National Research Development Corporation

David M Groffman

Alan D Wilson

Havard J Prosser

William M Allen

Bernard F Sansom

Gary S Sayers

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. The trace chemical element is exemplified by selenium, cobalt and iodine and the cement is exemplified by a phosphate cement.

Sustained release composition

A hardenable composition which comprises (i) a poly(carboxylic acid) or precursor thereof (as herein defined); (ii) a particulate ion-leachable silicate, aluminosilicate or metal oxide reactable with (i) in the presence of water to set to a hardened composition; and (iii) a compound comprising at least one phosphorus-carbon or phosphorus-boron covalent bond, in an amount effective in service to extend the working time of the composition.

Cement-forming compositions

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. A preferred cement is copper phosphate cement.

Growing community of inventors

Harrow, United Kingdom

David M Groffman