Qualification of In Vitro Dissolution Absorption System 2 (IDAS2) with Caco-2 and MDCK Cell Monolayers: Dose Sensitivity Study Using BCS Class I and III Drugs.

This study aimed to validate the In vitro Dissolution Absorption System 2 (IDAS2) containing a biological barrier of Caco-2 or Madin-Darby canine kidney (MDCK) cell monolayer through dose sensitivity studies. Metoprolol and propranolol were selected as Biopharmaceutics Classification System (BCS) Class I model drugs, and atenolol as a Class III model drug. The IDAS2 is comprised of a dissolution vessel (500 mL) and two permeation chambers (2 × 8.0 mL) mounted with Caco-2 or MDCK cell monolayer. One or two immediate-release tablet(s) of the model drug were added to the dissolution vessel, and the time profiles of dissolution and permeation were observed. Greater than 85% of metoprolol and propranolol (tested at two dosing concentrations) were dissolved by 15 min, and all drugs were fully dissolved by 30 min. All three drugs were more permeable across Caco-2 cells than MDCK cells with a linear increase in permeation across both cells at both dose concentrations. Thus, the dose sensitivity of the IDAS2 was demonstrated using both cell barriers. These results indicate a successful qualification of IDAS2 for the development/optimization of oral formulations and that MDCK cells can be utilized as a surrogate for Caco-2 cells.

The impact of surface area per volume (SA/V) ratio on drug transport from supersaturated solutions of ketoconazole.

The purpose of this study aimed to evaluate the impact of the surface area per volume (SA/V) ratio on drug transport from two supersaturated solutions (SSs) of ketoconazole with and without hydroxypropyl methylcellulose (HPMC), used as a precipitation inhibitor. In vitro dissolution, membrane permeation with two SA/V ratios, and in vivo absorption profiles for both SSs were determined. For the SS without HPMC, a two-step precipitation process due to the liquid-liquid phase separation was observed; the constant concentration with approximately 80 % of the dissolved amount was maintained for the first 5 min and subsequently decreased between 5 and 30 min. For the SS with HPMC, a parachute effect was observed; the constant concentration with approximately 80 % dissolved amount was maintained for more than 30 min and decreased very slowly thereafter. Assessment of the SA/V ratio using in vitro and in vivo models demonstrated that when the SA/V ratio was small, the SS with HPMC resulted in a significantly higher permeated amount than the SS without HPMC. In contrast, when the SA/V ratio was large, the HPMC-mediated parachute effect on drug transport from SSs was attenuated, both in vitro and in vivo. The parachute effect by HPMC decreased as the SA/V ratio increased, and the performance of supersaturating formulations would be overestimated by in vitro studies with small SA/V ratios.

Clinical Association of Thyroid Stimulating Hormone Receptor Antibody Levels with Disease Severity in the Chronic Inactive Stage of Graves' Orbitopathy.

PURPOSE: To investigate associations between serum thyroid stimulating hormone (TSH) receptor antibody (TRAb) levels and Graves' orbitopathy (GO) activity/severity in chronic-stage GO and compare the performance of two newly-developed TRAb assays (third-generation TSH-binding inhibition immunoglobulin [TBII] assay versus Mc4 thyroid-stimulating immunoglobulin [TSI] bioassay). METHODS: This study is a retrospective review of medical charts and blood tests from Korean GO patients who first visited the departments of ophthalmology and endocrinology, Yonsei University College of Medicine from January 2008 to December 2011, were diagnosed with GO and Graves' hyperthyroidism, and were followed up for ≥18 months. Third-generation M22-TBII and Mc4-TSI assays were performed in the chronic-inactive GO patients in whom euthyroidism status was restored. Patients' GO activity/severity clinical activity scores (CAS), and modified NOSPECS scores were examined for a correlation with TRAb assays. RESULTS: Fifty patients (mean age, 41.3 years; 41 females) were analyzed. The mean duration of Graves' hyperthyroidism symptom was 63 months (range, 18 to 401 months) and that of GO was 46 months (range, 18 to 240 months). All patients had been treated previously with anti-thyroid drugs for a median period of 52.3 months, and two patients underwent either radioiodine therapy or total thyroidectomy. Mean CAS and NOSPECS scores were 0.5 ± 0.9 (standard deviation) and 4.8 ± 3.1, respectively. Mean M22-TBII and Mc4-TSI values were 7.5 ± 10.2 IL/L and 325.9 ± 210.1 specimen-to-reference control ratio. TSI was significantly correlated with NOSPECS score (R = 0.479, p < 0.001); however, TBII was not associated with NOSPECS score (p = 0.097). Neither TSI nor TBII correlated with CAS (p > 0.05), because GO inflammatory activity subsided in the chronic stages of GO. CONCLUSIONS: In chronic-inactive GO after euthyroid restoration, GO activity score did not associate with serum levels of TRAb or TBII. However, levels of the functional antibody Mc4-TSI did correlate with GO severity. Therefore, the TSI bioassay is a clinically relevant measure of disease severity even in chronic inactive GO.