(Reuters) - British drugmaker GlaxoSmithKline Plc has reached a $150 million preliminary settlement with U.S. drug wholesalers who claimed the company improperly delayed entry to the market of generic alternatives to its nasal spray Flonase, according to court documents.

The settlement was reached with, among others, AmerisourceBergen Corp, Cardinal Health Inc, and McKesson Corp, who maintained that Glaxo had abused the citizen's petition process to maintain a market monopoly and overcharge for the spray by restricting access to less expensive generic versions.

The preliminary settlement was approved by the United States District Court for the Eastern District of Pennsylvania.

(Reporting By Toni Clarke; Editing by Gerald E. McCormick)