Usually 20 years.

A drug patent expires 20 years from the date on which the patent application was filed in the United States. In some cases, a term extension is provided if the original patent was delayed due to secrecy orders, interferences, or appellate review periods.

Generics can be launched once the patent-protected drug surpasses the patent expiry and exclusivity date.

Pharsight provides the drug patents list expiring in a particular year like 2023, 2024, and more.

Generic medicines are cheaper than their brand-name counterparts because the manufacturers of generic drugs do not have to bear the costs of the development and research of a new drug.

When a brand-name drug goes off-patent, other drug companies can start selling generic versions. These companies do not have to spend money on research and development, and can therefore sell the drug at a lower price.

Additionally, competition among multiple companies producing the same generic drug also drives down the price.

One common tactic is to make minor changes to the drug's formulation or packaging and then file secondary patents for the "same" drug (also known as "evergreening"). This can extend the life of the patent by several years.

Additionally, companies can also use regulatory loopholes and legal challenges to slow down the approval of generic drugs, this could temporarily delay the entry of generic versions of the drug into the market.

A patent thicket is like a big wall made out of blocks.

Each block is a special kind of paper called a patent, and it says that only one person or company can use a certain idea or invention.

Sometimes, there are so many blocks stacked on top of each other that it's hard to build anything new without breaking some of the blocks.

That's what a patent thicket is!

It's a lot of patents that make it hard for people to create new things.

The Orange Book is called that because it has an orange cover. It came out in October 1980, which is close to Halloween, and that's why they picked orange."

The Purple Book gets its name from the purple cover of the print edition. The Purple Book has been published in this format since it was first issued in 2020 and the color purple was chosen as a way to easily identify and differentiate it from other publications. The choice of color for the cover of the Purple Book was likely an arbitrary decision made by the FDA during the early design and production phase of the publication.

You can seek FDA approval to launch a generic drug before the expiration of brand-name drug's patents related by providing a 'paragraph IV certification' in your application, which states that the patent submitted by the brand-name drug's sponsor is invalid, unenforceable, or will not be infringed by your generic product.

The approval process for generic drugs in the United States is regulated by the Food and Drug Administration (FDA). To be approved, a generic drug must demonstrate bioequivalence (i.e., the generic drug must have the same active ingredient, dosage form, and route of administration as the brand-name product, and must have the same intended use) and must pass certain quality standards.

Additionally, the generic drug manufacturer must prove that the product is safe and effective through appropriate testing. Once a generic drug is approved by the FDA, it can be marketed and sold to consumers.