Development of a model for robust and exploratory analysis of the rodent brief-access taste aversion data

Investigating in-vitro functionality and in-vivo taste assessment of eco-friendly Tadalafil Pastilles

Tadalafil (TDL) has poor bioavailability due to the less aqueous solubility and bitter taste. Oral solid dosage forms, especially tablets, have a broad market worldwide. Constraints of tablets are a long process, pollution, high processing cost, and requiring more excipient. The research was performed to optimize an eco-friendly immediate-acting pastille of TDL to put forward an alternate formulation to a tablet using advanced data mining tools. Another objective is to assess the taste masking of TDL using the Brief Access Taste Aversion (BATA) model. The amount of PEG-4000, Polyox N-10, and Kyron T-314 were chosen as critical material attributes from failure mode effect analysis. Box-Behnken design (BBD) was utilized to optimize the pastilles and ascertained the significant impact of chosen variables on disintegration time and % CDR at 10 min. The control strategy and optimal region were located using an overlay plot. The pastilles were able to release the drug within 15 min due to faster disintegration. The formulated pastilles were of uniform size, shape, and mechanical strength. The bitter taste of TDL was masked and confirmed by the BATA model. The newer formulation may be helpful in the industry due to its eco-friendly, single-step, and economical process. It unlocks a new direction in the field of oral solid dosage form as an alternative to tablets.

BitterMatch: recommendation systems for matching molecules with bitter taste receptors

Bitterness is an aversive cue elicited by thousands of chemically diverse compounds. Bitter taste may prevent consumption of foods and jeopardize drug compliance. The G protein-coupled receptors for bitter taste, TAS2Rs, have species-dependent number of subtypes and varying expression levels in extraoral tissues. Molecular recognition by TAS2R subtypes is physiologically important, and presents a challenging case study for ligand-receptor matchmaking. Inspired by hybrid recommendation systems, we developed a new set of similarity features, and created the BitterMatch algorithm that predicts associations of ligands to receptors with ~ 80% precision at ~ 50% recall. Associations for several compounds were tested in-vitro, resulting in 80% precision and 42% recall. The encouraging performance was achieved by including receptor properties and integrating experimentally determined ligand-receptor associations with chemical ligand-to-ligand similarities.

BitterMatch can predict off-targets for bitter drugs, identify novel ligands and guide flavor design. The novel features capture information regarding the molecules and their receptors, which could inform various chemoinformatic tasks. Inclusion of neighbor-informed similarities improves as experimental data mounts, and provides a generalizable framework for molecule-biotarget matching.

Evaluating the Taste Masking Ability of Two Novel Dispersible Tablet Platforms Containing Zinc Sulfate and Paracetamol Reconstituted in a Breast Milk Substitute

Milk is often used as a dispersion medium for medicines administration in young children but its taste-masking ability is unknown. A human taste panel was conducted to assess the potential of infant formula milk (Aptamil^® 1) to mask the taste of two model WHO priority medicines, zinc sulfate and paracetamol, manufactured as dispersible tablets. Simultaneously, the palatability of powder blends of the tablet platforms was assessed. Twenty healthy adult volunteers performed a swirl-and-spit assessment of placebos and API-containing blends in either a lactose-based or a mannitol-based dispersible tablet platform, reconstituted in 10 mL of either water or Aptamil^® 1. Eighteen samples were rated for aversion using a 100-mm Visual Analogue Scale, grittiness using a 5-point Likert scale, and “acceptability-as-a-medicine” evaluated as: “Would you find this sample acceptable to swallow as a medicine?” with binary answers of Yes/No. The API-containing formulations were more aversive than the placebos; the paracetamol-containing samples being more aversive than zinc sulfate samples. The platforms themselves were not aversive. Non-gritty samples had four-fold greater odds of being acceptable as a medicine. Aptamil^® 1 masked the taste of zinc sulfate in the mannitol-based formulation but did not mask the taste of paracetamol in either platform, suggesting a limited taste-masking ability, which may be API and formulation dependent.

Palatability of pediatric formulations: do rats predict aversiveness?

BACKGROUND

The brief-access taste aversion (BATA) model has been used as an alternative taste assessment tool to human taste panels and became an important element of pharmaceutical drug development, especially regarding pediatric patient's compliance. This model has been validated, demonstrating a concentration-dependent sensitivity to drug aversiveness, as well as the capacity to evaluate the taste-masking effects of cyclodextrins. In the BATA model, samples are presented randomly to rodents in numerous sipper tubes and a lickometer is used for the electronic record of licks in a sophisticated approach.

