Influence of process parameters on fluidised hot-melt granulation and tablet pressing of pharmaceutical powders

This study investigates the influence of process parameters on the fluidised hot melt granulation of lactose and PEG 6000, and the subsequent tablet pressing of the granules. Granulation experiments were performed to assess the effect of granulation time and binder content of the feed on the resulting granule properties such as mass mean granule size, size distribution, granule fracture stress, and granule porosity. These data were correlated using the granule growth regime model. It was found that the dominant granule growth mechanisms in this melt granulation system were nucleation followed by steady growth (PEG 10–20% w/w). However, with binder contents greater than 20% w/w, the granulation mechanism moved to the “over-wet massing” regime in which discrete granule formation could not be obtained. The granules produced in the melt fluidised bed process were subsequently pressed into tablets using an industrial tablet press. The physical properties of the tablets: fracture stress, disintegration time and friability were assessed using industry standards. These analyses indicated that particle size and binder content of the initial granules influenced the mechanical properties of the tablets. It was noted that a decrease in initial granule size resulted in an increase in the fracture stress of the tablets formed.

Co-melt fluidised bed granulation of pharmaceutical powders: Improvements in drug bioavailability

This study investigates the use of co-melt fluidised bed granulation for the agglomeration of model pharmaceutical powders, namely, lactose mono-hydrate, PEG 10000, poly-vinyl pyrolidone and ibuprofen as a model drug. Granulation within the co-melt system was found to follow a nucleationâ??steady growthâ??coating regime profile. Using high molecular weight PEG binder, the granulation mechanism and thus the extent of granulation was found to be significantly influenced by binder viscosity. The compression properties of the granulate within the hot fluidised bed were correlated using a novel high temperature experimental procedure. It was found that the fracture stress and fractural modulus of the materials under hot processing conditions were orders of magnitude lower than those measured under ambient conditions. A range of particle velocities within the granulator were considered based on theoretical models. After an initial period of nucleation, the Stokes deformation number analysis indicated that only velocities within the high shear region of the fluidised bed were sufficient to promote significant granule deformation and therefore, coalescence. The data also indicated that larger granules de-fluidised preventing agglomeration by coalescence. Furthermore, experimental data indicated that dissipation of the viscous molten binder to the surface was the most important factor in the latter stages of the granulation process. From a pharmaceutical perspective the inclusion of the model drug, ibuprofen, combined with PVP in the co-melt process proved to be highly significant. It was found that using DSC analysis on the formulations that the decrease in the heat of fusion associated with the melting of ibuprofen within the FHMG systems may be attributed to interaction between PVP and ibuprofen through inter-molecular hydrogen bonding. This interaction decreases the crystallinity of ibuprofen and facilitates solubilisation and bioavailability within the solid matrix.

Effects of the stockperson on dairy cow behaviour and milk yield

The relationship between stockperson behaviour, measured as verbal and physical interactions with the dairy cows (no. ¼ 210), during milking and the subsequent milk yield obtained was examined. The numbers of steps and kicks made by the cows during milking was recorded. The behaviour of two stockteams, each consisting of two stockmen, were recorded over 10 weekend sessions. The two teams varied in the types of interactions and when the stockteam that performed more positive interactions worked with the cows (team A), the cows had a significantly higher milk yield (P , 0·05) although this difference was small (17·54 v. 17·44 kg). When team A was milking the cows also stepped and kicked on the platform significantly more ( P , 0·05) compared with team B. The results also indicated that while each stockteam tended to interact with the same cows each session, different stockpersons interacted with different cows. These findings highlight the importance of the role of the stockperson in milk output and dairy cow behaviour in a commercial setting.

Mycobacterium avium ssp. paratuberculosis: its incidence, heat resistance and detection in milk and dairy products

Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism: and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining ifa problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined.