Dissolution methodology for taste masked oral dosage forms

Effects of nano zinc oxide and nano chitosan on the taste masking paracetamol granules

OBJECTIVE

The purpose of this study is to investigate the taste masking of Paracetamol granules in the range of 250-850 µm, coated by two nanocomposites prepared from Eudragit® E100, nanozinc oxide, and nanochitosan, respectively, from 1 to 5% by the weight of the granules.

METHODS

In this study, Paracetamol granules were coated in several formulas with two different types of nanocomposites (polymeric and mineral) on two sizes of granules to reduce bitter taste and with the FBC method and pH-sensitive polymers (Eudragit® E100).

RESULTS

The effect of nanoparticles (Nano zinc oxide and Nanochitosan) on taste-masking Paracetamol was studied with dissolution-coated granules in vitro by simulating in the oral (pH 6.8) range. Based on the results of the studies, the rate of drug release was confirmed by the taste test, and the formulated granule with 5% nano-chitosan (F14) had the best bitter taste mask function of all samples. These results were also confirmed by scanning electron microscopy (SEM) analysis, which showed a smoother and more stable surface than the samples obtained from other formulations.

CONCLUSION

In the comparison of the release of two types of nanocomposites in the dissolution test, it was shown that the type B granules of Paracetamol's 5% nano-chitosan-coated granule (F14) were released 99% less than Paracetamol's 5% nano-ZnO-coated granule (F11). and Paracetamol's 1% nano-chitosan-coated granule (F12) was released 91% less than Paracetamol's 1% nano-ZnO-coated granule (F9). The results showed that nano-chitosan-coated granules have better coverage of bitter taste instead of nano-ZnO.

Taste-masking methods in multiparticulate dosage forms with a focus on poorly soluble drugs

In the past, the administration of medicines for children mainly involved changes to adult dosage forms, such as crushing tablets or opening capsules. However, these methods often led to inconsistent dosing, resulting in under- or overdosing. To address this problem and promote adherence, numerous initiatives, and regulatory frameworks have been developed to develop more child-friendly dosage forms. In recent years, multiparticulate dosage forms such as mini-tablets, pellets, and granules have gained popularity. However, a major challenge that persists is effectively masking the bitter taste of drugs in such formulations. This review therefore provides a brief overview of the current state of the art in taste masking techniques, with a particular focus on taste masking by film coating. Methods for evaluating the effectiveness of taste masking are also discussed and commented on. Another important issue that arises frequently in this area is achieving sufficient dissolution of poorly water-soluble drugs. Since the simultaneous combination of sufficient dissolution and taste masking is particularly challenging, the second objective of this review is to provide a critical summary of studies dealing with multiparticulate formulations that are tackling both of these issues.

Quantifying the bitter masking effect of drug-cyclodextrin complexation: NMR-ROESY mixing time approach

Taste, especially unpleasant taste, can be key for patient compliance. In the formulation development process, drug-cyclodextrin (CD) inclusion complexes are often used to improve the solubility of a drug and/or mask its bitterness. This study aimed to evaluate the bitter masking effect of CDs on different drugs using NMR-ROESY analysis, human sensory tests, and e-tongue measurements. The strength of inclusion complex formation between drugs and CDs was investigated by NMR-ROSEY, and these results were compared to human sensory test results. In the sensory test, participants identified which drug-CD inclusion complexes were not bitter. NMR-ROSEY results aligned with the sensory tests; short magnetization transfer times corresponded to masked bitterness. The electrical tongue was not able to detect the taste of any of the drug-CD inclusion complexes. Additionally, we used NMR-ROSEY to determine which drug-CD inclusion complex formed in a system with multiple drug substances present. This research offers valuable insights into the bitter masking effect of CDs on different drugs and presents a comprehensive evaluation approach using various methods. This knowledge has significant implications for the pharmaceutical industry, clinical practice, and patient care, contributing to improved patient compliance and satisfaction with bitter medications.

