Details for Patent: 5,869,100
Summary for Patent: 5,869,100
| Title: | Extended release clonidine formulation (tablet) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | A method of providing a patient needing clonidine with an extended dosage of clonidine over a prolonged period of time. Such method involves administering to the patient an oral dosage unit comprising a homogenous mixture of a therapeutically effective amount of clonidine, about 30 to about 70 percent by weight of one or more cellulose ethers such as hydroxypropyl methylcellulose, and about 30 to about 70 percent by weight of an inert substance such as cornstarch. The oral dosage unit may be contained in a gelatin capsule or in the form of a tablet. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Inventor(s): | H. Joseph Horacek | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assignee: | Concordia Pharmaceuticals Inc USA | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Application Number: | US08/881,314 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Patent Claim Types: see list of patent claims | Use; Formulation; Dosage form; | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Patent landscape, scope, and claims: | US Patent 5,869,100: Scope, Claims, Expiration, and Clonidine Extended-Release Patent LandscapeUS Patent 5,869,100 protects a narrow oral extended-release clonidine tablet for attention deficit hyperactivity disorder. The core combination requires clonidine at 0.025-0.40 mg, 30-70% cellulose ether, and cornstarch, lactulose, or dextrose. Dependent claims narrow the cellulose ether, hydroxypropyl methylcellulose specifications, adjunct concentration, and 8-12-hour release period. The patent issued on February 9, 1999. Its enforceable term has expired under the applicable United States patent term framework. It therefore does not currently block generic clonidine extended-release tablets, liquid extended-release clonidine products, or competing ADHD products. Its principal commercial importance is historical: it describes the formulation architecture later associated with extended-release clonidine products such as Kapvay. What invention does US Patent 5,869,100 cover?The patent covers a tablet matrix that releases clonidine over a prolonged period. The matrix uses a cellulose ether as the release-controlling polymer and an inert adjunct selected from three specified materials:
The invention is a composition patent, not a broad clonidine-use patent. It does not cover every extended-release clonidine product. A competing product must satisfy each limitation of at least one asserted claim to infringe. The claim structure is cumulative. A product containing clonidine and a cellulose ether but using an adjunct outside the claimed group would not literally satisfy claim 1. A product using a different polymer, such as a non-cellulosic hydrophilic polymer, would also fall outside the express wording of claim 1 unless an infringement theory based on the doctrine of equivalents were available. How broad is independent claim 1?Claim 1 is relatively narrow because it combines multiple quantitative and qualitative limitations. Clonidine dose limitationThe claimed clonidine range is approximately 0.025-0.40 mg. A formulation outside that range would not literally meet claim 1. The range is broad enough to cover common low-dose clonidine extended-release strengths, including 0.1 mg and 0.2 mg tablets, but it does not cover all clonidine dosage forms or all therapeutic doses. The claim also ties the dosage range to ADHD treatment. That language strengthens the commercial connection to ADHD products but creates potential claim-construction issues. A formulation with the same composition marketed solely for hypertension could present a different method-of-use question, although the composition claim is not converted into a method claim merely because the specification identifies ADHD. Cellulose ether limitationThe formulation must contain approximately 30-70% by weight cellulose ether. This is the central technical limitation. The claim does not require one specific cellulose ether in independent claim 1, but it requires a member of the cellulose-ether class. Claim 3 identifies the covered alternatives:
The percentage is stated as a weight percentage of the tablet formulation. A product containing 20% hydroxypropyl methylcellulose would be outside the literal 30-70% range. A formulation containing 75% cellulose ether would face the same issue. Adjunct-material limitationThe adjunct must be selected from:
This is a closed Markush group in the claim. Common tablet excipients such as lactose, microcrystalline cellulose, mannitol, sorbitol, povidone, magnesium stearate, or dicalcium phosphate are not expressly listed as alternatives. The claim does not state that only one adjunct can be present. A tablet could potentially contain one or more claimed adjuncts, subject to the claim language and specification. Excipients outside the Markush group may also be present if the claim does not exclude them, but the formulation still must contain a qualifying adjunct. What do claims 2 through 9 add?Claims 2 through 9 narrow the formulation in separate directions.
Claims 4 and 5 are technically important because they identify polymer grades by substitution level, molecular weight, and solution viscosity. Those parameters can be used to distinguish a generic formulation from the claimed HPMC embodiments. They also create analytical risk because commercial excipient specifications may be reported using different test methods or supplier-grade designations. A formulation using HPMC with a different methoxyl or hydroxypropoxyl profile may avoid claims 4 and 5 while still potentially falling within claims 1 or 3. What does claim 10 protect?Claim 10 is a method claim covering administration of the extended-release formulation of claim 1 to a mammalian species to produce prolonged central alpha-adrenergic stimulation. Because claim 10 depends on claim 1, the administered product must retain the claim 1 limitations:
Claim 10 is not a standalone claim to administering any clonidine product. Its scope is limited by the incorporated formulation definition. The claim does not expressly limit treatment to ADHD, although claim 1 describes the clonidine amount as being for ADHD treatment. The specification and prosecution history would be important in determining whether the method claim covers indications beyond ADHD. What does claim 11 protect?Claim 11 requires an 8-12-hour release period. It is a performance-based dependent claim rather than a simple ingredient claim. The phrase "release period" may require interpretation through the patent specification, including the dissolution method, sampling conditions, and definition of completion. A product with an approximately 12-hour clinical effect may not necessarily satisfy an 8-12-hour in vitro release limitation unless the patent defines the measurement differently. The claim is commercially directed at twice-daily or once-daily extended-release behavior, but it does not by itself require a specific tablet strength, dosing schedule, or pharmacokinetic profile. When did US Patent 5,869,100 lose exclusivity?US Patent 5,869,100 is expired. It issued in 1999 and reached the end of its enforceable statutory term based on the relevant filing history and United States patent-term rules. Public patent records classify the patent as expired.
