data will be analyzed using linear mixed-effects ER models. Criteria for QT-positive drugs will be the demonstration of an upper bound (UB) of the 2-sided 90% confidence interval (CI) of the projected QTc effect at the peak plasma level of the lower dose above the threshold of regulatory concern (currently 10 ms) and a positive slope of ER relationship. The criterion for QT-negative drug will be an UB of the CI of the projected QTc effect of the higher dose <10 ms. It is expected that a successful outcome in this study will provide evidence supporting replacement of the TQT study with ECG assessments in standard early clinical development studies for a new chemical entity.


Subject(s)
Clinical Trials, Phase I as Topic/methods , Drug Evaluation, Preclinical/methods , Electrocardiography/drug effects , Electrocardiography/methods , Prospective Studies , Research Design/statistics & numerical data , Dose-Response Relationship, Drug , Electrocardiography/statistics & numerical data , Humans , Randomized Controlled Trials as Topic/methods , Reference Values
9.
J Clin Pharmacol ; 52(5): 645-55, 2012 May.
Article in English | MEDLINE | ID: mdl-21659626

ABSTRACT

Single-pill combinations (SPCs) of complementary antihypertensive agents provide patients with a simple and effective treatment regimen. To ensure that the efficacy and safety of an SPC is the same as that for the individual drugs administered together (free combination), SPC and free-combination formulations must be shown to be bioequivalent. Three open-label, randomized studies compared the pharmacokinetics of SPC tablets of the direct renin inhibitor aliskiren and hydrochlorothiazide (HCT), at doses of 150/25, 300/12.5, and 300/25 mg, with the corresponding free combinations in healthy volunteers. Data from 2 randomized, double-blinded studies of patients with hypertension were used to assess inhibition of plasma renin activity (PRA) by the aliskiren/HCT 300/25 mg SPC and the free combination. At all dose combinations, aliskiren and HCT systemic drug exposure was similar when administered as an SPC or free combination, indicating bioequivalence. Aliskiren/HCT 300/25 mg SPC inhibited PRA to the same extent as the free combination. HCT alone increased PRA through activation of the renin-angiotensin system; aliskiren prevented this diuretic-induced increase to the same extent when administered as the free combination or as the SPC. In conclusion, aliskiren/HCT SPCs are pharmacokinetically and pharmacodynamically bioequivalent to aliskiren and HCT in free combination.


Subject(s)
Amides/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Blood Pressure/drug effects , Diuretics/pharmacokinetics , Fumarates/pharmacokinetics , Hydrochlorothiazide/pharmacokinetics , Hypertension/drug therapy , Administration, Oral , Adolescent , Adult , Amides/administration & dosage , Amides/adverse effects , Analysis of Variance , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/adverse effects , Cross-Over Studies , Diuretics/administration & dosage , Diuretics/adverse effects , Double-Blind Method , Drug Combinations , Drug Therapy, Combination , Female , Fumarates/administration & dosage , Fumarates/adverse effects , Humans , Hydrochlorothiazide/administration & dosage , Hydrochlorothiazide/adverse effects , Hypertension/blood , Hypertension/physiopathology , Least-Squares Analysis , Male , Middle Aged , Models, Biological , Renin/antagonists & inhibitors , Renin/metabolism , Tablets , Therapeutic Equivalency , Treatment Outcome , Young Adult
10.
Eur J Clin Pharmacol ; 68(5): 697-708, 2012 May.
Article in English | MEDLINE | ID: mdl-22124880

ABSTRACT

PURPOSE: To conduct a mechanistic investigation of the interaction between aliskiren and grapefruit juice in healthy subjects. METHODS: Twenty-eight subjects received an oral dose of aliskiren 300 mg (highest recommended clinical dose) with 300 mL of either water or grapefruit juice in a two-way crossover design. Safety and pharmacokinetic analyses were performed. In vitro studies were performed in HEK293 cells to investigate the role of organic anion transporting polypeptide (OATP) transporter-mediated uptake of aliskiren. RESULTS: Co-administration of a single dose of aliskiren with grapefruit juice decreased the plasma concentration of aliskiren, with mean decreases in the AUC(inf), AUC(last), and C(max) of 38, 37, and 61%, respectively. The uptake of [¹4C]aliskiren into OATP2B1-expressing cells was essentially the same as that into control cells, and the inhibitor combination atorvastatin and rifamycin had no effect on [¹4C]aliskiren accumulation in either cell type. The uptake of [¹4C]aliskiren and [³H]fexofenadine was linear in OATP1A2-expressing cells and was reduced by naringin, with IC50 values of 75.5 ± 11.6 and 24.2 ± 2.0 µM, respectively. CONCLUSIONS: Grapefruit juice decreases exposure of aliskiren partially via inhibition of intestinal OATP1A2.


