Preparation and In Vitro/In Vivo Evaluation of Orally Disintegrating/Modified-Release Praziquantel Tablets

The Use of Systemically Absorbed Drugs to Explore An In Vitro Bioequivalence Approach For Comparing Non-Systemically Absorbed Active Pharmaceutical Ingredients in Drug Products For Use in Dogs

PURPOSE

Currently, for veterinary oral formulations containing one or more active pharmaceutical ingredient (API) that are not systemically absorbed and act locally within the gastrointestinal (GI) tract, the use of terminal clinical endpoint bioequivalence (BE) studies is the only option for evaluating product BE. This investigation explored the use of a totality of evidence approach as an alternative to these terminal studies.

METHODS

Three formulations of tablets containing ivermectin plus praziquantel were manufactured to exhibit distinctly different in vitro release characteristics. Because these APIs are highly permeable, plasma drug concentrations served as a biomarker of in vivo dissolution. Tablets were administered to 27 healthy Beagle dogs (3-way crossover) and the rate and extent of exposure of each API for each formulation was compared in a pairwise manner. These results were compared to product relative in vitro dissolution profiles in 3 media. In vivo and in vitro BE predictions were compared.

RESULTS

In vivo/in vitro inconsistencies in product relative performance were observed with both compounds when considering product performance across the 3 dissolution media. Formulation comparisons flagged major differences that could explain this outcome.

CONCLUSIONS

The finding of an inconsistent in vivo/in vitro relationship confirmed that in vitro dissolution alone cannot assure product BE for veterinary locally acting GI products. However, when combined with a comparison of product composition and manufacturing method, this totality of evidence approach can successfully alert scientists to potential therapeutic inequivalence, thereby supporting FDA's efforts to Replace, Reduce, and/or Refine terminal animal studies.

Effects of Functional Biomaterials on the Attributes of Orally Disintegrating Tablets Loaded with Furosemide Nanoparticles: In Vitro and In Vivo Evaluations

Furosemide (FUR) is a diuretic used to relieve edema, congestive heart failure, cirrhosis, end-stage renal disease, and hypertension. FUR is a class IV according to the Biopharmaceutics Classification System. It is practically insoluble in water. This study aimed to optimize and formulate porous orally disintegrating tablets (ODTs) prepared by sublimation and loaded with FUR nanoparticles prepared by using a planetary ball mill. Different functional biomaterials called stabilizers were used to stabilize the nanoparticle formula. Pluronic F-127 was the optimum stabilizer in terms of particle size (354.07 ± 6.44), zeta potential (-25.3 ± 5.65), and dissolution efficiency (56.34%). The impact of the stabilizer concentration was studied as well, and a concentration of 3% showed the smallest particle size (354.07 ± 6.44), best zeta potential value (-25.3 ± 5.65), and percentage of dissolution rate (56.34%). A FUR-loaded nanoparticle formula was successfully prepared. The nanoparticle formula was stabilized by using 3% pluronic F-127, and 3% was chosen for further study of the incorporation into oral disintegration tablets prepared by the sublimation technique. The impact of the matrix sublimating agent and superdisintegrant on the ODTs' attributes (in vitro disintegration, wetting time, and in vitro dissolution efficiency) was studied using 32 full factorial designs. In vivo, the diuretic activity was tested for the optimized FUR ODTs by calculating the Lipschitz value using rats as an animal model. The stability of the ODTs loaded with FUR nanoparticles was assessed under accelerated conditions for 6 months. Finally, the ODT formula loaded with FUR NPs showed a rapid onset of action that was significantly faster than untreated drugs. Nanonization and ODT formulation enhances the dissolution rate and bioavailability of FUR. Many factors can be controlled to achieve optimization results, including the formulation and process parameters.

A double-layered gastric floating tablet for zero-order controlled release of dihydromyricetin: Design, development, and in vitro/in vivo evaluation

Dihydromyricetin (DHM) is an important natural flavonoid. However, most of DHM preparations have shown shortcomings such as low drug loading, poor drug stability, and/or large fluctuations in blood concentration. This study aimed to develop a gastric floating tablet with a double-layered structure for zero-order controlled release of DHM (DHM@GF-DLT). The final product DHM@GF-DLT showed a high average cumulative drug release at 24 h that best fit the zero-order model, and had a good floating ability in the stomach of the rabbit with a gastric retention time of over 24 h. The FTIR, DSC, and XRPD analyses indicated the good compatibility among the drug and the excipients in DHM@GF-DLT. The pharmacokinetic study revealed that DHM@GF-DLT could prolong the retention time of DHM, reduce the fluctuation of blood drug concentration, and enhance the bioavailability of DHM. The pharmacodynamic studies demonstrated that DHM@GF-DLT had a potent and long-term therapeutic effect on systemic inflammation in rabbits. Therefore, DHM@GF-DLT had the potential to serve as a promising anti-inflammatory agent and may develop into a once-a-day preparation, which was favorable to maintain a steady blood drug concentration and a long-term drug efficacy. Our research provided a promising development strategy for DHM and other natural products with a similar structure to DHM for improving their bioavailability and therapeutic effect.

Kinetics of Drug Release from Clay Using Enhanced Sampling Methods

A key step in the development of a new drug, is the design of drug-excipient complexes that lead to optimal drug release kinetics. Computational chemistry and specifically enhanced sampling molecular dynamics methods can play a key role in this context, by minimizing the need for expensive experiments, and reducing cost and time. Here we show that recent advances in enhanced sampling methodologies can be brought to fruition in this area. We demonstrate the potential of these methodologies by simulating the drug release kinetics of the complex praziquantel-montmorillonite in water. Praziquantel finds promising applications in the treatment of schistosomiasis, but its biopharmaceutical profile needs to be improved, and a cheap material such as the montmorillonite clay would be a very convenient excipient. We simulate the drug release both from surface and interlayer space, and find that the diffusion of the praziquantel inside the interlayer space is the process that limits the rate of drug release.

Optimization of the Preformulation and Formulation Parameters in the Development of New Extended-Release Tablets Containing Felodipine

Herein, new extended-release tablets containing felodipine were developed. For the orally administered formulations, optimization of the preformulation and formulation parameters was performed to assess the performance of the dosage form. Initially, the morphological and physical characterization of two forms of felodipine (microcrystalline and macrocrystalline) using Fourier transform infrared spectroscopy, differential scanning calorimetry and optical microscopy was performed. The pharmaco-technical properties of the two felodipine forms were also determined. Subsequently, formulation studies for felodipine extended-release tablets were performed. Mathematical modelling of release kinetics of felodipine from developed formulations using a power law model was also performed. Based on the influence of formulation factors on the in vitro availability of felodipine in experimental tablets, a new extended-release tablet formulation was established.