Anchored Aluminum Catalyzed Meerwein-Ponndorf-Verley Reduction at the Metal Nodes of Robust MOFs.

Catalytic Meerwein-Ponndorf-Verley reductions of ketones and aldehydes in the presence of isopropyl alcohol were performed at aluminum alkoxide sites that were postsynthetically introduced into robust metal-organic frameworks (MOFs). The aluminum was anchored at the bridging hydroxyl sites inherent in some MOFs. MOFs in the UiO-66/67 family as well as DUT-5 were successfully adapted to this strategy. Incorporation of catalytically active aluminum species greatly enhanced the reactivity of the native MOF at 80 °C in the case of both UiO-66, and was almost solely responsible for catalytic activity in the case of metalated UiO-66 and DUT-5. The site isolation of the catalyst prevented aggregation and complete deactivation of the molecular aluminum catalyst, allowing it to be recovered and recycled in the case of UiO-67. This catalyst also proved to be moderately tolerant to wet isopropyl alcohol.

Topical safety and vasoconstrictive assay-based bioequivalence of a new reformulated mometasone cream.

OBJECTIVES: A new improved mometasone furoate (Elocon™) cream with an emulsification system that produces a stable emulsion has been developed. In order to register the product in various markets, it was essential to ensure the cream was topically well tolerated and that it was bioequivalent to the reference product. METHODS: Phase I clinical studies were performed to assess the local safety and tolerability upon multiple dosing of this new cream as well as to assess the single-dose bioequivalence relative to the marketed product. Bioequivalence was assessed using a vasoconstrictive assay (VCA) after a dose-duration pilot study was completed with the marketed Elocon cream. KEY FINDINGS: The new mometasone cream and its vehicle were nonirritating in healthy subjects during 21-day patch application (MCII <0.025). The positive control was moderately irritating in the same study. The pivotal VCA study enrolled 162 subjects with 105 detectors included in the analysis of bioequivalence. In the 105 detectors, the ratio (×100%) of AUEC values at ED50 for test vs. standard (90% CI) was 112.91% (105.55, 120.87), within the bioequivalence criteria of (80, 125). CONCLUSIONS: These studies supported the registration of reformulated mometasone cream in various markets.

Atazanavir increases the plasma concentrations of 1200 mg raltegravir dose.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice-daily (b.i.d.). Raltegravir 1200 mg once-daily (q.d.) (investigational q.d. formulation of 2 × 600 mg tablets; q.d. RAL) was found to be generally well tolerated and non-inferior to the marketed 400 mg b.i.d. dose at 48 weeks in a phase 3 trial. Since raltegravir is eliminated mainly by metabolism via a uridine diphosphate glucuronosyltransferase (UGT) 1A1-mediated glucuronidation pathway, co-administration of UGT1A1 inhibitors may increase the plasma levels of q.d. RAL. To assess this potential, the drug interaction of 1200 mg raltegravir using atazanavir, a known UGT1A1 inhibitor, was studied. An open-label, randomized, 2-period, fixed-sequence phase 1 study was performed in adult healthy male and female (non-childbearing potential) subjects ≥ 19 and ≤ 55 years of age, with a body mass index (BMI) ≥ 18.5 and ≤ 32.0 kg/m2 . Subjects (n = 14) received a single oral dose of 1200 mg raltegravir in period 1. After a washout period of at least 7 days, the subjects received oral doses of 400 mg atazanavir q.d. for 9 consecutive days, with a single oral dose of 1200 mg raltegravir co-administered on day 7 of period 2. Serial blood samples were collected for 72 h following raltegravir dosing and analysed using a validated bioanalytical method to quantify raltegravir plasma concentrations. Co-administration with atazanavir yielded GMRs (90% CIs) for raltegravir AUC0-∞ , Cmax and C24 of 1.67 (1.34, 2.10), 1.16 (1.01, 1.33) and 1.26 (1.08, 1.46), respectively. There was no effect of raltegravir on serum total bilirubin. In contrast, atazanavir increased the mean bilirubin by up to 200%, an effect that was preserved in the atazanavir/raltegravir treatment group. Administration of single q.d. RAL alone and co-administered with multiple oral doses of atazanavir were generally well tolerated in healthy subjects. The results show that atazanavir increased the PK exposure of raltegravir; therefore, co-administration of atazanavir with raltegravir q.d. is not recommended. Copyright © 2016 John Wiley & Sons, Ltd.

