Randomized, double-blind, noninferiority study of diclofenac diethylamine 2.32% gel applied twice daily versus diclofenac diethylamine 1.16% gel applied four times daily in patients with acute ankle sprain.

BACKGROUND: Diclofenac diethylamine (DDEA) gel has demonstrated efficacy for treatment of ankle sprains in both the 1.16% four-times-daily (QID) and 2.32% twice-daily (BID) formulations. The objective of this study was to compare, for the first time, the efficacy of DDEA 2.32% gel BID and DDEA 1.16% gel QID. METHODS: This was a phase 3, randomized, double-blind, multicenter, active-controlled, parallel-group study conducted in China from October 2019 to November 2020, designed to determine the noninferiority of DDEA 2.32% gel BID relative to DDEA 1.16% gel QID for treatment of grade I-II ankle sprain. At study entry, patients must have had pain on movement (POM) ≥50 mm on a 100-mm visual analogue scale (VAS), and not received any pain medication. The primary efficacy endpoint was the noninferiority of DDEA 2.32% gel BID vs DDEA 1.16% gel QID for POM as assessed by the patient using the 100-mm VAS, conducted on day 5. Secondary endpoints included measures of ankle tenderness, joint function, swelling, and patient-reported pain intensity and pain relief. RESULTS: A total of 302 patients were randomized and 95.4% completed the study. The mean (SD) change in POM from baseline to day 5 using the 100-mm VAS was - 42.8 mm (19.7 mm) with DDEA 2.32% gel BID and - 43.1 mm (18.1 mm) with DDEA 1.16% gel QID for the per-protocol population. The least squares mean difference (DDEA gel 2.32% - DDEA gel 1.16%) at this timepoint was 1.11 mm (95% CI - 3.00, 5.22; P = 0.595), and the upper limit (5.22 mm) of the 95% CI was less than the noninferiority margin of 13 mm, demonstrating that DDEA 2.32% gel BID was noninferior to DDEA 1.16% gel QID. Similar trends were seen for the secondary efficacy endpoints. There was no significant difference in the incidence of treatment-emergent adverse events or adverse events adjudicated as being treatment related. All treatment-related adverse events were dermatological; one patient discontinued from the DDEA 2.32% gel BID arm due to application-site inflammation. CONCLUSIONS: DDEA 2.32% gel BID offers a convenient alternative to DDEA 1.16% gel QID, with similar pain reduction and relief, anti-inflammatory effects, and tolerability. TRIAL REGISTRATION: NCT04052620.

Assessing the bioequivalence of over-the-counter esomeprazole banded capsules and multiple-unit pellet system tablets
.

OBJECTIVE: To demonstrate bioequivalence between two esomeprazole formulations under fasted and fed conditions. MATERIALS: Esomeprazole 20 mg multiunit pellet system (test; MUPS) tablets and over-the-counter esomeprazole 20 mg banded capsules (reference). MATERIALS AND METHODS: This open-label, randomized, 6-period crossover study assigned healthy males and females to receive single doses of each study drug under fasted or fed conditions. The primary pharmacokinetic endpoints were esomeprazole area under the concentration-time curve from time zero to infinity (AUCinf) and maximum observed concentration (Cmax). For endpoints with high within-subject standard deviations of the reference product (Swr ≥ 0.294), a reference scaled average bioequivalence (RSAB) approach was used. For endpoints not highly variable (Swr < 0.294), an unscaled approach was used. In the RSAB, bioequivalence was defined as the 95% criteria bound (CB) ≤ 0 and geometric mean ratios (GMRs) within 0.80, 1.25. For the unscaled approach, bioequivalence was defined as 90% confidence intervals (CIs) of the GMR being within 80%, 125%. RESULTS: 60 subjects were randomized, and 46 subjects (76.7%) completed all study periods. For esomeprazole AUCinf, the variability of the reference product was low (Swr = 0.202), so the unscaled approach was used. The GMR (90% CI) was 0.948 (0.890 - 1.010), indicating bioequivalence. For the comparison of esomeprazole Cmax, the variability of the reference product was high (Swr = 0.304), so the RSAB approach was used. The GMR (95% CB) was 1.009 (-0.050), indicating bioequivalence. CONCLUSION: Esomeprazole 20 mg MUPS tablets and banded capsules were found to be bioequivalent based on the AUCinf and Cmax in the fasted state.
.

