Details for Patent: 6,024,981
Summary for Patent: 6,024,981
| Title: | Rapidly dissolving robust dosage form | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | The invention is directed to a hard tablet that can be stored, packaged and processed in bulk. Yet the tablet dissolves rapidly in the mouth of the patient with a minimum of grit. The tablet is created from an active ingredient mixed into a matrix of a non-direct compression filler and a relatively high lubricant content. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Inventor(s): | Rajendra K. Khankari, John Hontz, Sara J. Chastain, Leo Katzner | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assignee: | Cima Labs Inc | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Application Number: | US09/057,884 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Patent Litigation and PTAB cases: | See patent lawsuits and PTAB cases for patent 6,024,981 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
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Patent Claim Types: see list of patent claims | Use; Composition; Dosage form; | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Patent landscape, scope, and claims: | US Patent 6,024,981: Claim Scope, Expiration, Litigation Risk and Fast-Dissolving Tablet Patent LandscapeUS Patent 6,024,981 is a Cima Labs platform patent covering hard-compressed, rapidly disintegrating oral tablets, including tablets made with a non-direct-compression filler, hydrophobic lubricant, optional wicking agent, and protected active-ingredient particles. The patent is directed to dosage-form technology rather than a specific active pharmaceutical ingredient. The patent issued on February 15, 2000, and its enforceable term expired in 2017 based on its ordinary 20-year term from the earliest nonprovisional filing date. It therefore presents no current US blocking position against generic, branded, or over-the-counter products. Its historical importance is tied to Cima Labs’ OraSolv-type fast-dissolving tablet technology and to the development of robust orally disintegrating tablets that could be stored and handled in bulk. What does US Patent 6,024,981 protect?The patent protects a combination of physical tablet properties, formulation components, particle structures, and manufacturing steps. The central combination is:
The claims do not require a particular active ingredient. They cover pharmaceutical ingredients, vitamins, minerals, dietary supplements, antacids, analgesics, antihistamines, antibiotics, beta blockers, antihypertensives and other active compounds listed in the specification. The patent is therefore best characterized as a formulation and manufacturing platform patent, not as a compound patent or drug-specific patent. How many independent claims does US 6,024,981 contain?The patent has four principal independent claim groups:
Claims 1, 3 and 32 are product claims. Claim 37 is a process claim. Claims 38 through 40 narrow the manufacturing process by adding packaging and direct-compression limitations. What formulation features are required by the claims?Non-direct-compression fillerThe filler is the principal structural component of the claimed matrix. Claims 14 through 17 require or define the filler in progressively narrower terms:
The claim language distinguishes the filler from conventional direct-compression excipients. The intended formulation strategy is to use a highly water-soluble, relatively fine material that can produce a strong tablet under compression while still allowing rapid penetration of saliva. Claim 33 adds an average particle size of 90 microns or less. Hydrophobic lubricantClaims 26 through 29 narrow the lubricant concentration:
The lubricant is material to the formulation strategy because conventional hydrophobic lubricants can delay wetting and dissolution. The claimed ranges attempt to balance tablet strength, manufacturability and rapid oral disintegration. Wicking agentClaims 30 and 31 add a wicking agent at less than about 5% by weight. Claim 33 narrows the range to 2% to 5%. A wicking agent promotes movement of saliva into the compacted matrix. A product that uses a wicking agent may fall within claims 30, 31, 32 or 33 even if the active ingredient itself is not coated. Protected active particlesClaims 9 through 13 and 22 through 25 address particles containing the active ingredient and a protective material. The protective material may be:
The coating may constitute:
The particles may be rapid-release or sustained-release particles. This gives the patent a broader technical reach than a simple uncoated fast-dissolving tablet. A formulation can use the tablet matrix for fast oral breakup while using coated particles to control taste, stability, release rate or compatibility. How do the independent claims differ?Claim 1: broad tablet-property claimClaim 1 is the broadest product claim. It does not require:
It requires the tablet to be hard, rapidly dissolving, low in friability and made with a non-direct-compression filler and a lubricant. The most important quantitative limitations are:
Claims 2 and 4 through 8 narrow those properties. The narrowest dissolution limitation is about 45 seconds or less under claim 8. Claim 3: packaged protected-particle productClaim 3 adds a packaging configuration and protected particles. It is narrower than claim 1 but more commercially specific. The key limitations are:
