Insight into the enhancement and mechanism of saltiness perception by salty peptides from bovine bone

Food-derived salty peptides have been considered promising substitutes for sodium salt. In this work, three novel salty dipeptides Asp-Pro (DP), Asp-Arg (DR), and Arg-Glu (RE) were identified from bovine bone hydrolysates. The salt reduction rates were 76.85 %, 77.28 %, and 73.72 % by the three peptides (2 mg/mL) in a NaCl concentration of 0.203 g/100 mL, respectively. According to Stevens' law, a non-linear relationship between saltiness intensity and concentration was quantified, showing a slower increase in the sensory intensity perception compared with the changes in physical concentration (β < 1). In molecular detail, electrostatic energy and van der Waals energy were the main energetic contributions to forming stable complexes. The binding of salty peptides to TMC4 was driven by hydrogen bonding and salt bridge, and the main binding sites were Glu319, Ala579, and Thr581. These results could provide new insight into the salt-enhancing property and interaction mechanism of salty peptides as novel sodium substitutes.

Orodispersible tablets for pediatric drug delivery: current challenges and recent advances

INTRODUCTION

Child appropriate dosage forms are indispensable in modern medicine and are a prerequisite for successful pediatric drug therapy. For years, experts have called for a paradigm shift, from liquid dosage forms to novel oral solid dosage forms. This review aims to shed light on recent developments in Orodispersible tablets (ODTs) and mini-tablets (ODMTs).

AREAS COVERED

This review focuses on the presentation and critical discussion of current challenges as well as recent advances in ODTs for pediatric drug delivery. Highlighted aspects are the evidence for acceptability by children, e.g. in comparison to other dosage forms, and limitations given by tablet size at different ages, as well as advances in special ODT formulations (taste masking, modified release, enabling formulations).

EXPERT OPINION

It is the authors' belief that OD(M)Ts have significant potential as dosage forms in pediatric therapy that has not yet been fully exploited. The reasons for this are, first, that the number of direct acceptance studies is extremely low and the resulting knowledge is therefore rather anecdotal. Despite the high relevance, there seems to be reluctance both in the therapeutic use and conduction of respective studies in children. However, if one combines the knowledge from the few existing studies, surveys, and from approved products, it becomes apparent that so far there is no evidence on limitations of the use of ODTs in pediatric patients.

Preparation of Novel Functional Drug Particles Embedded in a Gelling-Swelling Layer (PEGS) for Taste Masking and Subsequent Rapid Drug Release

The purpose of this research was to develop novel functional drug particles embedded in a gelling-swelling layer (PEGS) which are capable of achieving both taste-masking of unpalatable drugs and rapid drug elution. The functional particles had a three-layer structure consisting of a core drug layer, a gelling-swelling layer and an outer water-penetration control layer containing a water-insoluble polymer. The concept of formulation design was as follows: when water reaches the gelling-swelling layer, pulverized fine gelling-swelling particles gellate and swell from water absorption to form a rigid layer, thereby preventing drug release. After a defined lag time, the increased volume of the gelling-swelling layer breaks down the outer water-penetration control layer, leading to rapid drug release. In order to adapt this system for use in orally disintegrating tablets, PEGS were prepared at a size of about 250 µm using a fine particle-coating method. Ambroxol hydrochloride was used as a model drug for bitterness and the effects of different gelling-swelling agents and water-insoluble polymers on drug release characteristics from PEGS were examined. In in vitro dissolution tests, it was shown that the drug dissolution rate from PEGS could be suppressed to about 5% after 2 min and increased to more than 85% after 30 min by adjusting the composition and thickness of the outer layer. The PEGS expanded about 1.5-fold and the outer layer was ruptured after 5 min in water.

Palatability of Crushed Over-the-Counter Medications

CONTEXT

Dysphagia is a common concern, especially in the last several days of life. Medications are often crushed for ease of administration for individuals with swallowing difficulty.

OBJECTIVES

To assess palatability of commonly used crushed over-the-counter (OTC) medications. A secondary objective is to evaluate pharmacist knowledge and opinions of crushing medications.