Efavirenz does not meaningfully affect the single dose pharmacokinetics of 1200 mg raltegravir.

Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once daily regimen (QD) at a dose of 1200 mg (2 x 600 mg) is under development and offers a new treatment option for HIV-1 infected treatment-naive subjects. Since raltegravir is eliminated mainly by metabolism via an UDP-glucuronosyltransferase (UGT) 1 A1-mediated glucuronidation pathway, co-administration of UGT1A1 inducers may alter plasma levels of raltegravir. Efavirenz, an UGT1A1 inducer, was used to assess the impact of altered UGT activity on a 1200 mg QD dose of raltegravir. An open label, randomized, 2-period fixed-sequence Phase 1 study was performed in adult healthy male and female subjects (non-childbearing potential) ≥ 19 and ≤55 years of age, with a body mass index (BMI) ≥ 18.5 and ≤32.0 kg/m2 . Subjects (n = 21) received a single oral dose of 1200 mg raltegravir at bedtime on an empty stomach on Day 1 in Period 1. After a washout period of at least 7 days, subjects received oral doses of 600 mg efavirenz QD at bedtime for 14 consecutive days in Period 2. Subjects received a single oral dose of 1200 mg raltegravir co-administered with 600 mg efavirenz on Day 12 of Period 2. Pharmacokinetic (PK) samples were collected for 72 hours following raltegravir dosing and analyzed using a validated bioanalytical method to quantify raltegravir plasma concentrations. PK parameters were estimated using non-compartmental analysis. Administration of single 1200 mg oral doses of raltegravir alone and co-administered with multiple oral doses of efavirenz were generally well tolerated in healthy subjects. Co-administration with efavirenz yielded geometric mean ratios (GMRs) and their associated 90% confidence intervals (90% CIs) for raltegravir AUC0-∞, Cmax , and C24 of 0.86 (0.73, 1.01), 0.91 (0.70, 1.17), and 0.94 (0.76, 1.17), respectively. The results show that efavirenz modestly reduced the exposure of raltegravir. The reduction in raltegravir exposure is not considered clinically meaningful. Copyright © 2016 John Wiley & Sons, Ltd.

A Phase 1 Trial to Evaluate the Relationship Between Fluoride Intake and Urinary Fluoride Excretion in Healthy Participants.

Chronic overexposure to fluoride can have deleterious effects in the musculoskeletal system. Some fluorine-containing therapeutics, such as voriconazole, release fluoride through metabolism. Therefore, drug-related fluoride exposure should be assessed for novel therapeutics suspected of releasing fluoride through metabolism. Two trials were conducted to identify the optimal method of assessing drug-related fluoride exposure. In trial 1, designed to assess reproducibility of fluoride pharmacokinetics in urine and plasma, 14 participants were administered a fluoride-restricted diet and once-daily doses of sodium fluoride (2.2 mg [1 mg of fluoride] on days 1 and 2; and 13.2 mg of sodium fluoride [6 mg of fluoride] on days 3 and 4). In trial 2, designed to confirm the selected method for fluoride detection, 12 participants were administered a fluoride-restricted diet and randomized to receive voriconazole (400 mg twice, 12 hours apart, on day 1 [131 mg/d of fluoride maximum], then 3 doses of 200 mg every 12 hours [65.3 mg/d of fluoride maximum]) or placebo. Plasma fluoride concentrations and urinary fluoride excretion were assessed in each trial. Assessment of plasma fluoride concentrations in trial 1 was limited by 301 of 854 samples (35.2%) below the lower limit of quantitation. Urine fluoride excretion was readily measured and demonstrated a decrease from baseline during the fluoride-restricted diet phase, as well as dose-proportional increases with fluoride administration. In trial 2, increases in urine fluoride were successfully observed in participants administered voriconazole. In conclusion, fluoride exposure was optimally assessed by urinary fluoride excretion in conjunction with strict dietary fluoride restrictions, as measurements were consistent and reproducible.