Diclofenac systemic bioavailability of a topical 1% diclofenac + 3% menthol combination gel vs. an oral diclofenac tablet in healthy volunteers: a randomized, open-label, crossover study
.

OBJECTIVE: Evaluate systemic exposure with repeated topical application of a fixed-combination topical gel product containing 1% diclofenac sodium and 3% menthol in either of 2 formulation packages relative to oral administration. METHODS: In this phase 1, single-center, 4-way crossover study, healthy volunteers aged 18 - 50 years underwent consecutive 3-day treatment regimens in a randomly assigned sequence with each of 4 treatment groups: 4 g of topical 1% diclofenac + 3% menthol gel administered via an aluminum tube or roll-on device applied 4 times daily; 4 g of topical 1% diclofenac sodium gel (Voltaren Gel) applied 4 times daily; and oral diclofenac sodium tablets 50 mg 3 times daily. Treatment regimens were separated by 2-day washout periods. RESULTS: A total of 18 subjects enrolled and completed the study. Relative to oral administration, area under the concentration time curve from 48 to 72 hours (AUC48-72) with topical administration of 1% diclofenac + 3% menthol gel from a tube or roll-on device was 16.1% (90% CI: 12.2 - 21.1%) and 14.4% (90% CI: 11.0 - 19.0%), respectively. The diclofenac/menthol combination delivered significantly higher exposures of diclofenac compared with Voltaren Gel. A higher number of adverse events (AEs) occurred with the topical diclofenac/menthol combination (61%) vs. Voltaren Gel (22%) or oral diclofenac (6%); most were local skin reactions. No difference in systemic AEs was observed among the groups. CONCLUSION: As expected, systemic exposure was significantly lower with the topical diclofenac/menthol treatment regimens compared with oral diclofenac. Local skin AEs were increased with the topical combination product, but the risk of systemic AEs was low.
.

Understanding the effect of the HCV polymerase inhibitor mericitabine on early viral kinetics in the phase 2 JUMP-C and PROPEL studies.

AIMS: The aim was to evaluate early viral kinetics in patients receiving mericitabine [hepatitis C virus (HCV) nucleoside polymerase inhibitor] with peginterferon alfa-2a (40KD) and ribavirin in two clinical trials (PROPEL and JUMP-C). METHODS: We examined rapid virological responses (RVRs; week 4 HCV RNA <15 IU ml(-1) ) and complete early virological responses (cEVR; week 12 HCV RNA <15 IU ml(-1) ) in HCV genotype 1/4-infected patients receiving mericitabine (500 or 1000 mg) or placebo twice daily plus peginterferon alfa-2a and ribavirin. RESULTS: Among IL28B rs12979860 CC genotype patients receiving 500 or 1000 mg mericitabine or placebo, respectively, RVR rates were 64.3% (95% confidence interval: 38.8-83.7%), 95.1% (83.9-98.7%) and 33.3% (20.2-49.7%), and cEVR rates were 100% (78.5-100%), 100% (91.4-100%) and 80.6% (65.0-90.3%). Among non-CC genotype patients, RVR rates were 26.5% (14.6-43.1%), 52.3% (43.0-61.3%) and 5.7% (2.2-13.8%), and cEVR rates were 76.5% (60.0-87.6%), 84.6% (76.6-90.1%) and 28.6% (19.3-40.1%), respectively. In multiple regression analysis, IL28B genotype (P < 0.0001), mericitabine dose (P < 0.0001) and bodyweight (P = 0.0009) were associated with first-phase (α) slope (change in log10 HCV RNA from baseline to week 1). CONCLUSIONS: Mericitabine-containing triple therapy reduces the impact of IL28B genotype on RVR and cEVR compared with peginterferon alfa-2a and ribavirin dual therapy. The IL28B genotype, mericitabine dose and bodyweight are the most important factors associated with the α slope, and there is no evidence of a pharmacokinetic drug-drug interaction between mericitabine and ribavirin.

The effect of mild to moderate renal impairment on the pharmacokinetics of the nucleoside analog hepatitis C virus polymerase inhibitor mericitabine.

