UPDATE 1-States allege Abbott blocked generic TriCor

(Adds details on generics, new Abbott formulations)

NEW YORK, March 18 (Reuters) - State regulators are suing Abbott Laboratories Inc (ABT.N: Quote, Profile, Research, Stock Buzz) and Solvay (SOLB.BR: Quote, Profile, Research, Stock Buzz) unit Fournier, alleging the drug makers illegally conspired to prevent and delay low-cost generic versions of their TriCor cholesterol drug.

The suit was filed on Tuesday by attorneys general of 18 states and the District of Columbia in U.S. District Court in Delaware, the Iowa attorney general's office said.

The lawsuit alleges that Abbott and Fournier brought sham patent-infringement lawsuits against generic companies, without a reasonable basis to believe the patents were enforceable, according to a copy of the lawsuit posted on the Iowa attorney general's Web site.

According to the lawsuit, Abbott and Fournier also improperly attempted to monopolize the TriCor market by reformulating it to different dosage strengths and ending sales of the original formulations.

The drug, which is a leading treatment for a type of blood fat called triglycerides, has annual sales of more than $1 billion.

Abbott spokeswoman Melissa Brotz defended Abbott's actions as lawful.

"There is nothing anti-competitive about ceasing manufacturing and marketing (of) older versions of products when improvements are developed," Brotz said.

Brotz said the improvements of the new formulations include having to take fewer pills, requiring lower dosages and being able to take them with or without food.