Taste Masking of Dexketoprofen Trometamol Orally Disintegrating Granules by High-Shear Coating with Glyceryl Distearate

Orally disintegrating granules (ODGs) are a pharmaceutical form commonly used for the administration of NSAIDs because of their easy assumption and fast dispersion. The development of ODGs is not easy for drugs like dexketoprofen trometamol (DXKT), which have a bitter and burning taste. In this work, high-shear coating (HSC) was used as an innovative technique for DKXT taste masking. This study focused on coating DXKT granules using the HSC technique with a low-melting lipid excipient, glyceryl distearate (GDS). The HSC technique allowed for the coating to be developed through the thermal rise resulting from the friction generated by the granules movement inside the equipment, causing the coating excipient to soften. The design of the experiment was used to find the best experimental coating conditions in order to gain effective taste masking by suitably reducing the amount of drug released in the oral cavity. The influence of the granule dimensions was also investigated. Coating effectiveness was evaluated using a simulated saliva dissolution test. It was found that low impeller speed (300 rpm) and a 20% coating excipient were effective in suitably reducing the drug dissolution rate and then in taste masking. The coated granules were characterized for their morphology and solid-state properties by SEM, BET, XRPD, DSC, and NIR analyses. A human taste panel test confirmed the masking of DXKT taste in the selected batch granules.

Novel bioequivalent oral disintegrating tablet of aripiprazole prepared by direct compression technique with shortened disintegration time

Herein, we aimed to formulate a novel oral disintegrating tablet (ODT) of aripiprazole (ARP) capable of rapid disintegration using a direct compression technique. Different ODTs were fabricated with directly compressible excipients, and their disintegration time, wettability (water absorption ratio and wetting time), and mechanical properties (hardness and friability) were evaluated. The optimized ODT comprised F-Melt® type C, Prosolv® SMCC HD90, and Na croscarmellose (10 mg of ARP in a 130 mg tablet). The ODT with 3.1-5.2 kp hardness exhibited rapid disintegration (14.1-17.2 sec), along with appropriate mechanical strength (friability < 0.24%). In a bioequivalent study in Korean healthy subjects (randomized, single-dose, two-period crossover design, n = 37), the novel ODT offered the equivalent pharmacokinetic profile to that of a conventional immediate release tablet (Otsuka, Abilify®, Japan), despite different disintegration and dissolution profiles. The 90% confidence intervals of the geometric mean test to reference ratios considering the area-under-the-curve and maximum plasma drug concentrations were 1.0306-11051 and 0.9448-1.1063, respectively, satisfying FDA regulatory criteria for bioequivalence. The novel ART ODT was physicochemically stable under the accelerated storage condition (40 °C, RH75%) for 24 weeks. Therefore, the novel ARP-loaded ODT is expected to be an alternative to oral ARP therapy, providing improved patient adherence.

A Guide to Best Practice in Sensory Analysis of Pharmaceutical Formulations

It is well established that treatment regime compliance is linked to the acceptability of a pharmaceutical formulation, and hence also to therapeutic outcomes. To that end, acceptability must be assessed during the development of all pharmaceutical products and especially for those intended for paediatric patients. Although acceptability is a multifaceted concept, poor sensory characteristics often contribute to poor patient acceptability. In particular, poor taste is often cited as a major reason for many patients, especially children, to refuse to take their medicine. It is thus important to understand and, as far as possible, optimise the sensory characteristics and, in particular, the taste/flavour/mouthfeel of the formulation throughout the development of the product. Sensory analysis has been widely practiced, providing objective data concerning the sensory aspects of food and cosmetic products. In this paper, we present proposals concerning how the well-established principles of sensory analysis can best be applied to pharmaceutical product development, allowing objective, scientifically valid, sensory data to be obtained safely. We briefly discuss methodologies that may be helpful in reducing the number of samples that may need to be assessed by human volunteers. However, it is only possible to be sure whether or not the sensory characteristics of a pharmaceutical product are non-aversive to potential users by undertaking sensory assessments in human volunteers. Testing is also required during formulation assessment and to ensure that the sensory characteristics remain acceptable throughout the product shelf life. We provide a risk assessment procedure to aid developers to define where studies are low risk, the results of a survey of European regulators on their views concerning such studies, and detailed guidance concerning the types of sensory studies that can be undertaken at each phase of product development, along with guidance about the practicalities of performing such sensory studies. We hope that this guidance will also lead to the development of internationally agreed standards between industry and regulators concerning how these aspects should be measured and assessed throughout the development process and when writing and evaluating regulatory submissions. Finally, we hope that the guidance herein will help formulators as they seek to develop better medicines for all patients and, in particular, paediatric patients.

