Interest of molecular/crystalline dispersions for the determination of solubility curves of drugs into polymers

International audienc

The role of cracks in the crystal nucleation process of amorphous griseofulvin

In this paper we have investigated the recrystallization properties of amorphous griseofulvin obtained by melt quenching. We have shown that the maximum nucleation rates of crystalline forms 2 and 3 are located around the glass transition temperature. However, it appears that these nucleation rates are strongly increased by the sudden formation of cracks into the amorphous solid during deep quenches below Tg. Suitable thermal treatments have revealed that these cracks strongly promote the development of crystalline nuclei, but do not produce the nuclei themselves. The investigations have been performed by differential scanning calorimetry and by thermal microscopy

Mechanistic explanation of the (up to) 3 release phases of PLGA microparticles: Diprophylline dispersions

International audienc

Dynamic nuclear polarization of a glassy matrix prepared by solid state mechanochemical amorphization of crystalline substances

A mechanochemical "solvent-free'' route is presented for the preparation of solid samples ready to be employed in the Dynamic Nuclear Polarization (DNP). H-1-DNP build-up curves at 3.46 T as a function of temperature and radical concentration show steady state nuclear polarization of 10% (0.5% TEMPO concentration at 1.75 K)

Lipolytic enzymes and hydrolytic rancidity

Lipolysis, the enzymic hydrolysis of milk lipids to free fatty acids and partial glycerides, is a constant concern to the dairy industry because of the detrimental effcts it can have on the flvor and other properties of milk and milk products. However, free fatty acids also contribute to the desirable flavor of milk and milk products when present at low concentrations and, in some cheeses, when present at high concentrations. The enzymes responsible for the detrimental effects of lipolysis are of two main types: those indigenous to milk, and those of microbial origin. The major indigenous milk enzyme is lipoprotein lipase. It is active on the fat in natural milk fat globules only after their disruption by physical treatments or if certain blood serum lipoproteins are present. The major microbial lipases are produced by psychrotrophic bacteria. Many of these enzymes are heat stable and are particularly significant in stored products. Human milk differs from cows' milk in that it contains two lipases, a lipoprotein lipase and a bile salt-stimulated lipase. The ability of the latter to cause considerable hydrolysis of ingested milk lipids has important nutritional implications