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Single- and Multiple-Dose Pharmacokinetics of Pioglitazone in Adolescents With Type 2 Diabetes

From the Pediatric Pharmacology Research Units, the University of Tennessee and LeBonheur Children's Medical Center, Memphis, (Dr Christensen, Dr Meibohm, Dr Velasquez-Mieyer, Dr Burghen); the University of California, San Diego (Dr Capparelli); and Yale University, New Haven, Connecticut (Dr Tamborlane).

Address for reprints: Michael L. Christensen, PharmD, University of Tennessee, 50 North Dunlap, Room 306, Memphis, TN 38103.

	ABSTRACT

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 
This study assessed the single- and multiple-dose pharmacokinetics of 3 doses (15 mg, 30 mg, and 45 mg) of pioglitazone in 36 adolescents with type 2 diabetes. Blood samples were obtained over a 48-hour interval after the first dose (day 1) and over a 72-hour interval after the last dose (day 15) of pioglitazone and were assayed for pioglitazone and active metabolites (M-III and M-IV). Pioglitazone systemic exposure increased dose dependently but was less than dose proportional during multiple dosing. The median peak pioglitazone concentration occurred at 2 hours. The mean half-life was 8 to 9 hours for pioglitazone and 24 to 32 hours for M-III and M-IV, with similar values at each dose level. During multiple dosing, accumulation for pioglitazone was negligible, but it reached 2.5- to 3.0-fold for M-III and M-IV. The sustained total serum concentration of active compounds during multiple dosing provides the basis for once-daily dose administration of pioglitazone in adolescents.

Key Words: Pioglitazone • pharmacokinetics • type 2 diabetes • adolescents

The purpose of this study was to determine the single- and multiple-dose pharmacokinetics, safety, and tolerance of pioglitazone and its active metabolites M-III and M-IV in adolescents with T2D at 3 doses: 15, 30, and 45 mg.

	RESEARCH DESIGN AND METHODS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 
Subjects
Study subjects were recruited at the University of Tennessee, Memphis; the University of California, San Diego; and Yale University, New Haven, Connecticut. The study protocol and the consent form were approved by the respective institutional review boards. Before enrollment and the beginning of study procedures, informed consent and assent was obtained for each subject.

Subjects were male or female, aged 12 to <17 years, with T2D (based on American Diabetes Association criteria).¹⁹ Screening procedures included medical history, physical examination, height and weight, vital signs, laboratory profile including serum transaminases, serum pregnancy test (female subjects), urine drug screen, and electrocardiogram. Subjects were excluded if there was evidence of a clinically important medical disease or laboratory abnormality. Subjects were also excluded if they were taking drugs or nondrugs known to be inducers or inhibitors of pioglitazone metabolism within 1 week of study day 1 or during the study.

Study Design
This was an open-label, 18-day, single- and multiple-dose, dose-escalation, pharmacokinetic and safety study. The study was performed using 3 dosing cohorts: 15 mg/d, 30 mg/d, and 45 mg/d. All study procedures, including review of the safety data, were completed from each dose cohort before proceeding to the next cohort.

Eligible subjects entered the research unit on day 1, fasted overnight (minimum 8 hours), and were given a single oral dose of pioglitazone (ACTOS; Takeda Pharmaceuticals, Lincolnshire, Ill) at 15, 30, or 45 mg. Three hours after taking the pioglitazone dose, subjects were provided a standard breakfast. Baseline laboratory samples were drawn prior to dosing, and serial blood samples and safety assessments were obtained after dosing. Subjects remained in the research unit for 12 hours following the dose of pioglitazone; subjects received their usual regimen of diabetic therapy and meals and snacks, similar to their routine at home. Diabetes control was monitored by 2 capillary glucose measurements daily. The subjects returned on days 2 and 3 for blood samples. After the 48-hour blood draw, each subject took a single daily dose of pioglitazone for 13 consecutive days. Subjects were called daily to be reminded to take their study medication. The subjects returned to the research unit on day 15, and a pill count was performed to assess compliance. Subjects were given their last pioglitazone dose and had serial blood samples and safety assessments obtained, returning on the mornings of days 16, 17, and 18 for blood samples. On day 18, a physical examination as well as weight, vital signs, and laboratory profile, including serum transaminases and serum pregnancy test (female subjects) were completed.

Pharmacokinetic Sampling and Drug Analysis
Blood samples (5 mL each) for the measurement of pioglitazone and the active metabolites (M-III and M-IV) were obtained at time 0 (before the dose) and at 1, 2, 3, 4, 6, 8, 10, 12, 24, and 48 hours after drug administration on days 1 and 15. An additional blood sample was obtained at 72 hours after the day-15 dose to characterize the steady-state pharmacokinetic parameters of M-III and M-IV. The blood samples were centrifuged within 1 hour of collection at 1500g and 4°C for 10 minutes, and the serum was stored frozen at –20°C until analysis. The serum concentrations of pioglitazone, M-III, and M-IV were measured by liquid chromatography–ion spray tandem mass spectroscopy (LC/MS/MS; Bioanalytical Systems Inc, West Lafayette, Ind). The assay was fully validated and in conformity with US Food and Drug Administration guidelines. Briefly, a 100-ng/50-µL aliquot of internal standard (AD-4875) was added to 100-µL aliquots of serum, and 1.0 mL of 10-mM acetic acid was added. The serum samples were mixed, and the samples were applied to preconditioned Oasis HLB solid-phase extraction cartridges (Waters, Milford, Mass). The serum was allowed to pass through the cartridge by gravity for approximately 3 minutes; the remaining sample was drawn through the cartridge by vacuum. The cartridge was rinsed with 2 mL of deionized water; it was then eluted using 2 mL of methanol by gravity for approximately 10 minutes. The eluant was collected and evaporated to dryness at approximately 40°C under nitrogen. The residue was reconstituted with mobile phase, centrifuged, then injected on the LC/MS/MS system. Chromatography was on a Betasil C-18, 20 x 2.0-mm pre-column (Thermo Hypersil, Bellefonte, Pa) and a Capcell Pak C-18, 150 x 2.0-mm, 5-µm analytical column (ESA Biosciences, Chelmsford, Mass). The mobile phase consisted of 500 mL water, 500 mL acetonitrile, 0.39 g ammonium acetate, and 1 mL glacial acetic acid. The flow rate was 0.2 mL/min. Mass spectrometry detection was on a Finnigan TSQ 7000 (ThermoQuest, San Jose, Calif), using positive ion electrospray tandem mass spectrometry. The ions monitored were m/z 356.9 134.0, m/z 370.9 148.0, and m/z 372.9 150.0 for pioglitazone, M-III, and M-IV, respectively. The assay was validated over a concentration range of 25 ng/mL to 2500 ng/mL for pioglitazone, M-III, and M-IV. The accuracy and precision of the method during the sample analysis were determined from quality control samples at 3 levels: 74.9, 1000, and 2000 ng/mL. Interbatch accuracy ranged from 98.6% to 104%, and the interbatch precision ranged from 3.7% to 8.1% (expressed as percent coefficient of variation [%CV]).

Pharmacokinetic and Statistical Analysis
Pharmacokinetic parameters were calculated for pioglitazone, M-III, and M-IV using noncompartmental analysis techniques using Kinetica 4.1 (Innaphase, Philadelphia, Pa). The parameters determined after the single dose (day 1) included area under the concentration-time curve from 0 to 24 hours (AUC_0-24), AUC from 0 to infinity (AUC_0-), peak serum concentration (C_max), time to maximum concentration (t_max), and terminal half-life (t). Additional parameters determined after multiple dosing (day 15) were minimum serum concentration prior to the last dose (C_min), percent fluctuation (%Fluc), and the accumulation factor [AUC_0-24(day 15)/AUC_0-24(day 1)].

C_max, t_max, and C_min were taken directly from the original data. The terminal rate constant (_z) was determined as the negative of the slope of the linear regression of the natural log concentration (ln) versus time profile during the terminal phase, and t was calculated by ln2/_z. The AUC values were calculated by the linear trapezoidal rule to the 24-hour observed concentration for AUC_0-24, and to infinity (AUC_0-) by calculating the AUC up to the last measured concentration (48 hours for day 1; 72 hours for day 15), plus the ratio of the last measured concentration and _z. The %Fluc over a 24-hour dosing interval was computed as 100% x (C_max–C_min)/C_avg, where C_max and C_min are from day 15, and C_avg = AUC_0-24/, with being the dosing interval of 24 hours. Pioglitazone's apparent oral clearance (Cl/F) was also determined in a post hoc analysis as ratio of dose and AUC_0- after single dosing and as a ratio of daily dose and AUC_0-24 during multiple dosing.

The demographic and pharmacokinetic data are presented as mean (SD), except when noted. Dose proportionality of systemic exposure was determined by general linear modeling of log-transformed, dose-normalized AUC values using SAS 8.2 (SAS Institute, Cary, NC).

	RESULTS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 
Human Subjects
A total of 37 subjects were enrolled in the study; 1 was excluded from pharmacokinetic analysis because the subject had impaired glucose tolerance but not diabetes. Safety information was included on all subjects, including the subject excluded from the pharmacokinetic analysis. Pharmacokinetic analysis was completed on all 36 T2D subjects. As shown in Table I, patients in each of the dosing groups were similar in age, gender, weight, and body mass index.

Single-Dose Pharmacokinetics
Mean serum concentration-time curves for pioglitazone, and M-III, and M-IV for each dose cohort are shown in Figure 1, and pharmacokinetic parameters are summarized in Table II. Pioglitazone was rapidly absorbed following oral administration, with peak serum concentrations reached at all dose levels after 1 to 4 hours (median 2 hours). Systemic exposure increased dose dependently, with an interindividual variability of 50% at the lower dose level and 30% to 35% at higher dose levels. The median AUC_0- indicated approximate dose proportionality with 4474, 7845, and 11370 ng·h/mL for the 15-mg, 30-mg, and 45-mg dose cohorts, respectively. The oral clearance of pioglitazone was 3.23 (1.08), 5.53 (5.39), and 3.92 (1.19) L/h for the 15-mg, 30-mg, and 45-mg dose cohorts, respectively. Following single-dose administration, pioglitazone disappeared from the serum with a mean t of approximately 8 to 9 hours (range, 4-17 hours) and was independent of the dose level.

View larger version (17K): [in this window] [in a new window]   Figure 1. Mean serum concentrations of pioglitazone (P) as well as M-III and M-IV metabolites after a single oral dose (day 1) of 15 mg, 30 mg, or 45 mg pioglitazone hydrochloride.

The M-III and M-IV metabolites appeared in the serum after an average delay of approximately 1 to 2 hours, and M-III serum concentration was always lower than M-IV. The peak serum M-III and M-IV concentrations were achieved 16 and 22 hours after dose administration. The t could not be estimated for the M-III and M-IV metabolites with the 48-hour sampling period. M-III AUC_0-24 was only 40% to 50% of pioglitazone, and M-IV AUC_0-24 was similar to pioglitazone.

Multiple-Dose Pharmacokinetics
Mean serum concentration-time curves for pioglitazone, M-III, and M-IV for each dosing cohort are shown for the multiple doses in Figure 2. Corresponding pharmacokinetic parameter values are summarized in Table III. The Cl/F of pioglitazone after multiple dosing was similar to single-dose values: 3.37 (1.39), 4.63 (1.83), and 5.96 (2.82) L/h for the 15-mg, 30-mg, and 45-mg dose cohorts, respectively. AUC_0-24 increased less than proportionally with dosage. Based on an approximate t of 8 to 9 hours, accumulation of pioglitazone during once-daily dosing was negligible, with a median accumulation factor of 1.05 in the 15-mg cohort and 1.16 in the 30-mg cohort. In the 45-mg cohort, systemic exposure during multiple dosing was lower than after single-dose administration, resulting in an accumulation factor of 0.75. For the active metabolites M-III and M-IV, however, an accumulation factor of 2.5 to 3.0 was observed based on their t of approximately 24 to 32 hours. During multiple dosing, M-III AUC_0-24 was similar to pioglitazone, and M-IV AUC_0-24 was 1.5 to 2 times that of pioglitazone.

View larger version (17K): [in this window] [in a new window]   Figure 2. Mean serum concentrations of pioglitazone, M-III, and M-IV metabolites after multiple oral doses (day 15) of once-daily pioglitazone hydrochloride at 15 mg, 30 mg, or 45 mg.

For the total serum concentration of active compounds (the sum of pioglitazone, M-III, and M-IV), the peak concentration occurred 2 to 4 hours after dose administration, and accumulation averaged 1.7 to 3.1. Systemic exposure to active compounds increased less than proportionally, with increasing doses during multiple dosing.

