The Bioequivalence Between Valsartan Oral Solution and Suspension Formulations Developed for Pediatric Use

The bioequivalence of valsartan 160 mg oral solution compared to suspension was assessed in a single-dose, open-label, randomized, 2-period, 2-way crossover study in 82 healthy adults. The participants were randomly assigned (1:1) to receive a single dose of the solution or suspension formulation in each of the two treatment periods. Serial blood samples for pharmacokinetic evaluation were collected up to 48 hours post-dose. The pharmacokinetic parameters were estimated by noncompartmental methods and analyzed as per bioequivalence criteria of statistical analysis. The peak plasma concentration of valsartan was reached with median time of 1 and 3 hours with solution and suspension formulation, respectively. Compared to suspension formulation, the mean peak plasma concentration with solution formulation was higher by 32% (90%CI, 1.27-1.38) while the geometric mean ratios (1.09) and the associated 90%CIs (1.05-1.13) of both the areas under the concentration time-curves (from time zero to the last quantifiable concentration and from time zero to infinity) were contained in the required range of 0.80 to 1.25. No new safety signals were observed with either of the formulations.

Zoledronic Acid vs Placebo in Pediatric Glucocorticoid-induced Osteoporosis: A Randomized, Double-blind, Phase 3 Trial

CONTEXT

Glucocorticoids (GCs) prescribed for chronic pediatric illnesses are associated with osteoporotic fractures.

OBJECTIVE

This study aims to determine the efficacy and safety of intravenous (IV) zoledronic acid (ZA) compared with placebo to treat pediatric GC-induced osteoporosis (GIO).

METHODS

Children aged 5 to 17 years with GIO were enrolled in this multinational, randomized, double-blind, placebo-controlled phase 3 trial (ClinicalTrials.gov NCT00799266). Eligible children were randomly assigned 1:1 to 6 monthly IV ZA 0.05 mg/kg or IV placebo. The primary end point was the change in lumbar spine bone mineral density z score (LSBMDZ) from baseline to month 12. Incident fractures and safety were assessed.

RESULTS

Thirty-four children were enrolled (mean age 12.6 ± 3.4 years [18 on ZA, 16 on placebo]), all with low-trauma vertebral fractures (VFs). LSBMDZ increased from -2.13 ± 0.79 to -1.49 ± 1.05 on ZA, compared with -2.38 ± 0.90 to -2.27 ± 1.03 on placebo (least squares means difference 0.41 [95% CI, 0.02-0.81; P = .04]); when corrected for height z score, the least squares means difference in LBMDZ was 0.75 [95% CI, 0.27-1.22; P = .004]. Two children on placebo had new low-trauma VF vs none on ZA. Adverse events (AEs) were reported in 15 of 18 children (83%) on ZA, and in 12 of 16 (75%) on placebo, most frequently within 10 days after the first infusion. There were no deaths or treatment discontinuations due to treatment-emergent AEs.

CONCLUSION

LSBMDZ increased significantly on ZA compared with placebo over 1 year in children with GIO. Most AEs occurred after the first infusion.

Pharmacodynamic interaction between intravenous nitroglycerin and oral sacubitril/valsartan (LCZ696) in healthy subjects

PURPOSE

Sacubitril/valsartan (LCZ696) and nitroglycerin share the second messenger cGMP and lower blood pressure. Given the potential for co-administration of both drugs in patients with heart failure, this study was designed to investigate the potential for a pharmacodynamic drug interaction affecting blood pressure.

METHODS

In this double-blind, placebo-controlled, randomised, crossover study, 40 healthy subjects received sacubitril/valsartan 200 mg bid (97/103 mg bid) or placebo for 5 days. Two hours after the morning dose of sacubitril/valsartan or placebo on day 5, subjects received intravenous nitroglycerin infusion at increasing doses up to 40 μg/min or placebo. Serial measurements of blood pressure (BP), heart rate, biomarkers and sacubitril/valsartan pharmacokinetics were conducted.

RESULTS

Administration of nitroglycerin alone led to a dose- and time-dependent decrease in supine systolic BP (SBP) and diastolic BP (DBP) which was similar when nitroglycerin was co-administered with sacubitril/valsartan. At the highest dose of nitroglycerin, the mean (95% CI) decrease from baseline of SBP/DBP was 19.54 (- 21.99, - 17.09)/12.38 (- 13.85, - 10.92) mmHg for nitroglycerin alone compared to 22.63 (- 25.06, - 20.21)/12.94 (- 14.38, - 11.49) mmHg when co-administered with sacubitril/valsartan. Co-administration of sacubitril/valsartan and nitroglycerin did not result in further plasma cGMP increase compared to sacubitril/valsartan alone. The co-administration of nitroglycerin and sacubitril/valsartan was safe and well tolerated and did not impact the pharmacokinetics of sacubitril/valsartan.

CONCLUSIONS

The results from this study demonstrate no pharmacodynamic drug interaction between nitroglycerin and sacubitril/valsartan in healthy subjects, suggesting that no change of dose selection and escalation recommendations or clinical monitoring during nitroglycerin administration is required.

Clinical Pharmacokinetics of Sacubitril/Valsartan (LCZ696): A Novel Angiotensin Receptor-Neprilysin Inhibitor

Sacubitril/valsartan (LCZ696) is indicated for the treatment of heart failure with reduced ejection fraction. Absorption of sacubitril/valsartan and conversion of sacubitril (prodrug) to sacubitrilat (neprilysin inhibitor) was rapid with maximum plasma concentrations of sacubitril, sacubitrilat, and valsartan (angiotensin receptor blocker) reaching within 0.5, 1.5-2.0, and 2.0-3.0 h, respectively. With a two-fold increase in dose, an increase in the area under the plasma concentration-time curve was proportional for sacubitril, ~1.9-fold for sacubitrilat, and ~1.7-fold for valsartan in healthy subjects. Following multiple twice-daily administration, steady-state maximum plasma concentration was reached within 3 days, showing no accumulation for sacubitril and valsartan, while ~1.6-fold accumulation for sacubitrilat. Sacubitril is eliminated predominantly as sacubitrilat through the kidney; valsartan is eliminated mainly by biliary route. Drug-drug interactions of sacubitril/valsartan were evaluated with medications commonly used in patients with heart failure including furosemide, warfarin, digoxin, carvedilol, levonorgestrel/ethinyl estradiol combination, amlodipine, omeprazole, hydrochlorothiazide, intravenous nitrates, metformin, statins, and sildenafil. Co-administration with sacubitril/valsartan increased the maximum plasma concentration (~2.0-fold) and area under the plasma concentration-time curve (1.3-fold) of atorvastatin; however, it did not affect the pharmacokinetics of simvastatin. Age, sex, or ethnicity did not affect the pharmacokinetics of sacubitril/valsartan. In patients with heart failure vs. healthy subjects, area under the plasma concentration-time curves of sacubitril, sacubitrilat, and valsartan were higher by approximately 1.6-, 2.1-, and 2.3-fold, respectively. Renal impairment had no significant impact on sacubitril and valsartan area under the plasma concentration-time curves, while the area under the plasma concentration-time curve of sacubitrilat correlated with degree of renal function (1.3-, 2.3-, 2.9-, and 3.3-fold with mild, moderate, and severe renal impairment, and end-stage renal disease, respectively). Moderate hepatic impairment increased the area under the plasma concentration-time curves of valsartan and sacubitrilat ~2.1-fold.