Subject(s)
Amides/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Beverages/adverse effects , Citrus paradisi/chemistry , Food-Drug Interactions , Fumarates/pharmacokinetics , Intestinal Mucosa/enzymology , Organic Anion Transporters/antagonists & inhibitors , Adult , Amides/adverse effects , Amides/blood , Amides/metabolism , Antihypertensive Agents/adverse effects , Antihypertensive Agents/blood , Antihypertensive Agents/metabolism , Beverages/analysis , Biological Transport/drug effects , Cross-Over Studies , Flavanones/analysis , Flavanones/pharmacology , Fruit/chemistry , Fumarates/adverse effects , Fumarates/blood , Fumarates/metabolism , HEK293 Cells , Half-Life , Humans , Male , Organic Anion Transporters/genetics , Organic Anion Transporters/metabolism , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/metabolism , Renin/antagonists & inhibitors , Terfenadine/analogs & derivatives , Terfenadine/metabolism , Young Adult
11.
J Clin Pharmacol ; 51(11): 1549-60, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21406600

ABSTRACT

To explore the clinical relevance of inhibition of multidrug resistance transporter 1 and organic anion transporting polypeptide transporter, a drug-drug interaction study was conducted using aliskiren and cyclosporine. This was an open-label, single-sequence, parallel-group, single-dose study in healthy subjects. Subjects (n = 14) first received aliskiren 75 mg orally (period 1), followed by aliskiren 75 mg + cyclosporine 200 mg (period 2) after a 7-day washout period, and aliskiren 75 mg + cyclosporine 600 mg (period 3) after a 14-day washout period. Safety and pharmacokinetics were analyzed during each period. The primary objective was to characterize pharmacokinetics of aliskiren (single-dose and combination with cyclosporine). The increases in area under the time-concentration curve from time 0 to infinity and maximum concentration associated with cyclosporine 200 mg or 600 mg were 4- to 5-fold and 2.5-fold, respectively. Mean half-life increased from 25 to 45 hours. Based on comparison to literature, a single-dose of aliskiren 75 mg did not alter the pharmacokinetics of cyclosporine. Aliskiren 75 mg was well tolerated. Combination with cyclosporine increased the number of adverse events, mainly hot flush and gastrointestinal symptoms, with no serious adverse events. Two adverse events led to withdrawal (ligament rupture, not suspected to be study-drug related; and vomiting, suspected to be study-drug related). Laboratory parameters, vital signs, and electrocardiographs showed no time- or treatment-related changes. As cyclosporine significantly altered the pharmacokinetics of aliskiren in humans, its use with aliskiren is not recommended.


Subject(s)
Amides/pharmacokinetics , Cyclosporine/pharmacokinetics , Fumarates/pharmacokinetics , ATP Binding Cassette Transporter, Subfamily B , ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Administration, Oral , Adult , Amides/adverse effects , Area Under Curve , Cyclosporine/adverse effects , Cytochrome P-450 CYP3A/metabolism , Cytochrome P-450 CYP3A Inhibitors , Drug Interactions , Female , Fumarates/adverse effects , Half-Life , Humans , Male , Middle Aged , Organic Anion Transporters/antagonists & inhibitors , Organic Anion Transporters/metabolism , Young Adult
12.
J Clin Pharmacol ; 51(6): 933-42, 2011 Jun.
Article in English | MEDLINE | ID: mdl-20852001