Safety Results
A total of 20 out of 37 subjects experienced one or more adverse events (AEs) during one or more of the treatment periods. Adverse events not considered related to the study medication, including pain at the venipuncture site, upper respiratory tract infection, nasal congestion, and headache, occurred in 13 of the 20 subjects. Of the 20 subjects who experienced an AE, 7 subjects experienced one or more AEs possibly or probably related to study medication. Those AEs included the following. In the 15-mg dose group (1 subject with possibly related AEs): nausea and headache in 1 subject; in the 30-mg dose group (3 subjects with possibly related AEs): hypoglycemia in 2 subjects, increased -glutamyltransferase in 1 subject, and peripheral edema in 1 subject; and in the 45-mg dose group (2 subjects with possibly and 1 subject with probably related AEs): hypoglycemia in 3 subjects, diarrhea in 1 subject, nausea in 1 subject, and headache in 1 subject. The hypoglycemia resolved in all 5 subjects without any intervention. The safety profile appeared to be similar for all dosing groups. All AEs reported by the subjects were mild or moderate in severity, and all AEs resolved without discontinuing pioglitazone. No subjects were withdrawn as a result of the AEs.

	CONCLUSIONS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 
The pharmacokinetics of pioglitazone observed in subjects during this study were similar to those previously reported in adults.^20,21 Pioglitazone was rapidly absorbed, with the median time to maximal serum concentration occurring within 2 hours. In adult studies, food had little effect on absorption, slightly delaying the peak serum concentration but not the extent of absorption.²⁰ Serum concentrations for the total of active pioglitazone compounds (pioglitazone plus active metabolite) in our study remained elevated 24 hours after once-daily dosing. The range of observed terminal half-lives of pioglitazone is consistent with previous results in adults and was independent of the dose administered. Accumulation of pioglitazone during multiple dosing was minimal. There is no obvious explanation for the lower accumulation factor observed in the 45-mg cohort. The less than dose-proportional increase in C_max and AUC for pioglitazone, M-III, and M-IV during multiple dosing observed in our study has also been described previously for adults. Because of the unchanged terminal half-life between single and multiple dosing, a potential explanation for this nonproportionality in systemic exposure is a decrease in oral bioavailability during multiple dosing, rather than an increase in systemic clearance. Although we did not measure protein binding, another potential mechanism might be a dose-dependent reduction in the plasma protein binding, since pioglitazone is highly protein bound (>99%).²⁰ One would expect more displacement with multiple dosing because of accumulation. Saturation of plasma protein binding sites at higher plasma concentrations would result in an increase in the unbound drug fraction accessible for hepatic metabolism, which would ultimately lead to a reduced systemic exposure-per-dose unit at higher dose levels.

Pioglitazone is extensively metabolized in the liver to 5 primary metabolites (M-I, M-II, M-IV, M-V, and M-VI), of which M-IV is further metabolized to M-III. The M-III and M-IV metabolites are pharmacologically active and have a potency of about 40% to 60% that of pioglitazone. At steady state during once-daily dosing, pioglitazone only composes approximately 30% to 50% of the total peak serum concentration and 20% to 25% of the total AUC of active compounds. The substantial contribution of M-III and M-IV to systemic exposure is the result of their long terminal half-lives and moderate accumulation during multiple dosing, which ensures sustained pharmacologic activity with once-daily pioglitazone administration despite the relatively short terminal half-life of the parent drug.

Pioglitazone belongs to a relatively new class of insulin-sensitizing drugs, the thiazolidinediones. Troglitazone, the first drug available in this class, was withdrawn from the world market after severe liver disease became evident as a side effect. There has been no evidence that pioglitazone exhibits hepatotoxicity, and its use in adults continues to increase.²² There is a great need to study additional oral diabetic agents in children with T2D. In this study, the systemic exposure of pioglitazone, M-III, and M-IV after oral dosing was predictable and reproducible, and total serum concentrations of pharmacologically active pioglitazone compounds were maintained without major fluctuation during the once-daily dosing interval. These favorable pharmacokinetic properties, together with a well-established safety profile, form the basis for studying the use of pioglitazone in children with T2D.

	ACKNOWLEDGEMENTS

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 
This research was supported by Takeda Pharmaceuticals and in part by grants HD-31326 (University of Tennessee), HD-31318 (University of California, San Diego), and HD-37251 and RR06022 (Yale University) from the National Institutes of Health.

