** Shares of contract drugmaker Sai Life Sciences SAIE.NS fall 3.7% to 873 rupees
** PE firm TPG preparing to exit SAIE by selling its 14.7% stake via block deals worth 25 bln rupees ($285.7 mln), CNBC-TV18 reports on Monday
** Stake sale at floor price of 860 rupees, report says, about a 5% discount to SAIE's closing price on Monday
** TPG and Sai Life Sciences did not immediately respond to Reuters requests for comment
** Stock up ~21% YTD
($1 = 87.5060 Indian rupees)
(Reporting by Urvi Dugar)
((UrviManoj.Dugar@thomsonreuters.com;))