Mericitabine is the prodrug of RO4995855, a selective inhibitor of the hepatitis C virus (HCV) NS5B polymerase. This study assessed the effect of renal impairment on RO4995855 pharmacokinetics. In this open-label study, HCV-negative volunteers (18-75 years) with normal renal function (NRF: creatinine clearance [CLCR ] >80 mL/min, n = 10) or stable renal impairment (mild: CLCR 50-80 mL/min, n = 10; moderate: CLCR 30-49 mL/min, n = 10) received oral mericitabine 1000 mg twice daily (BID) (500 mg BID for moderate renal impairment) for 5 days. Primary outcome measures were renal clearance, maximum plasma concentration (Cmax), and area under the concentration-time curve (0-12 h) (AUC0-12) for RO4995855. Renal clearance decreased as renal function decreased. Relative to subjects with NRF, the geometric mean ratios (GMR) for AUC0-12 and Cmax in mild renal impairment subjects were 1.45 (90% confidence interval [CI], 1.26-1.66) and 1.14 (1.02-1.28), respectively. For moderate renal impairment subjects, the dose-normalized GMR for AUC0-12 and Cmax relative to NRF subjects were 2.51 (90% CI, 2.19-2.88) and 1.76 (1.56-1.97), respectively. Renal clearance of RO4995855 declined in subjects with mild/moderate renal impairment following mericitabine. Dose adjustment of mericitabine may be required in patients with moderate renal impairment.

Objective and self-reported evidence of dextromethorphan antitussive efficacy in children, aged 6-11 years, with acute cough due to the common cold.

OBJECTIVE: To determine objective and subjective endpoints most suitable for evaluating antitussive efficacy of dextromethorphan hydrobromide (DXM) in children. Spontaneous resolution of acute cough and large placebo effects are impediments to evaluating antitussive efficacy. Another impediment is paucity of age-appropriate, validated cough assessment tools. METHODS: This was a multiple-dose, double-blind, placebo-controlled, randomized, pilot clinical study in children, aged 6-11 years, with cough due to the common cold. Eligible subjects met entry criteria and qualified by completing a run-in period where coughs were recorded with a cough monitor after they were dosed with sweet syrup. They were subsequently randomized to receive DXM or placebo over 4 days. Coughs were recorded during the initial 24 h; subjective assessments of cough severity and frequency were self-reported daily during treatment. RESULTS: Data from 128 evaluable subjects (67 DXM; 61 placebo) were analyzed. Total coughs over 24-hours (primary endpoint) and cough frequency during daytime were reduced by 21.0% and 25.5%, respectively, with DXM relative to placebo. Also, greater reductions in cough severity and frequency were self-reported with DXM. These findings were statistically significant and medically relevant. No effects were detected between treatments for nighttime cough rates or impact of cough on sleep. Multiple doses of DXM and placebo were generally well-tolerated. CONCLUSION: Evidence of DXM antitussive efficacy was shown in children using objective and subjective assessment tools validated in pediatric populations. Diurnal variation of cough frequency over 24 h reduced the assay sensitivity needed to detect treatment differences at nighttime, as coughs/hour decreased during sleep for both groups.

Evaluation of the combined glucose-insulin and intravenous glucose tolerance tests for insulin dysregulation diagnosis in donkeys.

BACKGROUND: Insulin dysregulation (ID) and donkey metabolic syndrome (DMS) are common in this species. Contrary to horses, diagnostic guidelines compiling insulin cut-offs values and dynamic testing interpretations have not been reported for this species. OBJECTIVES: To evaluate resting serum insulin concentrations, the combined glucose-insulin test (CGIT) and the glucose intravenous tolerance test (IVGTT) for the diagnosis of DMS with ID suspicion. STUDY DESIGN: Diagnostic test comparison. METHODS: Six of 80 mix-breed adult donkeys fulfilled the inclusion criteria for DMS based on history or clinical evidence of recurrent laminitis, body condition >6 and neck score >2 or baseline insulin and leptin concentrations >20 µIU/mL and >12 ng/mL respectively. CGIT and IVGTT were performed in all donkeys within a week and interpreted following guidelines reported for equine metabolic syndrome (EMS). Insulin and glucose curves were analysed, proxies calculated and correlations and multivariate analysis assessed. RESULTS: Following EMS guidelines, CGIT classified 2 (using glucose-positive phase duration) or 3 (using insulin concentration) and IVGTT classified 5 donkeys as ID. ID donkeys showed a lower glucose/insulin ratio, QUICKI and RISQI, and a higher insulin/glucose ratio, MIRG and HOMA-B%. MAIN LIMITATIONS: Comparison of these tests with additional dynamic testing including a larger number of ID donkeys is necessary. CONCLUSIONS: This is the first study evaluating dynamic tests to assess ID/DMS in DMS-suspected donkeys. IVGTT detected more ID donkeys than CGIT. EMS recommendations could also be used for DMS diagnosis, although a baseline insulin cut-off value is needed.