Fluoride Pharmacokinetics in Urine and Plasma Following Multiple Doses of MK-8507, an Investigational, Oral, Once-Weekly Nonnucleoside Reverse Transcriptase Inhibitor.

MK-8507 is an investigational HIV-1 nonnucleoside reverse transcriptase inhibitor being developed for the treatment of HIV-1 infection. MK-8507 contains 2 trifluoromethyl groups that may result in fluoride release through metabolism, but the extent of MK-8507-related fluoride release in humans has yet to be determined. This double-blind, placebo-controlled, 2-period, parallel-group, multiple-dose trial in healthy participants without HIV-1 who were administered a fluoride-restricted diet and once-weekly doses of MK-8507 aimed to estimate the relationship between MK-8507 dose and fluoride exposure. A total of 15 adult male and 3 adult female (of non-childbearing potential) participants were randomized to receive MK-8507 200 mg (n = 6), MK-8507 800 mg (n = 6), or placebo (n = 6). Change from baseline in mean daily fluoride excretion averaged over 7 days following the administration of MK-8507 200 mg resulted in a net mean increase of 19.8 µmol (90% confidence interval, 12.2-27.4) relative to placebo and did not exceed 57 µmol, a threshold related to the mean difference between the daily reference dose set by the US Environmental Protection Agency and the average dietary fluoride intake in the United States. However, daily urinary fluoride excretion exceeded the threshold following administration of 800 mg MK-8507 (75.1 µmol [90% confidence interval, 67.5-82.7]). Assuming a linear relationship between MK-8507 dose and estimated mean daily fluoride released at steady-state, data interpolation suggests that the US Environmental Protection Agency reference dose for fluoride would not be exceeded in most patients when administering MK-8507 at doses currently under clinical investigation (≤400 mg once weekly).

Evaluation of pharmacokinetic parameters and dipeptidyl peptidase-4 inhibition following single doses of sitagliptin in healthy, young Japanese males.

AIMS: Sitagliptin is a selective inhibitor of dipeptidyl peptidase-4 (DPP-4) used to treat type 2 diabetes. The present aim was to evaluate pharmacokinetic (PK), pharmacodynamic (PD) and safety characteristics of sitagliptin following single doses in healthy, young Japanese males. METHODS: In this alternating two-panel, randomized, controlled double-blind study, six healthy Japanese male subjects (aged 20-46 years) in each panel received single oral doses of 5-400mg sitagliptin and two received placebo. Plasma and urine drug concentrations were measured from 0-48h post dose and plasma DPP-4 inhibition from 0-24h post dose. The results were compared with historical data from young, healthy non-Japanese males. RESULTS: Plasma concentrations of sitagliptin increased approximately in proportion to dose; maximum concentrations occurred 2-6h post-dose. The mean apparent terminal half-life for plasma sitagliptin was 9-14h, with the half-life slightly decreasing as the dose increased. The mean dose fraction excreted unchanged in the urine was 0.73-1.00. Ingestion of a traditional Japanese breakfast prior to dosing had only a minor effect on PK parameters. After correction for dilution and competition effects during assay, doses of sitagliptin ≥50mg resulted in weighted average DPP-4 inhibition from 0-24h post-dose >94% (without correction, >78%). No clinically meaningful differences in PK and DPP-4 inhibition parameters were found between Japanese and non-Japanese subjects. Sitagliptin was generally well tolerated and there were no serious adverse experiences or episodes of hypoglycaemia. CONCLUSIONS: The PK and PD findings from this study are consistent with once daily dosing of sitagliptin in Japanese patients with type 2 diabetes.

A Microdose Cocktail to Evaluate Drug Interactions in Patients with Renal Impairment.