Effect of the angiotensin receptor-neprilysin inhibitor sacubitril/valsartan on the pharmacokinetics and pharmacodynamics of a single dose of furosemide

Aims

Sacubitril/valsartan is indicated for the treatment of heart failure and reduced ejection fraction (HFrEF). Furosemide, a loop diuretic commonly used for the treatment of HFrEF, may be coadministered with sacubitril/valsartan in clinical practice. The effect of sacubitril/valsartan on the pharmacokinetics and pharmacodynamics of furosemide was evaluated in this open label, two‐period, single‐sequence study in healthy subjects.

Methods

All subjects (n = 28) received 40 mg oral single‐dose furosemide during period 1, followed by a washout of 2 days. In period 2, sacubitril/valsartan 200 mg (97/103 mg) was administered twice daily for 5 days and a single dose of 40 mg furosemide was coadministered on day 6. Serial plasma and urine samples were collected to determine the pharmacokinetics of furosemide and sacubitril/valsartan and the pharmacodynamics of furosemide. The point estimates and the associated 90% confidence intervals for pharmacokinetic parameters were evaluated.

Results

Coadministration of furosemide with sacubitril/valsartan decreased the maximum observed plasma concentration (C_max) [estimated geometric mean ratio (90% confidence interval): 0.50 (0.44, 0.56)], area under the plasma concentration–time curve (AUC) from time 0 to infinity [0.72 (0.67, 0.77)] and 24‐h urinary excretion of furosemide [0.74 (0.69, 0.79)]. When coadministered with sacubitril/valsartan, 0–4‐h, 4–8‐h and 0–24‐h diuresis in response to furosemide was reduced by ~7%, 21% and 0.2%, respectively, while natriuresis was reduced by ~ 28.5%, 7% and 15%, respectively. Post hoc analysis of the pivotal phase III Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure trial (PARADIGM‐HF) indicated that the median furosemide dose was similar at baseline and at the end of the study in the sacubitril/valsartan group.

Conclusions

Sacubitril/valsartan reduced plasma C_max and AUC and 24‐h urinary excretion of furosemide, while not significantly affecting its pharmacodynamic effects in healthy subjects.

Evaluation of Pharmacokinetic and Pharmacodynamic Drug-Drug Interaction of Sacubitril/Valsartan (LCZ696) and Sildenafil in Patients With Mild-to-Moderate Hypertension

Sacubitril/valsartan (LCZ696) is indicated for the treatment of patients with heart failure and reduced ejection fraction (HFrEF). Since patients with HFrEF may receive sacubitril/valsartan and sildenafil, both increasing cyclic guanosine monophosphate, the present study evaluated the pharmacokinetic and pharmacodynamic drug interaction potential between sacubitril/valsartan and sildenafil. In this open‐label, three‐period, single sequence study, patients with mild‐to‐moderate hypertension (153.8 ± 8.2 mmHg mean systolic blood pressure (SBP)) received a single dose of sildenafil 50 mg, sacubitril/valsartan 400 mg once daily for 5 days, and sacubitril/valsartan and sildenafil coadministration. When coadministered with sildenafil, the AUC and C_max of valsartan decreased by 29% and 39%, respectively. Coadministration of sacubitril/valsartan and sildenafil resulted in a greater decrease in BP (–5/–4/–4 mmHg mean ambulatory SBP/DBP/MAP (mean arterial pressure)) than with sacubitril/valsartan alone. Both treatments were generally safe and well tolerated in this study; however, the additional BP reduction suggests that sildenafil should be administered cautiously in patients receiving sacubitril/valsartan. Unique identifier: NCT01601470.

Assessment of Drug-Drug Interaction Potential Between Atorvastatin and LCZ696, A Novel Angiotensin Receptor Neprilysin Inhibitor, in Healthy Chinese Male Subjects

BACKGROUND AND OBJECTIVE

LCZ696 (sacubitril/valsartan), a novel angiotensin receptor neprilysin inhibitor has been recently approved for the treatment of patients with heart failure (HF) and reduced ejection fraction. As several HF patients are likely to use statins as co-medications, the potential for a pharmacokinetic drug-drug interaction between atorvastatin and LCZ696 was evaluated.

METHODS

This was an open-label, three-period, single-sequence study in 28 healthy Chinese male subjects wherein LCZ696 200 mg was administered twice daily for 5 days in period 1. Following a washout period, atorvastatin 80 mg was administered once daily for 4 days (period 2) and subsequently co-administered with LCZ696 200 mg for 5 days (period 3). Serial plasma samples were collected to determine pharmacokinetic parameters of LCZ696 analytes (sacubitril, LBQ657, and valsartan) and atorvastatin and its metabolites.

RESULTS

Atorvastatin co-administration had no effect on the pharmacokinetics of LBQ657, while the AUC_τ,ss and C _max,ss of sacubitril increased by 30 and 19 %, respectively, and the corresponding values for valsartan decreased by 19 and 9 %, respectively. Co-administration with LCZ696 increased C _max,ss of atorvastatin, o-hydroxyatorvastatin, and p-hydroxyatorvastatin by 74, 68, and 108 %, respectively, and the AUC_τ,ss of corresponding analytes increased by 34, 22, and 26 %, respectively.

CONCLUSIONS

While atorvastatin had no significant impact on the pharmacokinetics of LCZ696 analytes upon co-administration, the C _max of atorvastatin and its metabolites increased twofold, with a marginal increase in AUC (<1.3-fold). Multiple-dose administration of LCZ696 200 mg twice daily and atorvastatin 80 mg once daily either alone or in combination was generally safe and well tolerated in healthy subjects.

Erratum to: Clinical Pharmacokinetics of Sacubitril/Valsartan (LCZ696): A Novel Angiotensin Receptor-Neprilysin Inhibitor

Sacubitril/valsartan (LCZ696) is indicated for the treatment of heart failure with reduced ejection fraction. Absorption of sacubitril/valsartan and conversion of sacubitril (prodrug) to sacubitrilat (neprilysin inhibitor) was rapid with maximum plasma concentrations of sacubitril, sacubitrilat, and valsartan (angiotensin receptor blocker) reaching within 0.5, 1.5-2.0, and 2.0-3.0 h, respectively. With a twofold increase in dose, an increase in the area under the plasma concentration-time curve was proportional for sacubitril, ~1.9-fold for sacubitrilat, and ~1.7-fold for valsartan in healthy subjects. Following multiple twice-daily administration, steady-state maximum plasma concentration was reached within 3 days, showing no accumulation for sacubitril and valsartan, while ~1.6-fold accumulation for sacubitrilat. Sacubitril is eliminated predominantly as sacubitrilat through the kidney; valsartan is eliminated mainly by biliary route. Drug-drug interactions of sacubitril/valsartan were evaluated with medications commonly used in patients with heart failure including furosemide, warfarin, digoxin, carvedilol, levonorgestrel/ethinyl estradiol combination, amlodipine, omeprazole, hydrochlorothiazide, intravenous nitrates, metformin, statins, and sildenafil. Co-administration with sacubitril/valsartan increased the maximum plasma concentration (~2.0-fold) and area under the plasma concentration-time curve (1.3-fold) of atorvastatin; however, it did not affect the pharmacokinetics of simvastatin. Age, sex, or ethnicity did not affect the pharmacokinetics of sacubitril/valsartan. In patients with heart failure vs. healthy subjects, area under the plasma concentration-time curves of sacubitril, sacubitrilat, and valsartan were higher by approximately 1.6-, 2.1-, and 2.3-fold, respectively. Renal impairment had no significant impact on sacubitril and valsartan area under the plasma concentration-time curves, while the area under the plasma concentration-time curve of sacubitrilat correlated with degree of renal function (1.3-, 2.3-, 2.9-, and 3.3-fold with mild, moderate, and severe renal impairment, and end-stage renal disease, respectively). Moderate hepatic impairment increased the area under the plasma concentration-time curves of valsartan and sacubitrilat ~2.1-fold.