Patent expiration does not invalidate the technical disclosure. It means the claimed subject matter is no longer enforceable against later products in the United States. What is the Orange Book status of the patent?US Patent 5,869,100 should be separated from later patents that may have been listed for branded clonidine products. The Orange Book lists patents identified by an approved product sponsor for a specific FDA-approved drug product. A patent can be relevant to a formulation without being listed in the Orange Book. Conversely, an Orange Book listing does not establish that every claim is valid or infringed. For clonidine extended-release tablets, the relevant FDA product was Kapvay, clonidine hydrochloride extended-release tablets. FDA approval of Kapvay established the regulatory product category, while any patent listing depended on the sponsor's submissions and FDA's publication practices. Because US 5,869,100 is expired, it is not a current enforceable barrier to an ANDA applicant. The patent's historical relationship to Kapvay does not create present-day exclusivity. [1][2] Did the patent block generic clonidine extended-release tablets?During its enforceable term, the patent could have created formulation risk for a generic tablet that reproduced the claimed combination. A generic applicant could address the patent through one or more strategies:
Because the patent is expired, a current ANDA applicant no longer needs to manage launch timing around this patent. Any current generic-entry assessment should focus on other unexpired patents, regulatory exclusivities, manufacturing capability, and FDA approval requirements. Which companies and products compete with extended-release clonidine?The relevant competitive field includes extended-release clonidine, immediate-release clonidine, extended-release guanfacine, stimulant ADHD products, and newer clonidine delivery systems.
Onyda XR is particularly relevant because it demonstrates a modern product design that does not depend on the tablet-matrix limitations of US 5,869,100. Its liquid extended-release formulation can create separate intellectual-property issues involving suspension stability, release-control excipients, dosing devices, and manufacturing processes. [3] What patent strategies can avoid the claim scope?A product-development team evaluating freedom to operate can map the claim limitations as follows:
These strategies would have been relevant while the patent was active. Today, they remain relevant for avoiding other active patent families, but they are not needed to avoid enforcement of US 5,869,100 itself. How strong was the patent estate?US 5,869,100 had moderate historical strength as a formulation patent and limited breadth as a platform patent. Strengths
Weaknesses
The patent was therefore more valuable as a product-specific formulation right than as a broad control point over clonidine therapy. What manufacturing and IP barriers remain after expiration?Expiration removes the patent barrier but does not eliminate commercial or regulatory barriers. A generic clonidine extended-release tablet still must demonstrate pharmaceutical equivalence and bioequivalence under the applicable FDA pathway. Manufacturing controls include:
The high potency of clonidine at low tablet weights can make content uniformity and segregation control more demanding than the patent's simple composition language suggests. What generic launch scenarios are most likely?The strongest post-expiration scenario is generic entry through an ANDA for clonidine hydrochloride extended-release tablets. The principal commercial variables are product approval, supplier qualification, manufacturing scale, and market concentration rather than US 5,869,100. A second scenario involves differentiated products such as extended-release oral suspensions. These products compete through administration flexibility, pediatric dosing, and product-specific formulation intellectual property. A third scenario involves substitution by guanfacine extended-release products or stimulant therapies. These products do not infringe the clonidine formulation claims because they use different active ingredients, but they compete for the same ADHD treatment population. Key Takeaways
FAQs About US Patent 5,869,100Does US Patent 5,869,100 cover Kapvay?The patent's claim structure is consistent with the extended-release clonidine tablet technology associated with Kapvay, but product coverage depends on the actual Kapvay formulation and the patent claims in force at the relevant time. The patent is now expired. Can a generic use hydroxypropyl methylcellulose?Yes. US Patent 5,869,100 does not create a current prohibition on HPMC. During the patent term, a formulation using HPMC could have presented risk if it also met the claimed concentration, adjunct, clonidine dose, tablet, and release limitations. Does the patent cover Onyda XR?No. Onyda XR is an extended-release oral suspension, while claim 1 of US 5,869,100 requires a tablet. Separate patents and regulatory protections may apply to the Onyda XR formulation. Is a 0.1 mg clonidine extended-release tablet within the claimed dose range?Yes. A 0.1 mg tablet falls within the claimed 0.025-0.40 mg range. Dose alone, however, is insufficient for infringement because every limitation of the relevant claim must be met. Can the expired patent be used to challenge a new clonidine product?No. An expired patent generally cannot support an infringement action against a later product. Its disclosure may remain relevant as prior art against later patent applications, subject to the applicable prior-art rules and the later patent's claims. References
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Drugs Protected by US Patent 5,869,100
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Patented / Exclusive Use | Submissiondate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| >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 5,869,100
| Country | Patent Number | Estimated Expiration | Supplementary Protection Certificate | SPC Country | SPC Expiration |
|---|---|---|---|---|---|
| Australia | 5259396 | ⤷ Start Trial | |||
| Australia | 707843 | ⤷ Start Trial | |||
| Canada | 2211325 | ⤷ Start Trial | |||
| Germany | 69534283 | ⤷ Start Trial | |||
| >Country | >Patent Number | >Estimated Expiration | >Supplementary Protection Certificate | >SPC Country | >SPC Expiration |