Paediatric Medicinal Formulation Development: Utilising Human Taste Panels and Incorporating Their Data into Machine Learning Training

This review paper explores the role of human taste panels and artificial neural networks (ANNs) in taste-masking paediatric drug formulations. Given the ethical, practical, and regulatory challenges of employing children, young adults (18-40) can serve as suitable substitutes due to the similarity in their taste sensitivity. Taste panellists need not be experts in sensory evaluation so long as a reference product is used during evaluation; however, they should be screened for bitterness taste detection thresholds. For a more robust evaluation during the developmental phase, considerations of a scoring system and the calculation of an acceptance value may be beneficial in determining the likelihood of recommending a formulation for further development. On the technological front, artificial neural networks (ANNs) can be exploited in taste-masking optimisation of medicinal formulations as they can model complex relationships between variables and enable predictions not possible previously to optimise product profiles. Machine learning classifiers may therefore tackle the challenge of predicting the bitterness intensity of paediatric formulations. While advancements have been made, further work is needed to identify effective taste-masking techniques for specific drug molecules. Continuous refinement of machine learning algorithms, using human panellist acceptability scores, can aid in enhancing paediatric formulation development and overcoming taste-masking challenges.

An Overview of Taste-Masking Technologies: Approaches, Application, and Assessment Methods

It is well-known that plenty of active pharmaceutical ingredients (API) inherently possess an unpleasant taste, which influences the acceptance of patients, especially children. Therefore, manufacturing taste-masked dosage forms has attracted a lot of attention. This review describes in detail the taste-masking technologies based on the difference in the taste transmission mechanism which is currently available. In particular, the review highlights the application of various methods, with a special focus on how to screen the appropriate masking technology according to the properties of API. Subsequently, we overviewed how to assess taste-masking efficacy, guiding researchers to rationally design taste-masking formulations.

Modernising Orodispersible Film Characterisation to Improve Palatability and Acceptability Using a Toolbox of Techniques

Orodispersible films (ODFs) have been widely used in paediatric, geriatric and dysphagic patients due to ease of administration and precise and flexible dose adjustments. ODF fabrication has seen significant advancements with the move towards more technologically advanced production methods. The acceptability of ODFs is dependent upon film composition and process of formation, which affects disintegration, taste, texture and mouthfeel. There is currently a lack of testing to accurately assess ODFs for these important acceptability sensory perceptions. This study produced four ODFs formed of polyvinyl alcohol and sodium carboxymethylcellulose using 3D printing. These were assessed using three in vitro methods: Petri dish and oral cavity model (OCM) methods for disintegration and bio-tribology for disintegration and oral perception. Increasing polymer molecular weight (MW) exponentially increased disintegration time in the Petri dish and OCM methods. Higher MW films adhered to the OCM upper palate. Bio-tribology analysis showed that films of higher MW disintegrated quickest and had lower coefficient of friction, perhaps demonstrating good oral perception but also stickiness, with higher viscosity. These techniques, part of a toolbox, may enable formulators to design, test and reformulate ODFs that both disintegrate rapidly and may be better perceived when consumed, improving overall treatment acceptability.

Development and optimisation of simulated salivary fluid for biorelevant oral cavity dissolution

