Pfizer is buying Hospira for approximately $15.23 billion, saying it is a good fit with its established global pharmaceutical business. The buyout will also help Pfizer tap into the growing market for biosimilars, which are cheaper versions of biologic drugs that are used to treat conditions such as anemia. Hospira Inc., based in Lake Forest, Illinois, is a provider of injectable drugs and infusion technologies. It also offers biosimilars. Pfizer Inc. will pay $90 per share in cash, which is a 39 percent premium to Hospira’s Wednesday closing price of $64.80. The companies put the deal’s value at about $17 billion including debt. Pfizer — which is the world’s second-largest drugmaker by revenue — said Thursday that it will use its global network to help expand Hospira’s reach to Europe and key emerging markets. Hospira’s products are currently distributed mostly in the U.S.