ABSTRACT

The steady-state pharmacokinetic (PK) interaction potential between amlodipine (10 mg), valsartan (320 mg), and hydrochlorothiazide (HCTZ; 25 mg) was evaluated in patients with hypertension in a multicenter, multiple-dose, open-label, 4-cohort, parallel-group study. Eligible patients were randomly allocated to the dual combination of valsartan + HCTZ, amlodipine + valsartan, or amlodipine + HCTZ and nonrandomly allotted to amlodipine + valsartan + HCTZ triple combination treatment. After 6 days of treatment with a half-maximal dose of different combinations, patients were up-titrated to the maximal drug doses from day 7 through day 17. PK parameters of corresponding analytes from the triple- and dual-treatment groups were estimated on day 17 and compared. Safety and tolerability of all treatments was assessed. The C ( ssmax ) and AUC(0-τ) values of amlodipine or HCTZ remained unaffected when administered with valsartan + HCTZ or valsartan + amlodipine, respectively. On the other hand, valsartan exposure increased by 10% to 25% when coadministered with HCTZ and amlodipine, which is not considered clinically relevant. In conclusion, there were no clinically relevant PK interactions with amlodipine, valsartan, and HCTZ triple combination compared with the corresponding dual combinations. All treatments were safe and well tolerated.


Subject(s)
Amlodipine/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Hydrochlorothiazide/pharmacokinetics , Hypertension/drug therapy , Tetrazoles/pharmacokinetics , Valine/analogs & derivatives , Adolescent , Adult , Amlodipine/administration & dosage , Amlodipine/adverse effects , Amlodipine, Valsartan Drug Combination , Antihypertensive Agents/administration & dosage , Dose-Response Relationship, Drug , Drug Combinations , Drug Interactions , Drug Therapy, Combination/adverse effects , Drug Therapy, Combination/methods , Female , Humans , Hydrochlorothiazide/administration & dosage , Hydrochlorothiazide/adverse effects , Male , Middle Aged , Tetrazoles/administration & dosage , Tetrazoles/adverse effects , Valine/administration & dosage , Valine/pharmacokinetics , Valsartan
13.
J Clin Pharmacol ; 51(2): 218-28, 2011 Feb.
Article in English | MEDLINE | ID: mdl-20413453

ABSTRACT

The authors describe the drug-drug interaction between aliskiren and verapamil in healthy participants. Eighteen participants first received an oral dose of aliskiren 300 mg (highest recommended clinical dose) in period 1. After a 10-day washout period, the participants received verapamil 240 mg/d for 8 days (period 2). On day 8, the participants also received an oral dose of aliskiren 300 mg. Safety and pharmacokinetic analyses were performed during each treatment period. Concomitant administration of a single dose of aliskiren during steady-state verapamil resulted in an increase in plasma concentration of aliskiren. The mean increase in AUC(0-∞), AUC(last), and C(max) was about 2-fold. On day 8, in the presence of aliskiren, AUC(τ,ss) of R-norverapamil, R-verapamil, S-norverapamil, and S-verapamil was decreased by 10%, 16%, 10%, and 25%, respectively. Similarly, the C(max,ss) of R-norverapamil, R-verapamil, S-norverapamil, and S-verapamil was decreased by 13%, 18%, 12%, and 24%, respectively. Aliskiren did not affect the AUC(τ,ss) ratios of R-norverapamil/R-verapamil and S-norverapamil/S-verapamil. Aliskiren administered alone or in combination with verapamil was well tolerated in healthy participants. In conclusion, no dose adjustment is necessary when aliskiren is administered with moderate ABCB1 inhibitors such as verapamil (240 mg/d).


Subject(s)
Amides/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Calcium Channel Blockers/pharmacology , Fumarates/pharmacokinetics , Verapamil/pharmacology , ATP Binding Cassette Transporter, Subfamily B , ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors , Administration, Oral , Adolescent , Adult , Amides/adverse effects , Amides/pharmacology , Antihypertensive Agents/adverse effects , Antihypertensive Agents/pharmacology , Area Under Curve , Calcium Channel Blockers/adverse effects , Drug Interactions , Fumarates/adverse effects , Fumarates/pharmacology , Humans , Male , Prospective Studies , Verapamil/adverse effects , Verapamil/analogs & derivatives , Verapamil/pharmacokinetics , Young Adult
14.
Clin Drug Investig ; 30(4): 221-8, 2010.
Article in English | MEDLINE | ID: mdl-20192280