Penetration of topical diclofenac into synovial tissue and fluid of osteoarthritic knees: a multicenter, randomized, placebo-controlled, pharmacokinetic study.

BACKGROUND: Topical diclofenac, a nonsteroidal anti-inflammatory drug, has proven efficacy and safety in the management of osteoarthritis pain. We investigated penetration of topical diclofenac into knee synovial tissue and fluid (primary objective) and evaluated relative exposure in the knee versus plasma (secondary objective). METHODS: In this phase I, double-blind, multicenter study, patients scheduled for arthroplasty for end-stage knee osteoarthritis were randomly assigned 2:1 to 4 g diclofenac diethylamine 2.32% w/w gel (92.8 mg diclofenac diethylamine, equivalent to 74.4 mg diclofenac, per application) or placebo gel, applied to the affected knee by a trained nurse/designee every 12 h for 7 days before surgery. Diclofenac concentrations were measured in synovial tissue, synovial fluid and plasma from samples obtained during surgery ⩾12 h after last application. Treatment-emergent adverse events (TEAEs) were evaluated. RESULTS: Evaluable synovial tissue or fluid samples were obtained from 45 (diclofenac n = 29; placebo n = 16) of 47 patients. All diclofenac-treated participants had measurable diclofenac concentrations in synovial tissue [geometric mean 1.57 (95% confidence interval (CI) 1.12, 2.20) ng/g] and fluid [geometric mean 2.27 (95% CI 1.87, 2.76) ng/ml] ⩾12 h after the last dose. Geometric mean (95% CI) ratio of diclofenac in synovial tissue:plasma was 0.32 (0.23, 0.45) and in synovial fluid:plasma was 0.46 (0.40, 0.54). TEAE rates were similar for diclofenac (55.2%) and placebo (58.8%); none were treatment related. CONCLUSIONS: Topical diclofenac diethylamine 2.32% w/w gel penetrated into the osteoarthritic knee after repeated application and remained detectable in synovial tissue and fluid at the end of the final 12 h dosing cycle.

Efficacy and safety of twice daily sustained-release paracetamol formulation for osteoarthritis pain of the knee or hip: a randomized, double-blind, placebo-controlled, twelve-week study.

OBJECTIVE: Evaluate efficacy and safety of an investigational, twice daily sustained-release (SR) paracetamol formulation in subjects with knee or hip osteoarthritis (OA). METHODS: In this multicenter, double-blind, parallel study (NCT02311881), subjects with hip or knee OA were randomly assigned to SR paracetamol 2 × 1000 mg BID, extended-release (ER) paracetamol 2 × 665 mg TID or placebo for 12 weeks. Primary endpoint was mean change from baseline through 12 weeks in WOMAC Osteoarthritis Index pain. Secondary efficacy endpoints included other WOMAC categories, Global Patient Assessment of Osteoarthritis (GPAOA), Patient Global Assessment of Response to Therapy (PGART) and responder rate. RESULTS: A total of 676 subjects were included in the analysis population (mITT). Mean change from baseline in WOMAC pain subscale was not significantly greater with SR paracetamol BID versus placebo (LS mean [SE]: -28.25 [1.697] vs. -25.74 [1.713]; p = .163). Reduction in WOMAC physical function and stiffness subscales with SR paracetamol BID was not significantly greater than with placebo (p = .089 and .054, respectively). Significant improvement over placebo was observed for GPAOA (p = .043), PGART (p = .012), and proportion of high-improvement responders (p = .015). Safety and tolerability were consistent with the known profile of paracetamol. CONCLUSIONS: Improvement in WOMAC pain, physical function and stiffness subscales from treatment with SR paracetamol BID versus placebo in subjects with knee or hip OA was not significant. SR paracetamol BID demonstrated significant improvements in GPAOA, PGART, and high-responder rate. High placebo response may have contributed to lack of statistical separation on some outcomes. All interventions were generally well tolerated.

