What does it mean that a drug was "repatented"?

From the New York Times:

Albuterol, one of the oldest asthma medicines, typically costs $50 to $100 per inhaler in the United States, but it was less than $15 a decade ago, before it was repatented.

I get that it means the patients will have to pay, however, how can you re-patent something? Intuitively, I believed that once the patent expires, it's over. And that you can only patent novel inventions.

2 Answers 2


This refers to adding a putatively useful feature to the thing. For instance, a drug can have a certain active ingredient, and the patent on the active ingredient can expire, but you may discover a way to make the drug more effective or in some other way more useful (e.g. by reducing side-effects) by coating it with a purple wax. This product can be patented. This is the situation with Albuterol: the delivery system is new. The active ingredient is now free for the copying, but the particular combination of drug and delivery system known as Proventil is protected by patent.

  • Does it actually need to be "more effective"? Similar stories I've read seem to imply that any change (usually to the non-active ingredients) is enough to apply for a new patent.
    – pboss3010
    Jun 5, 2019 at 16:38
  • 2
    @pboss3010 It need not be more effective just new, useful, and non-obvious. Useful could be cheaper or more compact.
    – A. K.
    Jun 5, 2019 at 16:51
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    I believe in the case of albuterol, the previous formulation used a propellant which was banned because it included CFCs, and the patent is for a CFC-free delivery system. So the "useful" aspect of the new system is that it's legal. Jun 6, 2019 at 6:06

Drugs are also (re)patented for different uses. I see that two new patents were granted on uses of asprin recently (March 2019).

MARCH 01, 2019 Jennifer Nessel, Assistant Editor The US Patent and Trade Office (USPTO) has granted 2 new patents related to a novel inhaled rapid-onset aspirin formulation (Asprihale, OtiTopic) in development to treat suspected myocardial infarction (MI).

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