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Background: Sildenafil citrate is indicated for the treatment of erectile dysfunction. An orally disintegrating tablet (ODT) of sildenafil citrate has been developed for the benefit of patients who have difficulty swallowing solid dosage forms., Objective: The main goal of this study was to evaluate the bioequivalence of sildenafil ODT with and without water versus marketed sildenafil oral film-coated tablets. A secondary objective was to evaluate the effects of a high-fat meal on the pharmacokinetics of sildenafil ODT., Methods: The bioequivalence study of sildenafil ODT given with and without water versus marketed sildenafil citrate film-coated oral tablets was conducted in 36 subjects. In a food-effect study, the effect of a standard high-fat meal on the pharmacokinetics of sildenafil ODT was evaluated in 12 subjects. Both studies were randomized, open-label, crossover, single-dose (50 mg) studies in healthy men aged ≥45 years. Plasma samples were collected for 14 hours postdose, and pharmacokinetics were determined by using noncompartmental analyses., Results: All subjects in both studies were Asian males between the ages of 45 and 69 years. Sildenafil ODT without water was bioequivalent to the marketed sildenafil film-coated oral tablet as the 90% CI for the ratio of geometric means of Cmax, AUC0-∞, and AUC0-last were contained within equivalence limits (80%-125%). When sildenafil ODTs were given with water, the 90% CIs for sildenafil AUC0-∞ and AUC0-last were contained within the range of 80% to 125%; however, the 90% CI for sildenafil Cmax was not (79.76-92.78). This difference in Cmax is unlikely to have any clinically meaningful impact. High-fat meals reduced the rate but not the extent of absorption of sildenafil. Mean Cmax was reduced by 59%, and median Tmax was delayed from 0.625 hour (fasting) to 4 hours (high-fat meal). However, AUC values were comparable between fed and fasted treatments., Conclusions: Sildenafil ODT, given with or without water, provides equivalent systemic exposure compared with marketed sildenafil film-coated oral tablets, thus offering a convenient alternative method of administration. Considering the results of the food-effect study, sildenafil ODT should be taken on an empty stomach. ClinicalTrials.gov identifiers: NCT01254383 (bioequivalence) and NCT01254396 (food effect)., (Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.)

Background: The solubility of valsartan is dependent on pH and thus may cause patient variability in drug absorption and failure in bioequivalence studies; thus, increasing the solubility and release of valsartan at low pH has been suggested for a more favorable pharmacokinetic profile. However, due to this pH dependence, the change in the formulation process could alter the disintegration and/or dissolution profile of the drug, possibly making the results of bioequivalence studies misleading., Objective: The aim of this study was to assess the bioavailability and tolerability of a newly developed oral formulation of valsartan 160 mg (wet-granulation tablet) in healthy Korean male volunteers., Method: This study was performed with the subjects under fasted conditions, using a randomized, single-dose, 2-period crossover design. Subjects were assigned to receive, in randomized order, a single dose of the test formulation and a reference formulation (valsartan 160-mg dry-granulation tablet), with a washout period of 7 days between the administrations. Blood samples were collected up to 24 hours after dosing, and pharmacokinetic parameters were determined after the plasma valsartan concentration was analyzed using UPLC-MS/MS. The dissolution studies of both formulations were conducted using USP apparatus 2 at 50 rpm with 1000 mL of phosphate buffer solution (pH, 6.8) at 37°C ± 0.5°C. Bioequivalence was defined per Korean Food and Drug Administration's regulatory criteria as 90% CIs of the geometric mean test/reference ratios of AUC0-t and Cmax within the range of 0.8 to 1.25. Tolerability was assessed using physical examination and subject interviews., Results: Sixty subjects were enrolled (mean [SD] age [range], 23.6 [2.4] years [21-31]; height, 173.7 [6.6] cm [161-190]; and weight, 68.0 [8.7] kg [54-85]). The mean AUC0-∞ values with the test and reference tablets were 31,784 (13,844) and 32,714 (14,512) ng · h/mL, respectively; Cmax, 5094 (2061) and 5064 (1864) ng/mL; Tmax, 2.92 (1.04) and 3.08 (1.01) hours. The 90% CIs for the geometric mean test/reference ratios of AUC0-t and Cmax were 0.9295 to 1.0546 and 0.9190 to 1.0848, respectively, which met the criteria for bioequivalence. The most frequently reported adverse event was dizziness after blank blood sampling, recorded in 4 subjects, 2 cases each with the test and reference formulations., Conclusions: In this study in healthy Korean male volunteers, the test and reference formulations of 160-mg valsartan met the Korean Food and Drug Administration's regulatory criteria for bioequivalence despite the difference in formulation (wet granulation vs dry granulation). Both formulations were well tolerated, with no serious adverse events reported., (Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.)

Clinical data from five subjects with pill-induced esophageal strictures and from the English-language literature on pill-induced esophageal damage were reviewed to determine risk factors for stricture development and to characterize this complication. Including our five cases, 195 patients with pill-induced damage and 39 patients with pill-induced strictures have been reported to date. Seventy-eight percent of the strictures were located in the proximal or mid-esophagus. Potassium chloride or quinidine preparations were incriminated in 60% of cases and were more likely to produce stricture than other medications commonly associated with esophageal damage (e.g., tetracycline). Older age, male gender, left atrial enlargement, ingestion of sustained-release formulations, and prior esophageal structural abnormality were all more commonly present in the subset with strictures (p less than 0.05 for each), even after appropriately controlling for medication. A logistic regression analysis revealed that older age and ingestion of sustained-release formulations were the most significant independent factors associated with stricture development (p less than 0.0001 for each). These findings indicate that stricture formation from pill-induced esophageal damage is dependent upon host-related factors as well as the caustic nature of the pill.