A Physiologically Based Pharmacokinetic Model to Describe Artemether Pharmacokinetics in Adult and Pediatric Patients

Artemether is co-administered with lumefantrine as part of a fixed-dose combination therapy for malaria in both adult and pediatric patients. However, artemether exposure is higher in younger infants (1-3 months) with a lower body weight (<5 kg) as compared to older infants (3-6 months) with a higher body weight (≥5 to <10 kg), children, and adults. In contrast, lumefantrine exposure is similar in all age groups. This article describes the clinically observed artemether exposure data in pediatric populations across various age groups (1 month to 12 years) and body weights (<5 or ≥5 kg) using physiologically based pharmacokinetic (PBPK) mechanistic models. A PBPK model was developed using artemether physicochemical, biopharmaceutic, and metabolic properties together with known enzyme ontogeny and pediatric physiology. The model was verified using clinical data from adult patients after multiple doses of oral artemether, and was then applied to simulate the exposure in children and infants. The simulated PBPK concentration-time profiles captured observed clinical data. Consistent with the clinical data, the PBPK model simulations indicated a higher artemether exposure for younger infants with lower body weight. A PBPK model developed for artemether reliably described the clinical data from adult and pediatric patients.

In vitro and clinical evaluation of OATP-mediated drug interaction potential of sacubitril/valsartan (LCZ696)

WHAT IS KNOWN AND OBJECTIVE

Sacubitril/valsartan (LCZ696) has been recently approved for the treatment of heart failure (HF) patients with reduced ejection fraction. Several HF patients receive statins as co-medication.

METHODS

Because clearance of statins is meditated via OATP1B1/1B3, the inhibition potential of these transporters by LCZ696 analytes was evaluated in vitro. Furthermore, an open-label, fixed-sequence clinical study was conducted to determine the effect of LCZ696 on the exposure of simvastatin and its active metabolite simvastatin acid. In this clinical study, 26 healthy subjects received simvastatin 40 mg alone or in combination with LCZ696 or after 1 or 2 h of LCZ696 dosing.

RESULTS AND DISCUSSION

Although no significant inhibition by LBQ657 (an active metabolite of sacubitril) and valsartan was observed, sacubitril inhibited OATP1B1 and OATP1B3 in vitro, with IC50 of 1·91 and 3·81 μm, respectively. Upon co-administration of simvastatin with LCZ696, the Cmax of simvastatin and simvastatin acid decreased by 7% and 13%, respectively. When administered 1 h after LCZ696 dosing, the corresponding Cmax of simvastatin and simvastatin acid decreased by 16% and 4%, respectively. When administered 2 h after LCZ696 dosing, the Cmax of simvastatin decreased by 33% and that of simvastatin acid increased by 16%. However, no notable changes were observed in the AUCs of simvastatin or simvastatin acid upon co-administration or time-separated administration with LCZ696. No notable impact of simvastatin co-administration was observed on the pharmacokinetics of LCZ696 analytes. LCZ696 and simvastatin were generally well tolerated when administered alone or in combination.

WHAT IS NEW AND CONCLUSIONS

Overall, the results of this study suggest that although sacubitril inhibited OATP1B1 and OATP1B3 in vitro, it does not translate into any clinically relevant in vivo effect.

Pharmacokinetics and Pharmacodynamics of Canakinumab in Patients With Systemic Juvenile Idiopathic Arthritis

The characterization of the pharmacokinetic (PK) and pharmacodynamic (PD) properties in pediatric patients is essential in supporting the recommended dosage of canakinumab in the relevant population. Here the PK and PD properties of canakinumab-a monoclonal antibody-in pediatric patients with systemic juvenile idiopathic arthritis (SJIA) are presented. Blood samples were obtained from 4 phase 2/3 clinical studies in patients with SJIA. Canakinumab PK properties and total interleukin (IL)-1β kinetic properties were characterized by a population-based PK-binding model. On administration, canakinumab increased total IL-1β complex in SJIA patients. Canakinumab clearance and volume of distribution were not impacted by age in pediatric patients after correction for the patient's body weight. The estimated serum clearance of canakinumab was 0.106 ± 0.00689 L/day, with a corresponding volume of distribution at steady state of 3.2 L and an estimated half-life of 22 days, based on a model typical body weight of 33 kg. Body-weight-based dosing provided comparable canakinumab exposure across the age groups in patients 2 to <20 years with SJIA. In younger children, a modest increase in the turnover rate of IL-1β was observed. Compared to other indications, IL-1β production rate was higher and clearance was slower in patients with SJIA. Low immunogenicity incidence of 3.1% was observed, and none of the patients had neutralizing antibodies. In conclusion, the PK/PD findings further support dose selection of canakinumab in patients with SJIA.

Pharmacokinetic drug-drug interaction assessment of LCZ696 (an angiotensin receptor neprilysin inhibitor) with omeprazole, metformin or levonorgestrel-ethinyl estradiol in healthy subjects

LCZ696 is a novel angiotensin receptor neprilysin inhibitor in development for the treatment of cardiovascular diseases. Here, we assessed the potential for pharmacokinetic drug-drug interaction of LCZ696 (400 mg, single dose or once daily [q.d.]) when co-administered with omeprazole 40 mg q.d. (n = 28) or metformin 1000 mg q.d. (n = 27) or levonorgestrel-ethinyl estradiol 150/30 μg single dose (n = 24) in three separate open-label, single-sequence studies in healthy subjects. Pharmacokinetic parameters of LCZ696 analytes (sacubitril, LBQ657, and valsartan), metformin, and levonorgestrel-ethinyl estradiol were assessed. Omeprazole did not alter the AUCinf of sacubitril and pharmacokinetics of LBQ657; however, 7% decrease in the Cmax of sacubitril, and 11% and 13% decreases in AUCinf and Cmax of valsartan were observed. Co-administration of LCZ696 with metformin had no significant effect on the pharmacokinetics of LBQ657 and valsartan; however, AUCtau,ss and Cmax,ss of metformin were decreased by 23%. Co-administration of LCZ696 with levonorgestrel-ethinyl estradiol had no effect on the pharmacokinetics of ethinyl estradiol and LBQ657 or AUCinf of levonorgestrel. The Cmax of levonorgestrel decreased by 15%, and AUCtau,ss and Cmax,ss of valsartan decreased by 14% and 16%, respectively. Co-administration of LCZ696 with omeprazole, metformin, or levonorgestrel-ethinyl estradiol was not associated with any clinically relevant pharmacokinetic drug interactions.

