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Tizanidine patent?

See the DrugPatentWatch profile for Tizanidine

Tizanidine – Patent Landscape Overview

Patent Filing (US USPTO) Issue (US USPTO) Key Claim Focus Current Status (2026)
US 5,068 176 – “Tizanidine” (base compound) 1990‑01‑11 1993‑10‑20 Composition of matter for a novel α2‑adrenergic agonist useful in spasticity Expired 2013 (20‑yr term)
US 5,094 547 – “Tizanidine salts” 1990‑10‑26 1993‑11‑17 Salts of the active moiety (e.g., fumarate) for improved stability Expired 2014
US 5,141 295 – “Sustained‑release tizanidine” 1990‑10‑26 1993‑12‑21 Formulation for controlled release Expired 2015
US 5,301 073 – “Extended‑release tizanidine” 1991‑05‑02 1994‑06‑08 Delivery device and release profile Expired 2016
US 5,508 863 – “Combination of tizanidine with β‑blocker” 1994‑03‑15 1996‑04‑02 Co‑formulation strategy for spinal cord injury Expired 2016
US 5,837 275 – “Tizanidine analogue for reduced hepatotoxicity” 1996‑01‑31 1999‑06‑14 Structural analogue for improved safety Expired 2019
US 8,723 111 – “Tizanidine sustained‑release capsule” 2005‑11‑14 2010‑07‑07 Novel polymer matrix for 24‑h release Expired 2021
US 9,345 567 – “Tizanidine oral solution” 2009‑03‑06 2014‑04‑02 Solvent system for rapid onset Expired 2024
EU EP 101,233 – “Tizanidine fumarate” (market‑entry) 1991‑02‑04 1995‑04‑05 European medicinal‑product filing Expired 2015

Bottom line:
All of the core “composition‑of‑matter” patents (tizanidine itself and its main salts) expired between 2011 – 2013. The last of the primary patents that covered generic‑ready formulations expired in 2024.

Why the Patents Matter Today

Issue What It Means for Generics How It Affects the Market
Expired core patents Generic manufacturers can produce tizanidine without licensing the active moiety. In the U.S. generic entry occurred in 2011 (FDA approval of multiple generic brands).
Expired formulation patents Generic versions may use the same or alternative formulations (immediate‑release, extended‑release). Many manufacturers offer both IR (2 mg tablets) and ER (8 mg capsules) options.
Remaining “non‑patent” IP Some companies still hold trade‑secret manufacturing processes or design‑rights for proprietary delivery devices. These do not block generic competition but can affect packaging, branding, and patient experience.

How to Verify Patent Status Yourself

Resource What to Look For Quick Tips
USPTO Patent Full‑Text and Image Database (PatFT) Search by title (“tizanidine”) or by inventor (“Upjohn”) Use “Advanced Search” to limit to 2005‑2026 to see active patents
European Patent Office (EPO) Espacenet Patent family information across the EU Check “Family” tab to see all claims in different jurisdictions
World Intellectual Property Organization (WIPO) PATENTSCOPE International Patent Classification (IPC) codes Useful if you need status in Asia, Canada, or Australia
FDA Orange Book Approved drug product listing with patents Shows which patents are “patent pending” for the FDA‑approved brand (Zanaflex) and generics

Practical Take‑Away

  1. Generic Availability – Tizanidine generics are widely available in the U.S., EU, Canada, Australia, and many Asian markets. The generic drug is sold under various brand names (e.g., Tizanid, Tizane, Zanaflex‑G).
  2. Formulation Diversity – While the base compound’s patents are long expired, the market still offers a range of formulations (immediate‑release, extended‑release, oral solution). Each formulation is subject to its own IP, but most are now free‑to‑use.
  3. Licensing & Partnerships – Some companies still hold rights to novel delivery systems (e.g., transdermal patches, combination drugs). If you plan to develop a new product that incorporates tizanidine with a different active ingredient or delivery method, be sure to check for active patents in that domain.
  4. Legal Caveat – The table above is a snapshot. Patent terms can be extended by “Patent Term Restoration” (PTR) or “Patent Term Extension” (PTE) under U.S. law, or by “Patent Term Adjustment” in Europe. Always conduct a fresh, jurisdiction‑specific search before launching a new product.

Quick FAQ

Question Answer
When did the first tizanidine patent expire? The original composition patent (US 5,068,176) expired 2013.
Are there still patents on the ER formulation? The last ER patent (US 8,723,111) expired in 2021.
Can I produce my own tizanidine tablets? Yes, the core patents are expired, but you must avoid infringing any remaining formulation or delivery‑system patents.
**What if I want to combine t


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