The Evaluation of Valsartan Biopharmaceutics Properties

Formulation and Characterization of Buccal Films Containing Valsartan with Additional Support from Image Analysis

The present study was aimed to the development and characterization of valsartan-containing buccal films with an introduction to a novel technique of image analysis. Visual inspection of the film provided a wealth of information that was difficult to quantify objectively. The obtained images of the films observed under the microscope were embedded in a convolutional neural network (CNN). The results were clustered according to their visual quality and on the basis of data distances. Image analysis proved to be a promising method to characterize buccal films appearance and their visual properties. The differential behavior of film composition was investigated using a reduced combinatorial experimental design. Formulation properties such as dissolution rate, moisture content, valsartan particle size distribution, film thickness, and drug assay were evaluated. In addition, more advanced methods such as Raman microscopy and image analysis were used to characterize the developed product in more detail. The results of dissolution tests using four different dissolution apparatuses showed a significant difference between the formulations containing the active ingredient in different polymorphic states. The dynamic contact angle of a water droplet on the surface of the films was measured, which correlated well with the dissolution times at 80% of the released drug (t80).

Efficient Evaluation of In Vivo Performance in Human for Generic Formulation by Novel Dissolution-Absorption Prediction (DAP) Workflow

PURPOSE

The pharmaceutical bioequivalence of generic medicines must be confirmed with corresponding original drugs. Although the in vitro dissolution tests are required, results of the mandatory in vitro study do not necessarily reflect the in vivo performance after oral administration. Then, we have tried to develop the novel "Dissolution-Absorption Prediction (DAP) workflow" to evaluate the in vivo performance of generic medicines.

METHODS

The DAP workflow consists of an "In vitro two-cell connected dissolution (TCCD) system" mimicking the changes in the luminal pH associated with gastrointestinal transit of medicines, "Evaluation of pharmacokinetics of active pharmaceutical ingredient (API)" and "Prediction of plasma concentration-time profile". TCCD system-evaluated dissolution kinetics of APIs from generic formulations and pharmacokinetic parameters based on human data regarding the original drugs were used to calculate the plasma concentration-time profiles of APIs after the oral administration of generic medicines.

RESULTS

The mandatory in vitro dissolution tests indicated that the dissolution properties of valsartan (BCS class II) and fexofenadine (BCS class III/IV) in generic formulations did not coincide with those in the corresponding original formulations. The TCCD system provided the very similar dissolution kinetics for the generic and original formulations for the two APIs. Plasma concentration-time profiles evaluated utilizing the dissolution profiles obtained by the TCCD system were in good agreement with the observed profiles for both the generic and original formulations for each API.

CONCLUSIONS

The DAP workflow would be valuable for estimating the in vivo performance of generic formulation and deducing their bioequivalence with the original formulation.