Formulation of enamel matrix derivative for surface coating. Kinetics and cell colonization.

Enamel Matrix Derivative (EMD) contains a protein complex belonging to the amelogenin family. Enamel matrix as well as EMD have been found to promote periodontal regeneration when applied onto denuded root surfaces in dehiscence models. In the present studies it is shown that propylene glycol alginate (PGA) is a suitable vehicle for EMD for its local application. EMD can be dissolved in PGA at an acidic pH, resulting in a highly viscous solution. At neutral pH and body temperature the viscosity decreases and EMD precipitates. Multilayers of EMD on mineral or protein surfaces have been analysed using ellipsometry, total internal reflection fluorescence (TIRF) and biospecific interaction analysis (BIA). The studies show that EMD adsorbs both to hydroxyapatite and collagen and to denuded dental roots. It forms insoluble spherical complexes, and detectable amounts remain at the site of application on the root surface for two weeks, as shown with radiolabelled protein in rats and pigs. Scanning electron micrograph (SEM) studies on monkey teeth further indicate that EMD in PGA may promote repopulation of fibroblast-like cells during the first weeks after application.

Percutaneous absorption of 4 organic solvents in the guinea pig (II). Effect of surfactants.

Percutaneous absorption of 4 organic solvents (1,1,1-trichloroethane, 1,1,2-trichloroethane, toluene and butanol) from various colloidal preparations in a surfactant-water-organic solvent system was studied in vivo in guinea pigs. The preparations examined were binary solutions of organic solvents and surfactants, o/w emulsions and microemulsions. Phase diagram, birefringence microscopy and droplet size distribution analysis were used for characterization of the preparations. It was found that skin absorption of the solvents depends on the type of surfactant, type of preparation and also on phase equilibria in the systems studied. The presence of nonionic surfactants in the solvents and in a microemulsion with butanol caused skin absorption to decrease. A reduced uptake of solvents from o/w emulsions was observed. The absorption of butanol from a microemulsion with anionic surfactant was greater than from the pure solvent.

Lung expansion in premature newborn rabbits treated with emulsified synthetic surfactant; principles for experimental evaluation of synthetic substitutes for pulmonary surfactant.

This paper presents a sequence of tests for experimental evaluation of potential substitutes for pulmonary surfactant. Differential thermal analysis and the pulsating bubble technique were applied to identify an emulsified mixture of synthetic lipids with properties similar to those of natural surfactant. Instilled into the airways of premature newborn rabbits, this emulsion improved pulmonary pressure-volume characteristics and enhanced lung-thorax compliance during artificial ventilation. However, the in vivo effect was inferior to that of natural surfactant, especially as the emulsion failed to prevent the development of bronchiolar epithelial lesions.