Optimisation of a lozenge-based sensor for detecting impending blockage of urinary catheters.

Catheter-associated urinary tract infections resulting from urease-positive microorganisms are more likely to cause a urinary catheter blockage owing to the urease activity of the microbes. Catheter blockage can be dangerous and increases the risk of severe infections, such as sepsis. Ureases, a virulence factor in Proteus mirabilis, cause an increase in urine pH - leading to blockage. An optimised biosensor "lozenge" is presented here, which is able to detect impending catheter blockage. This lozenge has been optimised to allow easy manufacture and commercialisation. It functions as a sensor in a physiologically representative model of a catheterised urinary tract, providing 6.7 h warning prior to catheter blockage. The lozenge is stable in healthy human urine and can be sterilized for clinical use by ethylene oxide. Clinically, the lozenge will provide a visible indication of impending catheter blockage, enabling quicker clinical intervention and thus reducing the morbidity and mortality associated with blockage.

Taste masking of propranolol hydrochloride by microbeads of EUDRAGIT® E PO obtained with prilling technique for paediatric oral administration.

The purpose of this study was to develop a new solid paediatric formulation for propranolol hydrochloride (PR). This drug is used to treat various paediatric diseases, and recently received clearance to treat haemangioma. However, PR has a bitter salty taste that does not facilitate high rates of compliance among children, especially in liquid formulations. In addition, the solid formulations are designed for adults and often their dosage is not suitable for children that require a flexible dose based on their weight. Therefore, matrix microbeads of EUDRAGIT® E PO containing PR were manufactured to overcome these limitations. Nine different samples were prepared using the prilling-congealing technique with high yield. Using 2 nozzles, 300 and 450 µm (code n), the diameters obtained of microbeads (from 333 to 699 µm) were homogenous and appropriate to be swallowed by children. In this study, the ratio drug:matrix for the microbeads was also examined in detail: 1:25 (F1), 1:15 (F2) and 1:10 (F3) in aqueous and tert-butyl alcohol/aqueous (code t) media. Most of the examined microbeads were characterized by high percentage of encapsulation efficiency (22-100%) and drug loading (22-77 mg of drug per g of matrix) effective for the administration of low and high doses of PR. SEM analysis revealed a matrix with a radial or a spongy structure, with numerous pores that generated soft floating microbeads in aqueous solution. Release studies confirmed a low release and dissolution of the drug in artificial saliva, mainly F1n > F1 > F2nt, and a prompt dissolution in simulated gastric media. Finally, electronic tongue measurements revealed the ability of these formulations to mask the bitter drug taste, especially for the sample with a ratio 1:25 (F1n and F1). These samples were chemically and physically stable for six months. In conclusion, the projected microbeads F1, and F1n reached the goal of the study, and could be proposed as new solid oral formulations dedicated to use by children.