	REFERENCES

TOP ABSTRACT RESEARCH DESIGN AND METHODS RESULTS CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES

 

1. Dostou J, Gerich J. Pathogenesis of type 2 diabetes mellitus. Exp Clinic Endocrinol Diabet. 2001;109: S149-S156.[CrossRef]

2. Harris MI, Flegal KM, Cowie CC, et al. Prevalence of diabetes, impaired fasting glucose, and impaired glucose tolerance in U.S. adults. Diabetes Care. 1998;21: 518-524.[Abstract]

3. Diabetes in Children Adolescents Work Group of the National Diabetes Education Program. An update on type 2 diabetes in youth from the National Diabetes Education program. Pediatrics. 2004;114: 259-263.[Free Full Text]

4. Pinhas-Hamiel O, Dolan LM, Daniels SR, Standiford D, Khoury PR, Zeitler P. Increased incidence of non-insulin-dependant diabetes mellitus among adolescents. JPediatr. 1996;128: 608-615.[CrossRef][Web of Science][Medline] [Order article via Infotrieve]

5. Scott CR, Smith JM, Cradock MM, Pihoker C. Characteristics of youth-onset noninsulin-dependent diabetes mellitus and insulindependent diabetes mellitus at diagnosis. Pediatrics. 1997;100: 84-91.[Abstract/Free Full Text]

6. Pihoker C, Scott CR, Lensing SY, Cradock MM, Smith J. Non-insulin dependent diabetes mellitus in African-American youths of Arkansas. Clin Pediatr. 1998;37: 97-102.

7. Kaufman FR. Type 2 diabetes mellitus in children and youth: a new epidemic. J Pediatr Endocrinol Metab. 2002;15(suppl 2): 737-744.

8. Saltiel AR, Olefsky JM. Thiazolidinediones in the treatment of insulin resistance and type II diabetes. Diabetes. 1996;45: 1661-1669.[Abstract]

9. Burant CF, Sreenan S, Hirano K, et al. Troglitazone action is independent of adipose tissue. J Clin Invest. 1997;100: 2900-2908.[Web of Science][Medline] [Order article via Infotrieve]

10. Spiegelman BM. PPAR-gamma: adipogenic regulator and thiazolidinedione receptor. Diabetes. 1998;47: 507-514.[Abstract]

11. Flemmer M, Scott J. Mechanism of action of thiazolidinediones. Curr Opin Investig Drugs. 2001;11: 1564-1567.

12. O'Moore-Sullivan TM, Prins JB. Thiazolidinediones and T2DM: new drugs for an old disease. Med J Aust. 2002;176: 381-386.[Web of Science][Medline] [Order article via Infotrieve]

13. Fajas L, Auboeuf D, Raspe E, et al. The organization, promoter analysis, and expression of the human PPAR gamma gene. J Biol Chem. 1997;272: 18779-18789.[Abstract/Free Full Text]

14. Maggs DG, Buchanan TA, Burant CF, et al. Metabolic effects of troglitazone monotherapy in type 2 diabetes mellitus: a randomized double-blind, placebo-controlled trial. Ann Intern Med. 1998;128: 176-185.[Abstract/Free Full Text]

15. Fonseca VA, Valiquett TR, Huang SM, Ghazzi MN, Whitcomb RW, and the Troglitazone Study Group. Troglitazone monotherapy improves glycemic control in patients with type 2 diabetes mellitus: a randomized, controlled study. J Clin Endocrinol Metab. 1998;83: 3169-3176.[Abstract/Free Full Text]

16. Kemnitz JW, Elson DF, Roecker EB, Baum ST, Bergman RN, Meglasson MD. Pioglitazone increases insulin sensitivity, reduces blood glucose, insulin, and lipid levels, and lowers blood pressure, in obese, insulin-resistant rhesus monkeys. Diabetes. 1994;43: 204-211.[Abstract]

17. Miyazaki Y, Matsuda M, DeFronzo RA. Dose-response effect of pioglitazone on insulin sensitivity and insulin secretion in type 2 diabetes. Diabetes Care. 2002;25: 517-523.[Abstract/Free Full Text]

18. Miyazaki Y, Mahankali A, Matsuda M, et al. Improved glycemic control and enhanced insulin sensitivity in type 2 diabetic subjects treated with pioglitazone. Diabetes Care. 2001;24: 710-719.[Abstract/Free Full Text]

19. American Diabetes Association. Consensus statement: Type 2 diabetes in children and adolescents. Diabetes Care. 2000;23: 1-9.[Abstract]

20. Eckland DA, Danhof M. Clinical pharmacokinetics of pioglitazone. Exp Clin Endocrinol Diabetes. 2000;108: S234-S242.[CrossRef][Web of Science]

21. Hanefeld M. Pharmacokinetics and clinical efficacy of pioglitazone. Int J Clin Pract Suppl. 2001;121: 19-25.

22. Belcher G, Matthews DR. Safety and tolerability of pioglitazone. Exp Clin Endocrinol Diabetes. 2000;108: S267-S273.[CrossRef]
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