METHODS

Pharmacist participants sampled crushed OTC medications and completed presampling and postsampling surveys about crushing medications. Participants were excluded for current smoking or tobacco use, pregnancy, allergy to any study medication or applesauce, or potential drug-drug interaction with study medications. Eight OTC medications were crushed and mixed in applesauce: naproxen, fexofenadine, phenazopyridine, multivitamin, loperamide, famotidine, sennosides, and sennosides-docusate. Participants were blinded to medication samples and control (plain applesauce). Samples were rated from one (least palatable) to five (most palatable). Investigators recorded participants' comments, behaviors, and facial expressions during sampling.

RESULTS

Nineteen volunteers completed the study. Most participants rated three samples as not palatable (score of two or less): fexofenadine, 16 (84%); loperamide, 13 (68%); and sennosides-docusate, 16 (84%). All participants rated famotidine and sennosides palatable. The percentage of participants who would consider palatability in recommendations for crushing medications increased from 47% prestudy to 79% poststudy.

CONCLUSION

Palatability should be considered when recommending crushed medications. Survey responses indicate that pharmacists' opinions of crushed medications changed after this palatability experiment. Clinicians should evaluate the appropriateness of all medications when dysphagia is a concern and deprescribe medications when appropriate to reduce burden for patients and caregivers.

Acceptability of generic versus innovator oral medicines: not only a matter of taste

Optimum use of generic products would require equivalence, not only in terms of quality, safety, and efficacy in clinical studies, but also patient acceptability to not jeopardize treatment success because of non-adherence which would de facto limit the potential cost saving anticipated by their use. Although acceptability is a requirement for the authorization of pediatric innovator products, a survey of European Union (EU) regulatory authorities showed that few have a formal process for assessing patient acceptability of generic products during the registration processes. The current International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) focus on unifying guidance for the development and scrutiny of generics but should include acceptability alongside the other factors being considered for harmonization.

Critical Evaluation of Laboratory Potentiometric Electronic Tongues for Pharmaceutical Analysis-An Overview

Electronic tongue systems equipped with cross-sensitive potentiometric sensors have been applied to pharmaceutical analysis, due to the possibility of various applications and developing new formulations. Many studies already proved the complementarity between the electronic tongue and classical analysis such as dissolution tests indicated by Pharmacopeias. However, as a new approach to study pharmaceuticals, electronic tongues lack strict testing protocols and specification limits; therefore, their results can be improperly interpreted and inconsistent with the reference studies. Therefore, all aspects of the development, measurement conditions, data analysis, and interpretation of electronic tongue results were discussed in this overview. The critical evaluation of the effectiveness and reliability of constructed devices may be helpful for a better understanding of electronic tongue systems development and for providing strict testing protocols.

Critical review of electronic nose and tongue instruments prospects in pharmaceutical analysis

Electronic nose (enose, EN) and electronic tongue (etongue, ET) have been designed to simulate human senses of smell and taste in the best possible way. The signals acquired from a sensor array, combined with suitable data analysis system, are the basis for holistic analysis of samples. The efficiency of these instruments, regarding classification, discrimination, detection, monitoring and analytics of samples in different types of matrices, is utilized in many fields of science and industry, offering numerous practical applications. Popularity of both types of devices significantly increased during the last decade, mainly due to improvement of their sensitivity and selectivity. The electronic senses have been employed in pharmaceutical sciences for, among others, formulation development and quality assurance. This paper contains a review of some particular applications of EN and ET based instruments in pharmaceutical industry. In addition, development prospects and a critical summary of the state of art in the field were also surveyed.

An advanced technique using an electronic taste-sensing system to evaluate the bitterness of orally disintegrating films and the evaluation of model films

Taste detection systems using electronic sensors are needed in the field of pharmaceutical design. The aim of this study was to propose an advanced technique using a taste-sensing system to evaluate the bitterness of an orally disintegrating film (ODF) samples. In this system, a solid film sample is kept in the test medium with stirring, and the sensor output is recorded. Model films were prepared using a solution-casting method with a water-soluble polymer such as pullulan, HPMC, HPC or PVP as film formers, and donepezil hydrochloride and quinine hydrochloride as model bitter-tasting active pharmaceutical ingredients (APIs). The results showed that this advanced techniques could detect the emergence of bitterness along the time course. Increasing the amount of donepezil hydrochloride increased the sensor output. The sensor output was suppressed at the very early stage of the test, and then increased. Both the film thickness and the use of additives markedly affected the delay of the sensor output. The profile of the sensor output was accurately related to the release of APIs. It was concluded that this advanced technique could detect the onset of bitterness during the initial stage of ODF administration.