Drug release within the oral cavity can be of paramount importance for formulations that are designed for specific purposes such as taste-masking, faster onset of therapeutic action, localization of treatment or avoidance of first-pass metabolism. Preclinical methods for assessment of dissolution in the oral cavity are necessary for design and development of these formulation but currently there is no consensus on what variables should be defined to achieve biorelevance in these tests. In this study, biorelevant simulated salivary fluids (SSFs) that can be uniformly applied for oral cavity dissolution testing were developed. Unstimulated saliva (US) SSF and stimulated saliva (SS) SSF were separately developed since the two states significantly differ. Physicochemical properties including pH, buffer capacity, surface tension and viscosity were assessed during development and optimised to mimic human saliva (HS). In order to account for the salivary proteins in HS, use of bovine submaxillary mucin (BSM) and porcine gastric mucin (PGM) in SSFs was evaluated. Following optimisation of the SSFs, biorelevance of the developed SSFs to HS was assessed by their comparative physicochemical properties as well as dissolution profiles of three diverse model compounds (sildenafil citrate, efavirenz, and caffeine) which showed comparable profiles between the SSFs and HS. This work addresses the lack of uniformed biorelevant dissolution media for oral cavity dissolution studies and provides a basis for standardised dissolution tests that provide consistency and harmonisation in future oral cavity dissolution studies. We envisage that this will have a positive impact on the development of new medicines that require functionality in the oral cavity.

A review of the flavor profile of metal salts: understanding the complexity of metallic sensation

The oral sensation of metallic is a complex experience. Much of our current understanding of metallic sensation is from the investigation of metal salts, which elicit diverse sensations, including taste, smell, and chemesthetic sensations, and therefore meet the definition of a flavor rather than a taste. Due to the involvement of multiple chemosensory systems, it can be challenging to define and characterize metallic sensation. Here, we provide a comprehensive review of the psychophysical studies quantifying and characterizing metallic sensation, focusing on metal salts. We examine the factors that impact perception, including anion complex, concentration, nasal occlusion, and pH. In addition, we summarize the receptors thought to be involved in the perception of metallic sensation (i.e., TRPV1, T1R3, TRPA1, and T2R7) either as a result of in vitro assays or from studies in knock-out mice. By enhancing our scientific understanding of metallic sensation and its transduction pathways, it has the potential to improve food and pharmaceuticals, help identify suppression or masking strategies, and improve the ability to characterize individual differences in metallic sensation. It also has the potential to translate to clinical populations by addressing the disparities in knowledge and treatment options for individuals suffering from metallic taste disorder (i.e., phantom taste or "metal mouth"). Future psychophysical studies investigating the sensory perception of metal salts should include a range of compounds and diverse food matrices, coupled with modern sensory methods, which will help to provide a more comprehensive understanding of metallic sensation.

Studies on the in vitro ion exchange kinetics and thermodynamics and in vivo pharmacokinetics of the carbinoxamine-resin complex

The short half-life and bitter taste of carbinoxamine maleate² (CAM) lead to poor compliance by pediatric patients who are being treated for allergic rhinitis. To address these issues, carbinoxamine-resin complexes³ (CRCs) were prepared by ion exchange and then coated with Kollicoat SR 30D. The resultant microencapsulated carbinoxamine-resin complexes⁴ (MCRCs) were dispersed into the medium to obtain the final suspensions. The drug loading kinetics and thermodynamics of CRCs, anti-swelling mechanism of the impregnant in MCRCs, in vitro release, and in vivo pharmacokinetics of the suspensions were systematically evaluated. The drug loading process was found to obey a first-order kinetic process that was spontaneous, entropy-reduced and exothermic, and the diffusion of CAM into the resin was the rate-limiting step. During microencapsulation, the impregnant could create a certain buffer space to control the swelling of CRCs and maintain the coating film intact. The homemade preparations had release behaviors similar to that of the reference in vitro and achieved sustained release in vivo. The low drug loading preparation had a higher relative bioavailability of 109% owing to its faster release and better dispersibility. Therefore, the suspensions based on MCRCs could be successfully applied to treating allergic rhinitis in children.

Orodispersible Polymer Films with the Poorly Water-Soluble Drug, Olanzapine: Hot-Melt Pneumatic Extrusion for Single-Process 3D Printing

