1.1.2 . Organoleptic properties
Color is a vital means of identification for many pharmaceutical tablets and is also usually important for consumer acceptance. The color of the product must be uniform within a single tablet, from tablet to tablet and from lot to lot. Non uniformity of coloring not only lack esthetic appeal but could be associated by the consumer with non uniformity of content and general poor product quality. Non uniformity of coloring is usually referred to as mottling. The eye cannot differentiate small differences in color nor can it precisely define color and efforts have been made to quantitate color evaluations. Reflectance spectrophotometry, tristimulus colorimetric measurements and micro reflectance photometer have been used to measure color uniformity and gloss on a tablet surface 2 .
Odor may also be important for consumer acceptance of tablets and can provide an indication of the quality of tablets as the presence of an odor in a batch of tablets could indicate a stability problem, such as the characteristic odor of acetic acid in degrading aspirin tablets. However, the presence of an odor may be characteristic of the drug (e.g. vitamins), added ingredients (e.g. flavoring agent) or the dosage form (e.g. film-coated tablets).
Taste is also important for consumer acceptance of certain tablets (e.g. chewable tablets) and many companies utilize taste panels to judge the preference of different flavors and flavor levels in the development of a product. Taste preference is however subjective and the control of taste in the production of chewable tablets is usually based on the presence or absence of a specified taste.