Spray-Dried Cascara sagrada Extract for Direct Compression: Tablet Formulation and a Simple HPLC Method for Tablet Performance Evaluation

Abstract

Cascara sagrada bark is extensively used in the treatment of occasional constipation. Despite its wide diffusion, Cascara sagrada dried extracts with good flow and compactability properties for tablet formulation by direct compression and simple methods for the determination of Cascara sagrada extract release from tablets are not available. To overcome this lack of information, this article is focused on the design of tablets based on a Cascara sagrada extract obtained by spray-drying and on the quantification of its active constituents using a novel and isocratic HPLC-UV technique, which was validated. Flow properties of the Cascara sagrada spraydried extract and of the physical mixtures of it with conventional excipients were evaluated. The different formulated powders were compacted and their properties (i.e., hardness, friability, disintegration and dissolution) were studied. The proposed tablet formulations, based on the Cascara sagrada spray-dried extract, reached the pharmacopoeial requirements for immediate release tablets. In particular, the formulas containing a superdisintegrant showed the best pharmaceutical performance. Nevertheless, the use of excipients to improve the powder flow and/or the tablets properties was not strictly necessary. Besides, the HPLC-UV method used to monitor the extract release from tablets was validated, proving to be linear within the concentration range adequate for therapeutic purposes and appropriate for routine analysis due to its simplicity, good sensitivity, accuracy and precision.