Drug Discovery Today  Volume 12, Numbers 5/6  March 2007 REVIEWS The latest trends in the taste assessment of pharmaceuticals Vikas Anand 1 , Mahesh Kataria 1 , Vipin Kukkar 1 , Vandana Saharan 2 and Pratim Kumar Choudhury 3 1 Seth G.L. Bihani S.D. College of Technical Education, Gaganpath, Sri Ganganagar, Rajasthan, India 2 A.S.B.A.S.J.S. Memorial College of Pharmacy, Bela, District Ropar, Punjab, India 3 Department of Pharmacy, School of Health Sciences, Fiji School of Medicine, Suva, Fiji Islands To date, the most widely used method for measuring the taste characteristics of pharmaceutical preparations is psychophysical evaluation by a taste panel. However, conventional chemical analyses, on the basis of release studies, have been shown to be useful subsidiary methods. More recently, novel in vitro taste assessment apparatus and methodologies have been developed for high-throughput taste screening and quality control. Biomimetic taste sensing systems (BMTSSs), such as multichannel taste sensors or electronic tongues with global selectivity, have been welcomed by both pharmaceutical scientists and the industry as a whole. As we discuss here, the emerging in vitro approaches for assessing taste characteristics of taste masked drug and drug products will result in a decreased reliance on human panel tests. Introduction Taste has an important role in the development of oral pharma- ceuticals, with respect to patient acceptability and compliance, and is one of the prime factors determining the market penetra- tion and commercial success of oral formulations, especially in pediatric medicine. Hence, pharmaceutical industries invest time, money and resources into developing palatable and pleasant- tasting products and industries adopt various taste-masking tech- niques to develop an appropriate formulation. Taste assessment is one important quality-control parameter for evaluating taste-masked formulations. Any new molecular entity, drug or formulation can be assessed using in vitro or in vivo methods for taste (Table 1). In vivo approaches include human taste panel studies, electrophysiological methods and animal pre- ference studies. Several innovative in vitro drug release studies utilizing taste sensors, specially designed apparatus and drug release by modified pharmacopoeial methods have been reported in the literature for assessing the taste of drugs or drug products. The multichannel taste sensor, also known as the electronic ton- gue or e-tongue, is claimed to determine taste in a similar manner to biological taste perception in humans. Furthermore, such taste sensors have a global selectivity that has the potential to classify an enormous range of chemicals into several groups on the basis of properties such as taste intensities and qualities. In vivo approaches for taste assessment In in vivo studies, stimuli are applied on to the tongues of either humans or animals. The stimulus interacts with receptors embedded in the membrane of the taste buds and the information is ultimately transduced as an electrical signal, which is further transmitted along the nerve fiber to the brain, where taste is perceived. Such studies include human taste panel studies, elec- trophysiological methods and animal preference tests. Human taste panel studies Human taste panel studies evaluate tastants (food, chemicals, drugs and so on) by estimating the gustatory sensation responses in healthy human volunteers within well-controlled procedures. Such studies are therefore also known as physiological evaluation, psychophysical evaluation, gustatory sensation tests, sensory tests or taste trials. They are sensitive measures of taste and are statis- tically designed to minimize bias and variable responses within Reviews  POST SCREEN Corresponding author: Anand, V. (vikas.pharmaceutics@gmail.com) 1359-6446/06/$ - see front matter ß 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.drudis.2007.01.010 www.drugdiscoverytoday.com 257