Details for Patent: 4,673,405

Summary for Patent: 4,673,405

Title:	Osmotic system with instant drug availability
Abstract:	An osmotic device is disclosed for delivering a beneficial agent. The device comprises a wall surrounding a compartment containing drug, a passageway in the wall connecting the exterior of the device with the compartment, and drug in the wall. The device delivers the drug from the compartment and the wall.
Inventor(s):	George V. Guittard, Joseph C. Deters, Felix Theeuwes, Richard Cortese
Assignee:	Alza Corp
Application Number:	US06/817,211
Patent Claim Types: see list of patent claims	Composition; Formulation; Delivery; Device;

United States Patent 4,673,405: Scope, Claims, and US Landscape for Osmotic Delivery of Pharmacologic Agents

US Patent 4,673,405 is directed to an osmotic delivery device that packages a beneficial agent in a compartment and also includes the beneficial agent in the device wall. The wall is substantially inert, permeable to external fluid, and substantially impermeable to the beneficial agent in the compartment. The device contains at least one passageway that forms when exposed to the use fluid, allowing dispensing from the compartment to the exterior during operation.

What does the patent claim, at the highest level?

The invention claims a dual-role structure:

• Compartment wall: a substantially inert wall that surrounds and forms a compartment containing a beneficial agent formulation.
• Wall-localized beneficial agent: the wall itself contains a beneficial agent.
• Osmotic fluid ingress: the wall is permeable to exterior fluid present in the environment of use.
• Drug retention in the compartment: the wall is substantially impermeable to beneficial agent passage in the wall before the device operates.
• On-contact passage formation: at least one passageway forms in the wall when the device is in the fluid environment, with fluid contact triggering passage formation.
• Dispensing pathway: the formed passageway communicates with the compartment and the exterior, enabling dispensing from the compartment during operation.

Claims extend beyond baseline osmotic delivery by specifying multiple passageways, pulsed release, and short burst plus prolonged compartment release.

Claim 1: core architecture and agent scope

Claim 1 recites:

1. An osmotic device with:

   • (a) a wall at least in part comprising a “substantially inert composition” that:
     • surrounds and forms a compartment containing a beneficial agent formulation;
     • is permeable to exterior fluid; and
     • is substantially impermeable to beneficial agent.
   • (b) a beneficial agent in the wall, selected from a broad list of pharmacologic target systems (peripheral nerves, adrenergic receptors, cholinergic receptors, skeletal and smooth muscle, cardiovascular and circulatory systems, synaptic and neuroeffector sites, endocrine and hormone systems, immunological system, reproductive system, skeletal system, autocoid system, alimentary system, excretory system).
   • (c) at least one passageway formed during use when the fluid contacts the device; the passageway communicates with the compartment and the exterior to dispense beneficial agent.

2. Mechanistic release elements are built into the claim:

   • beneficial agent is released from the wall when the device is operating; and
   • the passageway formation enables dispensing from the compartment.

Claims 2-4: claim-width knobs

• Claim 2: device comprises more than one passageway.
• Claim 3: beneficial agent in the wall is released in a pulsed amount.
• Claim 4: beneficial agent is released from the wall in a short period of time while the compartment provides prolonged period release.

How broad is the claim scope on “beneficial agent”?

The agent scope in Claim 1 is not limited to a named compound. It is a functional/therapeutic target list covering multiple physiologic systems and receptor classes. The claim language includes:

• peripheral nerves
• adrenergic receptors
• cholinergic receptors
• skeletal muscles and smooth muscles
• cardiovascular system and blood circulatory system
• synoptic sites and neuroeffector sites
• endocrine system and hormone system
• immunological system
• reproductive system
• skeletal system
• autocoid system
• alimentary system and excretory system

Scope effect: this is a system-level functional taxonomy rather than a chemical genus limited to a particular class (like alkaloids or organophosphates). As drafted, it can cover most drug entities that “act on” the recited targets, provided the device is built as claimed (wall contains agent, wall is inert/permeable to fluid, passageway forms during use, etc.).

