P-1 Medium is intended for use in culturing human gametes and embryos during fertilization and growth through Day 3 of development. P-1 Medium was developed by Dr. Thomas B. Pool, Fertility Center of San Antonio, based upon the original HTF formula but modified to provide a glucose-free and phosphate-free environment. This formulation also contains taurine, an amino acid shown to have protective and embryogenic functions. P-1 Medium is bicarbonate-based and is designed for procedures utilizing a CO2 incubator.