Title: Method for administering drug to the gastrointestinal tract

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Claims: We claim:

1. A method for orally administering an active agent at a controlled rate to the gastrointestinal tract of a warm blooded animal comprising,

A. admitting into the gastrointestinal tract a device comprising;

(1) a shaped wall formed of a semipermeable material that is permeable to the passage of gastrointestinal fluid and substantially impermeable to active agent, said wall surrounding and forming;

(2) a compartment containing the active agent that is soluble in fluid that enters the compartment and which agent exhibits an osmotic pressure gradient across the wall against the gastrointestinal fluid;

(3) a layer formed of an erodible enteric material on the exterior surface of the semi-premeable wall;

(4) a passageway in the wall for releasing said agent from said device, said passageway having a maximum cross-sectional area A.sub.s, of ##EQU20## wherein L is the length of passageway, Q.sub.p /t is the mass of agent released per unit time, D is the diffusion coefficient of agent in the released solution, S is the solubility of agent in the fluid and F has a value of approximately 2 to 1000, said passageway having a minimum area, A.sub.s defined by ##EQU21## wherein L is the length of the passageway, t is the volume of agent released per unit time, .pi. is 3.14, .eta. is the viscosity of the solution being released, and .DELTA.P is the hydrostatic pressure differences between the inside and the outside of the compartment and having a value of up to about 20 atmospheres;

B. bioeroding the enteric layer in the gastro-intestinal fluids in the environment of use at a controlled rate to regulate the amount of fluid available to the wall for imbibition, with fluid imbibed through the wall into the compartment in a tendency towards osmotic equilibrium at a rate determined by the permeability of the wall and the osmotic pressure gradient across the wall thereby continuously dissolving said active agent and, thereby

C. dispensing said active agent from the device to the gastro-intestinal tract through the passageway at a controlled rate over a prolonged period of time.

Other info:

Inventors: Zaffaroni, Alejandro (Atherton, CA, US)
Michaels, Alan S. (Atherton, CA, US)
Theeuwes, Felix (Los Altos, CA, US)

Application Number: 775774
Filing Date: 1977-03-09
Publication_date: 1978-06-20
Assignee: Alza Corporation (Palo Alto, CA)
Primary Class(es): 424/467
Other Classes:
US Patent Ref:

216107	Jun, 1879	Richards	424/15.
3113076	Dec, 1963	Jacobs	424/15.
3146169	Aug, 1964	Stephenson et al.	424/15.
3845770	Nov, 1974	Theeuwes et al.	128/260.
3916899	Nov, 1975	Theeuwes et al.	128/260.
4036227	Jul, 1977	Zaffaroni et al.	128/260.

Other Refs:
Primary Examiner: Rose, Shep K.
Assistant Examiner:
Attorney: Sabatine; Paul L., Ciotti; Thomas E., Mandell; Edward L.