Pharmacokinetics and Safety of Valganciclovir in Pediatric Heart Transplant Recipients 4 Months of Age and Younger.

BACKGROUND: Valganciclovir (VGCV) effectively prevents cytomegalovirus disease in adult and pediatric solid organ transplant recipients. A dosing algorithm for VGCV for pediatric patients, based on body surface area and renal function, provides a personalized dose using age-appropriate formulations. The suitability of this dosing algorithm has not been assessed specifically in infants and neonates 4 months of age and younger receiving a solid organ transplant. METHODS: This multicenter prospective study evaluated the pharmacokinetics (PK) and safety of VGCV oral solution in 17 heart transplant recipients 4 months of age and younger who received 2 doses of VGCV on consecutive days using the pediatric dosing algorithm. Plasma concentrations of ganciclovir (GCV) were analyzed at specified times up to 24 hours post VGCV administration. RESULTS: GCV concentration data were available from 16 patients. The combined data from this study and historic study datasets were used to establish a 2-compartment population PK model with first-order formation to describe the PK of GCV after oral VGCV administration in patients across all pediatric age ranges, including those younger than 4 months of age. Estimated mean area under the curve during the 0-24 hours dosing interval for these patients was 68.1 µg·h/mL. CONCLUSIONS: The pediatric dosing algorithm for VGCV (utilizing individuals' body surface area and renal function) provides systemic GCV exposures in patients younger than 4 months that are similar to those observed in older pediatric populations. The data indicate that this dosing algorithm is appropriate across the entire pediatric age range, including this youngest age group.

Characterization of the transmembrane transport and absolute bioavailability of the HCV protease inhibitor danoprevir.

BACKGROUND AND OBJECTIVES: Understanding transmembrane transport provides a more complete understanding of the pharmacokinetics of a drug and mechanistic explanations for drug-drug interactions. Here, the transmembrane transport of danoprevir (hepatitis C virus protease inhibitor) and the effects of ritonavir and ciclosporin on transmembrane transport of danoprevir were evaluated and clinical pharmacokinetic studies of danoprevir co-administered with/without ritonavir and ciclosporin were conducted. METHODS: Transcellular transport of danoprevir was evaluated in Lewis lung cancer porcine kidney, Madin-Darby canine kidney, or Chinese hamster ovary cells transfected with human transport proteins, and in human hepatocytes. The pharmacokinetics of intravenous and oral danoprevir administered with/without ritonavir, and the impact of ciclosporin on danoprevir pharmacokinetics were evaluated in randomized, open-label, crossover studies in healthy subjects. RESULTS: Danoprevir transport in vitro involved organic anion transporting polypeptide (OATP) 1B1, OATP1B3, P-glycoprotein, and multidrug resistance protein-2, but not breast cancer resistance protein. Ritonavir and ciclosporin inhibited transport of danoprevir by human hepatocytes. The pharmacokinetics of intravenous danoprevir 6 mg were not altered by oral ritonavir 100 mg. In contrast, exposure to oral danoprevir 100 mg increased two- to threefold when co-administered with ritonavir. Absolute bioavailability of danoprevir 100 mg was low (1.15%), but increased more than threefold (3.86%) when co-administered with ritonavir. Oral ciclosporin 100 mg increased exposure to intravenous danoprevir 2 mg and oral ritonavir 100 mg. CONCLUSION: Collectively, these studies provide insight into the transmembrane transport and pharmacokinetics of danoprevir and the mechanisms that underlie a recently reported, three-way drug-drug interaction involving danoprevir, ritonavir, and ciclosporin.

Single-dose pharmacokinetics of the HCV polymerase inhibitor mericitabine in healthy Caucasian and Japanese subjects.

To investigate the pharmacokinetics of mericitabine in healthy Caucasian and Japanese subjects, healthy Caucasian (n = 32) and Japanese (n = 32) subjects were randomized to receive single 500, 1,000, or 2,000 mg doses of mericitabine or a placebo, after which plasma and urine samples were collected for 72 h. Mericitabine (prodrug), RO4995855 (parent), and RO5012433 (uridine metabolite) concentrations were quantified by tandem mass spectrometry. Pharmacokinetics were estimated by non-compartmental methods, and pharmacokinetic parameters of RO4995855 were normalized by body weight. Exposure to RO4995855 was similar in both populations after administration of mericitabine 500, 1,000, and 2,000 mg. Mean AUCinf of RO4995855 increased in a dose-proportional manner from 28.8 to 52.3, and 113.0 µg·h/mL in Caucasian subjects, and from 32.5 to 57.1 and 119 µg·h/mL in Japanese subjects. A linear relationship was observed between the weight-adjusted dose of mericitabine and Cmax (r(2) = 0.83 and 0.80) and AUC (r(2) = 0.94 and 0.74) for RO4995855 in Caucasian and Japanese subjects, respectively. Mean half-life and renal clearance of RO4995855 were similar and independent of dose in both populations. The results support the use of the same dosing regimens in Caucasian and Asian subjects.