Early pediatric formulation development with new chemical entities: Opportunities of e-tongue besides human taste assessment

The palatability of a pediatric drug formulation is one of the key prerequisites for therapeutic success. Liquid formulations are often chosen for pediatric drug products, and they require special attention regarding their taste, as they have direct contact to the taste buds and a relatively long residence time in the oral cavity. For ethical reasons, the role of electronic tongues in the development of oral drug formulations with new chemical entities (NCEs) for pediatric use is growing, however, little is known about the strategies how this instrumental taste assessment can be performed. The present study illustrates two possibilities to combine in-vitro and in-vivo data for the characterization of the palatability of the new drug candidates CSE3104 and CSE3165. As a first step, the implementation and suitability of electronic tongue measurements has been demonstrated by comparison of in-vivo and in-vitro data. In alignment with the taste assessment results during a single-center, double-blinded, randomized, placebo-controlled, single ascending dose (SAD) study in healthy subjects, the bitter taste perception of CSE3104 was assessed with e-tongue measurements. Moreover, the sensor response pattern showed comparable results of the e-tongue measurements to the human taste study of CSE3165: With increasing concentration, the bitterness values were increased. In addition, the human taste pattern showed increasing values for sourness due to higher volumes of the citric acid buffer. Results of the hedonic descriptor "unpleasant" within the human taste assessments could be related to bitterness in the instrumental taste assessment. For the second step in electronic tongue guided formulation development two possibilities are depicted in the article focusing on the effect of different excipients on the formulation on the one hand and on the assessment and comparison of two drug formulations on the other hand. Based on these results, the low number of healthy volunteers for the taste assessment in a Phase 1 study led to a meaningful interpretation, by applying in addition the electronic tongue. Using this instrumental approach led to reproducible data versus the human taste assessment, without ethical concerns, and with a reduction in time and costs.

Influence of Experimental Conditions on Electronic Tongue Results-Case of Valsartan Minitablets Dissolution

A potentiometric electronic tongue was applied to study the release of valsartan from pharmaceutical formulations, i.e., minitablets uncoated and coated with Eudragit E. Special attention was paid to evaluate the influence of medium temperature and composition, as well as to compare the performances of the sensor arrays working in various hydrodynamic conditions. The drug dissolution profiles registered with the ion-sensitive electrodes were compared with standard dissolution tests performed with USP Apparatus 2 (paddle). Moreover, the signal changes of all sensors were processed by principal component analysis to visualize the release modifications, related to the presence of the coating agent. Finally, the importance and influence of the experimental conditions on the results obtained using potentiometric sensor arrays were discussed.

Identification of key umami-related compounds in Yangtze Coilia ectenes by combining electronic tongue analysis with sensory evaluation

The smaller the euclidean distance of two samples in PCA map, the more similar their tastes were. The closest in euclidean distance of the five basic tastes from the flesh samples were NaCl and MSG, which means that umami and saltiness are the primary sensory attributes.

Taste-masking assessment of solid oral dosage forms--a critical review

Approaches to improve the taste of oral dosage forms that contain unpleasant tasting drugs are versatile. Likewise, the analytical in vitro and in vivo methods to assess taste-masking efficacy are diverse. Taste-masking has gained in importance since the EU legislation on medicines for children came into force in 2007, and taste-masking attributes are often required by regulatory authorities. However, standardized guidance for the analytical evaluation is still poor. Published protocols rarely consider real conditions, such as the volume of saliva or the residence time of solid oral dosage forms in the mouth. Methodological limitations and problems regarding time point of evaluation, sampling or sample pretreatment are hardly ever addressed. This critical review aims to evaluate and discuss published strategies in this context.

Evaluation of palatability of 10 commercial amlodipine orally disintegrating tablets by gustatory sensation testing, OD-mate as a new disintegration apparatus and the artificial taste sensor

Objectives

The purpose of this study was to evaluate and compare the palatability of 10 formulations (the original manufacturer's formulation and nine generics) of amlodipine orally disintegrating tablets (ODTs) by means of human gustatory sensation testing, disintegration/dissolution testing and the evaluation of bitterness intensity using a taste sensor.

Methods

Initially, the palatability, dissolution and bitterness intensity of the ODTs were evaluated in gustatory sensation tests. Second, the disintegration times of the ODTs were measured using the OD-mate, a newly developed apparatus for measuring the disintegration of ODTs, and lastly, the bitterness intensities were evaluated using an artificial taste sensor.

