The board of directors of GlaxoSmithKline Pharmaceuticals, at its meeting held today, have considered and approved buyback of its equity shares from the existing shareholders through the stock exchange route.According to a release issue to the BSE, the board has fixed the price not exceeding Rs 800 per share amounting to Rs 230.65 crore .The buyback amount is 25% of the total paid-up equity share capital and free reserves of the company, the release added.