Renal impairment (RI) is known to influence the pharmacokinetics of nonrenally eliminated drugs, although the mechanism and clinical impact is poorly understood. We assessed the impact of RI and single dose oral rifampin (RIF) on the pharmacokinetics of CYP3A, OATP1B, P-gp, and BCRP substrates using a microdose cocktail and OATP1B endogenous biomarkers. RI alone had no impact on midazolam (MDZ), maximum plasma concentration (Cmax ), and area under the curve (AUC), but a progressive increase in AUC with RI severity for dabigatran (DABI), and up to ~2-fold higher AUC for pitavastatin (PTV), rosuvastatin (RSV), and atorvastatin (ATV) for all degrees of RI was observed. RIF did not impact MDZ, had a progressively smaller DABI drug-drug interaction (DDI) with increasing RI severity, a similar 3.1-fold to 4.4-fold increase in PTV and RSV AUC in healthy volunteers and patients with RI, and a diminishing DDI with RI severity from 6.1-fold to 4.7-fold for ATV. Endogenous biomarkers of OATP1B (bilirubin, coproporphyrin I/III, and sulfated bile salts) were generally not impacted by RI, and RIF effects on these biomarkers in RI were comparable or larger than those in healthy volunteers. The lack of a trend with RI severity of PTV and several OATP1B biomarkers, suggests that mechanisms beyond RI directly impacting OATP1B activity could also be considered. The DABI, RSV, and ATV data suggest an impact of RI on intestinal P-gp, and potentially BCRP activity. Therefore, DDI data from healthy volunteers may represent a worst-case scenario for clinically derisking P-gp and BCRP substrates in the setting of RI.

The effect of etoricoxib on the pharmacokinetics of oral contraceptives in healthy participants.

The pharmacokinetics of oral contraceptive (OC) components, ethinyl estradiol (EE) and norethindrone (NET), were evaluated after coadministration with etoricoxib in 3 double-blind, randomized, 2-period crossover studies of healthy women. There were 16, 39, and 24 participants enrolled in studies 1 (part I, part II), and 2, respectively. Each participant received triphasic OC (EE 35 microg/NET 0.5 mgx7 days, 0.75 mgx7 days, 1.0 mgx7 days) throughout each 28-day period. OC was coadministered with 21 days of etoricoxib daily followed by placebo for 7 days; the alternate period followed the reverse regimen (placebo to etoricoxib). Study 1 (part I) examined concurrent (morning) administration of OC/etoricoxib 120 mg, study 1 (part II) examined staggered (morning/night) administration of OC/etoricoxib 120 mg, and study 2 examined concurrent (morning) administration of OC/etoricoxib 60 mg. Coadministration of OC and etoricoxib 120 mg once daily was associated with a approximately 50% to 60% increase in EE concentrations, whereas etoricoxib 60 mg once daily was associated with a approximately 37% increase in EE concentrations. Coadministration of OC and etoricoxib was generally well tolerated. A clinically important change in NET AUC0-24 h was not observed. Adverse events included dyspepsia, diarrhea, headache, nausea, fatigue, loss of appetite, and taste disturbance.

Comparative inhibitory activity of etoricoxib, celecoxib, and diclofenac on COX-2 versus COX-1 in healthy subjects.

We determined cyclo-oxygenase-1 and cyclo-oxygenase-2 inhibition in healthy middle-aged subjects (41-65 years) randomly assigned to four 7-day treatment sequences of etoricoxib 90 mg every day, celecoxib 200 mg twice a day, diclofenac 75 mg twice a day, or placebo in a double-blind, randomized, 4-period crossover study. Maximum inhibition of thromboxane B(2) (cyclo-oxygenase-1 activity) in clotting whole blood on day 7 (0-24 hours postdose) was the primary endpoint. Inhibition of lipopolysaccharide-induced prostaglandin E(2) in whole blood (cyclo-oxygenase-2 activity) was assessed on day 7 (0-24 hours postdose) as a secondary endpoint. Diclofenac had significantly greater maximum inhibition of thromboxane B(2) versus each comparator (P < .001); placebo 2.4% (95% confidence interval: -8.7% to 12.3%), diclofenac 92.2% (91.4% to 92.9%), etoricoxib 15.5% (6.6% to 23.5%), and celecoxib 20.2% (11.5% to 28.1%). Prostaglandin E(2) synthesis was inhibited with a rank order of potency of diclofenac > etoricoxib > celecoxib. In summary, at doses commonly used in rheumatoid arthritis, diclofenac significantly inhibits both cyclo-oxygenase-1 and cyclo-oxygenase-2, whereas etoricoxib and celecoxib significantly inhibit cyclo-oxygenase-2 and do not substantially inhibit cyclo-oxygenase-1.