OBJECTIVES

The aim of this study was to test possible drug taste-masking strategies. Additionally, we have used an alternative approach to measure the animal lick number in the presence of different compounds, non-simultaneously.

RESULTS

In the present work we show for the first time the licking profile of different compounds during the time course of the experiment, with each animal being exposed to only one bottle of testing product. To validate the experiments, quinine hydrochloride dihydrate (QHD) was used as a bitter reference compound.

CONCLUSION

The results obtained using this simple approach showed that aversiveness is dependent on the assay duration, and that it is possible to predict the aversiveness just by measuring the mass of the tested substance consumption. Moreover, some taste-masking strategies, such as those used in pediatric formulations and corresponding to the addition of sweeteners or flavors, cannot be predicted from rodents BATA model.

Pediatric formulation development - Challenges of today and strategies for tomorrow: Summary report from M-CERSI workshop 2019

A workshop on "Pediatric Formulation Development: Challenges of Today and Strategies for Tomorrow" was organized jointly by the University of Maryland's Center of Excellence in Regulatory Science and Innovation (M-CERSI), the U.S. Food and Drug Administration (FDA) and the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) Drug Product Pediatric Working Group (PWG). This multi-disciplinary, pediatric focused workshop was held over a two-day period (18-19 Jun 2019) and consisted of participants from industry, regulatory agencies, academia and other organizations from both US and Europe. The workshop consisted of sequential sessions on formulation, analytical, clinical, and regulatory and industry lessons learned and future landscape. Each session began with a series of short framing presentations, followed by facilitated breakout sessions and panel discussion. The formulation session was dedicated to three main topics pertaining to drug product acceptability, excipients in pediatrics and oral administration device considerations. The analytical session discussed key considerations for dosing vehicle selection and analytical strategies for testing of different dosage forms, specifically mini-tablets (multiparticulates). The clinical session highlighted the influence of pediatric pharmacokinetics prediction on formulation design, pediatric drug development strategies and clinical considerations to support pediatric formulation design. The regulatory and industry lessons learned and future landscape session explored the regional differences that exist in regulatory expectations, requirements for pediatric formulation development, and key patient-centric factors to consider when developing novel pediatric formulations. This session also discussed potential collaboration opportunities and tools for pediatric formulation development. This manuscript summarizes the key discussions and outcomes of all the sessions in the workshop with a broadened review and discussion of the topics that were covered.

Quantitative prediction of the bitterness of atomoxetine hydrochloride and taste-masked using hydroxypropyl-β-cyclodextrin: A biosensor evaluation and interaction study

The bitterness of a drug is a major challenge for patient acceptability and compliance, especially for children. Due to the toxicity of medication, a human taste panel test has certain limitations. Atomoxetine hydrochloride (HCl), which is used for the treatment of attention deficit/hyperactivity disorder (ADHD), has an extremely bitter taste. The aim of this work is to quantitatively predict the bitterness of atomoxetine HCl by a biosensor system. Based on the mechanism of detection of the electronic tongue (E-tongue), the bitterness of atomoxetine HCl was evaluated, and it was found that its bitterness was similar to that of quinine HCl. The bitterness threshold of atomoxetine HCl was 8.61 µg/ml based on the Change of membrane Potential caused by Adsorption (CPA) value of the BT0 sensor. In this study, the taste-masking efficiency of 2-hydroxypropyl-β-cyclodextrin (HP-β-CyD) was assessed by Euclidean distances on a principle component analysis (PCA) map with the SA402B Taste Sensing System, and the host-guest interactions were investigated by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM). Biosensor evaluation and characterization of the inclusion complex indicated that atomoxetine HCl could actively react with 2-hydroxypropyl-β-cyclodextrin.

