Development strategies for herbal products reducing the influence of natural variance in dry mass on tableting properties and tablet characteristics

Evaluation of Microwave-Assisted Extraction Method for Preparation and Assessment of Thai Herbal Medicine Oral Tablets With Enriched Phytochemical Compounds

In developing countries, populations have employed herbal medicines for primary health care because they are believed to be more appropriate to the human body and have less side effects than chemically synthesized drugs. The present study aimed to develop and evaluate herbal tablets incorporated with a Thai traditional medicinal extract, U-pa-ri-waat (URW), using microwave-assisted extraction (MAE). The extraction efficiency for URW using MAE and traditional solvent extraction was compared based on the percent yield after spray drying. URW tablets were prepared using the dry granulation method. The optimized products were assessed using standard characterization methods based on the United States and British Pharmacopeias. DPPH and ABTS radical scavenging assays were performed to analyze the antioxidant capacity of the microwave-assisted extracts. The results revealed that the flowability of the dry granule with added maltodextrin was improved compared to a granule without additives, as indicated by an angle of repose of 33.69 ± 2.0°, a compressibility index of 15.38 ± 0.66, and a Hausner's ratio of 1.18 ± 0.06. The resulting formulation produced flat tablets with uniform weight variation, hardness, thickness, friability, and optimum disintegration time. The URW extracts showed antioxidant activity and MAE with maltodextrin carrier displayed the strongest DPPH and ABTS radical activities with IC50 values of 1.60 ± 0.02 μg/mL and 4.02 ± 0.24 μg/mL, respectively. The URW tablet formulation passed the quality control tests. Storage of the formulation tablets for 90 days under accelerated conditions had minimal effects on tablet characteristics.

Multivariate Statistical Optimization of Tablet Formulations Incorporating High Doses of a Dry Herbal Extract

The development of oral tablet formulation for herbal medicines has been restricted by large drug loadings and the poor physicochemical and mechanical properties of dry herbal extracts (DHEs). Herein, statistical experimental designs were applied to herbal tablet formulation development and optimization using Wuzi Yanzong dry extract (WYE). The tablet disintegration time and hardness were identified as the critical quality attributes (CQAs) of the product. The tablet formulation was designed to achieve a high drug loading (50% or higher of WYE), shorter tablet disintegration time (less than 30 minutes), and suitable hardness (6.0 to 7.5 kp). A D-optimal mixture design was used to evaluate the effects of excipients on CQAs to minimize the risk compression failure and improve the tabletability in formulations containing WYE at 50% and 65% by weight. A partial least squares model was used to elucidate the multivariate relationships between a large number of formulation variables and product CQAs, and determine the maximum possible WYE loading. From overlaid plots of the effects of formulation variables on CQAs, it was found that a maximum WYE loading of 67% in tablet formulation satisfied the acceptance criteria of CQAs. In conclusion, this study shows that multivariate statistical tools are useful for developing tablet formulations containing high doses of herbal extracts and establishing control strategies that ensure product quality.