* Sells 28.2 million Aspen shares for 372 rand each
* GSK says move increases "financial flexibility"
* British group retains 6.2 percent stake in Aspen (Updates with actual amount raised following sale)
LONDON, March 13 (Reuters) - GlaxoSmithKline hastaken profits in Aspen Pharmacare by selling half itsstake in the South African drugmaker for $853 million, followinga long investment in the firm.
The sale, which was conducted through a share placing at adiscount to the market price, is the latest example of GSKpruning non-core investments as it refocuses its business andworks to protect its sizeable dividend payments to shareholders.
Britain's biggest drugmaker will remain a 6.2 percentshareholder in Aspen and has undertaken not to sell any moreshares in the South African group for 180 days.
GSK said on Friday it had sold 28.2 million Aspen shares ata 372 rand each, compared to Thursday's closing price of 406.5.The sale was handled by Citi and UBS.
In November 2013, GSK sold another similar sized tranche ofAspen stock for 250 rand a share.
Simon Dingemans, GSK's chief financial officer, said thedisposal would help give his company flexibility to invest innew opportunities in the wake of a $20 billion-plus asset swaptransaction with Novartis.
"As we continue to reshape the group around our corefranchises and drive the benefits from the Novartis transaction,optimising our financial flexibility to invest behind thesepriorities is key," he said in a statement.
"As a result we have decided now is the right time torealise further value from this successful relationship. Wecontinue to believe in the strategy of Aspen and we remaincommitted to working together in the future."
GSK said that the net profit on the disposal would not beincluded in core operating profit and core earnings in 2015, andGSK would no longer account for Aspen as an associate.
However, the British group's head of strategy David Redfern,who was recently appointed as GSK's nominee director on Aspen'sboard to replace GSK president of pharmaceuticals Abbas Hussain,will remain a director, Aspen said.
GSK has been suffering from weak sales of its keyrespiratory drugs in the past year, especially in the UnitedStates, and has implemented a 1 billion pounds ($1.49 billion)cost-cutting programme.
It is also considering an initial public offering for itsmajority-owned HIV unit, known as ViiV Healthcare. But plans tosell a portfolio of older drugs were dropped in December. ($1 = 0.6731 pounds) (Reporting by Freya Berry, Vikram Subhedar and Ben Hirschler;Editing by Greg Mahlich and William Hardy)