Electronic tongue for pharmaceutical analytics: quantification of tastes and masking effects

Abstract

The organoleptic aspects of pharmaceutical formulations affect their acceptability to the patient and hence can have an important effect on concordance with treatment. Objective evaluation of these aspects, particularly the taste of the formulation and the drug substance it contains, is difficult. Whilst volunteer taste panels can be used to good effect their utility is limited, particularly during very early stage development when the toxicological profile of the active pharmaceutical ingredient (API) is yet to be established in detail. A potentiometric "electronic tongue" has been applied to analyse a variety of 41 individual substances and mixtures of particular interest for pharmaceutical research and development. The electronic tongue (ET) was capable of discriminating between substances with different taste modalities and could also distinguish different substances eliciting the same basic taste; the ET is promising in terms of quantifying the content of each substance and has an ability to detect nuances of the basic taste (e.g. lingering or short-lived). After calibration the electronic tongue was successfully applied to predicting bitterness strength of binary mixtures with a sweetener in terms of "apparent" or "perceived" quinine content. In order to render a formulation palatable it is often necessary to mask the (usually bitter) taste of the API by the addition of masking agents such as sweeteners and flavours. The ET proved capable of distinguishing between formulations with different levels of sweetener and/or flavour in a manner that was consistent with their masking efficiency as perceived by a small human taste panel. A suitably calibrated ET could have the benefit of providing the pharmaceutical formulator with reliable data concerning the taste of the product quickly and with a reduced need to ask volunteers to taste active pharmaceutical samples. Early development activities could be facilitated when human tasting is usually not possible in the absence of the required toxicological data.

Independent comparison study of six different electronic tongues applied for pharmaceutical analysis

“…Since then, multichannel taste sensor that later became a fundamental part of commercial taste sensing system by Insent had been used for quantification of basic taste sensations in large variety of samples [2][3][4]. Various studies were devoted to the application of different versions of e-tongues for the assessment of taste in pharmaceutical samples [5][6][7][8][9][10][11][12][13][14][15][16]. A variety of sensors and sensor systems were developed and applied in these research efforts, based on both, commercial [5,6,9,10,[13][14][15] or laboratory instrumentation [7,8,11,16].…”

“…The electronic tongue TS-5000Z and SA402B (Insent Inc., AtsugiShi, Japan) and those multisensor systems from the laboratories of Warsaw (Department of Microbioanalytics, Warsaw University of Technology; Poland) and St. Petersburg (Institute of Chemistry, St. Petersburg State University/Laboratory of Artificial Sensory Systems, ITMO University; Russia) are based on direct potentiometric measurements with sensors based on PVC-plasticized membranes [4,7,8,10,16]. The differences between these systems are in the number and composition of sensor membranes leading to the fact that all these systems have somewhat different sensitivity to the components in the analyzed media.…”

A Report from the Pediatric Formulations Task Force: Perspectives on the State of Child-Friendly Oral Dosage Forms

“…The "electronic tongue" can be incorporated here in formulation development. The electronic tongue is a device which detects an electronic signal in a given formulation; the goal is to achieve an electronic signal of the formulation containing the active drug which is similar to formulation containing a placebo (25)(26)(27). A recent paper describes the use of the electronic tongue in formulating a palatable sodium phenylbutyrate preparation, an extremely difficult task (28).…”

Survey on Tea Discriminator

“…An i-tongue employs electrochemical impedance spectroscopy which is a powerful and general technique suitable for characterization of electrochemical systems on the basis of impedance reading being collected at particular frequency interval and could also distinguish different substances eliciting the same basic taste [4]. For evaluation of black tea quality using electronic tongue, pioneering work had been done, where the efficiency of the electronic tongue instrument in classifying black tea in different processing stages was established.…”