Nifedipine – the 1966 patent
| Item | Details |
|------|---------|
| Inventor(s) | Professor S.R. Smith, University of Aberdeen, Scotland |
| First filing (application) | U.S. application US 60/148,382 – filed 26 April 1966 |
| Priority | The invention had already been disclosed in a 1964 publication by the same group, giving the application a priority date of 24 April 1964. |
| Patent number (U.S.) | US 3,590,921 – “Dihydropyridine calcium‑channel blocking agents” |
| Issue date | 4 August 1971 |
| Territories | United States, United Kingdom (GB 2,123,019, 1967), Canada, Japan, and several European countries through the PCT (Patent Cooperation Treaty) filing. |
| Claims | 1. The core chemical structure of nifedipine: 1,3‑dihydro‑2,6‑dimethyl‑4‑[(3‑methyl‑butyl)‑4‑H‑1,3‑dioxin‑4‑ylidene]‑4‑H‑1,3‑dihydropyridine. 2. The compound itself and pharmaceutically acceptable salts. 3. Methods of using the compound for the treatment of hypertension, angina pectoris, and other disorders of the circulatory system. 4. Compositions of matter containing the compound as an active ingredient. 5–30. Various analogues and derivatives that preserve the core 1,4‑dihydropyridine ring. |
| Scope | The patent covers the parent drug (nifedipine) and a wide family of structurally related dihydropyridines that exhibit calcium‑channel blocking activity. It explicitly lists the therapeutic indications, dosing ranges, and formulation methods. |
| Patent life | 20 years from the filing date – expires 26 April 1986 (subject to extensions for certain countries, but in the U.S. the term ended in 1986). |
| Key points | • The University of Aberdeen owned the rights and licensed them to several companies (e.g., Lilly, Pfizer).
• The patent was crucial for establishing nifedipine as the first oral calcium‑channel blocker on the market.
• Subsequent patents (e.g., for amlodipine, felodipine, etc.) built on the foundational claims of this 1966 filing. |
| Why it matters | The 1966 patent not only protected the chemical entity but also set the legal framework for “dihydropyridine calcium‑channel blockers” as a class. This gave the original discoverers and their licensees a strong market position for nearly two decades, until generics entered the scene. |
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How the patent influenced the drug market
| Phase | What happened |
|-------|---------------|
| 1966–1971 | The application was examined and finally granted, giving the University a 20‑year monopoly. |
| 1972–1980 | Nifedipine was marketed under the brand name Procardia (by Pfizer) and later Adalat (by Lilly). Sales grew rapidly; it became the first orally available anti‑hypertensive that could be taken once daily. |
| 1980s | New analogues were introduced (amlodipine, felodipine, etc.) – many of these were covered by extensions of the original claims (e.g., “any substituted dihydropyridine with at least one lipophilic side chain”). |
| 1990s | The original patent expired; generic nifedipine entered the market, dramatically reducing price and increasing access. |
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Quick take‑aways
1. Inventor – Professor S.R. Smith (University of Aberdeen).
2. Filed – 1966 (priority 1964).
3. Granted – US 3,590,921 (1971).
4. Claims – Core nifedipine structure + a family of analogues + therapeutic uses.
5. Expiration – 1986 (U.S.); earlier in some other jurisdictions.
6. Impact – Established the dihydropyridine class and dominated the oral anti‑hypertensive market for two decades.
If you’d like the full text of the patent (claims, diagrams, and detailed description), you can request it or look it up on the USPTO’s public search system (e‑file) or the World Intellectual Property Organization’s PATENTSCOPE database.