Multi-Methodological Quantitative Taste Assessment of Anti-Tuberculosis Drugs to Support the Development of Palatable Paediatric Dosage Forms

The unpalatability of antituberculosis drugs is often cited as a major cause of non-adherence in children, yet limited quantitative taste assessment data are available. The aim of this research was to quantify the bitterness of isoniazid, rifampicin, pyrazinamide, and ethambutol dihydrochloride using two in vivo (a human taste panel and a rat brief-access taste aversion (BATA) model) and one in vitro (sensor) method. The response of the Insent TS-5000Z electronic tongue was compared to the in vivo drug concentration found to elicit and suppress half the maximum taste response (EC₅₀ in human and IC₅₀ in rats). Using dose-relevant concentrations, an overarching rank order of bitterness was derived (rifampicin > ethambutol > pyrazinamid~isoniazid). In vitro, only ethambutol exhibited a linear response for all sensors/concentrations. Based on the EC₅₀/IC₅₀ generated, a ‘taste index’ was proposed to allow for anticipation of the likelihood of taste issues in practice, taking in account the saturability in the saliva and therapeutic doses; ethambutol and isoniazid were found to be the worst tasting using this measure. The study presents the first quantitative taste analysis of these life-saving drugs and has allowed for a comparison of three methods of obtaining such data. Such information allows the operator to identify and prioritise the drugs requiring taste masking to produce palatable formulations.

Sex Differences in Medicine Acceptability: A New Factor to Be Considered in Medicine Formulation

Palatability is a recognized driver of medicine acceptability in pediatrics but deemed less relevant in older populations due to sensory decline. Preliminary findings from an observational study implicated palatability problems with one Alzheimer's medicine. Among 1517 observer reports combining multiple measures on medicines uses in patients aged over 64, we focused on two original formulations of memantine (Ebixa^®, tablets (n = 25) and oral solution (n = 60)). Evaluations were scored with an acceptability reference framework (CAST), the rodent Brief Access Taste Aversion (BATA) model tested aversiveness. Focusing on women treated with Ebixa^® (n = 54), the oral formulation sub-group was classified as "negatively accepted", while the coated tablet was associated with the "positively accepted" cluster. In men, both formulations belonged to the "positively accepted" profile. Using BATA, the original oral solution was categorized as highly aversive/untolerated while solutions of excipients only were well tolerated. Furthermore, the number of licks was significantly lower in female than in male rats. These results revealed that medicine palatability remains important for acceptability in older populations. Moreover, converging results from humans and animal models highlighted that palatability profiles can significantly vary between the sexes. These drivers should be closely considered during drug development to enhance acceptability in this population.

In Vitro Dissolution Model Can Predict the in Vivo Taste Masking Performance of Coated Multiparticulates

The majority of active pharmaceutical ingredients (APIs) are bitter. Therefore, compliance can be a problem where adequate taste masking has not been achieved; this is most problematic in pediatrics. Taste masking is thus a key stage during pharmaceutical development with an array of strategies available to the formulation scientist. Solid oral dosage forms can be taste-masked quite simply by polymer coating, which prevents drug release in the mouth, without unwantedly impairing drug release further down the gastrointestinal tract. At the early stages of pharmaceutical development, an in vitro method for the assessment of taste masking is necessary given the lack of toxicological data preventing the use of human taste panels. Currently, there is no such tool allowing prediction of taste masking efficiency. In this study, drug dissolution in the context of aversive taste thresholds was proposed as a means to bridge this knowledge gap. Thus, a biorelevant buccal dissolution test was developed in which previously determined taste thresholds in vivo were used to evaluate taste masking efficiency: if drug release exceeded said thresholds, the formulation was deemed to be poorly taste-masked, and vice versa. This novel dissolution test was compared to the USP I (basket) dissolution test, and the biopharmaceutical implications of taste masking were also assessed by performing USP I (basket) dissolution testing in simulated gastric fluid (SGF). Chlorphenamine maleate, a model bitter BCS class 1 API, was layered onto sugar spheres and taste-masked using polymer coatings. An array of coating technologies were employed and assessed single blinded: two pH-independent water-insoluble coatings (Surelease:Opadry at 8, 12, and 16% weight gain and Opadry EC at 4, 6, and 8% weight gain) and a pH-dependent water-insoluble reverse-enteric coating (developmental fully formulated system based on Kollicoat Smartseal 100P at 10% weight gain). Both the biorelevant buccal and the USP I dissolution tests were capable of discriminating between both type and level of coating used. However, only the buccal dissolution test was able to provide absolute quantification of the level of taste masking achieved in the context of previously determined taste thresholds, while the USP I test merely provided a relative comparison between the different technologies assessed. When the release data from the buccal test were assessed in parallel to that in SGF, it was possible to predict in vitro optimized taste masking without compromising bioavailability. The fully formulated system based on Smartseal 100P was identified as the most effective coating and Surelease:Opadry the least effective. The developed methodology provides true insight for the formulator, enabling more informed patient-centric formulation decisions, better taste masking, and ultimately more effective medicines.