How broad is the claim scope on device structure and materials?

The structural limitations in Claim 1 are specific in function, but leave material choice room:

• The wall comprises a substantially inert composition.
• It must be permeable to exterior fluid and substantially impermeable to beneficial agent.
• The device has a compartment containing a “beneficial agent formulation.”
• The wall itself contains “a beneficial agent” (not just the compartment).
• The wall includes at least one passageway formed during use by fluid contact.
• The formed passageway communicates the compartment with the exterior.

Scope effect: the claim is structurally framed around osmotic function and fluid-triggered passage formation rather than specifying polymer brands, membrane pore sizes, or a particular passage-forming chemistry. That creates potential coverage across multiple membrane/passage-forming technologies, as long as they meet the functional performance thresholds tied to the claim.

What is the release profile coverage?

Claim set covers release patterns tied to the wall-hosted agent and the compartment payload:

• Wall release on operation: Claim 1 requires the beneficial agent in the wall releases when the device operates.
• Pulsed wall release: Claim 3 covers pulsed release from the wall.
• Short wall release + prolonged compartment release: Claim 4 captures a two-phase release profile:
  • wall releases a beneficial agent for a short period; and
  • compartment releases over a prolonged period.

Scope effect: it supports both:

• immediate or near-immediate “wall dose” signaling and
• delayed sustained dosing from the compartment, without requiring explicit numeric timing in the claims.

What does Claim 1 require for infringement (element-by-element)?

To fall within Claim 1, a device must meet all of these elements:

1. Osmotic device that delivers a beneficial agent to a fluid environment of use.
2. Wall forms a compartment containing a beneficial agent formulation.
3. Wall is:
   • “substantially inert” (composition);
   • permeable to exterior fluid; and
   • substantially impermeable to beneficial agent in the compartment before passage formation/operation.
4. Beneficial agent is present in the wall (not only in the compartment).
5. Beneficial agent is one that acts on at least one of the listed physiologic/receptor systems.
6. At least one passageway is formed in the wall when in the fluid environment such that:
   • fluid contact causes/participates in forming the passageway; and
   • the passageway communicates with the compartment and the exterior.
7. During operation:
   • beneficial agent releases from the wall; and
   • dispensing from the compartment occurs through the formed passageway.

Claims 2-4 add specific limitations:

• Claim 2: more than one passageway.
• Claim 3: pulsed wall release.
• Claim 4: wall short-period release with compartment prolonged release.

How does this claim positioning fit the broader US osmotic delivery patent landscape?

US osmotic drug delivery has a long-established claim ecosystem around:

• semipermeable or selectively permeable walls,
• osmotic fluid ingress,
• internal swelling or leaching phenomena,
• passageway formation (including mechanically-formed or chemically-formed apertures),
• controlled release by reservoir fill plus exit rate control.

This patent’s distinguishing claim feature is the co-location of agent in the wall coupled with fluid-contact passageway formation and a two payload regime (wall release profile + compartment prolonged dispensing). That combination is what differentiates the claimed subject matter from simpler “reservoir-only” osmotic devices.

Competitive design-around themes likely relevant to Claim 1

A competitor assessing freedom-to-operate would evaluate whether its device:

• omits agent in the wall (agent only in compartment);
• uses a solid or pre-formed exit that does not depend on “passageway formed when the device is in the fluid environment”;
• uses a wall that does not satisfy the “substantially impermeable to the passage of the beneficial agent” requirement pre-operation; or
• targets therapeutic action but is not designed so that the wall itself contains and releases the agent on operation.

Because Claim 1 is functional and broad on agent targets, the strongest design-around pressure is structural: where the agent sits and what triggers the outlet.

What is the patent landscape impact in US (claim strength and likely citation dynamics)?

