Differences in a child´s development stage, unacceptable taste profile such as bitter taste or age-related physical disabilities could cause difficulties when treating paediatric or geriatric patients with conventional oral dosage forms. Considering that the threshold for stimulation of the bitter taste is 10000-times lower than the threshold needed to stimulate sweet taste it is necessary to approach bitter taste masking with more advanced solutions which will exceed the traditional addition of sweeteners and flavours to the formulation. The bitter taste of medicines can stimulate repulsive behaviour in patients and result in reduced patient adherence and compliance which will negatively impact therapeutic efficacy. Therefore, finding efficient taste masking techniques is an important aspect of the formulation development process.
For our bitter model substance, we have chosen paracetamol, which we coated with four different taste-masking polymers available on the market, namely Eudragit® E PO, Kollicoat® Protect, Kollidon® VA 64 and gelatine. In order to maintain sufficient particle movement, particle circulation but also uniform coating we needed to adjust the process parameters as well as the composition of formulations for further coating attempts. Coating with Kollicoat® Protect has proved to be most effective among polymers due to a minimal agglomeration of particles during the coating process. In contrast when coating with the sucrose solution, Kollidon® VA 64 or gelatine we experienced excessive agglomeration and tackiness of the particles consequently having to pause several times during coating. That being the case, we acknowledged that changes are needed in formulations and process parameters. We proceeded with alternating the process parameters such as temperature and air flow and altering formulation parameters with additional pacificators and anti-adherents.
The polymer coated crystals of paracetamol were filled into a patented drinking straw, whose innovative design enables easy application and use for paediatric or other patients. Sipping of the medium through filled straw creates negative pressure within the straw which correlates with the medium flow and flush volume of medium, required to empty the straw. Incomplete clearance of the straw´s content disables administration of the entire dosage, therefore we tried to improve sipping characteristics with incorporating placebo (sucrose granulates). Several mixtures of paracetamol crystals with different portions of placebo were prepared and filled into straws full and half-full. Results showed a positive impact of increasing portion of placebo on decline in pressure within the straw. Given that we can conclude that higher dissolution rate of granulated sucrose in water medium enables the creation of new paths for the sipping medium, affecting rearrangement of the straw content and flush volume needed.
By overview of assembled data of sweeteners and flavours incorporated in the marketed medicines for paediatric use we observed that the most used flavours are orange, cherry and banana while the most frequently used sweetener is sucrose, following by aspartame and saccharin sodium.
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