Rats can predict aversiveness of Active Pharmaceutical Ingredients

Taste is crucial for patient acceptability and compliance with prescribed medicines, in particular with pediatric patients. Evaluating the taste of new active pharmaceutical ingredients (APIs) is therefore essential to put in place adequate taste-masking techniques, if needed, which will lead to acceptable palatable formulations. Thus, there is an urgent need to develop and optimize taste assessment methods that could be used at different stages of the drug development process. The aim of this study was to investigate the suitability of the rat brief-access taste aversion (BATA) model as a screening tool for assessment of APIs aversiveness that could predict human taste responses. Presently, the taste intensity of nine marketed APIs known to have different levels of bitter intensity (quinine hydrochloride dihydrate, 6-n-propylthiouracil, sildenafil citrate, diclofenac sodium, ranitidine hydrochloride, caffeine citrate, isoniazid, telbivudine and paracetamol) was investigated at different overlapping concentrations with two in vivo taste assessment methods: the rat BATA model and human taste panels with the intention of determining the drugs' concentrations to produce half of the maximal rating. Overall there was a strong correlation (R² = 0.896) between rats IC₅₀ and humans EC₅₀ values. This correlation verifies the BATA model as a rapid and reliable tool for quantitative assessment of API aversiveness. A comparable ranking order was obtained mainly for high and medium aversive compounds, whereas it was less aligned for weakly aversive compounds. It was nonetheless possible to propose a classification of poor taste intensity determined in rats that would predict human taste tolerability.

Development and evaluation of an oral fast disintegrating anti-allergic film using hot-melt extrusion technology

The main objective of this novel study was to develop chlorpheniramine maleate orally disintegrating films (ODF) using hot-melt extrusion technology and evaluate the characteristics of the formulation using in vitro and in vivo methods. Modified starch with glycerol was used as a polymer matrix for melt extrusion. Sweetening and saliva-simulating agents were incorporated to improve palatability and lower the disintegration time of film formulations. A standard screw configuration was applied, and the last zone of the barrel was opened to discharge water vapors, which helped to manufacture non-sticky, clear, and uniform films. The film formulations demonstrated rapid disintegration times (6-11s) and more than 95% dissolution in 5min. In addition, the films had characteristic mechanical properties that were helpful in handling and storage. An animal model was employed to determine the taste masking of melt-extruded films. The lead film formulation was subjected to a human panel for evaluation of extent of taste masking and disintegration.

Assessment of swallowability and palatability of oral dosage forms in children: Report from an M-CERSI pediatric formulation workshop

The acceptability of pediatric pharmaceutical products to patients and their caregivers can have a profound impact on the resulting therapeutic outcome. However, existing methodology and approaches used for acceptability assessments for pediatric products is fragmented, making robust and consistent product evaluations difficult. A pediatric formulation development workshop took place in Washington, DC in June 2016 through the University of Maryland's Center of Excellence in Regulatory Science and Innovation (M-CERSI). A session at the workshop was dedicated to acceptability assessments and focused on two major elements that affect the overall acceptability of oral medicines, namely swallowability and palatability. The session started with presentations to provide an overview of literature, background and current state on swallowability and palatability assessments. Five parallel breakout discussions followed the presentations on each element, focusing on three overarching themes, risk-based approaches, methodology and product factors. This article reports the key outcomes of the workshop related to swallowability and palatability assessments.

