The US-based Medicis Pharmaceutical Corporation has filed a patent law suit against Ranbaxy Pharmaceuticals Inc and also against Ranbaxy Laboratories Ltd for alleged infringement of its patent on minocycline hydrochloride extended release tablets - Solodyn, used to treat acne.

In the petition filed with the District Court of Delaware, US, Medicis alleges that Ranbaxy has violated one or more claims three, four, 12 and 13 of the US Patent No.5,908,838 for method for the treatment of acne, issued on June, 1999. Ranbaxy has filed an abbreviated new drug application (ANDA) with the US Food and Drugs Administration (FDA) to manufacture and sell the minocycline HCL with a Para IV certification.

The petition sought an adjudication that will restrain Ranbaxy from manufacturing and selling the generic product prior to the expiry of `838 patent and that the FDA should only issue approval for sales after the expiry of the said patent.

IMS sales data shows that the annual US sales of Solodyn were about US$ 365 million for the twelve months ended January 31, 2009. According to available information, Solodyn constitutes 50 per cent of Medicis' total revenue.

In March 2009, the company has settled a similar patent infringement litigation with the Israel-based generic drug major, Teva Pharmaceuticals, which received final approval from the FDA to market the generic version of acne drug Solodyn or minocycline HCl, extended-release tablets, 45 mg, 90 mg and 135 mg. The settlement allows Teva to market its generic version beginning in November 2011, at the time when the Solodyn patent gets expired, or earlier under certain conditions.

Teva is reportedly one of the first companies to file ANDA with a Para IV certification for minocycline HCL. It has also been awarded a 180-day period of marketing exclusivity. It is also learnt that the FDA has denied Medicis' petition seeking a 30 month ban on making generic version of the drug.