Without a full prosecution history record and family mapping in the provided materials, the landscape assessment must focus on what the claim language signals to practitioners and examiners:

• High-level agent taxonomy invites broad interpretation to cover many drugs.
• Agent-in-wall requirement functions as the critical structural hook. That limitation is typically the portion that becomes differentiator and the portion that can be attacked via prior art showing similar dual-locus dosing (wall + compartment).
• Fluid-contact passage formation aligns with known osmotic membrane dissolution/formation concepts. The novelty question in prior art is usually whether the prior device taught the same outlet formation trigger and communication arrangement.

Practical reading for portfolio strategy: 4,673,405 is built to claim a robust “architecture pattern” (wall inert-permeable, agent-in-wall, fluid-activated outlet formation, compartment for prolonged release). If that architectural pattern was already widely taught in the earlier osmotic device art, the patent’s enforceable scope may be more sensitive to narrowing constructions or invalidity arguments based on close prior art. If not, the patent can operate as a blocking position on dual-locus wall-and-compartment osmotic dispensing.

How does the claim set map to product forms likely implicated?

These claims most naturally cover implantable or oral osmotic systems that:

• use semipermeable inert walls,
• contain a reservoir formulation,
• expose a portion of the wall to drug loading,
• create outlet passages on fluid exposure,
• optionally provide “burst + sustain” behavior.

Because Claim 1 does not confine dosage form geometry, the scope is not limited to a specific physical size or administration route in the claim language provided.

What do Claims 2-4 add for enforcement leverage?

Claims 2-4 are narrowing but still valuable:

• Multiple passageways: may broaden coverage to devices with distributed exits rather than one exit.
• Pulsed wall release: captures designs where wall-localized drug is dosed in pulses, even when reservoir release remains more constant.
• Short wall + prolonged compartment release: aligns with many commercial “immediate-start plus sustained dosing” osmotic strategies. This can be used to assert infringement against products that stage dosing.

Key takeaways for business and R&D decisions

• Claim 1 is a broad but architecture-constrained osmotic device claim: it requires drug in the wall, an inert permeable wall, substantially impermeable behavior, and a fluid-activated passageway that enables compartment dispensing.
• The drug element is broad: it covers agents acting on a wide set of therapeutic target systems and receptor categories, without limiting chemical class.
• Claims 3 and 4 map directly to burst/pulse release patterns, increasing the likelihood that real products with staging behaviors fall within the claim set.
• The main infringement risk lever is the “beneficial agent in the wall” requirement and the “passageway formed when in use fluid” mechanism. These are the elements most amenable to technical differentiation in competing designs.

FAQs

1) Does this patent require the beneficial agent to be in both the wall and the compartment?

Yes. Claim 1 requires a compartment containing a beneficial agent formulation and also requires a beneficial agent in the wall that releases when the device operates.

2) Is the therapeutic agent limited to a specific drug family?

No. Claim 1 defines the beneficial agent by therapeutic target systems and receptor classes, listed as peripheral nerves, adrenergic/cholinergic receptors, muscles, cardiovascular/circulatory, synaptic/neuroeffector sites, endocrine/hormone, immunological, reproductive, skeletal, autocoid, alimentary, and excretory systems.

3) What triggers the formation of the passageway?

Claim 1 requires passageway formation when the device is in the fluid environment and the fluid contacts the device.

4) Do the dependent claims broaden or narrow scope?

They narrow Claim 1 by adding specific structural or release-pattern limitations: multiple passageways, pulsed wall release, or short wall release combined with prolonged compartment release.

5) What release profile is explicitly claimed?

A two-phase profile is explicitly claimed in Claim 4: short-period release from the wall with prolonged release from the compartment.

References

[1] United States Patent 4,673,405.

Drugs Protected by US Patent 4,673,405

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 4,673,405

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	396056
Austria	397179
Austria	A150889
Austria	A72784