China Resources Pharma, China’s second largest drugmaker, has been approved to stage its IPO on the Hong Kong Exchange, according to reliable, though not official sources. The offering will raise as much as $2 billion, up from earlier estimates of $1 billion to $1.5 billion. Because Hong Kong requires IPO companies to list at least 25% of their shares, the offering terms imply a valuation of $8 billion for CR Pharma. CR Pharma, a unit of state-owned conglomerate China Holdings, already has two subsidiaries that are listed on China exchanges.