Britain’s AstraZeneca Plc (AZN.L) said on Friday it had agreed to buy ZS Pharma (ZSPH.O), paying a total $2.7 billion for its proprietary technology to develop novel treatments for hyperkalaemia, or high potassium levels. AstraZeneca said it had agreed to pay $90 a share for the San Mateo, California-based firm. Hyperkalaemia is typically associated with chronic kidney disease and chronic heart failure, AstraZeneca said, adding that peak sales of the company’s ZS-9 potassium-binding compound, which is under review by the FDA, were forecast to exceed $1 billion.