Key findings

Using factor analysis, the factors most affecting the palatability of amlodipine ODTs were found to be disintegration and taste. There was high correlation between the disintegration times of the 10 amlodipine ODTs estimated in human gustatory testing and those found using the OD-mate. The bitterness intensities of amlodipine ODTs 10, 20 and 30 s after starting the conventional brief dissolution test and the values determined by the taste sensor were highly correlated with the bitterness intensities determined in gustatory sensation testing.

Conclusions

The OD-mate and the taste sensor may be useful for predicting the disintegration and bitterness intensity of amlodipine ODTs in the mouth.

Bitterness evaluation of intact and crushed Vesicare orally disintegrating tablets using taste sensors

Objective

Vesicare tablets, whose main component is solifenacin succinate, are known to be extremely bitter. The purpose of this study was to evaluate the effect of crushing on the bitterness of the Vesicare orally disintegrating tablets (ODTs).

Method

Vesicare ODTs and conventional Vesicare tablets (CTs) were crushed either heavily or lightly. The bitterness scores and release rates of sample solutions obtained 5, 10, 30, 60, 90 or 120 s after placing a crushed CT or ODT containing 5 mg solifenacin in 40 ml of water were predicted using two taste sensors (SA402B and a-ASTREE) and HPLC, respectively. The particle size and the surfaces of the crushed tablets were observed microscopically.

Key findings

The predicted bitterness scores and the drug release rates of CTs were high, irrespective of the degree of crushing. The lightly crushed ODT was predicted to be less bitter than the heavily crushed ODT. In lightly crushed ODTs, spherical particles were observed, about 200 mm in diameter.

Conclusions

The degree of crushing was a critical factor in determining the expression of bitterness by crushed ODTs. When intact tablets of Vesicare must be crushed to adjust the dosage, it is strongly recommended that ODTs be crushed gently.

Evaluation of the odour of Aminoleban® EN, taste-masked with flavoured powders, by human and electronic noses

OBJECTIVES

Aminoleban® EN is a bitter total enteral nutrient product with an unpleasant odour. The purpose of this study was to evaluate the odour of Aminoleban® EN, taste-masked with various flavoured powders, by human testing and by using an electronic nose system (Alpha M.O.S.).

METHODS

Initially, the odour of Aminoleban® EN alone at various concentrations was evaluated. Secondly, the odour of Aminoleban® EN with the addition of various flavoured powders was evaluated; the evaluation included data on odour intensity, preference levels and evoked taste image.

KEY FINDINGS

With the human nose, a concentration of 0.43 g/100 ml seemed to be the taste threshold for Aminoleban® EN. In the electronic nose system, principal component analysis revealed that concentrations over 0.39 g/100 ml Aminoleban® EN could be distinguished from water. It was clear from both human testing and using the electronic nose system that the unpleasant odour of Aminoleban® EN could be masked by pineapple- and plum-flavoured powders, both of which contain not only sweet but also sour components.

CONCLUSIONS

The electronic nose system may be useful for detecting odours at or below the level detectable by the human olfactory system and for classifying the quality of different odours, thus reducing the amount of human testing required.

Verification of aroma profiles of Jiashi muskmelon juice characterized by odor activity value and gas chromatography-olfactometry/detection frequency analysis: aroma reconstitution experiments and omission tests

To verify the aroma profile of Jiashi muskmelon previously identified by gas chromatography-olfactometry/detection frequency analysis (GC-O/DFA) and odor activity value (OAV) calculation, the synthetic blends of odorants (aroma models) were prepared and then were compared with the original Jiashi muskmelon juice aroma using quantitative descriptive analysis (QDA) and electronic nose analysis (ENA), respectively. QDA and ENA both indicated that the model solution derived from OAV calculation more closely resembled the original melon juice aroma than that based on DFA data. Omission tests corroborated the significant contribution of five unsaturated aldehydes and alcohols with nine carbon atoms as well as five branched esters, in particular, the "fruity"-smelling ethyl butanoate and the "cucumber-like" (2E,6Z)-nona-2,6-dienal to Jiashi muskmelon overall aroma.