Amorphous solid dispersions (ASDs) improve the oral delivery of poorly water-soluble drugs. ASDs of olanzapine (OLZ), which have a high melting point and low solubility, are performed using a complicated process. Three-dimensional (3D) printing based on hot-melt pneumatic extrusion (HMPE) is a simplified method for producing ASDs. Unlike general 3D printing, printlet extrusion is possible without the preparation of drug-loaded filaments. By heating powder blends, direct fused deposition modeling (FDM) printing through a nozzle is possible, and this step produces ASDs of drugs. In this study, we developed orodispersible films (ODFs) loaded with OLZ as a poorly water-soluble drug. Various ratios of film-forming polymers and plasticizers were investigated to enhance the printability and optimize the printing temperature. Scanning electron microscopy (SEM) showed the surface morphology of the film for the optimization of the polymer carrier ratios. Differential scanning calorimetry (DSC) was used to evaluate thermal properties. Powder X-ray diffraction (PXRD) confirmed the physical form of the drug during printing. The 3D printed ODF formulations successfully loaded ASDs of OLZ using HMPE. Our ODFs showed fast disintegration patterns within 22 s, and rapidly dissolved and reached up to 88% dissolution within 5 min in the dissolution test. ODFs fabricated using HMPE in a single process of 3D printing increased the dissolution rates of the poorly water-soluble drug, which could be a suitable formulation for fast drug absorption. Moreover, this new technology showed prompt fabrication feasibility of various formulations and ASD formation of poorly water-soluble drugs as a single process. The immediate dissolution within a few minutes of ODFs with OLZ, an atypical antipsychotic, is preferred for drug compliance and administration convenience.

How Do Orodispersible Tablets Behave in an In Vitro Oral Cavity Model: A Pilot Study

Orodispersible tablets (ODTs) offer rapid disintegration of the dosage form when placed on the tongue, which leads to fast release of the active pharmaceutical ingredient. Despite increased use in diverse patient populations, there have been numerous challenges associated with ODTs. One such concern is the lack of standardised assessment of disintegration behaviour. In the European Pharmacopoeia, ‘orodispersibles’ are defined as such if disintegration time is faster than 3 min. Common in vitro measurement methods only provide single time point data and have limited physiological accuracy. To determine more bio-predictive disintegration kinetics, a bench-top in vitro oral cavity model (OCM) was modified and piloted to assess disintegration of three ODTs of differing hardness. All ODTs disintegrated similarly within the OCM—surface breakdown/swelling, initial ‘wash away’ and final ‘wash away’. The distinct advantage presented within this pilot study using the OCM is the opportunity to ascertain disintegration behaviour profiles of ODTs by evaluating changes in the observable area during simulated oral processing. The model could be implemented as a decision-support tool during the early stages of the drug design process to improve acceptability and further understand ODT disintegration behaviour.

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.

Taste masking of water-soluble drug by solid lipid microspheres: a child-friendly system established by reversed lipid-based nanoparticle technique

Objectives

A child-friendly taste-masking strategy using solid lipid microsphere (SLM) has been proposed to obscure the undesirable taste of some water-soluble drugs. In this study, the reversed lipid-based nanoparticle (RLBN) technique was used to encapsulate a water-soluble drug to facilitate the preparation of SLM.

Methods

The model drug used was atomoxetine hydrochloride (ATX), and a three-step method was used to prepare ATX-RLBN. Taste-masking microsphere (ATX-RLBN-SLM) was prepared by the spray chilling method. The drug release mechanism was studied by high-performance liquid chromatography and scanning electron microscopy. Moreover, in vitro taste evaluation method was established and ATX bioavailability was investigated employing pharmacokinetic studies.

Key findings

The obtained ATX-RLBN-SLM had smooth spherical particles with a size of about 80 μm. The drug encapsulation and loading efficiencies were 98.28% ± 0.59% and 0.89% ± 0.04%, respectively. In vitro drug release studies showed that nearly 96% drug was retained in the microspheres within 10 min at pH 6.8 and a complete release was triggered by lipase, accompanied by variation in the morphology. Taste assessment revealed that ATX-RLBN-SLM could efficiently mask the bitter taste and improved the bioavailability of ATX.

Conclusions

Atomoxetine hydrochloride-reversed lipid-based nanoparticle-solid lipid microsphere exhibited excellent taste-masking effect with negligible leakage in the oral cavity environment and thorough collapse upon lipase stimulation, simultaneously enhancing the bioavailability of ATX. The study paves a new way to efficiently mask the undesirable taste of some water-soluble drugs.

Is rat a good model for assessment of particulate-based taste-masked formulations?

