David M Rivera

US Patent:

54434610, Aug 22, 1995

Filed:

Aug 31, 1993

Appl. No.:

8/114800

Inventors:

Linda E. Atkinson - Portola Valley CA
John T. Dunn - Palo Alto CA
Robert M. Gale - Los Altos CA
David L. Rivera - San Jose CA

Assignee:

ALZA Corporation - Palo Alto CA

International Classification:

A61K 922

US Classification:

6048921

Abstract:

Diffusional delivery devices are constructed in two or more compartments, each containing a separate drug or other beneficial agent, and each arranged to permit diffusion of the agent out of the device through an individually-characterized agent-permeable wall segment. The diffusion rates of the various agents relative to one another are set and controlled by the parameters of the individual wall segments, such as the surface area of the wall segment, the average thickness of the wall segment, and the permeability of the wall segment for the particular agent. The permeability may be varied by variations in the chemical composition of the wall segment. Using these parameters rather than blending the agents at calculated ratios in a single formulation for diffusion through a single wall permits a wider range of, and greater flexibility in, variation between the diffusion rates of the different agents. This is of value when the simultaneous administration of agents at a specified ratio is desired.