ABSTRACT

BACKGROUND: Aliskiren is the first oral direct renin inhibitor to be approved for the treatment of hypertension. The pharmacokinetic and pharmacodynamic profile of aliskiren has been extensively characterized in Caucasian individuals; however, drug disposition, treatment response and tolerability can vary among ethnic groups, and these variations are difficult to predict. OBJECTIVE: To evaluate the single- and multiple-dose pharmacokinetics of aliskiren in healthy Chinese subjects. METHODS: This was a randomized, single-blind, parallel-group, placebo-controlled study. On day -1, subjects were randomized to one of four cohorts (aliskiren 75, 150, 300 or 600 mg). On day 1, eight individuals in each cohort received a single dose of active treatment and two received placebo. Subjects randomized to aliskiren 300 mg received additional once-daily doses on days 5-11 to establish steady-state pharmacokinetics. Subjects receiving aliskiren 75, 150 or 600 mg (cohorts 1, 2 and 4) completed the study at the end of the 96-hour pharmacokinetic assessment period. Subjects receiving aliskiren 300 mg (cohort 3) had additional pharmacokinetic assessments on days 5-15. The study was carried out at the Peking Union Medical College Hospital, Beijing, China, and included 40 healthy Chinese subjects. The main outcome measures were the pharmacokinetic parameters for aliskiren, including area under the plasma concentration-time curve from time zero to infinity (AUC(infinity)) and maximum plasma concentration (C(max)). RESULTS: Aliskiren AUC(infinity) and C(max) increased greater than proportionally across the 8-fold dose range (75-600 mg; mean AUC(infinity) 291-4726 ng x h/mL, mean C(max) 62-699 ng/mL), but a dose-proportional 2-fold increase was observed within the clinically approved dose range (150-300 mg; mean AUC(infinity) 876-1507 ng x h/mL, mean C(max) 137-271 ng/mL). CONCLUSION: At steady state, the mean AUC during the dosage interval (AUC(tau)) for aliskiren 300 mg (1532 +/- 592 ng x h/mL) was similar to the AUC(infinity) observed following a single dose. Aliskiren exhibits similar single-dose and steady-state pharmacokinetics in Chinese subjects compared with those observed in Caucasian individuals in previous studies.


Subject(s)
Amides/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Fumarates/pharmacokinetics , Renin/antagonists & inhibitors , Administration, Oral , Adult , Amides/administration & dosage , Amides/adverse effects , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/adverse effects , Area Under Curve , Asian People , China , Cohort Studies , Dose-Response Relationship, Drug , Female , Fumarates/administration & dosage , Fumarates/adverse effects , Humans , Male , Single-Blind Method , Young Adult
15.
J Clin Pharmacol ; 50(12): 1358-66, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20150520

ABSTRACT

Gender and body weight influence the pharmacokinetics and pharmacodynamics of many drugs. This pooled analysis of 17 clinical studies evaluated the effect of gender, body mass index (BMI), body weight, and lean body weight (LBW) on the pharmacokinetics of the direct renin inhibitor aliskiren in healthy volunteers (n = 392). A separate pooled analysis of 5 clinical studies in patients with hypertension (n = 2327) assessed the influence of gender and BMI on the effects of aliskiren on plasma renin activity and blood pressure. Area under the aliskiren plasma concentration-time curve (AUC(τ)) was 22% lower and the peak aliskiren plasma concentration (C(max)) was 24% lower in men than women (P < .05). BMI was not significantly correlated with AUC(τ) (r = 0.005; P = .917); AUC(τ) was negatively correlated with body weight (r = -0.235; P < .0001) and LBW (r = -0.295; P < .0001). Results were similar for C(max). Adjusting individual aliskiren AUC(τ) and C(max) values for overall mean body weight or LBW abolished gender differences. Based on r(2) values, LBW variation accounted for 8.9% of aliskiren AUC(τ) variation. In patients with hypertension, gender and BMI did not significantly influence the effects of aliskiren on plasma renin activity or blood pressure. It was concluded that lower systemic exposure to aliskiren in men versus women relates to differences in body weight; neither gender nor body weight has clinically relevant effects on the pharmacokinetics or pharmacodynamics of aliskiren.