Effect of ritonavir-boosted danoprevir, a potent hepatitis C virus protease inhibitor, on the pharmacokinetics of methadone in healthy subjects undergoing methadone maintenance therapy.

STUDY OBJECTIVE: To investigate the steady-state pharmacokinetics of methadone when coadministered with ritonavir-boosted danoprevir (DNVr). DESIGN: Open-label, two-period, single-sequence pharmacokinetic study. SETTING: Two U.S. research centers. PATIENTS: Eighteen methadone-maintained healthy adults. MEASUREMENTS AND MAIN RESULTS: In Period 1 (Day -1), subjects received their daily methadone maintenance therapy (MMT). In Period 2 (Days 1-10), subjects received MMT plus DNVr 100/100 mg twice/day. Pharmacokinetic parameters for the total concentrations of (R)- and (S)-methadone on Days -1 and 10 were determined using noncompartmental methods. Unbound (R)- and (S)-methadone concentrations at 3 hours postdose were also assessed on Days -1 and 10. Geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were used to compare steady-state (R)- and (S)-methadone pharmacokinetics when MMT was administered with or without DNVr. Methadone withdrawal was assessed using the Subjective Opiate Withdrawal Scale. Compared with MMT alone, methadone AUCtau and Cmax GMR (90% CI) following coadministration with DNVr were 1.02 (0.91-1.15) and 1.01 (0.90-1.13) for (R)-methadone, and 1.01 (0.90-1.13) and 0.99 (0.89-1.10) for (S)-methadone, respectively. Unbound (R- and (S)-methadone concentrations were comparable with or without DNVr. No instances of methadone withdrawal were reported. MMT in combination with DNVr was well tolerated. CONCLUSION: Coadministration of DNVr with MMT resulted in no significant pharmacokinetic interactions or signs of methadone withdrawal. No dosage adjustment is needed for MMT when coadministered with DNVr.

Effect of meal and antisecretory agents on the pharmacokinetics of danoprevir/ritonavir in healthy volunteers.

OBJECTIVES: To evaluate the effect of a low- and high-fat meal and co-administration of ranitidine or omeprazole on the pharmacokinetics of ritonavir-boosted danoprevir (DNVr). METHODS: In this randomised, open-label, cross-over study, healthy subjects received a single dose of DNVr. In group 1, DNVr was administered while fasting or with a low-fat or high-fat meal. In group 2, DNVr was administered alone or with ranitidine 150 mg (single dose) or omeprazole 40 mg (multiple doses). KEY FINDINGS: Group 1 (n = 16): relative to fasting conditions, food slightly prolonged absorption but did not alter the extent of absorption. DNV area under the plasma concentration-time curve extrapolated to infinity (AUC0-∞), maximum plasma concentration (C(max)), and plasma concentration 12 h after administration (C12h) geometric mean ratios (GMR%) (90% confidence interval (CI)) with a low-fat meal were 92.3 (80.2-106), 61.8 (51.0-74.9) and 95.2 (80.9-112), versus fasting conditions, and with a high-fat meal 99.5 (86.4-115), 58.9 (48.5-71.6) and 101 (86.0-119). Group 2 (n = 13): ranitidine or omeprazole had no clinically significant effect on DNV pharmacokinetics. DNV AUC0-∞, Cmax and C12h GMR% (90% CI) with ranitidine: 81.9 (68.3-98.1), 104 (86.9-123) and 87.5 (69.3-111), and with omeprazole: 83.0 (67.4-102), 92.7 (70.6-122) and 93.3 (65.6-133). CONCLUSIONS: The absence of clinically relevant effects of food, ranitidine or omeprazole on DNVr pharmacokinetics suggests that DNVr can be administered without regard to meals and in combination with H2 antagonists or proton pump inhibitors.