Single- and Multiple-Dose Pharmacokinetics of Once-Daily Formulations of Raltegravir.

A new once-daily formulation of raltegravir, an integrase strand transfer inhibitor indicated in combination with other antiretroviral drugs for the treatment of human immunodeficiency virus-1 infection, is under development. Single-dose and steady-state pharmacokinetics of 1200 mg for 2 formulations of raltegravir were characterized in 2 open-label phase 1 studies in healthy male and female subjects aged 18 to 55 years. The new raltegravir 600-mg formulation had a higher relative bioavailability compared with the 400-mg tablets. Once absorbed, both 3 × 400-mg and 2 × 600-mg dosage forms of raltegravir exhibited similar systemic pharmacokinetics; in dictating bioavailability, differences were from increased absorption that was the result of improved in vivo disintegration/dissolution. Food had a smaller effect on the pharmacokinetics of raltegravir when given as 2 × 600-mg formulation (42% vs 73% decrease in AUC0-last ). Steady state was generally reached in 2 days, with little to no accumulation with multiple-dose administration. Raltegravir 1200 mg was found to exhibit pharmacokinetic properties amenable for once-daily dosing and was generally well tolerated in healthy subjects after single and multiple doses. The new formulation improved the bioavailability of this Biopharmaceutics Classification System class II compound.

Effect of a single cyclosporine dose on the single-dose pharmacokinetics of sitagliptin (MK-0431), a dipeptidyl peptidase-4 inhibitor, in healthy male subjects.

Sitagliptin (MK-0431) is an orally active, potent, and selective dipeptidyl peptidase-4 inhibitor used for the treatment of patients with type 2 diabetes mellitus. Sitagliptin has been shown to be a substrate for P-glycoprotein in preclinical studies. Cyclosporine was used as a probe P-glycoprotein inhibitor at a high dose to evaluate the potential effect of potent P-glycoprotein inhibition on single-dose sitagliptin pharmacokinetics in healthy male subjects. Eight healthy young men received a single oral 600-mg dose of cyclosporine with a single 100-mg oral sitagliptin dose and a single oral 100-mg sitagliptin dose alone in an open-label, randomized, 2-period, crossover study. Single doses of sitagliptin with or without single doses of cyclosporine were generally well tolerated. The sitagliptin AUC(0-infinity) geometric mean ratio was 1.29 with a 90% confidence interval of (1.24, 1.34). The sitagliptin Cmax geometric mean ratio was 1.68 with a 90% confidence interval of (1.35, 2.08). Cyclosporine coadministration did not appear to affect apparent sitagliptin renal clearance, t(1/2), or C(24 h), suggesting that effects of these high doses of cyclosporine are more likely due to enhanced absorption of sitagliptin, potentially through inhibition of intestinal P-glycoprotein. These results rationalize the use of a single high-dose cyclosporine as a probe inhibitor of P-glycoprotein for compound candidates whose elimination is less dependent on CYP3A4-mediated metabolism.

On the Use of Group Sequential Study Designs for the Test of Bioequivalence for Complicated Products.

