RPMI-1640 medium was developed by Moore et al., at Roswell Park Memorial Institute, hence the acronym RPMI. The formulation is based on the RPMI-1630 series of media and alterations in the amounts of amino acids and vitamins. RPMI1640 media is used primarily for various types of mammalian myeloma and hybridoma cells including mouse hybridomas, human leukocytes, and B and T lymphocytes. Recently, RPMI 1640 media have been shown to support several cell lines in the absence of serum. HEPES buffer is included in the formulation at a final concentration of 25 mM to compensate for the loss of buffering capacity incurred by eliminating serum. RPMI 1640 without L-glutamine, with 25 mM HEPES is a sterile, liquid medium which contains essential and non-essential amino acids, vitamins, organic and inorganic compounds, hormones. It is well suited for supporting the growth of a broad range of mammalian cell lines. This product is for research use only. It is not approved for human or animal use, or for application in in vitro diagnostic procedures.