Taste sensing systems (electronic tongues) for pharmaceutical applications

Electronic tongues are sensor array systems able to detect single substances as well as complex mixtures by means of particular sensor membranes and electrochemical techniques. Two systems are already commercially available, the Insent taste sensing system and the αAstree electronic tongue. In addition, various laboratory prototype versions exist. Besides the successful use in food industry, the implementation for pharmaceutical purposes has strongly grown within the recent years. A reason for this is the increased interest of developing palatable formulations, especially for children. As taste assessment of drugs comes along with challenges due to possible toxicity and subjectivity of the taste assessors, electronic tongues could offer a safe and objective alternative. In order to provide guidance on the use of these systems, possible fields of interest are presented in this review, as for example, system qualification, quality control, formulation development, comparison between marketed drug products, and the validation of the methods used. Further, different approaches for solid and liquid dosage forms are summarized. But, also the difficulty to obtain absolute statements regarding taste was identified and the need of more validated data was discussed to offer guidance for the next years of research and application of electronic tongues for pharmaceutical applications.

[Method for the evaluation of the stability and usability after opening packages of orally disintegrating tablets: case of amlodipine besilate products]

Orally disintegrating (OD) tablets are widely used in clinical practice. However, drug information on the choice and dispensing based on their stability after opening packages and usability in patients and dispensaries is not sufficient. The aim of this study was to investigate possible evaluation methods of the stability and usability of amlodipine OD tablets. Additives of the brand were changed in April 2009, and therefore the previous and current forms and two generics, current and newly marketed (in November 2009) products of different firms, were used. OD tablets were stored at 25 degrees C and 75% relative humidity for 3 months after opening the packages, and their physicochemical properties were evaluated. Their weight, diameter, thickness, and color difference increased slightly from the initial state. The extent of the change in their hardness, disintegration time, and friability was different among products. These physicochemical changes were acceptable in dispensary practice. Storage after opening the packages did not affect their dissolution rate. The dissolution rate at the initial state of the current brand was slower than that of the previous one. All products used were able to be dispensed by an automatic tablet-packing machine and applied to the so-called simple suspension method for intubational administration. Sensory evaluation tests revealed no major difference in the oral disintegration time, taste, impression, and preference among products. In conclusion, the stability and usability of amlodipine OD tablets used in this study were examined using several methods, and they can be used equivalently from the stability and usability viewpoints.

An electronic tongue: evaluation of the masking efficacy of sweetening and/or flavoring agents on the bitter taste of epinephrine

An epinephrine (E) tablet is under development for sublingual (SL) administration for the first-aid treatment of anaphylaxis; however, the inherent bitterness of E may hinder acceptability by patients, especially children. To assess the degree of E bitterness and to predict the masking effects of sweetening and/or flavoring non-medicinal ingredients (NMIs), the potential usefulness of an electronic tongue (e-Tongue) was evaluated. The e-Tongue sensors were conditioned, calibrated, and tested for taste discrimination. Six standard active pharmaceutical ingredients were used to build and validate a bitterness model which was then used to assess E bitartrate (EB) solutions from 0.3-9 mM. Taste-masking efficiency of aspartame (ASP), acesulfame potassium (ASK), and citric acid (CA) each at 0.5 mM was evaluated. Using EB 9 mM, the bitterness score was 20 on a scale of 20 (unacceptable) down to 1 (not detected). When NMIs 0.5 mM were added, neither ASK (17.2, unacceptable) nor was ASP (14.0, limit acceptable) effective in masking the bitter taste. When the combination of ASK and ASP was used, the bitterness score was reduced to 9.2 (acceptable). However, the addition of CA alone resulted in the best reduction of the bitterness score to 3.3 (not detected). Using the e-Tongue, the incorporation of a variety of sweetening and/or flavoring NMIs into a SL tablet of E could be shown to mask its bitter taste by up to 80%. These results should be confirmed by in vivo studies.

Chemometric brains for artificial tongues

The last years showed a significant trend toward the exploitation of rapid and economic analytical devices able to provide multiple information about samples. Among these, the so-called artificial tongues represent effective tools which allow a global sample characterization comparable to a fingerprint. Born as taste sensors for food evaluation, such devices proved to be useful for a wider number of purposes. In this review, a critical overview of artificial tongue applications over the last decade is outlined. In particular, the focus is centered on the chemometric techniques, which allow the extraction of valuable information from nonspecific data. The basic steps of signal processing and pattern recognition are discussed and the principal chemometric techniques are described in detail, highlighting benefits and drawbacks of each one. Furthermore, some novel methods recently introduced and particularly suitable for artificial tongue data are presented.