Pharmacokinetic and pharmacodynamic interaction of vildagliptin and voglibose in Japanese patients with Type 2 diabetes.

OBJECTIVE: To assess the extent of pharmacokinetic and pharmacodynamic interaction between vildagliptin, a potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4) enzyme, and voglibose, an α-glucosidase inhibitor widely prescribed in Japan, when coadministered in Japanese patients with Type 2 diabetes. METHODS: In this open-label, randomized, 3-treatment, 3-period and 6-way crossover study, 24 Japanese patients with Type 2 diabetes received 50 mg vildagliptin twice daily; 50 mg vildagliptin twice daily co-administered with 0.2 mg voglibose three times daily; or 0.2 mg voglibose three times daily for 3 days in each period. Plasma concentrations of vildagliptin, DPP-4, glucagon-like peptide-1 (GLP-1), glucose, insulin, and glucagon were determined from blood samples collected at steady state. RESULTS: Exposure to vildagliptin 50 mg (area under the concentration-time curve from 0 to 12 hours (AUCτ,ss)) and maximum plasma concentration at steady state (Cmax,ss) was reduced by 23% and 34% respectively with co-administration of voglibose. The percentage of DPP-4 inhibition by vildagliptin remained unchanged when vildagliptin was given alone or co-administered with voglibose; maximum inhibition was 98.3 ± 1.4% (mean ± SD) for vildagliptin alone and 97.4 ± 1.1% with co-administration. Coadministration of vildagliptin and voglibose led to a greater increase in the active GLP-1 plasma concentration than did vildagliptin alone (geometric mean ratio 1.63 (90% CI, 1.30, 2.03), p = 0.0007). The combination of vildagliptin and voglibose also led to a significantly lower plasma glucose levels (p < 0.0001). CONCLUSIONS: Plasma vildagliptin levels were decreased when voglibose was co-administered, although DPP- 4 inhibition remained unchanged. Co-administration led to significantly better pharmacodynamic response compared with each treatment alone, including higher active GLP-1 and lower glucose levels. The results indicate that this coadministration may be beneficial in the clinical situation. Vildagliptin and voglibose treatments, alone or when co-administered, were well tolerated in Japanese patients with Type 2 diabetes.

Systemic pharmacokinetics of indacaterol, an inhaled once-daily long-acting beta2-agonist, in different ethnic populations.

RATIONALE: To assess ethnic sensitivity of indacaterol systemic pharmacokinetics in Japanese vs. non-Japanese patients. METHODS: Analyses were in three parts: data from a single "all Asian" clinical study; and two on pooled data - one using a linear mixed effects (LME) model and the other a non-linear mixed effects (NLME) model. The NLME model analyzed pharmacokinetic data from nine indacaterol studies; the LME model analyzed peak (C(max)) and trough (C(min)) serum concentration using data from four of these studies. RESULTS: In the all-Asian study, indacaterol serum concentration-time pharmacokinetic profiles in Japanese patients (n = 102) were similar to those in the overall population (n = 229). In the LME model, C(max) (4,392 observations, 1,845 patients) and C(min) (4,664 observations, 1,796 patients) for Japanese patients (n = 94) were on average 25% and 18% higher, respectively, than non-Japanese patients. However, after adjusting for study differences, this apparent ethnicity effect was not significant (p = 0.25 and 0.39, respectively). In the NLME model (25,540 observations, 2,857 patients), there was no statistically significant effect of Japanese (n = 230) ethnicity on indacaterol serum pharmacokinetics. CONCLUSION: No ethnicity effect was observed on indacaterol systemic pharmacokinetic profile for Japanese patients when compared with the overall Asian patient population or with the Caucasian patient population.

Effects of meal timing relative to dosing on the pharmacokinetics and pharmacodynamics of vildagliptin in Japanese patients with Type 2 diabetes.

OBJECTIVE: To assess the effects of meal timing on the pharmacokinetics and pharmacodynamics of the dipeptidyl peptidase IV (DPP-4) inhibitor vildagliptin in Japanese patients with Type 2 diabetes. METHODS: In this open-label, single-center crossover study, 12 Japanese patients with Type 2 diabetes were randomized to twice-daily vildagliptin 50 mg, administered 30 min before or immediately before breakfast and dinner for 7 days. After a 7-day washout period, patients received the other regimen. Blood samples were collected for the determination of vildagliptin, DPP-4, glucagon-like peptide-1 (GLP-1) and glucose. RESULTS: Vildagliptin absorption appeared slower when administered 30 min before rather than immediately before meals (tmax absolute range: 1.00 - 2.00 h vs. 0.33 - 1.58 h). Vildagliptin Cmax and AUC0-8 h were essentially the same irrespective of meal timing (geometric mean ratio: Cmax 1.08 (90% CI; 0.92 - 1.26); AUC0-8 h 0.97 (90% CI; 0.91 - 1.05)). Meal timing did not affect pharmacodynamics; complete DPP-4 inhibition (> 90%) was sustained for 8 h post-dose, and plasma active glucagon-like peptide-1 levels increased 2 - 3-fold from baseline. Fasting plasma glucose (FPG) and postprandial plasma glucose (PPPG) reductions from baseline did not differ significantly with meal timing (30 min before vs. immediately before: FPG, -8.9 vs. -5.8 mg/dl; adjusted AUE0-4 h, -67.0 vs. -51.0 mg×h/dl). Vildagliptin was well tolerated. CONCLUSIONS: Dosing 30 min or immediately before meals did not affect vildagliptin pharmacokinetics or pharmacodynamics in Japanese patients with Type 2 diabetes.

