Technical Data
Media
Leibovitz L-15 Medium w/L-Glutamine, w/o Phenol Red (Powder)
L2101-01
Cell Culture Grade
Storage RT/4°C    Shipping RT
Components shown as g/liter
Inorganic Salts:
Calcium Chloride•2H2O0.185
Magnesium Chloride•6H2O0.2
Magnesium Sulfate0.09767
Potassium Chloride0.4
Potassium Phosphate Monobasic0.06
Sodium Chloride8
Sodium Phosphate Dibasic0.19
Amino Acids:
L-Alanine 0.225
L-Arginine0.5
L-Asparagine0.25
L-Cysteine0.12
L-Glutamine0.3
Glycine0.2
L-Histidine0.25
L-Isoleucine0.125
L-Leucine0.125
L-Lysine•HCl0.0937
L-Methionine0.075
L-Phenylalanine0.125
L-Serine0.2
L-Threonine0.3
L-Tryptophan0.02
L-Tyrosine0.3
L-Valine0.1
Vitamins:
Choline Chloride0.001
Folic Acid0.001
myo-Inositol0.002
Niacinamide0.001
D-Pantothenic Acid•Ca0.001
Pyridoxine•HCl0.001
Flavin Mononucleotide•Na0.0001
Thiamine Monophosphate•HCl0.001
Other:
D-Galactose0.9
Phenol Red, SodiumAbsent
Pyruvic Acid, Sodium0.55
Total:13.9g/liter
The most commonly used buffering system for mammalian cell cultures is a bicarbonate/CO2 system, which requires CO2 regulators and incubators to supply a constant level of CO2. As a replacement, Leibovitz developed a bicarbonate-free medium, L15, with relatively high levels of certain amino acids in the free base form.

The most common method in use today for buffering mammalian cell cultures is the bicarbonate/CO2 system, which is based on the following equilibrium:
CO2 + H2O<-->HCO3-- + H+

The use of bicarbonate is an attempt to mimic the buffering system of blood, but it has at least two major drawbacks. (1) The pKa of bicarbonate is 6.1, which is far removed from the desired pH range of cell culture media (7.0-7.4). (2) Although bicarbonate is cheap, supplying a constant level of CO2 to cell cultures is definitely not, as it requires expensive CO2 incubators or fermentors.


Directions per Liter: Dissolve 13.9g in 800-900ml of ddH2O, stirring gently until completely solubilized. Adjust pH of the medium to 0.1-0.3 pH unit below the desired level. Add additional water to bring the solution to 1L. Filter-sterilize using a 0.22 micron membrane filter. Aliquot into sterile containers. Do not autoclave. Contains heat-labile compounds that can be damaged with autoclaving.

Storage and Stability: Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.

Appearance: White, homogeneous free flowing powder

Solubility: Colorless, clear, complete

pH: As Reported

Endotoxin: 1Eu/ml


Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

1. Bernt, E. & Bergmeyer, H. U. (1974) Bergmeyer), p. 1304. Deerfield Beach, FL: Verlag Chemie Intl. 2. Eagle, H., Barban, S., Levy, M. & Schulze, H. O. (1958). The utilization of carbohydrates by human cell cultures.. Biol. Chem. 233, SS1-558. 3. D. Barngrover, J. Thomas and W. G. Thilly, J. Cell Set. 78, 173-189 (1985) 173
4. Leibovitz, A. (1963) Amer. J. Hyg. 78:173-180.