Subject(s)
Amides/pharmacology , Amides/therapeutic use , Antihypertensive Agents/pharmacology , Antihypertensive Agents/therapeutic use , Body Weight , Fumarates/pharmacology , Fumarates/therapeutic use , Hypertension/drug therapy , Sex Characteristics , Adult , Amides/blood , Amides/pharmacokinetics , Antihypertensive Agents/blood , Antihypertensive Agents/pharmacokinetics , Blood Pressure/drug effects , Body Composition , Body Mass Index , Clinical Trials as Topic , Female , Fumarates/blood , Fumarates/pharmacokinetics , Humans , Hypertension/blood , Male , Renin/antagonists & inhibitors , Renin/blood
16.
Drug Metab Pharmacokinet ; 24(2): 145-52, 2009.
Article in English | MEDLINE | ID: mdl-19430170

ABSTRACT

The objective of this work was to develop a population pharmacokinetic model to assess the influence of subject covariates on the pharmacokinetics of valsartan in children. Data were collected from a single dose study in 26 hypertensive children ages 1 to 16 years. Subjects received 2 mg/kg valsartan suspension up to a maximum dose of 80 mg. Plasma samples were collected and analyzed using LC/MS/MS. Several structural pharmacokinetic models were evaluated for appropriateness. Allometric scaling and standard covariate analyses were performed to explain interindividual variabilities. Objective function values and goodness of fit plots were used for model selection. A posterior predictive check was used for model evaluation. A linear 2-compartment first-order elimination model with zero-order absorption and lag-time best described the disposition of valsartan. Allometric scaling and standard covariate analysis revealed that age and body size have similar influence; however, after adjustment for body size using fat free mass (FFM), the effect of increasing age was no longer significant on valsartan clearance (2% per year relative to a typical 8 year old with FFM of 30 kg). The population pharmacokinetic model reveals that increase in age has minimal influence on body size dependent clearance of valsartan in children.


Subject(s)
Metabolic Clearance Rate , Population Groups/genetics , Tetrazoles/pharmacokinetics , Valine/analogs & derivatives , Adolescent , Child , Child, Preschool , Dose-Response Relationship, Drug , Humans , Infant , Models, Biological , Pediatrics , Valine/pharmacokinetics , Valsartan
17.
Clin Pharmacokinet ; 47(8): 515-31, 2008.
Article in English | MEDLINE | ID: mdl-18611061

