Atomic layer deposition-A novel method for the ultrathin coating of minitablets.

We introduce atomic layer deposition (ALD) as a novel method for the ultrathin coating (nanolayering) of minitablets. The effects of ALD coating on the tablet characteristics and taste masking were investigated and compared with the established coating method. Minitablets containing bitter tasting denatonium benzoate were coated by ALD using three different TiO2 nanolayer thicknesses (number of deposition cycles). The established coating of minitablets was performed in a laboratory-scale fluidized-bed apparatus using four concentration levels of aqueous Eudragit® E coating polymer. The coated minitablets were studied with respect to the surface morphology, taste masking capacity, in vitro disintegration and dissolution, mechanical properties, and uniformity of content. The ALD thin coating resulted in minimal increase in the dimensions and weight of minitablets in comparison to original tablet cores. Surprisingly, ALD coating with TiO2 nanolayers decreased the mechanical strength, and accelerated the in vitro disintegration of minitablets. Unlike previous studies, the studied levels of TiO2 nanolayers on tablets were also inadequate for effective taste masking. In summary, ALD permits a simple and rapid method for the ultrathin coating (nanolayering) of minitablets, and provides nanoscale-range TiO2 coatings on porous minitablets. More research, however, is needed to clarify its potential in tablet taste masking applications.

A novel set of behavioural indicators for measuring perception of food by cats.

Behavioural indicators provide a promising approach for objective assessment of the perceptions of animals. In cats, the frequency of specific behaviours as indicators of perception has been studied in connection with food palatability. The aim of this study was to expand that knowledge by identifying behavioural indicators correlating with three degrees of palatability. Thirty-four pet cats were presented with three types of items: favoured food (FF), favoured food with a placebo mini-tablet hidden inside (TFF) and non-favoured food (NFF). The items were presented in a pseudo-randomised sequence, with six trials per item and 18 trials per cat. The behaviour of cats before, during and after eating, or refusing to eat, was video-recorded. Two trained observers, blinded to the types of food items, independently determined the frequency of 16 behavioural patterns on the video recordings. The data were analysed using a mixed logistic regression model. Five behavioural patterns differentiated FF from NFF; 'flick ears backwards', 'lick nose, not eaten', 'flick tail' and 'groom body' were more frequent with NFF, whereas 'lick lips' was more frequent with FF. One indicator, 'drop item', was more frequent with TFF than FF. These findings provide evidence of new behavioural indicators for objective assessment of food perception in cats. The findings also have practical applicability in designing a novel palatability test to be utilised in developing veterinary pharmaceuticals with improved palatability for cats.

Real-Time assessment of granule and tablet properties using in-line data from a high-shear granulation process.

A method for real-time assessment of granule and tablet properties was investigated. A mixture of microcrystalline cellulose:mannitol:povidone (78.5:18.5:3) was used in the study and granulated with five different water amounts and two impeller speeds. This represents a full-factorial design with two factors, thus giving a causal structure to the variation between the experiments. Process data (power consumption, temperature and in-line near-infrared spectra) were collected during the granulations. In addition to the in-line process data, critical granule and tablet quality properties (such as particle size, porosity and tablet hardness) were measured in order to achieve in-depth process understanding. Neither power consumption nor temperature gave information that could be directly attributable to tablet properties, and these techniques were also heavily dependent on the speed of the impeller. In contrast, when using the first NIR overtone band for water (1460 nm), in-line real-time assessment of dry granule and tablet properties could be achieved.