Recently there has been an increased interest to develop specialised dosage forms that are better suited to specific patient populations, such as paediatrics and geriatrics. In these patient populations the acceptability of the oral dosage form can be paramount to the products success. However, many Active Pharmaceutical Ingredients (APIs) are known to cause an aversive taste response. One way to increase the acceptability and to enhance the palatability of the formulation is to design coated taste-masked particulate-based dosage forms. The masking of poorly tasting drugs with physical barriers such as polymer coatings can be utilised to prevent the release of drug within the oral cavity, thus preventing a taste response. However, currently, there are few assessment tools and models available to test the efficiency of these particulate-based taste-masked formulations. The rat brief access taste aversion model has been shown to be useful in assessment of taste for liquid dosage forms. However, the applicability of the rat model for particulate-based taste masked formulations is yet to be assessed. It is not understood whether dissolution, solubility and thus exposure of the drug to taste receptors would be the same in rat and human. Therefore, rat saliva must be compared to human saliva to determine the likelihood that drug release would be similar within the oral cavity for both species. In this study rat saliva was characterised for parameters known to be important for drug dissolution, such as pH, buffer capacity, surface tension, and viscosity. Subsequently dissolution of model bitter tasting compounds, sildenafil citrate and efavirenz, in rat saliva was compared to dissolution in human saliva. For all parameters characterised and for the dissolution of both drugs in rat saliva, a substantial difference was observed when compared to human saliva. This discrepancy in saliva parameters and dissolution of model drugs suggests that preclinical taste evaluation of particulate-based taste-masked formulations suggests rat is not a good model for predicting taste of solid dosage forms or undissolved drug where dissolution is required. Alternative preclinical in vivo models in other species, or improved biorelevant in vitro models should be considered instead.

Monitoring microsphere coating processes using PAT tools in a bench scale fluid bed

Among the factors that influence adherence to medication within the pediatric population, taste/irritation has been identified as a critical barrier to patient compliance. With the goal of improving compliance, microspheres (matrix systems within which the drug is dispersed) can be coated with a reverse enteric polymer that will prevent the release of the drug in the oral cavity while maintaining an immediate release once the drug product reaches the stomach, thereby achieving a taste neutral profile. In this work, the in-line performance of three process analytical technology (PAT) tools is evaluated in order to monitor the microsphere coating process. These tools are Raman spectroscopy, near-infrared spectroscopy and focused beam reflectance measurements, together with process data and raw material attributes. The ability of these different sources of information to predict the coating's barrier performance is evaluated by using a combined-data-approach: multiblock partial least squares (MBPLS). Results show that Raman spectroscopy has a superior predictive performance and that it has the potential to monitor the coating process of the microspheres as well as to detect process discrepancies (such as spray rate changes), demonstrating its usefulness for the monitoring of fluid bed coating processes. It was also demonstrated that Raman can be used to clearly differentiate batches with significantly difference in-vitro dissolution performance. This monitoring is considered critical to ensure consistent coating performance for this thin film barrier membrane that is essential to patient compliance.

Personalized anesthetic patches for dental applications

Topical anesthetics are widely used in dental procedures. However, most commercially available medications are in the form of liquid or semisolid, which cannot provide prolonged effect intraorally. To address this issue, we proposed the use of three-dimensional printing (3DP) to fabricate a customizable dental anesthetic patch loaded with lidocaine that can be fitted perfectly onto the affected tooth. It has been shown that that patch can adhere on the tooth for more than 1 h, while releasing lidocaine from the patch made of hydrogels. In addition, the results illustrated the possibility of controlling the drug release profile by altering the shape of the patch, as well the use of a 3DP tooth model as the drug testing platform. Taken together, these data further reinforce the vast potential of the application of 3DP technology in personalized medicine.

How to assess orodispersible film quality? A review of applied methods and their modifications

In recent years, there has been a tendency toward creating innovative, easy to use and patient-friendly drug delivery systems suitable for every consumer profile, which would ensure safety, stability and acceptability of a drug. One of the relatively novel and promising approaches is the manufacture of orodispersible films (ODFs), which is an upcoming area of interest in drug delivery. They are defined as polymer thin films that disintegrate in the oral cavity within seconds, without drinking water or chewing, and eliminate the risk of choking. Gaining special usefulness in therapies of children and the elderly, ODFs seem to fill the gap in the range of preparations available for these groups of patients. As no detailed monography of ODFs including testing methods and uniform requirements has been presented in any of the pharmacopoeias to date, the aim of this article is to give an overview of the applied testing methods, their modifications and innovative approaches related to ODF quality assessment.