ABSTRACT

Aliskiren is the first orally bioavailable direct renin inhibitor approved for the treatment of hypertension. It acts at the point of activation of the renin-angiotensin-aldosterone system, or renin system, inhibiting the conversion of angiotensinogen to angiotensin I by renin and thereby reducing the formation of angiotensin II by angiotensin-converting enzyme (ACE) and ACE-independent pathways. Aliskiren is a highly potent inhibitor of human renin in vitro (concentration of aliskiren that produces 50% inhibition of renin 0.6 nmol/L). Aliskiren is rapidly absorbed following oral administration, with maximum plasma concentrations reached within 1-3 hours. The absolute bioavailability of aliskiren is 2.6%. The binding of aliskiren to plasma proteins is moderate (47-51%) and is independent of the concentration. Once absorbed, aliskiren is eliminated through the hepatobiliary route as unchanged drug and, to a lesser extent, through oxidative metabolism by cytochrome P450 (CYP) 3A4. Unchanged aliskiren accounts for approximately 80% of the drug in the plasma following oral administration, indicating low exposure to metabolites. The two major oxidized metabolites of aliskiren account for less than 5% of the drug in the plasma at the time of the maximum concentration. Aliskiren excretion is almost completely via the biliary/faecal route; 0.6% of the dose is recovered in the urine. Steady-state plasma concentrations of aliskiren are reached after 7-8 days of once-daily dosing, and the accumulation factor for aliskiren is approximately 2. After reaching the peak, the aliskiren plasma concentration declines in a multiphasic fashion. No clinically relevant effects of gender or race on the pharmacokinetics of aliskiren are observed, and no adjustment of the initial aliskiren dose is required for elderly patients or for patients with renal or hepatic impairment. Aliskiren showed no clinically significant increases in exposure during coadministration with a wide range of potential concomitant medications, although increases in exposure were observed with P-glycoprotein inhibitors. Aliskiren does not inhibit or induce CYP isoenzyme or P-glycoprotein activity, although aliskiren is a substrate for P-glycoprotein, which contributes to its relatively low bioavailability. Aliskiren is approved for the treatment of hypertension at once-daily doses of 150 mg and 300 mg. Phase II and III clinical studies involving over 12,000 patients with hypertension have demonstrated that aliskiren provides effective long-term blood pressure (BP) lowering with a good safety and tolerability profile at these doses. Aliskiren inhibits plasma renin activity (PRA) by up to 80% following both single and multiple oral-dose administration. Similar reductions in PRA are observed when aliskiren is administered in combination with agents that alone increase PRA, including diuretics (hydrochlorothiazide, furosemide [frusemide]), ACE inhibitors (ramipril) and angiotensin receptor blockers (valsartan), despite greater increases in the plasma renin concentration. Moreover, PRA inhibition and BP reductions persist for 2-4 weeks after stopping treatment, which is likely to be of benefit in patients with hypertension who occasionally miss a dose of medication. Preliminary data on the antiproteinuric effects of aliskiren in type 2 diabetes mellitus suggest that renoprotective effects beyond BP lowering may be possible. Further studies to evaluate the effects of aliskiren on cardiovascular outcomes and target organ protection are ongoing and will provide important new data on the role of direct renin inhibition in the management of hypertension and other cardiovascular disease.


Subject(s)
Amides/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Fumarates/pharmacokinetics , Hypertension/drug therapy , Administration, Oral , Amides/pharmacology , Antihypertensive Agents/pharmacology , Biological Availability , Drug Interactions , Fumarates/pharmacology , Humans , Renin/antagonists & inhibitors
18.
Curr Med Res Opin ; 24(6): 1703-9, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18471347

ABSTRACT

OBJECTIVE: Vildagliptin is an orally active, potent and selective DPP-4 inhibitor that improves glycemic control in patients with type 2 diabetes by increasing alpha- and beta-cell responsiveness to glucose. RESEARCH DESIGN AND METHODS: This open-label, single-center, randomized, two-period crossover study in healthy subjects (n=23) ages 18-45 years investigated the effect of food on the pharmacokinetics of vildagliptin and metformin following administration of a vildagliptin/metformin (50/1000 mg) fixed-dose combination tablet. RESULTS: Administration of the fixed-dose combination tablet following a high-fat meal had no effect on vildagliptin AUC(0-infinity) (ratio of geometric mean for fed:fasted state, 1.10 [90% CI 1.03, 1.18]), C(max) (ratio of means 0.98 [90% CI 0.85, 1.13]) or median t(max) (2.5 h in fed and fasted states). The rate of absorption of metformin was decreased when given with food, as reflected by the prolonged t(max) (2-4 h) and reduction in C(max) (by 26%), but the extent of absorption was not changed. The food effect on the metformin component of the fixed-dose combination tablets was consistent with, but of a lesser magnitude compared with data stated. CONCLUSIONS: The vildagliptin/metformin (50/1000 mg) fixed-dose combination tablet can be administered in the same manner as metformin, and can be recommended to be taken with meals to reduce the gastrointestinal symptoms associated with metformin.


Subject(s)
Adamantane/analogs & derivatives , Dipeptidyl-Peptidase IV Inhibitors/administration & dosage , Dipeptidyl-Peptidase IV Inhibitors/pharmacology , Food-Drug Interactions , Metformin/administration & dosage , Metformin/pharmacokinetics , Nitriles/administration & dosage , Nitriles/pharmacokinetics , Pyrrolidines/administration & dosage , Pyrrolidines/pharmacokinetics , Adamantane/administration & dosage , Adamantane/pharmacokinetics , Adolescent , Adult , Cross-Over Studies , Diabetes Mellitus, Type 2/drug therapy , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Drug Combinations , Female , Humans , Male , Middle Aged , Vildagliptin
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