A novel modeling approach together with a use of group sequential study design for a complicated triple fixed-dose combination was attempted. Probability of success (POS) was used for determining a weighted average power, where weight was based on available information such as data from previous pilot studies or literature. A simulation study was conducted that resulted in the development of the necessary sample size for the studies in addition to identifying a decision algorithm that was prospectively defined in the protocols. Prospective inclusion of decision algorithms in the respective protocols facilitated a decision analytic approach to continuance or discontinuance of the product concept. Whereas the data suggested going to stage 2 was appropriate, the overall POS of meeting the equivalence requirements upon completion of the study were very low, leading to termination of the selected formulation concepts. The use of such novel designs for bioequivalence assessment can be applied for staged investments, particularly when there is uncertainty in formulation POS or when the pilot-scale pharmacokinetic studies are not likely to predict the final-scale pivotal studies.

Effects of ezetimibe on cyclosporine pharmacokinetics in healthy subjects.

This single-center, open-label, 2-period crossover study investigated the effects of multiple-dose ezetimibe (EZE) on a single dose of cyclosporine (CyA). Healthy subjects received 2 treatments in random order with a 14-day washout: (1) CyA 100 mg alone and (2) EZE 20 mg for 7 days with CyA 100 mg coadministered on day 7; EZE 20 mg alone was administered on day 8. AUC(0-last) and Cmax geometric mean ratios (90% confidence interval) for ([CyA + EZE]/CyA alone) were 1.15 (1.07, 1.25) and 1.10 (0.97, 1.26), respectively. Tmax (approximately 1.3 hours) was similar with and without EZE (P >.200). Mean CyA exposure slightly increased (approximately 15%) with multiple-dose EZE 20 mg; however, this value was contained within (0.80, 1.25). The implications for chronic EZE dosing within the usual clinical paradigm of chronic CyA dosing have not been established; caution is recommended when using these agents concomitantly. CyA concentrations should be monitored in patients receiving EZE and CyA.

Interaction of single-dose ezetimibe and steady-state cyclosporine in renal transplant patients.

This open-label, single-period study evaluated the single-dose pharmacokinetics of ezetimibe (EZE) 10 mg in the setting of steady-state cyclosporine (CyA) dosing in renal transplant patients. A single 10-mg dose of EZE was coadministered with the morning dose of CyA (75-150 mg twice a day). Total EZE (sum of unconjugated, parent EZE and EZE-glucuronide; EZE-total) AUC(0-last) and Cmax were compared to values derived from a prespecified database of healthy volunteers. Geometric mean ratios (90% CIs) for (EZE + CyA)/EZE alone for EZE-total AUC((0-last)) and Cmax were 3.41 (2.55, 4.56) and 3.91 (3.13, 4.89), respectively. Compared to healthy controls, EZE-total AUC((0-last)) was 3.4-fold higher in transplant patients receiving CyA; similar exposure levels were seen in a prior multiple-dose study in which EZE 50 mg was administered to healthy volunteers without dose-related toxicity. Because the long-term safety implications of both higher EZE exposures and undetermined effect on CyA are not yet understood, the clinical significance of this interaction is unknown.

Effect of metal-cation antacids on the pharmacokinetics of 1200 mg raltegravir.

