GlaxoSmithKline is paying Darwin Private Equity £162m in cash for protein drinks firm Maxinutrition.The British drugs giant, which already owns the Lucozade sports drink franchise, will own brands like Maximuscle used by weight-trainers. Maxinutrition is Europe's top sports nutrition company by market share and recorded sales of about £36m in the year ended April 2010. "The acquisition is a demonstration of GSK's strategy to expand our consumer healthcare business through appropriate bolt-on acquisitions which meet our strict financial criteria," said John Clarke, Glaxo President Consumer Healthcare.Maxinutrition boss Peter Boddy said: "Maxinutrition is a fast growing, focused sports nutrition business with excellent growth prospects and a strong management team - it's a natural fit for GSK and its ambition to extend and expand its Nutritional Healthcare business."