A pH-Responsive Fine Powder Coating Strategy for Simultaneous Taste Masking and Physical Modification of Herbal Extract

Abstract Herbal extracts are widely used as intermediates and fundamental materials in pharmaceutical processing. However, the pronounced drawback in powder flowability and intensely bitter taste present major obstacles to the innovation of herbal-derived oral dosage forms. Here, we report a fine powder coating strategy to overcome these challenges for an internally developed herbal extract that exhibits these drawbacks. By employing a tangential fluidized-bed coater, a composite polymer coating formulation was applied to the extract powder. Such a coating formulation achieved rapid release performance under acidic condition and sustained release performance under neutral condition, confirmed by dissolution and kinetic studies. The effect of coating modification on the extract powder was characterized by powder flowability measurements, Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC) analyses. We further demonstrated the efficacy of the taste masking strategy using an electronic tongue system. Our work provides a practical and feasible paradigm for coating fine herbal extract powders, presenting new perspectives for the development of modern oral dosage forms designed for pharmaceutical powders suffering from similar challenges.