OBJECTIVES: Raltegravir is a human immunodeficiency virus (HIV)-1 integrase strand transfer inhibitor currently marketed at a dose of 400 mg twice daily (BID). Raltegravir for once-daily regimen (QD) at a dose of 1200 mg is under development. The effect of calcium carbonate and magnesium/aluminium hydroxide antacids on the pharmacokinetics of a 1200 mg dose of raltegravir was assessed in this study. METHODS: An open-label, four-period, four-treatment, fixed-sequence study in 20 HIV-infected patients was performed. Patients needed to be on raltegravir as part of a stable treatment regimen for HIV, and upon entry into the trial received 5 days of 1200 mg raltegravir as pretreatment, before they entered the four-period study: 1200 mg of raltegravir alone (period 1), calcium carbonate antacid as TUMS® Ultra Strength (US) 1000 and 1200 mg raltegravir given concomitantly (Period 2), magnesium/aluminium hydroxide antacid as 20 ml MAALOX® Maximum Strength substitute MS given 12 h after administration of 1200 mg raltegravir (period 3), and calcium carbonate antacid as TUMS® US 1000 given 12 h after administration of 1200 mg raltegravir (period 4). Patients received their dose of 1200 mg QD raltegravir during the intervals between periods to re-establish steady state. AUC0-24 , C24 , Cmax and Tmax were calculated from the individual plasma concentrations of 1200 mg QD raltegravir after administration alone or with a calcium carbonate antacid or with a staggered dose of a calcium carbonate antacid or magnesium/aluminium hydroxide antacid. Adverse events, in addition to laboratory safety tests (haematology, serum chemistry and urinalysis), 12-lead electrocardiograms and vital signs were assessed. KEY FINDINGS: All treatments were well tolerated in the study. Metal-cation antacids variably affected the pharmacokinetics of 1200 mg QD raltegravir. When calcium carbonate antacid was given with 1200 mg raltegravir concomitantly, the geometric mean ratio (GMR) and its associated 90% confidence interval (90% CI) for AUC0-24 , Cmax and C24 h were 0.28 (0.24, 0.32), 0.26 (0.21, 0.32) and 0.52 (0.45, 0.61), respectively. When calcium carbonate antacid and magnesium/aluminium hydroxide were given 12 h after raltegravir 1200 mg QD dosing, the GMR (90% CI) values for AUC0-24 and Cmax were 0.90 (0.80, 1.03), 0.98 (0.81, 1.17), and 0.86 (0.73, 1.03), 0.86 (0.65, 1.15), respectively. However, significant reduction in the trough concentrations of raltegravir was observed: C24 h 0.43 (0.36, 0.51) in the presence of calcium carbonate antacids and 0.42 (0.34, 0.52) in presence of magnesium/aluminium hydroxide, respectively. CONCLUSIONS: Overall, the use of metal-cation antacids with 1200 mg QD raltegravir is not recommended.

Novel Gastroretentive Controlled Release Formulations for Once-Daily Administration: Assessment of Clinical Feasibility and Formulation Concept for Raltegravir.

BACKGROUND: Raltegravir is an integrase strand transfer inhibitor indicated in combination with other anti-retroviral medicinal products for the treatment of HIV-1 infection, given twice daily. Although a BCS class II compound, raltegravir exhibits low colonic absorption, thus making development of modified release formulations challenging. It was hypothesized that a gastroretentive (GR) formulation would increase trough (C24 h) concentrations of raltegravir, hence being amenable to a once-daily (QD) regimen. METHODS: Iterative prototype GR formulations were developed in monolithic, bilayer, and trilayer tablet designs. Four phase I studies in healthy subjects were conducted to provide proof of formulation concept. RESULTS: Raltegravir C24 h was increased by a GR formulation with scintigraphy data supporting gastric retention. Single-dose exposures from a trilayer tablet administered in the morning with a high-fat meal resulted in acceptable C24 h values. However, C24 h values for evening dosing with a high-fat meal did not meet the success criteria for QD administration. Raltegravir C24 h and area under the curve (AUC) values after AM dosing with a low-fat meal were significantly lower than after dosing with a moderate-fat meal. Skipping, delaying, or giving a low-fat, low-calorie lunch after dosing with a high-calorie breakfast also resulted in an unacceptable decline in C24 h values. The requirements for consistent product performance under varying conditions of diet, timing of dosing, and dose were not favorable when given as GR tablets. CONCLUSIONS: The findings from these studies offer valuable insights into modifying the absorption of candidate drugs with limiting colonic permeability and solubility characteristics and the interplay between meal, dose timing, and GR formulation performance.

Induction of adipocyte complement-related protein of 30 kilodaltons by PPARgamma agonists: a potential mechanism of insulin sensitization.