Assessment of pharmacokinetic drug-drug interaction between pradigastat and atazanavir or probenecid

Pradigastat, a novel diacylglycerol acyltransferase-1 inhibitor, has activity in common metabolic diseases associated with abnormal accumulation of triglycerides. In vitro studies suggest that glucuronidation is the predominant metabolism pathway for elimination of pradigastat in humans and confirmed the role of uridine 5'-diphosphoglucuronosyltransferase (UGT) enzymes, UGT1A1, -1A3, and -2B7. The in vitro studies using atazanavir as a selective inhibitor of UGT1A1 and -1A3 indicated that these enzymes contribute ∼55% toward the overall glucuronidation pathway. Therefore, a clinical study was conducted to assess the potential for drug interaction between pradigastat and probenecid (purported general UGT inhibitor) or atazanavir (selective UGT1A1, -1A3 inhibitor). The study included 2 parallel cohorts, each with 3 sequential treatment periods and 22 healthy subjects per cohort. The 90%CI of the geometric mean ratios for Cmax,ss and AUCτ,ss of pradigastat were within 0.80-1.25 when administered in combination with probenecid. However, the Cmax,ss and AUCτ,ss of pradigastat decreased by 31% (90%CI: 0.62-0.78) and 26% (0.67-0.82), respectively, when administered in combination with atazanavir. This magnitude of decrease in pradigastat steady-state exposure is not considered clinically relevant. Pradigastat was well tolerated by all subjects, either alone or in combination with atazanavir or probenecid.

Relative bioavailability of diclofenac potassium from softgel capsule versus powder for oral solution and immediate-release tablet formulation

The oral bioavailability of diclofenac potassium 50 mg administered as a soft gelatin capsule (softgel capsule), powder for oral solution (oral solution), and tablet was evaluated in a randomized, open-label, 3-period, 6-sequence crossover study in healthy adults. Plasma diclofenac concentrations were measured using a validated liquid chromatography-mass spectrometry/mass spectrometry method, and pharmacokinetic analysis was performed by noncompartmental methods. The median time to achieve peak plasma concentrations of diclofenac was 0.5, 0.25, and 0.75 hours with the softgel capsule, oral solution, and tablet formulations, respectively. The geometric mean ratio and associated 90%CI for AUCinf, and Cmax of the softgel capsule formulation relative to the oral solution formulation were 0.97 (0.95-1.00) and 0.85 (0.76-0.95), respectively. The geometric mean ratio and associated 90%CI for AUCinf and Cmax of the softgel capsule formulation relative to the tablet formulation were 1.04 (1.00-1.08) and 1.67 (1.43-1.96), respectively. In conclusion, the exposure (AUC) of diclofenac with the new diclofenac potassium softgel capsule formulation was comparable to that of the existing oral solution and tablet formulations. The peak plasma concentration of diclofenac from the new softgel capsule was 67% higher than the existing tablet formulation, whereas it was 15% lower in comparison with the oral solution formulation.

Population pharmacokinetic modeling and noncompartmental analysis demonstrated bioequivalence between metformin component of metformin/vildagliptin fixed-dose combination products and metformin immediate-release tablet sourced from various countries

Metformin is the first-line pharmacotherapy choice for treating type-2 diabetes mellitus, alone or in combination with other antidiabetic drugs. During the development of immediate-release (IR) metformin containing novel fixed-dose combination (FDC) products, several health-authorities require sponsors to demonstrate bioequivalence between FDC products and the country-sourced metformin for market approval. Eight bioequivalence studies that compared metformin/vildagliptin FDC product (test) to metformin IR tablet sourced from various countries (reference) were conducted. A population pharmacokinetic (PPK) analysis of pooled metformin concentration-time data was performed to evaluate whether country-sourced metformin is a significant covariate. The PPK analysis demonstrated that there was no clinically relevant effect of metformin source or race/ethnicity on metformin pharmacokinetics. Also, noncompartmental analysis conducted showed that 90%CI of geometric mean ratios of test to reference metformin formulations, calculated for maximum-concentration and exposure parameters, were within the 80%-125% criteria, indicating comparable metformin exposure regardless of the country-sourced metformin IR formulation. These results are consistent with the biopharmaceutics properties of metformin and provide scientific evidence that after assessing in vitro dissolution of novel FDC formulation, additional bioequivalence studies with multiple countries' reference products may not be required once bioequivalence is established with 1 country-sourced IR metformin formulation.

Evaluation of food effect on the oral bioavailability of pradigastat, a diacylglycerol acyltransferase 1 inhibitor

Pradigastat, a diacylglycerol acyltransferase 1 inhibitor, is being developed for the treatment of familial chylomicronemia syndrome. The results of two studies that evaluated the effect of food on the oral bioavailability of pradigastat using randomized, open-label, parallel group designs in healthy subjects (n=24/treatment/study) are presented. In study 1, a single dose of 20 mg pradigastat was administered under the fasted condition or with a high-fat meal. In study 2, a single dose of 40 mg pradigastat was administered under the fasted condition or with a low- or high-fat meal. At the 20 mg dose, the pradigastat Cmax and AUClast increased by 38% and 41%, respectively, with a high-fat meal. When 40 mg pradigastat was administered with a low-fat meal, the Cmax and AUClast increased by 8% and 18%, respectively, whereas with a high-fat meal the increase was 20% and 18%, respectively. The population pharmacokinetic analysis with the pooled data from 13 studies indicated that administration of pradigastat with a meal resulted in an increase of 30% in both the Cmax and AUC parameters. Based on these results, food overall increased pradigastat exposure in the range of less than 40%, which is not considered clinically significant. Both 20 and 40 mg doses of pradigastat were well tolerated under fasted or fed conditions.

Pharmacokinetic drug-drug interaction assessment between LCZ696, an angiotensin receptor neprilysin inhibitor, and hydrochlorothiazide, amlodipine, or carvedilol

LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor in development for treatments of hypertension and heart failure indications. In 3 separate studies, pharmacokinetic drug-drug interactions (DDIs) potential was assessed when LCZ696 was coadministered with hydrochlorothiazide (HCTZ), amlodipine, or carvedilol. The studies used a open-label, single-sequence, 3-period, crossover design in healthy subjects. Blood samples were collected to determine the pharmacokinetic parameters of LCZ696 analytes (AHU377, LBQ657, and valsartan), HCTZ, amlodipine, or carvedilol (R[+]- and S[-]-carvedilol) for statistical analysis. When coadministered LCZ696 with HCTZ, the 90% CIs of the geometric mean ratios of AUCtau,ss of HCTZ and that of LBQ657 were within a 0.80-1.25 interval, whereas HCTZ Cmax,ss decreased by 26%, LBQ657 Cmax,ss increased by 19%, and the AUCtau,ss and Cmax,ss of valsartan increased by 14% and 16%, respectively. Pharmacokinetics of amlodipine, R(+)- and S(-)-carvedilol, or LBQ657 were not altered after coadministration of LCZ696 with amlodipine or carvedilol. Coadministration of LCZ696 400 mg once daily (qd) with HCTZ 25 mg qd, amlodipine 10 mg qd, or carvedilol 25 mg twice a day (bid) had no clinically relevant pharmacokinetic drug-drug interactions. LCZ696, HCTZ, amlodipine, and carvedilol were safe and well tolerated when given alone or concomitantly in the investigated studies.