Comparative suppressive effects of tyrosine kinase inhibitors imatinib and nilotinib in models of autoimmune arthritis.

Imatinib and nilotinib are inhibitors that selectively target a set of protein tyrosine kinases, including abelson kinase (Abl), together with the chimeric oncoprotein, breakpoint cluster region-abelson kinase (Bcr-Abl), as well as stem cell factor receptor (KIT), platelet-derived growth factor receptor (PDGFR), discoidin domain receptor (DDR), and colony stimulating factor-1 receptor (CSF-1R). The aim of the present study was to investigate whether imatinib or nilotinib was effective against arthritis in the glucose-6-phosphate isomerase (GPI)-induced arthritis mouse model. Imatinib or nilotinib was administered orally to the arthritic mice at different time points. Efficacy was evaluated by visual scoring and by determining the production of anti-GPI antibody. Splenocytes from the arthritic mice were cultured with GPI in the presence of imatinib or nilotinib in vitro, and cytokine levels in the culture supernatants were analyzed. To investigate the effects of imatinib and nilotinib on T-cell proliferation, lymph node cells from the arthritic mice were cultured with GPI in the presence of imatinib or nilotinib in vitro. Interleukin (IL)-17 mRNA expression in the arthritic ankle joints from the onset of arthritis was analyzed by real-time polymerase chain reaction (PCR). The administration of imatinib from day 0 showed suppression of arthritis (P < 0.05), the administration of nilotinib from day 0 resulted in pronounced suppression of arthritis (P < 0.01), and that from day 7 showed significant inhibition of the progression of arthritis (P < 0.05). A reduction in anti-GPI antibodies was correlated with the therapeutic efficacy of imatinib, but not with that of nilotinib. Imatinib dose-dependently inhibited tumor necrosis factor (TNF)-α, IL-6, interferon (IFN)-γ, and IL-17 production by splenocytes in vitro, while nilotinib inhibited only IL-17 and IFN-γ production in a dose-dependent fashion. Imatinib at 3 µM exerted a mild antiproliferative effect on CD4+ T cells (P < 0.05), whereas imatinib at 10 µM and nilotinib at 3 and 10 µM demonstrated a marked antiproliferative effect (P < 0.01). The IL17 gene expression level on day 7 tended to be higher than that on day 14. These findings suggest that imatinib and nilotinib could prevent autoimmune arthritis, essentially via distinct mechanisms, in that imatinib inhibits both inflammatory and T-cell-derived cytokine production, whereas nilotinib suppresses T-cell-derived cytokine production. Imatinib and nilotinib could have therapeutic potential for rheumatoid arthritis (RA) and other inflammatory diseases.

Effect of application sites and multiple doses on nicotine pharmacokinetics in healthy male Japanese smokers following application of the transdermal nicotine patch.

The transdermal nicotine patch, which contains 25 mg nicotine per 30 cm(2), is designed to deliver approximately 15 mg nicotine to the blood circulation in 16 hours of application for the treatment of smoking cessation. It was applied to 3 different skin sites (upper arm, abdomen, and back) to examine regional variations in percutaneous nicotine absorption in a single-dose, 3-period, crossover study involving 9 healthy male Japanese smokers. Nicotine pharmacokinetics during once-daily application of the transdermal nicotine patch for 5 days was also investigated in 10 healthy smokers. There were statistically significant effects of application sites on percutaneous nicotine absorption. The ratios (90% confidence intervals) of AUC and C(max) for comparison to the upper arm were 102% (88, 117%) and 106% (95, 119%) for the back and 75% (65, 87%) and 75% (66, 84%) for the abdomen, respectively. These suggest that systemic exposure after application to the upper arm was greater compared with the abdomen but equivalent to the back. Following multiple doses, linear pharmacokinetics and no significant accumulation of nicotine concentrations were observed, and steady state was reached by day 2. Only mild itching and erythema were observed at the application sites. The transdermal nicotine patch was well tolerated in both studies.

Pharmacokinetics and safety of Fosfluconazole after single intravenous bolus injection in healthy male Japanese volunteers.

