Bearing Absorbable Polymers

Assignee Societe de Conseils de Recherches et d Applications Scientifiques (Paris, FR) 

A procedure for the slow and sustained release of the growth hormone inhibitor Lanreotide is described. The method entails incorporating Lanreotide to the isocitric acid lactone component on the backbone of a polyester block copolymer using sodium hydroxide as the saponification agent. 

Preparation of Poly(isocitric Acid Lactone-co-Propanediol) 

A reactor containing a Dean-Stark trap was charged with isocitric acid lactone (14.3 mmol), propanediol (15.7 mmol), and benzene was then refluxed at 90°C overnight. The mixture was concentrated and a viscous liquid isolated that solidified on cooling. 

Preparation of Poly[(Isocitric Acid Lactone-co-Propanediol)-fe/oc -(Glycolide-co-Lactide)] 

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The output of the gearbox is connected directly to the shank of the extruder screw. A thrust bearing is located at this junction (Fig. 2.3). The thrust bearing absorbs the backwards push of the screw generated by the pressure of the polymer at the output end of the screw. 

The force-distance profiles Al, A2 appear to show the relaxed, or quasi-equilibrium limit for the interaction between the mica plates bearing the PEO in the good solvent conditions of the present study. The adsorbed layer thicknesses 6 are then about half the value of D at which onset of repulsion (A curves) is first noted. 6 thus corresponds to some 3Rg for both polymers in the present investigation, a value comparable to that obtained for hydrodynamic layer thickness of PEO absorbed on latex particles in water, for similar molecular weights, from light scattering studies. 

For the past several years, our laboratory has studied the swelling properties of weakly basic, hydrophobic polymer gds. The gels are formed by bulk polymerization of hydro diobic n-alkyl methacrylates (n-AMA) with N,N-dimethylaminoethyl methacrylate (D( ), tte latter comonomer bearing a tertiary amine sidediain. To form a three-dimensional polymer network that will not dissolve upon swelling, small amounts of the crosslinker divinylbenzene (DVB) are added. These gds, when placed in aqueous solutions, absorb minimal amounts of water in neutral and alkaline media, but become swollen in addic media. Hence, they might be considered for applications in which drug release in the stomach is desirable. 

Table 3 further outlines the estimated capacities for 2-ethylhexanol (2-EH) production. In total, about 60 % of the C4 capacity (or about 70 % of the w-butanal capacity) is required to produce 2-EH. However, regional deviations in C4/2-EH capacities are obvious, indicating that n-butanal is to be considered a commodity with worldwide availability. Bearing in mind that 2-EH and the C9/C10 alcohols are nearly quantitatively absorbed in plasticizer production, the enormous significance of hydroformylation for the polymer industry, especially for PVC, is underlined. In contrast to repeatedly published predictions, a decrease in the application of 2-EH as plasticizer alcohol has not been observed to date. 

A recent development in solid bearing lubricants is microporous polymeric lubricants, MPL, where a polymer containing a continuous microporous network has oil contained within the pores, which may include appropriate additives [56], The oil content in the polymer can be more than 50% by weight and the microporous polymer acts as a sponge, releasing and absorbing oil when necessary. 

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