LONDON, UK: AstraZeneca has agreed to sell the commercial rights to Seroquel and Seroquel XR in the US and Canada to Cheplapharm Arzneimittel GmbH. Cheplapharm will make an upfront payment of $35 million to AstraZeneca and may also make future sales-contingent payments of up to $6 million. Seroquel and Seroquel XR, used primarily to treat…