This was a single blind, placebo-controlled, escalating single-dose, three-period crossover study using two subject cohorts to investigate the safety, tolerability, and pharmacokinetics in healthy male Japanese subjects after intravenous bolus injection of fosfluconazole 50 to 2000 mg, a phosphate prodrug of fluconazole (FLCZ). Fosfluconazole was rapidly converted to FLCZ with only minor amounts excreted in the urine (less than 4% of the dose). Fosfluconazole had a volume of distribution at the higher doses, which was similar to the extracellular volume in man (0.2 L/kg) and was eliminated with a terminal half-life of 1.5 to 2.5 hours. There was apparent dose proportionality in FLCZ pharmacokinetics. C(max) and AUC of FLCZ appeared to increase proportionally with increasing doses of fosfluconazole. There were no apparent dose-dependent trends in t(max), t(1/2), or mean residence time (MRT) of FLCZ. Bolus injection of fosfluconazole was well tolerated at doses of up to 2000 mg in healthy Japanese subjects.

Comparison of nicotine pharmacokinetics in healthy Japanese male smokers following application of the transdermal nicotine patch and cigarette smoking.

Transdermal nicotine patch (TNP) contains approximately 16.6 and 24.9 mg of nicotine per 20 and 30 cm2 (TNP-20 and TNP-30). The aims of the study are to investigate linearity of nicotine pharmacokinetics after single application of different strengths of TNP and to directly compare plasma nicotine concentrations with those during cigarette smoking. Twelve healthy Japanese male smokers were randomly allocated to 1 of 2 cohorts consisting of 6 subjects each. Cohort 1 subjects received 1 sheet of TNP-20 (TNP-20x1) in period 1, and 2 sheets of TNP-20 (TNP-20x2) in period 3. Cohort 2 subjects were received 1 sheet of TNP-30 (TNP-30x1) in period 2, and smoked a total of 12 cigarettes at 1 h intervals in period 4. Each TNP was applied to the upper arm for 16 h. After TNP-20x1 or TNP-20x2 treatment in cohort 1, the amount of nicotine delivered from TNP (Dose) was proportional to surface area of TNP. Cmax and AUC of nicotine increased with the surface area (Dose), and tmax, t(1/2), CL/F and percentage of dose excreted in urine were almost the same between both treatments. These suggest the linear pharmacokinetics of nicotine in proportion to the surface area and Dose following single application of TNP in identical subjects. In cohort 2, the plasma nicotine concentrations after TNP-30x1 treatment were approximately half those just before each smoking.

Difference in percutaneous absorption and intracutaneous distribution in guinea pigs among topical antifungal drugs (tioconazole solution, tioconazole cream, miconazole nitrate solution and bifonazole solution).

Tioconazole (TCZ) is an imidazole antifungal agent with broad spectrum activity. Percutaneous absorption and intracutaneous distribution of TCZ solution have been compared with TCZ cream, miconazole nitrate (MCZ) solution and bifonazole (BFZ) solution following a single topical application to abdominal skin of guinea pigs. Following application of TCZ solution, TCZ concentrations in the stratum corneum, epidermis-cutis and subcutaneous tissue were higher than those after TCZ cream application suggesting superior percutaneous penetration after TCZ solution application. The percutaneous penetration after applications of MCZ solution and BFZ solution was comparable to that of TCZ cream, but inferior to that of TCZ solution. TCZ concentrations in the stratum corneum were much higher than those in epidermis-cutis and subcutaneous tissue after applications of both TCZ formulations. The majority of applied TCZ remained in the stratum corneum at high levels for a long duration. TCZ concentrations in the stratum corneum within 24 h after applications of both TCZ formulations were more than several hundred times higher than the minimum inhibitory concentrations against most of the dermatophytes and yeasts. The effectiveness of both TCZ formulations against dermatophytoses may be due to this favorable pharmacokinetic property in the skin tissues, together with its potent antifungal activity. Percutaneous absorption of TCZ after applications of both formulations was negligible suggesting that these treatments are unlikely to produce systemic side effects.

Intracutaneous distributions of fluconazole, itraconazole, and griseofulvin in Guinea pigs and binding to human stratum corneum.

We have compared the distribution of fluconazole (FLC) with that of itraconazole (ITC) and griseofulvin (GRF) in the abdominal skin tissues after a single oral dose was administered to guinea pigs. The FLC concentrations in the stratum corneum reached a peak at 2 h after administration and were similar to those of ITC and higher than those of GRF in spite of the administration of a lower dose. GRF was eliminated from the stratum corneum faster than FLC and ITC. The FLC concentrations were also remarkably higher than those of ITC and GRF in the epidermis-cutis but lower in the subcutaneous fatty tissue. The distribution characteristics of each drug result from differences in their physicochemical properties. Following the administration of multiple doses, the FLC concentrations in the stratum corneum were highest in the abdominal skin tissues; those at 24 h after each administration increased gradually and were maintained at a level more than 10 times higher than that of the plasma concentrations. The FLC concentrations in the planta pedis stratum corneum and in the nail showed good dose proportionality and obvious accumulation and were 60 and 40 times as high as that in plasma on day 14. The extent of binding of FLC to human corneous keratin in vitro was about 10%, which is lower than those of ITC (94 to 97%) and GRF (36 to 38%). FLC, unlike ITC, therefore, is presumed to exist in the stratum corneum at high concentrations in an active nonbinding form. These excellent intracutaneous pharmacokinetic properties of FLC probably account in large part for the in vivo efficacy of FLC.