This claim is directed toward a product that combines the formulation with a consumer-use package, potentially including a multidose container. Claim 32: bulk-storable tabletClaim 32 covers a tablet that can be stored in bulk before packaging. It requires:
This claim addresses a manufacturing problem associated with fragile orally disintegrating tablets. Conventional orally disintegrating tablets may require individual blister packaging because they are susceptible to chipping, abrasion and breakage. The claimed technology seeks to provide rapid disintegration without sacrificing mechanical strength. Claim 37: process claimClaim 37 covers the manufacturing sequence:
Claim 40 specifies direct compression. A manufacturer using wet granulation, dry granulation or another compression process would not automatically satisfy claim 40, although it could still implicate other claims if the product meets their limitations. What are the key claim-construction issues?Several terms would have been important in an infringement or validity analysis. “Rapidly dissolving” and “dissolve spontaneously”The claims use both functional and numerical language. Claims 6 through 8 specify dissolution in 90, 60 or 45 seconds. Claims 3, 32 and 37 specify less than 60 seconds. The testing method matters. The patent’s claim scope would depend on how “dissolve,” “disintegrate” and “spontaneously” are construed and measured. A tablet that disintegrates into coated particles may raise a separate issue: whether the tablet itself has dissolved or whether the matrix has merely broken apart. “Non-direct-compression filler”This term is central. A formulation using a conventional direct-compression diluent could avoid the literal limitation if the selected excipient is properly characterized as direct-compression material. The distinction may depend on the material’s commercial grade, particle morphology, compressibility and intended use. A product using mannitol, sorbitol, lactose or another sugar alcohol would require a fact-specific analysis. The presence of a sugar or sugar alcohol alone does not necessarily establish that it is a non-direct-compression filler. “Hardness”The claims specify hardness in Newtons, with a broad threshold of 15 N and narrower ranges of 15-50 N, 20-50 N and approximately 35 N. Tablet hardness can vary with:
A product’s hardness should be measured under the same or a technically comparable protocol. A tablet outside the claimed numerical range may avoid literal infringement, but measurement variability could affect the analysis. “Friability”The claims refer to USP friability. Claim 1 permits about 2% or less, while claims 2, 3, 32 and 34 use tighter limits. Friability is a product property, not simply a formulation ingredient. A tablet may meet the friability limitation at release but fail it after transport or storage. The relevant test conditions and batch records would be material in an historical infringement dispute. “At least 60% rapidly water-soluble ingredients”This limitation appears in claims 3 and 32. It applies to the tablet matrix material, not necessarily to the entire tablet weight. Protected active particles may be treated separately depending on how the matrix is defined. The distinction between matrix ingredients and coated particles could have been a significant issue in claim construction. What patent landscape surrounds US 6,024,981?US 6,024,981 sits within the early fast-dissolving and orally disintegrating tablet patent field. The relevant technology clusters include:
The patent’s strongest historical distinction was the combination of rapid oral dissolution with sufficient mechanical strength for bulk storage. Many competing orally disintegrating technologies relied on porous or lyophilized structures rather than hard compressed tablets. Cima Labs’ technology was associated with the OraSolv and DuraSolv product platforms. OraSolv generally focused on rapid oral disintegration, taste-masked particles and specialized compression. DuraSolv emphasized stronger compressed orally disintegrating tablets suitable for more conventional handling and packaging. US 6,024,981 is most closely aligned with the compressed-tablet and protected-particle concept. When did US Patent 6,024,981 lose exclusivity?The patent expired in 2017 under its ordinary patent term. The relevant timeline is:
The patent is not subject to the five-year chemical patent term restoration framework applicable to certain approved drug products. It is a dosage-form patent, and the claims are not directed to a specific FDA-approved active ingredient. The expiration eliminates future infringement liability for acts occurring after expiration. It does not eliminate potential historical liability for conduct occurring while the patent was in force. What is the Orange Book status of US 6,024,981?US 6,024,981 is not an Orange Book drug patent in the ordinary sense. The FDA Orange Book lists patents submitted for approved drug products under the Hatch-Waxman framework. A general formulation platform patent with no identified active ingredient, dosage strength or approved product is not ordinarily listed by itself. Consequently:
