G Ranganathan, owner of Sresan Pharma that manufactures Coldrif cough syrup which allegedly led to the deaths of children in Madhya Pradesh and Rajasthan, is a Chennai-based pharmaceutical entrepreneur. Ranganathan, who has been arrested, is a graduate of Madras Medical College in pharmacy and first gained recognition in the early 1980s for Pronit, a nutritional syrup widely used in Chennai.