Pfizer Inc's subsidiary Hospira has secured an Indian patent for an improved process for the preparation of Cilastatin. Cilastatin is a chemical which acts with anti-biotic Imipenem for the treatment of infections in various body systems. Imipenem and Cilastatin are combined in a drug to make an anti-biotic. It is used to treat serious infections that are mild to moderate in severity, such as lower respiratory infection and heart valve infection.