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.

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.

Building Process Understanding of Fluid Bed Taste Mask Coating of Microspheres

Taste is routinely cited as one of the major contributing factors that negatively influence pediatric patient compliance. A promising solution is coated microsphere systems, which provide doses of active pharmaceutical ingredients (API) subdivided into a plurality of small dosage units. In this work, the microspheres were coated with Kollicoat® Smartseal, a reverse enteric polymer, which acts to minimize or prevent the release of API in the neutral pH of the oral cavity, which results in a masking effect of the unpleasant taste of the API. A screening of seven key variables in a Wurster coating process was evaluated by D-optimal design and by analysis of variance. The percentage of API released at pH 6.2 was used as a surrogate method for the taste-masking performance evaluation of Kollicoat® Smartseal. The seven studied variables were: product bed temperature, inlet airflow, atomizing air pressure, spray rate (process parameters), coating level, plasticizer level, solids in coating suspension (material attributes), and curing. Results show that coating level, plasticizer level, product bed temperature, and spray rate are the critical process parameters and reinforce the importance of curing to reduce the overall variability within the batch by promoting complete film formation. The link between material attributes, process parameters, and quality attributes were demonstrated to allow a better understanding of the parameters that affect the API release profile at neutral pH (in vitro) while not injuring release at acidic pH (in vitro). It was demonstrated that not only thickness but also coating morphology have an impact on the dissolution in 50 mM potassium phosphate buffer, pH 6.2.

In Vitro Oral Cavity Model for Screening the Disintegration Behavior of Orodispersible Films: A Bespoke Design

The availability of biorelevant methods for the disintegration study of pharmaceutical orodispersible dosage forms is required. The disintegration of orodispersibles should be assessed using in vitro methods that can combine biorelevant volumes of disintegration medium and mechanical stresses mimicking in vivo conditions. This study proposes an adaptation of a mechanical oral cavity model for the disintegration study of orodispersible films. A periodic compression is applied to the sample in the presence of a biorelevant volume of artificial salivary fluid. Four orodispersible film samples (P1, C1, P2, and C2), differing in polymer type and molecular weight, and Listerine^® were tested and filmed during disintegration. An image analysis program was developed for the determination of the volume reduction of the film matrix over time, as a descriptor of film disintegration behavior. Samples P1 and Listerine^® showed a volume reduction at 180 s of >90%, C1, P2, and C2 were 85%, 48%, and 37%, respectively. The model was able to detect differences in the disintegration behavior of the 4 samples, and results were comparable with the benchmark product. The concept of disintegration behavior of orodispersible films was introduced for the first time as an informative method for the study of orodispersible dosage form.

Creation of an assessment system for measuring the bitterness of azithromycin-containing reverse micelles

We aimed to develop a novel method for assessing the bitterness of azithromycin-containing reverse micelles (AM-containing RMs). Azithromycin-containing reverse micelles were prepared by processing Lipoid E80 and medium chain triglycerides via a freeze-drying method. The bitterness threshold of azithromycin was determined by human taste test, and an equation was derived to correlate the azithromycin concentrations and bitterness scores of standard solutions. Simulated salivary fluids and sampling times were fixed based on the drug release profile of AM-containing RMs, with Zithromax^® (a commercial formulation of azithromycin) used as the control. The drug release concentrations from stimulated salivary fluids were then used to assess the bitterness of AM-containing RMs and Zithromax^®. Afterward, the oral bioavailability of both formulations was evaluated by in vivo experiments in male Wistar rats. The results showed that the bitterness threshold of azithromycin standard solutions was between 25.3 µg/ml and 30.4 µg/ml. Thereafter, we calculated that the bitterness scores and the drug release concentrations of the azithromycin-containing reverse micelle formulation were similar to those of Zithromax^® at each time point after 10 min of dispersal in simulated salivary fluid. In addition, the AUC_0−t after oral administration of AM-containing RMs was 1.75-fold (P < 0.05) higher than that of Zithromax^®. In conclusions, a system for assessing bitterness was developed using an in vitro drug release evaluation method and a human taste test panel. We found that the bitterness of azithromycin was successfully masked by reverse micelles, which also improved the oral bioavailability of azithromycin compared to that of Zithromax^®.

