Pharmaceuticals group GlaxoSmithKline (GSK) has upped its stake in its Indian consumer healthcare subsidiary by investing over half a billion pounds in the unit.GSK, which first announced an open offer back in November, has now raised its stake in the Indian publicly-listed division from 43.2% to 72.5% in an effort to raise its exposure to a "key emerging market", according to the company's Chief Strategy Officer David Redfern.The offer period (January 17th-30th) saw shareholders in GSK Consumer Healthcare Ltd validly tender 12,319,749 shares representing 29.3% of the total shares outstanding.The offer of INR3,900 per share values the deal at INR48bn, around £568m.Redfern said: "We are very pleased with the outcome of this transaction, which will further increase our exposure to a key emerging market. "It is a significant vote of confidence in the long-term growth prospects of our Consumer Healthcare business in India."