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The work reported here describes the improvement of an industrial production of tablets formed by direct compression. This formulation contained 50% active substance of plant origin as a nonhygroscopic powder. The first step was to evaluate a number of direct compression excipients in preformulation tests and then make up a basic formulation providing tablets with correct characteristics. The second step was the optimization of the initial formulation using a two-level factorial experimental design. This enabled the best formulations to be selected objectively.

Matrix or monolithic systems can be considered to date as the easiest and least expensive means of controlling drug release. The principle of these dosage forms is based on the uniform dispersion of the active ingredient in an inert solid polymeric excipient. This excipient forms a skeleton in which the drug is trapped and released by erosion and/or diffusion.The aim of this work is to show the progress in the formulation of these dosage forms, their conception, design, and resulting biopharmaceutical properties. The first part is related to the classical matrix study according to the kind of excipient used. A more or less arbitrary classification can be considered: plastic, lipidic, and hydrophilic matrices. The various excipients used, the mechanisms allowing the drug to be released, and the formulation parameters influencing these dosage forms in in vitro/in vivo are also presented.The second part is dedicated to the new matrix systems. Their technology and conception derive directly from the experienc...

Caverns stability is monitored using a permanent seismic surveillance network operating since 1992. This paper summarized the results concerning underground storage monitoring in a seismo-tectonic context. Over the last 14 years, the seismic network has recorded 1800 internal micro-seismic events (magnitude < 0.5), and 500 external seismic events located close to the site. The objective is to show whether the seismicity is associated to exploitation activities (leaching) or to the local geological tectonic activity.

The ‘in vitro’ dissolution kinetics of two suppository formulations containing indomethacin were compared and a correlation with the ‘in vitro’ kinetics was established. The device used ‘in vitro’ was a special through flow cell. A mean dissolution curve was obtained for each dosage form, one containing a hydrophilic excipient (PEG), the other, a fatty base. A relative bioavailability study was then carried out on 12 healthy volunteers. Thus, from the pharmacokinetic parameters obtained, the simulation of plasma concentration values was made possible from the amounts of drug released and dissolved during the dissolution test. With the simulation programme used it was possible to predict the plasma level values and the results showed a good superimposition of the experimental plasma concentration curve validating the ‘in vitro’ study method of drug release from suppositories.