Assessment of pharmacokinetic drug-drug interaction between pradigastat and acetaminophen in healthy subjects

PURPOSE

The purpose of this study was to evaluate the effect of pradigastat, a diacylglycerol acyltransferase-1 inhibitor, on the pharmacokinetics of acetaminophen, a gastric emptying marker.

METHODS

Twenty-five healthy subjects were enrolled and received 1000 mg acetaminophen with meal in period 1, pradigastat (100 mg × 3 days followed by 40 mg × 7 days, 1 h before meal) in period 2, and 1000 mg acetaminophen at -2, -1, 0, +1, and +3 h with respect to meal timing in presence of steady-state pradigastat (40-mg maintenance dose) during periods 3-7.

RESULTS

The geometric mean ratio and 90% confidence interval of Cmax and AUC of acetaminophen were within 80-125% suggesting that the rate ad extent of acetaminophen were not affected when given at various time points with respect to pradigastat/meal timing. The acetaminophen Tmax was also not impacted under all treatment conditions but increased from 0.75 to 2.00 h when administered 1 h after food.

CONCLUSION

In the presence of steady-state pradigastat, the pharmacokinetics of acetaminophen is unchanged, when given before, with, or 3 h after a meal. However, when given 1 h after a meal, the Tmax of acetaminophen was delayed by ∼1.25 h without affecting Cmax or AUC.

The effects of CYP3A4 induction and inhibition on the pharmacokinetics of alisporivir in humans

In vitro data suggest that alisporivir is a substrate and inhibitor of CYP3A4 and P-gp. Hence, the potential for drug-drug interactions when alisporivir is co-administered with CYP3A4 and/or P-gp inhibitors such as ketoconazole, azithromycin and CYP3A4 inducers such as rifampin were evaluated in three separate clinical studies. Co-administration with ketoconazole (a strong CYP3A4 inhibitor) increased the Cmax , AUC and terminal elimination half-life of alisporivir by approximately two-, eight- ,and threefold, respectively. Co-administration with azithromycin (a putative weak CYP3A4 inhibitor and substrate) had no impact on the Cmax and AUC of alisporivir. Rifampin (a CYP3A4 inducer) caused an approximate 90% reduction in alisporivir Cmax and AUC and a fourfold reduction in alisporivir terminal elimination half-life. Alisporivir as an inhibitor of CYP3A4 caused a 39% increase in azithromycin exposure. The results from these studies establish alisporivir as a sensitive CYP3A4 substrate in vivo. Consequently, co-administered potent CYP3A4 inhibitors and inducers are likely to cause clinically significant changes in the exposure to alisporivir.

Pharmacokinetic and pharmacodynamic drug-drug interaction assessment between pradigastat and digoxin or warfarin

Pradigastat, a novel diacylglycerol acyltransferase-1 inhibitor, was evaluated for both pharmacokinetic (PK) and pharmacodynamic (PD) drug-drug interactions when co-administered with digoxin or warfarin in healthy subjects. This open-label study included two parallel subject cohorts each with three sequential treatment periods. Forty subjects were enrolled in the study with 20 subjects allocated to each cohort. PK and PD (PT/INR for warfarin only) samples were collected in each period. The statistical analysis results showed that the 90% CIs of the geometric mean ratios of digoxin, R-warfarin, and S-warfarin PK parameters (AUC and Cmax) were all within 0.80-1.25 interval. The 90% CIs of the geometric mean ratios of pradigastat PK parameters (AUC and Cmax) were within 0.80-1.25 interval when co-administered with warfarin; while co-administration with digoxin slightly reduced pradigastat exposure (∼15%). The results also showed that 90% CIs of the geometric mean ratios of warfarin PD parameters (AUC(PT), PTmax, AUC(INR), and INRmax) were within 0.80-1.25 interval. Pradigastat and digoxin or warfarin had no relevant clinical PK or PD drug-drug interactions. Administration of pradigastat and warfarin or pradigastat and digoxin as a mono or combined treatment appears to be safe and tolerated.

Abstract 449: Assessment of Pharmacokinetic Drug Interaction Between LCZ696 and Digoxin

Objective: LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) being developed for the treatment of cardiovascular diseases including hypertension and heart failure. Ingestion of LCZ696 results in systemic exposure to AHU377 (an inactive prodrug converted to LBQ657, a neprilysin inhibitor) and valsartan (angiotensin receptor inhibitor). Digoxin, a narrow therapeutic index drug, is a commonly administered medication to heart failure patients. Since LCZ696 and digoxin may be co-administered in this patient population, this study was conducted to evaluate the pharmacokinetic drug-drug interaction potential between LCZ696 and digoxin.

Methods: This study employed an open label, two-period, single sequence study design in 24 healthy subjects. In period 1, subjects received 200 mg LCZ696 b.i.d for 3 days and a single dose of 200 mg LCZ696 on Day 4 morning. Following a 4-7 day washout, in period 2, all subjects received 0.25 mg digoxin q.d. for 14 days and 200 mg LCZ696 b.i.d co-administered from Day 11 to Day 14. Serial PK samples were collected in both treatment periods and analyzed using validated LC/MS/MS bioanalytical methods. The PK parameters including Cmaxss and AUCtau of LCZ696 analytes (LBQ657, valsartan) and digoxin were determined using non-compartmental analysis and the results were statistically evaluated.

Results: The 90% confidence intervals of the geometric mean ratios (test/reference) for Cmaxss and AUCtau of digoxin were within the 0.8-1.25 range indicating that LCZ696 did not affect the PK of digoxin. Similarly, the 90% confidence intervals of the geometric mean ratios for Cmaxss and AUCtau for both LBQ657 and valsartan were within the 0.8-1.25 range indicating that digoxin did not affect the PK of LCZ696 analytes.

Conclusion: After co-administration of LCZ696 200 mg b.i.d with digoxin 0.25 mg q.d., exposures of digoxin and the LCZ696 analytes (LBQ657 and valsartan) remained unchanged. LCZ696 200 mg b.i.d was safe and well tolerated in healthy subjects when administered alone and in combination with digoxin 0.25 mg qd.

Abstract 457: Assessment of Pharmacokinetic Drug-drug Interaction between LCZ696 and Carvedilol

Objective: LCZ696 is a first-in-class angiotensin receptor neprlysin inhibitor (ARNI) being developed for the treatment of hypertension and heart failure. Ingestion of LCZ696 results in systemic exposure to AHU377 (inactive prodrug of LBQ657, a neprilysin inhibitor) and valsartan (angiotensin receptor blocker). Carvedilol is a third-generation, non-selective beta-blocker with vasodilating properties and one of three beta-blockers with efficacy in reducing the risk of death in patients with heart failure. Since LCZ696 may be co-administered with carvedilol for optimal blood pressure control, this study was conducted to evaluate the pharmacokinetic (PK) drug-drug interaction potential between LCZ696 and carvedilol.

Methods: An open-label, three-period, single sequence study in 28 healthy subjects was conducted. In Period 1, subjects received oral LCZ696 400 mg qd x 5 days and were discharged for a 4-10 day washout. In Period 2, subjects received oral carvedilol 12.5 mg bid x first 2 days, then 25 mg bid x 4 days, and in Period 3, LCZ696 400 mg qd + carvedilol 25 mg bid x 5 days. Serial PK samples were collected and analyzed by a validated LC-MS/MS method. PK parameters (AUCtau,ss, Cmax,ss) of LCZ696 analytes(LBQ657, valsartan) and carvedilol (R(+)-and S(-)-carvedilol) in plasma were determined using non-compartmental analysis, and results were statistically evaluated.

Results: The 90% CIs of the geometric mean ratio for AUCtau,ss and Cmax,ss of LBQ657, and AUCtau,ss of valsartan fell within the range of (0.80-1.25); the lower bound for Cmax,ss of valsartan (0.88, 0.78-0.98) was below the range, indicating PK of LBQ567 was not altered but Cmax,ss of valsartan decreased by 12% when co-administered with carvedilol. Those for AUCtau,ss and Cmax,ss of both R(+)-and S(-)carvedilol fell within the range (0.80-1.25), indicating no change in PK of Carvedilol in combination with LCZ696.

Conclusion: When LCZ696 400 mg qd and carvedilol 25 mg bid were co-dministered, PK of carvedilol (R(+)-and S(-)-carvedilol) was unchanged. PK of LBQ657 or AUCtau,ss of valsartan was unchanged, while Cmax,ss decreased by 12%. LCZ696 400 mg qd was safe and well tolerated in healthy subjects when administered alone and in combination with carvedilol 25 mg bid.

Abstract 455: Assessment of Pharmacokinetic Drug-drug Interaction between LCZ696 and Hydrochlorothiazide

Objective: LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) being developed for the treatment of cardiovascular diseases, including hypertension and heart failure. Ingestion of LCZ696 results in systemic exposure to AHU377 (inactive prodrug of LBQ657, a neprilysin inhibitor) and valsartan (angiotensin receptor blocker). Hydrochlorothiazide (HCTZ) is indicated as first line treatment of hypertension. Since LCZ696 and HCTZ may be co-administered for optimal blood pressure control, this study was conducted to evaluate the pharmacokinetic (PK) drug-drug interaction potential between LCZ696 and HCTZ.

Methods: An open-label, three-period, single sequence study in 27 healthy subjects was conducted. In Period 1, subjects received oral HCTZ 25 mg qd x 4 days and were discharged for a 4-10 day washout. In Period 2, subjects received LCZ696 400 mg qd x 5 days, and in Period 3, HCTZ 25 mg qd + LCZ696 400 mg qd x 4 days. Serial PK samples were collected and analyzed by a validated LC-MS/MS method. PK parameters (AUCtau,ss,Cmax,ss) of LCZ696 analytes (LBQ657, valsartan) and HCTZ in plasma were determined using non-compartmental analysis, and the results were statisticallyevaluated.

Results: The 90% CIs confidence intervals (CIs) for the geometric mean ratio for AUCtau,ss of HCTZ fell within the ( 0.8 - 1.25) range, while those of Cmax,ss (0.74, 0.70-0.78) fell outside the range, indicating Cmax,ss of HCTZ decreased by 26% when co-administered with LCZ696. Those for AUCtau,ss of LBQ657 fell within the range but the upper bound for Cmax,ss (1.19, 1.10-1.28) was outside the range, indicating Cmax of LBQ657 increased by 19%; the upper bound for valsartan exposures(AUCtau,ss: 1.14, 1.00-1.29; Cmax,ss: 1.16, 0.98-1.37) were above the range, indicating AUCtau,ss and Cmax,ss of valsartan increased by 14%and 16%, respectively.

Conclusion: When LCZ696 400mg qd and HCTZ 25mg qd were co- administered, AUCtau,ss of HCTZ was unchanged but Cmax,ss decreased by 26%; AUCtau,ss of LBQ657 was unchanged but Cmax,ss increased by 19%; and lastly, AUCtau,ss and Cmax,ss of valsartan increased by 14%and 16%, respectively. LCZ696 400 mg qd was safe and well tolerated in healthy subjects when administered alone and in combination with HCTZ 25 mg qd.

Abstract 448: Assessment of Drug Interaction Potential Between LCZ696 and Warfarin

Objective: LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) being developed for the treatment of cardiovascular diseases including hypertension and heart failure. Ingestion of LCZ696 results in systemic exposure to AHU377 (an inactive prodrug converted to LBQ657, neprilysin inhibitor) and valsartan (angiotensin receptor inhibitor). Warfarin, a CYP2C9 substrate and narrow therapeutic index drug , is administered to patients with cardiovascular diseases including heart failure . Since LCZ696 is a known weak inhibitor of CYP2C9, the objective of this study was to determine whether LCZ696 affects the pharmacokinetics (PK) and pharmacodynamics (PD) of warfarin. Also, the warfarin effect on the PK of LCZ696 was evaluated.

Methods: This study employed an open label, single blind, two-period, crossover design in 26 healthy subjects. In each period, subjects received either 200 mg LCZ696 or matching placebo b.i.d for 10 days with a single dose of 25 mg warfarin co-administered on Day 5. Serial PK samples were collected on Day 4 and Day 5 and analyzed using validated LCMS/MS methods. Prothrombin time (PTT) and INR values were measured for up to 144 hours post warfarin dose. The PK parameters including Cmax and AUCs of LCZ696 analytes (LBQ657 and valsartan) and warfarin (R-warfarin and S-warfarin) and PD parameters of warfarin (peak PTT, peak INR, AUC-PTT, and AUC-INR) were determined using noncompartmental methods and results were statistically evaluated.

Results: The 90% confidence intervals (CI) of geometric mean ratios of Cmax and AUCs (test/reference) for R-warfarin, S-warfarin, LBQ657, and valsartan were within the 80 - 125% suggesting lack of PK interaction between LCZ696 and warfarin. Further, the 90% CI of geometric mean ratios of average (AUC effect/144) and peak PD effects (PTT and INR) were also within the 80 - 125% range indicating no impact of LCZ696 on warfarin PD.

Conclusion: Co-administration of 200 mg LCZ696 b.i.d with single dose of 25 mg warfarin did not alter the PK exposures of LCZ696 analytes (LBQ657 and valsartan) and warfarin. Also, LCZ696 did not affect the PD effects of warfarin. LCZ696 200 mg b.i.d was safe and well tolerated when administered alone or with single dose of 25 mg warfarin.

Abstract 456: Assessment of Pharmacokinetic Drug Interaction between LCZ696 and Metformin

Objective: LCZ696 is a first-in-class angiotensin receptor neprilysin inhibitor (ARNI) being developed for the treatment of cardiovascular diseases, including hypertension and heart failure. Ingestion of LCZ696 results in systemic exposure to AHU377 (inactive prodrug that is converted to LBQ657, a neprilysin inhibitor) and valsartan (angiotensin receptor blocker). Metformin is the most commonly prescribed oral treatment for type 2 diabetes mellitus (T2DM), a condition prevalent in patients with cardiovascular diseases. Since LCZ696 and metformin may be co-administered, the potential for a pharmacokinetic (PK) interaction was assessed between these drugs.

Methods: The study was conducted in 27 healthy subjects of Japanese descent using an open-label, three-period, single-sequence design. In Period 1, subjects received metformin 1000 mg once daily (q.d.) for 4 days. Following a metformin washout of 4-10 days, subjects received LCZ696 400 mg q.d. for 5 days in Period 2. In Period 3, LCZ696 400 mg q.d. and metformin 1000 mg q.d. were co-administered for 4 days. Serial PK samples were taken during all treatment periods and analyzed using validated LC/MS/MS bioanalytical techniques. The PK parameters (Cmax,ss, AUCtau,ss) of active LCZ696 analytes (LBQ657 and valsartan) and metformin were determined using non-compartmental analysis, and the results were evaluated by statistical analysis.