Preparation and Evaluation of Taste Masking Iron Suspension: Taking Advantage of Weak Cationic Exchange Resin

The objective of this study is to use weak acid cation exchange resin to mask the taste and eliminate the teeth staining problems of ferrous sulfate liquid preparations for use in pediatrics. Amberlite IPR64 was loaded by Fe(II). Then, different suspensions of the iron-resin complex were prepared using various polymers as the suspending agents, and sorbitol as well as sucrose as sweeteners. Physical stability, rheological assessment, kinetics of Fe(II) release, and taste evaluation of suspensions were studied. The results implied that the prepared iron suspension was more stable when xanthan gum is used as the suspending agent. It was also shown that iron release in 0.7% NaCl (similar to saliva) was very negligible compared to relatively quick release in acidic medium (resembled the stomach). Overall, the volunteers confirmed that the formulations were successful in iron taste masking. The pH-dependent process of ion exchange by weak cationic resins opens an attractive approach to access a taste-masked iron suspension for infants.

Formulation of orodispersible films for paediatric therapy: investigation of feasibility and stability for tetrabenazine as drug model

Objectives

Orodispersible films (ODF) were formulated to facilitate tetrabenazine (TBZ) administration to paediatric population for the treatment of hyperkinetic movement disorders.

Methods

ODF were obtained by solvent casting/evaporation method using four different polymers (HPMC, PVP, pullulan and HEC). Physicochemical, mechanical and biopharmaceutical characterizations as well as API state in ODF by thermal analysis were investigated to define and compare formulations. ODF stability was also monitored during 6 months to follow evolution of properties.

Key findings

Analyses at T0 showed few differences between formulations: results of physicochemical and mechanical characterizations were almost similar for each formulation and TBZ appeared at the amorphous state in all cases. ODF delivery system allowed a major improvement of TBZ dissolution profile in buccal conditions compared with pure drug. However, after 3 and 6 months of stability, a TBZ recrystallization occurred for formulations based on PVP and HEC associated with a decrease of drug release in saliva conditions.

Conclusions

HPMC-ODF (F1) appeared as the best formulation. Indeed, physicochemical, mechanical and biopharmaceutical characteristic remained intact. In addition, TBZ remained in amorphous state during stability study.

In vitro and in vivo investigation of taste-masking effectiveness of Eudragit E PO as drug particle coating agent in orally disintegrating tablets

CONTEXT

Considering that bitter taste of drugs incorporated in orally disintegrating tablets (ODTs) can be the main reason for avoiding drug therapy, it is of the utmost importance to achieve successful taste-masking. The evaluation of taste-masking effectiveness is still a major challenge.

OBJECTIVE

The objective of this study was to mask bitter taste of the selected model drugs by drug particle coating with Eudragit^® E PO, as well as to evaluate taste-masking effectiveness of prepared ODTs using compendial dissolution testing, dissolution in the small-volume shake-flask assembly and trained human taste panel.

MATERIALS AND METHODS

Model drugs were coated in fluidized bed. Disintequik™ ODT was used as a novel co-processed excipient for ODT preparation. Selected formulations were investigated in vitro and in vivo using techniques for taste-masking assessment.

RESULTS AND DISCUSSION

Significantly slower drug dissolution was observed from tablets with coated drug particles during the first 3 min of investigation. Results of in vivo taste-masking assessment demonstrated significant improvement in drug bitterness suppression in formulations with coated drug. Strong correlation between the results of drug dissolution in the small-volume shake-flask assembly and in vivo evaluation data was established (R ≥ 0.970).

CONCLUSION

Drug particle coating with Eudragit^® E PO can be a suitable approach for bitter taste-masking. Strong correlation between in vivo and in vitro results implicate that small-volume dissolution method may be used as surrogate for human panel taste-masking assessment, in the case of physical taste-masking approach application.

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.