Comparative in vitro and in vivo taste assessment of liquid praziquantel formulations

The taste of pharmaceuticals strongly affects the compliance of patients. This study investigated the applicability of the electronic tongue and rodent brief-access taste aversion (BATA) model for the bitter compound praziquantel (PZQ) and taste masked liquid formulations for PZQ. In a comparative study maltodextrin (MD) Kleptose^® linecaps 17 was selected as an alternative taste masking agent to two cyclodextrins; hydroxypropyl-beta-cyclodextrin (HP-β-CD) and sulfobutyl ether-beta-cyclodextrin (SBE-β-CD). A phase solubility study showed the highest affinity and solubilization capabilities for SBE-β-CD over HP-β-CD and MD, suggesting the highest taste masking ability for SBE-β-CD. No reliable results were achieved for PZQ with the Insent electronic tongue. Thus this system was not used for further evaluation of solutions with MD and CDs to confirm the results of the solubility study. In contrast the BATA model demonstrated conclusive responses for the aversiveness of PZQ. The concentration of PZQ inhibiting 50% of water lick numbers (called IC₅₀ value) was 0.06mg/ml. In contrast to the phase solubility study, the MD enabled an equal taste masking effect in vivo in comparison to both CDs. Moreover HP-β-CD showed superior taste masking capabilities for PZQ compared to SBE-β-CD as the SBE-β-CD itself was less acceptable for the rodents than HP-β-CD. In conclusion, the BATA model was identified as a more efficient taste assessment tool for the pure PZQ and liquid formulations in contrast to the electronic tongue and the phase solubility study.

Solid state characterisation and taste masking efficiency evaluation of polymer based extrudates of isoniazid for paediatric administration

Hot melt extrusion has gained considerable attention as a novel technique for taste masking of bitter APIs. The aim of this study was to investigate whether hot melt extrusion could be used to develop taste masked formulations of isoniazid and also to evaluate and correlate different taste assessment methods Two polymers with different physico-chemical properties, Soluplus and Eudragit E-PO were chosen as carriers for the drug. Eudragit E-PO has already been widely used for taste masking due to its selective release properties, while Soluplus has not been studied in this regard but provides a useful comparator of a polymer that should release the drug reasonably efficiently. Polymeric formulations of isoniazid were produced with drug loadings of 20% and 30% w/w. The solid state characteristics of the formulations were assessed by differential scanning calorimetry and powder X-ray diffraction. The taste of isoniazid was assessed using the rodent Brief Access Taste Aversion (BATA) model, while formulations were assessed using the electronic tongue and dissolution under simulated oral conditions. Investigation into the drug loading effect with these two polymers showed that all Soluplus based extrudates with drug loading up to 30% w/w were fully amorphous while Eudragit E-PO based extrudates contained crystalline drug as demonstrated by both DSC and PXRD, dependent on loading. BATA testing of isoniazid gave an IC₅₀ value, i.e. the dose of drug which inhibits 50% of licks, of 11.1mg/mL. Taste assessment of the formulations using both simulated oral drug release and the electronic tongue demonstrated that Eudragit E-PO based formulations had a better taste masking efficiency than Soluplus. This is due to the fact that significantly less isoniazid is released from the Eudragit E-PO based formulations under oral conditions.

New generalized poisson mixture model for bimodal count data with drug effect: An application to rodent brief-access taste aversion experiments

Pharmacodynamic (PD) count data can exhibit bimodality and nonequidispersion complicating the inclusion of drug effect. The purpose of this study was to explore four different mixture distribution models for bimodal count data by including both drug effect and distribution truncation. An example dataset, which exhibited bimodal pattern, was from rodent brief-access taste aversion (BATA) experiments to assess the bitterness of ascending concentrations of an aversive tasting drug. The two generalized Poisson mixture models performed the best and was flexible to explain both under and overdispersion. A sigmoid maximum effect (Emax ) model with logistic transformation was introduced to link the drug effect to the data partition within each distribution. Predicted density-histogram plot is suggested as a model evaluation tool due to its capability to directly compare the model predicted density with the histogram from raw data. The modeling approach presented here could form a useful strategy for modeling similar count data types.

Non-human tools for the evaluation of bitter taste in the design and development of medicines: a systematic review

Taste evaluation is a crucial factor for determining acceptance of medicines by patients. The human taste panel test is the main method used to establish the overall palatability and acceptability of a drug product to a patient towards the end of development. Non-human in vitro and in vivo taste-evaluation tools are very useful for pre-formulation, quality control and screening of formulations. These non-human taste assessment tools can be used to evaluate all aspects of taste quality. The focus of this review is bitterness because it is a key aspect of taste in association with the development of medicines. In this review, recent in vitro (analytical) and in vivo (non-human) tools are described for the assessment of the bitter taste of medicines. Their correlations with human taste data are critically discussed. The potential for their use in early screening of the taste of active pharmaceutical ingredients (APIs) to expedite paediatric formulation development is also considered.