Results: The 90% confidence intervals for the geometric mean ratios for Cmax,ss and AUCtau,ss of LCZ696 analytes (LBQ657 and valsartan) were within the 0.8-1.25 range indicating that metformin did not affect the PK of the LCZ696 analytes. The lower bound of the 90% confidence intervals for the geometric mean ratios for metformin exposures were below the 0.8-1.25 range (Cmax,ss: 0.77, 0.70-0.84; AUCtau,ss: 0.77, 0.71-0.82), indicating a decrease in Cmax,ss and AUCtau,ss of metformin by 23%.

Conclusion: After co-administration of LCZ696 400 mg q.d. and metformin 1000 mg q.d., the exposures of LBQ657 and valsartan remained unchanged whereas the exposure to metformin decreased by 23%. LCZ696 400 mg q.d. was safe and well tolerated in healthy subjects when administered alone and in combination with metformin 1000 mg q.d..

Evaluation of Pharmacokinetic Interactions Between Vildagliptin and Digoxin in Healthy Volunteers

Vildagliptin is a novel antidiabetic agent that is an orally active, potent, and selective inhibitor of dipeptidyl peptidase IV, the enzyme responsible for degradation of the incretin hormones. This open-label, randomized, 3-period crossover study investigated the potential for pharmacokinetic interactions in 18 healthy subjects during coadministration of vildagliptin and digoxin. Subjects were randomized to receive each of 3 treatments: vildagliptin 100 mg qd, digoxin (0.5 mg, then 0.25 mg qd on days 2-7), and the combination vildagliptin/digoxin for 7 days. Coadministration of digoxin with vildagliptin had no effect on exposure to vildagliptin (geometric mean ratios [90% confidence interval]: AUC(0-24h), 0.99 [0.95-1.03]; C(max), 0.95 [0.85-1.06]) or to digoxin (AUC(0-24h), 1.02 [0.94-1.12]; C(max), 1.08 [0.97-1.20]). In addition, no changes in t(max), t((1/2)), and CL/F were observed for either drug. These results indicate that no dose adjustment is necessary when vildagliptin and digoxin are coadministered.

Evaluation of pharmacokinetic interactions between amlodipine, valsartan, and hydrochlorothiazide in patients with hypertension

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.

Population pharmacokinetics of valsartan in pediatrics

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.

Probenecid treatment enhances retinal and brain delivery of N-4-benzoylaminophenylsulfonylglycine: an anionic aldose reductase inhibitor

Anion efflux transporters are expected to minimize target tissue delivery of N-[4-(benzoylaminophenyl)sulfonyl]glycine (BAPSG), a novel carboxylic acid aldose reductase inhibitor, which exists as a monocarboxylate anion at physiological conditions. Therefore, the objective of this study was to determine whether BAPSG delivery to various eye tissues including the retina and the brain can be enhanced by probenecid, a competitive inhibitor of anion transporters. To determine the influence of probenecid on eye and brain distribution of BAPSG, probenecid was administered intraperitoneally (120 mg/kg body weight; i.p.) 20 min prior to BAPSG (50 mg/kg; i.p.) administration. Drug disposition in various eye tissues including the retina and the brain was determined at 15 min, 1, 2 and 4h after BAPSG dose in male Sprauge-Dawley rats. To determine whether probenecid alters plasma clearance of BAPSG, influence of probenecid (120 mg/kg; i.p.) on the plasma pharmacokinetics of intravenously administered BAPSG (15 mg/kg) was studied as well. Finally, the effect of probenecid co-administration on the ocular tissue distribution of BAPSG was assessed in rabbits following topical (eye drop) administration. Following pretreatment with probenecid in the rat study, retinal delivery at 1h was increased by about 11-fold (2580 ng/g vs. 244 ng/g; p<0.05). Further, following probenecid pretreatment, significant BAPSG levels were detectable in the brain (45 + or - 20 ng/g) at 1h, unlike controls where the drug was not detectable. Plasma concentrations, plasma elimination half-life, and total body clearance of intravenously administered BAPSG were not altered by i.p. probenecid pretreatment. In the topical dosing study, a significant decline in BAPSG delivery was observed in the iris-ciliary body but no significant changes were observed in other tissues of the anterior segment of the eye including tears. Thus, inhibition of anion transporters is a useful approach to elevate retinal and brain delivery of BAPSG.

Evaluation of the potential for steady-state pharmacokinetic interaction between vildagliptin and simvastatin in healthy subjects

BACKGROUND

Vildagliptin is an orally active, potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4), the enzyme responsible for the degradation of incretin hormones. By enhancing prandial levels of incretin hormones, vildagliptin improves glycemic control in type 2 diabetes. Co-administration of vildagliptin and simva statin, an HMG-CoA-reductase inhibitor may be required to treat patients with diabetes and dyslipidemia. There fore, this study was conducted to determine the potential for pharmacokinetic drug-drug interaction between vildagliptin and simvastatin at steady-state.

METHODS

An open label, single center, multiple dose, three period, crossover study was conducted in 24 healthy subjects. All subjects received once daily doses of either vildagliptin 100 mg or simvastatin 80 mg or the combination for 7 days with an inter-period washout of 7 days. Plasma levels of vildagliptin, simvastatin, and its active metabolite, simvastatin beta-hydroxy acid (major active metabolite of simvastatin) were determined using validated LC/MS/MS methods. Pharmacokinetic and statistical analyses were performed using WinNonlin and SAS, respectively.

RESULTS

The 90% confidence intervals of C(max) and AUC(tau) of vildagliptin, simvastatin, and simvastatin beta-hydroxy acid were between 80 and 125% (bioequivalence range) when vildagliptin and simvastatin were admin istered alone and in combination. These data indicate that the rate and extent of absorption of vildagliptin and simvastatin were not affected when co-administered, nor was the metabolic conversion of simvastatin to its active metabolite. All treatments were safe and well tolerated in this study.

CONCLUSIONS

The pharmacokinetics of vildagliptin, simvastatin, and its active metabolite were not altered when vildagliptin and simvastatin were co-administered.

Dose proportionality and the effect of food on vildagliptin, a novel dipeptidyl peptidase IV inhibitor, in healthy volunteers

Vildagliptin is a potent and selective dipeptidyl peptidase IV inhibitor in development for the treatment of type 2 diabetes that improves glycemic control by enhancing alpha- and beta-cell responsiveness to glucose. Two open-label, single-dose, randomized, crossover studies in healthy subjects (ages 18-45 years) investigated the dose proportionality of vildagliptin pharmacokinetics (n = 20) and the effect of food (n = 24) on vildagliptin pharmacokinetics. There was a linear relationship (r(2) = 0.999) between vildagliptin doses of 25, 50, 100, and 200 mg and area under the plasma concentration-time curve from time zero to infinity (AUC(0-infinity)) and maximum plasma concentration (C(max)). Dose proportionality was assessed using a statistical power model [X = alpha x (dose)(beta)]. The 90% confidence intervals of the proportionality coefficient, beta, for AUC(0-infinity) (1.15-1.19) and C(max) (1.04-1.14) indicated that deviations from dose proportionality were small (<7.7%). Doubling of dose led to 2.1- to 2.3-fold increases in AUC(0-infinity) and C(max) but no dose-dependent changes in time to reach C(max) or terminal elimination half-life. Administration of vildagliptin 100 mg following a high-fat meal decreased C(max) by 19% and AUC(0-infinity) by 10%. Vildagliptin displays approximately dose-proportional pharmacokinetics over the 25- to 200-mg dose range, and administration with food has no clinically relevant effect on vildagliptin pharmacokinetics.