Adipocyte complement-related protein of 30 kDa (Acrp30, adiponectin, or AdipoQ) is a fat-derived secreted protein that circulates in plasma. Adipose tissue expression of Acrp30 is lower in insulin-resistant states and it is implicated in the regulation of in vivo insulin sensitivity. Here we have characterized the ability of PPARgamma agonists to modulate Acrp30 expression. After chronic treatment of obese-diabetic (db/db) mice with PPARgamma agonists (11 d), mean plasma Acrp30 protein levels increased (>3x). Similar effects were noted in a nongenetic type 2 diabetes model (fat-fed and low-dose streptozotocin-treated mice). In contrast, treatment of mice (db/db or fat-fed) with metformin or a PPARalpha agonist did not affect plasma Acrp30 protein levels. In a cohort of normal human subjects, 14-d treatment with rosiglitazone also produced a 130% increase in circulating Acrp30 levels vs. placebo. In addition, circulating Acrp30 levels were suppressed 5-fold in patients with severe insulin resistance in association with dominant-negative PPARgamma mutations. Thus, induction of adipose tissue Acrp30 expression and consequent increases in circulating Acrp30 levels represents a novel potential mechanism for PPARgamma-mediated enhancement of whole-body insulin sensitivity. Furthermore, Acrp30 is likely to be a biomarker of in vivo PPARgamma activation.

Effect of a 28-d treatment with L-796568, a novel beta(3)-adrenergic receptor agonist, on energy expenditure and body composition in obese men.

BACKGROUND: Stimulation of energy expenditure (EE) with selective thermogenic beta-adrenergic agonists may be a promising approach for treating obesity. OBJECTIVE: We analyzed the effects of the highly selective human beta(3)-adrenergic agonist L-796568 on 24-h EE, substrate oxidation, and body composition in obese, weight-stable men. DESIGN: In this 2-center, double-blind, randomized, parallel-group study, we measured 24-h EE before and after 28 d of treatment with L-796568 (375 mg/d) or placebo during weight maintenance (ie, without dietary intervention) in nondiabetic, nonsmoking men aged 25-49 y with body mass index (in kg/m(2)) of 28-35 (n = 10 subjects per treatment group). RESULTS: The mean change in 24-h EE from before to after treatment did not differ significantly between groups (92 +/- 586 and 86 +/- 512 kJ/24 h for the L-796568 and placebo groups, respectively). The change in 24-h nonprotein respiratory quotient from before to after treatment did not differ significantly between groups (0.009 +/- 0.021 and 0.009 +/- 0.029, respectively). No changes in glucose tolerance were observed, but triacylglycerol concentrations decreased significantly with L-796568 treatment compared with placebo (-0.76 +/- 0.76 and 0.42 +/- 0.31 mmol/L, respectively; P < 0.002). Overall, treatment-related changes in body composition were not observed, but higher plasma L-796568 concentrations in the L-796568 group were associated with greater decreases in fat mass (r = -0.69, P < 0.03). CONCLUSIONS: Treatment with L-796568 for 28 d had no major lipolytic or thermogenic effect but it lowered triacylglycerol concentrations. This lack of chronic effect on energy balance is likely explained by insufficient recruitment of beta(3)-responsive tissues in humans, down-regulation of the beta(3)-adrenergic receptor-mediated effects with chronic dosing, or both.

An evaluation of the dose-dependent inhibition of CYP1A2 by rofecoxib using theophylline as a CYP1A2 probe.

This study was undertaken to determine whether rofecoxib can interfere with CYP1A2 activity in humans using theophylline as a probe substrate. Single oral doses of theophylline were administered to each of three panels of 12 healthy subjects receiving daily doses of rofecoxib for 7 days to examine the effect of rofecoxib administration on the absorption and disposition of theophylline. Each panel was administered doses of 12.5, 25, or 50 mg of rofecoxib or a matching placebo in a two-way, randomized, crossover fashion and administered a single oral 300-mg dose of theophylline on day 7 of rofecoxib or placebo administration. Plasma concentrations of theophylline were monitored for 48 hours postdose to assess differences in pharmacokinetics. All three commercially marketed doses of rofecoxib were found to slow the clearance of theophylline with no detectable effect on absorption. CL/F values for theophylline were estimated from AUC infinity and by point estimates from the concentrations of drug in plasma at 12 and 24 hours postdose. The point estimates of CL/F were found to be in agreement with those derived from AUC.