Taste is an important sense that influences the acceptability of drugs. Active ingredients often have an unpleasant taste, which affects patient compliance; therefore, taste masking can be crucial in pharmaceutical development. Common approaches include adding flavors, sweeteners, or amino acids, or coating particles with polymers.
The aim of this study was to incorporate an active ingredient into the pores of mesoporous silica and coat the particles with the pH-dependent polymer Eudragit® EPO, which is soluble at pH below 5. This approach was intended to reduce the release of the active ingredient in water to less than 10% of the dose and mask its taste in the mouth, even when delivered from orodispersible tablets. The five-minute period was chosen because it represents the time during which a patient could detect the taste of a tablet disintegrating in the mouth.
In the first part of the study, granules were prepared from Syloid® 244 FP, a synthetic amorphous silica with a large pore volume and high specific surface area, with the addition of either hypromellose or polyvinylpyrrolidone. The resulting granules were impregnated with fenofibrate in a rotary evaporator using a solvent-based method (ethyl acetate) and subsequently coated with Eudragit® EPO in a fluidized bed granulator. Because fenofibrate is poorly soluble in water, its release could not be evaluated, so it was replaced with a model active ingredient, saccharin. Saccharin was impregnated into the pores of silica via spray drying, and the resulting solid dispersion was coated with Eudragit® EPO in a rotary evaporator. The content and release profiles of coated and uncoated particles were determined in both a pH 1.2 medium, where the polymer coating dissolves and enables release, and in water, where the coating remains intact. The release rate of coated particles in water was significantly lower than that of uncoated particles. In six out of nine cases, the release after five minutes was below 10%, demonstrating a measurable delay in release and partial taste masking.
The sample showing the optimal combination of delayed release and higher active ingredient content was formulated into orodispersible tablets by adding a disintegrant and compressing the mixture using direct compression. The disintegrant is a critical component of such tablets, as it ensures disintegration in the mouth in less than three minutes. After tableting, it was observed that compression forces damaged the coating, resulting in saccharin release in water after five minutes exceeding the desired 10%.
Overall, this study demonstrates that coating with Eudragit® EPO effectively reduces the release of the active ingredient in water and can partially mask its taste. However, limitations such as damage to the coating during direct compression and low active ingredient content indicate that further optimization of the process is needed to develop fully effective orodispersible tablets.
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