Effect of the novel oral dipeptidyl peptidase IV inhibitor vildagliptin on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects

OBJECTIVE

Vildagliptin is a potent and selective dipeptidyl peptidase-IV (DPP-4) inhibitor that improves glycemic control in patients with type 2 diabetes by increasing alpha and beta-cell responsiveness to glucose. This study assessed the effect of multiple doses of vildagliptin 100 mg once daily on warfarin pharmacokinetics and pharmacodynamics following a single 25 mg oral dose of warfarin sodium.

RESEARCH DESIGN AND METHODS

Open-label, randomized, two-period, two-treatment crossover study in 16 healthy subjects.

RESULTS

The geometric mean ratios (co-administration vs. administration alone) and 90% confidence intervals (CIs) for the area under the plasma concentration-time curve (AUC) of vildagliptin, R- and S-warfarin were 1.04 (0.98, 1.11), 1.00 (0.95, 1.04) and 0.97 (0.93, 1.01), respectively. The 90% CI of the ratios for vildagliptin, R- and S-warfarin maximum plasma concentration (Cmax) were also within the equivalence range 0.80-1.25. Geometric mean ratios (co-administration vs. warfarin alone) of the maximum value and AUC for prothrombin time (PT(max), 1.00 [90% CI 0.97, 1.04]; AUC(PT), 0.99 [0.97, 1.01]) and international normalized ratios (INRmax, 1.01 [0.98, 1.05]; AUC(INR), 0.99 [0.97, 1.01]) were near unity with the 90% CI within the range 0.80-1.25. Vildagliptin was well tolerated alone or co-administered with warfarin; only one adverse event (upper respiratory tract infection in a subject receiving warfarin alone) was reported, which was judged not to be related to study medication.

CONCLUSIONS

Co-administration of warfarin with vildagliptin did not alter the pharmacokinetics and pharmacodynamics of R- or S-warfarin. The pharmacokinetics of vildagliptin were not affected by warfarin. No dosage adjustment of either warfarin or vildagliptin is necessary when these drugs are co-medicated.

Evaluation of a pharmacokinetic interaction between valsartan and simvastatin in healthy subjects

OBJECTIVE

The potential for a pharmacokinetic drug interaction between valsartan, an antihypertensive drug, and simvastatin, a lipid-lowering agent, was investigated in this study. This was an open-label, multiple-dose, randomized, three-period, cross over study in 18 healthy subjects. Each subject received one 160 mg valsartan tablet or one 40 mg simvastatin tablet or co-administration of valsartan (160 mg) and simvastatin (40 mg) tablets for 7 days, with a 7-day inter-dose washout period. The steady-state pharmacokinetics of valsartan, simvastatin beta-hydroxy acid (active metabolite of simvastatin) and simvastatin (pro-drug) were determined on day 7 of each dosing period.

RESULTS

The results were interpreted based on the point estimates and the 90% confidence intervals. These results indicated that the area under the curve of plasma concentration from 0 to 24 hours (AUC(0-24)) of valsartan, simvastatin beta-hydroxy acid and simvastatin was increased by 14%, 19%, and 23%, respectively, with the combination treatment. In addition, the maximum concentration (C(max)) of valsartan and simvastatin beta-hydroxy acid was increased by 10% and 22%, respectively, and the C(max) of simvastatin was decreased by 26% with the combination treatment. All treatments were safe and well tolerated.

CONCLUSIONS

Based on the wide therapeutic dosage ranges of valsartan and simvastatin, and the highly variable pharmacokinetics of three analytes, the observed differences in the exposure and C(max) of valsartan, simvastatin beta-hydroxy acid and simvastatin in the combination treatment are unlikely to be of clinical relevance.

Systemic and ocular pharmacokinetics of N-4-benzoylaminophenylsulfonylglycine (BAPSG), a novel aldose reductase inhibitor

To better develop N-[4-(benzoylamino)phenylsulfonyl]glycine (BAPSG), a potent and selective aldose reductase inhibitor capable of delaying the progression of ocular diabetic complications, the objective of this study was to assess its pharmacokinetics. The plasma pharmacokinetics of BASPG was assessed in male Sprague-Dawley rats following intravenous, intraperitoneal and oral routes of administration and its distribution to various tissues including those of the eye was studied following intraperitoneal administration. In addition, rat plasma protein binding of BAPSG was studied using ultracentrifugation method and its ocular tissue disposition was assessed following topical administration in rabbits. Plasma and tissue levels of BAPSG were analysed using an HPLC assay. BAPSG exhibited dose-proportionate AUC0 --> infinity (area under the plasma concentration-time curve) following both intravenous and intraperitoneal administration over the dose range (5-50 mg kg(-1)) studied and an erratic oral absorption profile with low oral bioavailability. The fraction bioavailability following oral and intraperitoneal administration was 0.06 and 0.7-1, respectively. BAPSG exhibited short plasma elimination half-lives in the range 0.5-1.5 h. BAPSG was bound to rat plasma proteins and the percent protein binding ranged from 83 to 99.8%. BAPSG was better distributed to cornea, lens and retina than to brain, following intraperitoneal administration in rats. However, the distribution was lower compared with kidney and liver. Following topical administration in rabbits, BAPSG delivery to the surface ocular tissues, cornea and conjunctiva was higher compared with intraocular tissues, aqueous humour, iris-ciliary body and lens. Thus, BAPSG was distributed to ocular tissues following systemic and topical modes of administration.

Iontophoretic in vivo transdermal delivery of beta-blockers in hairless rats and reduced skin irritation by liposomal formulation

PURPOSE

To demonstrate the in vivo transdermal delivery and establish the comparative pharmacokinetics of five beta-blockers in hairless rat.

METHODS

Intravenous dosing was initially done via jugular cannula. For iontophoretic delivery, current (0.1 mA/cm2) was applied for 2 h through a drug reservoir patch containing the beta-blocker (10 mg/ml). Blood samples were collected and analyzed by stereoselective HPLC assays. Any irritation resulting from patch application was quantified by a chromameter. Multilamellar liposomal formulation was prepared by the thin-film hydration method and converted to unilamellar liposomes by extrusion.

RESULTS

With transdermal iontophoresis, therapeutically relevant amounts of propranolol (83.78 +/- 7.4 ng/ml) were delivered within an hour and lasted for up to 4 h. Cmax (185.1 +/- 56.8 ng/ml) was reached at hour 3. A significantly higher amount (p < 0.05) of sotalol HCl was delivered compared to other beta-blockers. There was no significant difference in the S/R ratio of AUC0-t for enantiomers after both intravenous and transdermal delivery. Skin irritation was significantly reduced (p < 0.05) when a liposomal formulation of the propranolol base was used rather than the base itself.

CONCLUSIONS

The comparative pharmacokinetics of intravenous and transdermal iontophoretic delivery of five beta-blockers in hairless rats was established. It was shown that there is no stereoselective permeation.