The patent could have been relevant to an approved product if a specific NDA holder had submitted it for that product and FDA accepted the listing. The supplied claims alone do not identify such an Orange Book listing. Were Paragraph IV challenges or generic litigation likely?A Paragraph IV certification is product-specific. An ANDA applicant certifies against patents listed for the reference listed drug, not against every formulation patent in the historical patent record. For US 6,024,981:
The claims contain multiple objective parameters, which generally make product testing and laboratory evidence central to any infringement dispute. A claimant would need to establish that the accused product met the relevant hardness, friability, dissolution, composition and particle limitations. What generic launch risks exist today?There is no current US generic launch risk created by this patent. Any generic or branded manufacturer may develop a rapidly disintegrating tablet without obtaining a license from the expired patent holder. Current commercial barriers would instead arise from:
US 6,024,981 may still have technical value as prior art. A new patent application cannot generally reclaim the same disclosed combination merely by changing drafting language. New protection would need a patentable improvement, such as a distinct particle architecture, excipient combination, process parameter, stability profile or therapeutic application. Does the patent create biosimilar risk?No. Biosimilar products are biological products regulated under the Public Health Service Act and the Biologics Price Competition and Innovation Act. US 6,024,981 claims compressed oral dosage forms and small-molecule or supplement-type active ingredients. It does not claim:
The patent has no meaningful biosimilar relevance. What manufacturing and intellectual-property barriers remain?Although the patent has expired, the underlying technology can still present commercial execution challenges. A manufacturer must control:
The patent’s expired claims also identify areas where later patents may have been filed. A current freedom-to-operate review should separately examine:
How strong was the patent estate?Historically, the patent had meaningful platform value because it claimed the intersection of:
Its strength was greatest against products that reproduced the full formulation architecture. Its weaknesses included:
The patent is now best viewed as expired foundational prior art and a historical marker in orally disintegrating tablet technology, rather than as an active licensing or litigation asset. Key Takeaways
FAQs About US Patent 6,024,981Does US 6,024,981 cover Zydis tablets?Not necessarily. Zydis is associated with a distinct fast-dissolving dosage-form technology. A Zydis product would require a claim-by-claim comparison against the specific composition, manufacturing process and performance data. The patent primarily targets hard compressed tablets, while lyophilized dosage forms may use a different structural approach. Can a company still license US Patent 6,024,981?A company could obtain a historical or archival license, but the expired patent cannot provide prospective US patent exclusivity. Any commercial license would need to address other intellectual property, know-how, trademarks or foreign rights. Does the patent cover a tablet that disintegrates but does not fully dissolve?The answer depends on the claim and testing method. Claims use both “dissolve” and “disintegrable” terminology. A tablet that breaks into particles but leaves persistent material may not satisfy every dissolution limitation, particularly the claims requiring dissolution within 45 or 60 seconds. Can a formulation avoid the patent by using a direct-compression filler?Potentially. Claims requiring a non-direct-compression filler may not read on a formulation using a properly characterized direct-compression excipient. The result depends on the material, grade, formulation role and claim construction. Does expiration eliminate all business risk associated with the technology?No. Expiration eliminates the patent’s prospective US infringement risk, but later patents, foreign counterparts, trade secrets, regulatory requirements and product-specific patents may still affect commercialization. ReferencesCima Labs, Inc. (2000). Fast dissolving tablet, U.S. Patent No. 6,024,981. United States Patent and Trademark Office. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services. United States Congress. (2011). 35 U.S.C. § 154: Contents and term of patent; provisional rights. United States Code. United States Patent and Trademark Office. (2024). Patent term adjustment and patent term calculation. U.S. Department of Commerce. More… ↓ |
Drugs Protected by US Patent 6,024,981
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Patented / Exclusive Use | Submissiondate |
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| >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 6,024,981
| Country | Patent Number | Estimated Expiration | Supplementary Protection Certificate | SPC Country | SPC Expiration |
|---|---|---|---|---|---|
| Australia | 6896998 | ⤷ Start Trial | |||
| Australia | 726336 | ⤷ Start Trial | |||
| Canada | 2284663 | ⤷ Start Trial | |||
| Denmark | 2147669 | ⤷ Start Trial | |||
| Denmark | 2266538 | ⤷ Start Trial | |||
| >Country | >Patent Number | >Estimated Expiration | >Supplementary Protection Certificate | >SPC Country | >SPC Expiration |
