Modeling of In Vitro Dissolution Profiles of Carvedilol Immediate-Release Tablets in Different Dissolution Media

Quantitative evaluation of drug dissolution characteristics based on mathematical models is essential to understand and predict a particular drug release profile. In this study, model-dependent evaluation of the dissolution kinetics of reference and five test products (25-mg, immediate-release (IR) tablets) of an antihypertensive drug, carvedilol, was carried out using the DDSolver^® program. The effects of pH (pH 1.2, 4.5, and 6.8) and various media with/without 0.5% (w/v) anionic, cationic, and nonionic surfactants (sodium lauryl sulfate (SLS), hexadecyltrimethylammonium bromide (CTAB), and polysorbate 80) on the dissolution kinetics of the bioequivalent IR products of carvedilol were investigated. The Weibull-1 model was fitted successfully to the dissolution data of all products at pH 1.2 and pH 4.5, as well as in the pH 6.8 medium with CTAB according to the model goodness of fit (r² = 0.981-0.999, AIC = 14.5-42.6, MSC = 1.99-5.25). Model fitting produced good fits to Gompertz-1 for all products at pH 6.8 without a surfactant (r² = 0.975-0.998, AIC = 28.3-55, MSC = 2.53-5.82). For pH 6.8 media containing SLS or polysorbate 80, Logistic-2 was fitted successfully to the dissolution data of all products (r² = 0.974-0.999, AIC = 20.9-52.1, MSC = 1.90-5.69). Overall, the model-dependent analysis of in vitro dissolution data indicated in vitro equivalence of the reference and test products of carvedilol in each medium in terms of kinetic models, suggesting that it would have an important role in developing generic drug products of the BCS class II drug carvedilol.

Development and pharmacokinetic evaluation of Neusilin® US2-based S-SNEDDS tablets for bosentan: Fasted and fed states bioavailability, IVIS® real-time biodistribution, and ex-vivo imaging

The study reported here aimed to develop and optimize the S-SNEDDS tablet of bosentan (BOS) and to investigate its pharmacokinetic and biodistribution properties. The BOS-loaded SNEDDS have been developed and characterized in a previous study. The BOS-loaded SNEDDS formulation was converted to S-SNEDDS using Neusilin® US2. The S-SNEDDS tablets were obtained using the direct compression technique, and in vitro dissolution, in vitro lipolysis, and ex-vivo permeability studies of the tablets were performed. The S-SNEDDS tablet and reference tablet (Tracleer®) were administered to male Wistar rats at 50 mg/kg dose by oral gavage in fasted and fed state conditions. The biodistribution of the S-SNEDDS tablet was investigated in Balb/c mice using fluorescent dye. The tablets were dispersed in distilled water before administration to animals. The relationship between in vitro dissolution data and in vivo plasma concentration was examined. The S-SNEDDS tablets showed 2.47, 7.49, 3.70, and 4.39 increases in the percentages of cumulative dissolution in FaSSIF, FeSSIF, FaSSIF-V2, and FeSSIF-V2, respectively, when compared to the reference, and increased the Cmax and AUC 2.65 and 1.28-fold and 4.73 and 2.37-fold in fasted and fed states, respectively, when compared to the reference. S-SNEDDS tablets also significantly reduced interindividual variability in both fasted and fed states (p < 0.05). The XenoLight™ DiR and VivoTag® 680XL labeled S-SNEDDS tablet formulation increased the real-time biodistribution in the body by factors of 2.4 and 3.4 and organ uptake and total emission increased by factors of 2.8 and 3.1, respectively. The IVIVR has been successfully established for S-SNEDDS tablets (R2 > 0.9). The present study confirms the potential of the S-SNEDDS tablet to enhance the in vitro and in vivo performance of BOS.