Pharmacokinetics of a three-way drug interaction between danoprevir, ritonavir and the organic anion transporting polypeptide (OATP) inhibitor ciclosporin.

BACKGROUND: Danoprevir (RG7227) is a potent macrocyclic inhibitor of the hepatitis C virus NS3/4A protease, which is currently in development in combination with low-dose ritonavir for the treatment of chronic hepatitis C infection. Danoprevir is a substrate of cytochrome P450 3A4, and the organic anion transporting polypeptides (OATP) 1B1 and 1B3. OBJECTIVE: The objective of this study was to evaluate the effect of a potent OATP inhibitor, ciclosporin, on danoprevir pharmacokinetics, when administered as danoprevir/ritonavir. The effect of danoprevir/ritonavir on ciclosporin pharmacokinetics was also investigated. METHODS: This was a single-dose, randomized, open-label, two-sequence, three-period, crossover study in healthy volunteers. In the first period, subjects were randomized to receive either a single oral dose of danoprevir 100 mg in combination with ritonavir 100 mg or a single oral dose of ciclosporin 100 mg. After a 14-day washout, patients were crossed over to receive the opposite treatment. In period 3, all subjects received the combination of danoprevir/ritonavir and ciclosporin following a 14-day washout from period 2. Blood samples were collected serially with each dose for pharmacokinetic assessment. Pharmacokinetic parameters were estimated using non-compartmental analysis. Geometric mean ratios (GMRs) and 90 % confidence intervals (CIs) were used to compare pharmacokinetic parameters [maximum concentration (C max), area under the concentration-time curve from time zero to infinity (AUC∞), and concentration 12 h post-dose (C 12h)] of danoprevir/ritonavir and ciclosporin when administered alone or in combination. Measures of safety and tolerability were also evaluated. RESULTS: A total of 18 subjects were enrolled, and 17 completed the study. The C max, AUC∞, and C 12h GMRs (90 % CI) when danoprevir/ritonavir and ciclosporin were co-administered versus danoprevir/ritonavir or ciclosporin alone were 7.22 (5.42-9.62), 13.6 (11.2-16.6), and 22.5 (17.4-29.3), respectively, for danoprevir, 1.97 (1.72-2.27), 2.23 (2.07-2.42), and 2.50 (2.22-2.81), respectively, for ritonavir, and 1.42 (1.29-1.57), 3.65 (3.27-4.08), and 6.15 (5.32-7.11), respectively, for ciclosporin. All treatments were well tolerated, with no laboratory abnormalities, and no clinically significant changes in vital signs, electrocardiograms, or physical examinations observed. CONCLUSIONS: A significant drug-drug interaction was observed between ciclosporin and danoprevir/ritonavir, leading to substantial increases in exposure to danoprevir and a lesser impact on exposure to ritonavir. Therefore, co-administration of danoprevir/ritonavir with potent OATP inhibitors should be undertaken with appropriate precautions.

Improved human bioavailability of vemurafenib, a practically insoluble drug, using an amorphous polymer-stabilized solid dispersion prepared by a solvent-controlled coprecipitation process.

The present work deals with improving the solubility of vemurafenib, a practically insoluble drug, by converting it into an amorphous-solid dispersion using a solvent-controlled precipitation process. The dispersion containing vemurafenib and hypromellose acetate succinate (HPMCAS), an enteric polymer, is termed microprecipitated bulk powder (MBP), in which the drug is uniformly dispersed within the polymeric substrate. HPMCAS was found to be the most suitable polymer for vemurafenib MBP, among a series of enteric polymers based on superior physical stability and drug-release characteristics of the MBP. The MBP provided a greater rate and extent of dissolution than crystalline drug, reaching an apparent drug concentration of 28-35 µg/mL, almost 30-fold higher than solubility of crystalline drug at 1 µg/mL. The supersaturation was also maintained for more than 4 h. Upon exposure to high temperature and humidity, the MBP was destabilized, resulting in crystallization and lower dissolution rate. The control of moisture and temperature is essential to maintain the stability of the MBP. In a relative human bioavailability study, vemurafenib MBP provided a four- to fivefold increase in exposure compared with crystalline drug. Improving solubility with an amorphous-solid dispersion is a viable strategy for the development of practically insoluble compounds.