Officials at Philadelphia Park announced Monday that the purse for its marquee event, the Pennsylvania Derby (gr. III), would be increased from $300,000 to $500,000 for its 23rd renewal, set for Labor Day, September 3.The purse boost makes the 1-1/8 mile Pennsylvania Derby the richest race in the history of Pennsylvania horse racing.Philadelphia's director of racing Sal Sinatra said that the increase was due to monies accrued based on handle at the Bensalem, Pa. racetrack. He also indicated that, while a complete stakes schedule for Philadelphia was yet to be released, other stakes could also receive purse increases, including the Cotillion Handicap (gr. II)."In the past two years, the Pennsylvania Derby has drawn large fields, generated tremendous attendance, handle, and a strong response in simulcast exports," said Sinatra. "What we're trying to do by increasing the Pennsylvania Derby's purse, and the purses of our other stakes, is bring some attention to our racing product." Sinatra indicated that because the Philadelphia stable area was filled to capacity, field sizes have been large, which in turn has translated to more appeal at simulcast outlets. He also said that the date for the 2001 Philadelphia Park Claming Crown, a prelude to the Canterbury Claiming Crown, was set for June 9.