The taste of drugs is an important factor affecting pharmacotherapy effectiveness, and obtaining formulations with acceptable organoleptic properties is still an ongoing issue in pharmaceutical technology. One of the innovative methods of taste masking is preparation of microparticles by the spray drying technique, utilizing polymers with different physicochemical properties. Rupatadine fumarate (RUP) is one of the newest antihistamines, with an innovative and multidirectional mechanism of action, and an extremely bitter taste. The aim of this work was to investigate the feasibility of utilizing organic or aqueous forms of ethylcellulose (EC) for the preparation of microparticles with RUP by the spray drying technique. Spray dried samples at different drug:polymer ratios were prepared using organic solution (Ethocel®) or aqueous dispersions of EC (Surelease®, Aquacoat® ECD). Evaluation of the taste masking efficacy was performed in vivo in human taste panel, in vitro based on dissolution test, and by self-constructed electronic tongue. It was shown that microparticles obtained from aqueous dispersions of EC have superior pharmaceutical properties in terms of both morphology and taste masking efficacy in comparison to those obtained from organic solution.

Orally disintegrating tablets and oral lyophilisates are novel attractive dosage forms that disintegrate or dissolve in the buccal cavity within seconds without necessity of drinking. The major limitation in designing of these dosage forms is unpleasant taste of the drug substance. Cetirizine dihydrochloride is a H-antihistamine substance indicated for the treatment of allergy. It is characterized by extremely bitter taste, therefore in order to deliver cetirizine dihydrochloride using orodispersible formulations, effective taste-masking is required. The aim of this study was to investigate whether microparticles containing cetirizine dihydrochloride could be successfully used to formulate orally disintegrating tablets by direct compression method and oral lyophilisates by freeze-drying process. Taste masking of cetirizine dihydrochloride was achieved by the spray-drying technique using Eudragit E PO as the drug agent carrier. Based on the preliminary studies, optimal compositions of microparticles, tablets and lyophilisates were chosen. Obtained dosage forms were characterized for drug content, disintegration time and mechanical properties. In order to determine whether the microparticles subjected to direct compression and freeze-drying process effectively mask the bitter taste of cetirizine dihydrochloride, the and evaluation was performed. The results showed that designed formulates with microparticles containing cetirizine dihydrochloride were characterized by appropriate mechanical properties, uniformity of weight and thickness, short disintegration time, and the uniform content of the drug substance. Taste-masking assessment performed by three independent methods (e-tongue evaluation, human test panel and the drug release) revealed that microparticles with Eudragit E PO are effective taste - masking carriers of cetirizine dihydrochloride and might be used to formulate orally disintegrating tablets and oral lyophilisates.

Orally disintegrating (orodispersible) films provide a versatile tool for drug administration, especially in the pediatric and geriatric population, since they reduce the risk of choking and do not necessitate drinking water during application. By considering their direct contact with the taste buds, palatability is an influential aspect related to patient compliance. The microparticles based on taste-masking polymers containing drugs enclosed inside effectively mask the unpleasant taste of medicines. Ethylcellulose is a hydrophobic polymer widely used as a taste-masking material. Rupatadine fumarate, a second-generation antihistamine drug, is characterised by an intense bitter taste; therefore, it is crucial to achieve a tolerable taste whilst developing orodispersible formulations with its content. The objective of this study was to develop orally disintegrating films with rupatadine fumarate in the form of ethylcellulose-based microparticles obtained from aqueous dispersions of ethylcellulose—Surelease® or Aquacoat® ECD. It was a technological challenge to achieve homogenous drug content per dosage unit and sufficient mechanical properties for film operating due to the necessity to suspend the microparticles in the casting solution. Although the process of obtaining films consisted of several steps (mixing, pouring, drying), the particles were homogeneously dispersed, and each film of the desired size contained the proper dose of the drug. The taste-masking effect was also maintained. This parameter was confirmed by three independent methods: in vivo by healthy volunteers, an electronic tongue and a dissolution test. The applied taste-evaluation techniques showed that the films containing Aquacoat® ECD microparticles have the highest degree of bitter taste reduction, which confirms the results obtained in our previous studies.

Excitation-emission matrix fluorescence spectroscopy can be applied for label-free and non-destructive determination of cells viability, which is promising methodology for drug screening, biocompatibility testing, or pharmacodynamic studies.

Differential sensing techniques are becoming nowadays an attractive alternative to classical selective recognition methods due to the “fingerprinting” possibility allowing identifying various analytes without the need to fabricate highly selective binding recognition sites. This work shows for the first time that surfactant-based ion-sensitive microspheres as optodes in the microscale can be designed as cross-sensitive materials; thus, they are perfect candidates as sensing elements for differential sensing. Four types of the newly developed chemosensory microspheres—anion- and cation-selective, sensitive toward amine- and hydroxyl moiety—exhibited a wide range of linear response (two to five orders of magnitude) in absorbance and/or fluorescence mode, great time stability (at least 2 months), as well as good fabrication repeatability. The array of four types of chemosensitive microspheres was capable of perfect pattern-based identification of eight neurotransmitters: dopamine, epinephrine, norepinephrine, γ-aminobutyric acid (GABA), acetylcholine, histamine, taurine, and phenylethylamine. Moreover, it allowed the quantification of neurotransmitters, also in mixtures. Its selectivity toward neurotransmitters was studied using α- and β-amino acids (Ala, Asp, Pro, Tyr, taurine) in simulated blood plasma solution. It was revealed that the chemosensory optode set could recognize subtle differences in the chemical structure based on the differential interaction of microspheres with various moieties present in the molecule. The presented method is simple, versatile, and convenient, and it could be adopted to various quantitative and qualitative analytical tasks due to the simple adjusting of microspheres components and measurement conditions.

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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.

Minitablets in orodispersible form constitute a flexible drug delivery tool for paediatric and geriatric population as they eliminate the risk of chocking and do not require drinking water in the application. Due to their direct contact with taste buds, taste sensation is an important factor. Preparing microparticles with taste masking polymers utilizing spray drying is an efficient technique for reducing the bitterness of drugs. Ethylcellulose is a hydrophobic polymer widely used as a taste masking material. Rupatadine fumarate, one of the newest antihistamines, features an intensive bitter taste, hence in designing orodispersible formulations, achieving an acceptable taste is a crucial issue. The main objective of this work was to formulate orodispersible minitablets containing taste masked ethylcellulose-based microparticles with rupatadine fumarate and evaluation of their quality, especially in terms of taste masking efficacy. The accessed data indicated that all obtained minitablets were characterized by beneficial pharmaceutical properties. Three independent methods: in vivo with healthy volunteers, in vitro drug dissolution, and “electronic tongue” confirmed that all designed formulations provided satisfactory taste masking rate and that formulation F15 (prepared with Pearlitol® Flash and Surelease® microparticles with rupatadine fumarate) was characterized by the lowest bitterness score.