DEFINITION: It is a mixture of salts, amino acids, vitamins and other components that are essential for cellular growth.

ACTION: Acts like a nutritive solution in cell culture.

PRODUCT SPECIFICATIONS: It is applied for human and animal cell culture. There are two presentations: powder and liquid. The powder medium is stable for more than 24 months if well locked in freezer. Another advantage is the fidelity of results in programming cell culture at long term using the same lot. MEDIUM 199 has small amounts of folic acid and for this reason it is more used in research of the X chromosome fragile site. It also presents several vitamins that help the cellular metabolism.

ADVANTAGES: Tested in at least three different cellular lineages and also in lymphocyte culture. pH and osmolality are always determined. Each lot is only discharged if within biological limits. The medium also promotes a great cellular growth.

PHYSICAL-CHEMICAL CHARACTERISTICS:

-Appearance: rosy and homogeneous powder
-Particles size: approximately 20 microns
-Solubility: clear solution at final concentration (1x)
-pH at 25°C (without NaHCO3) : 4.12 + 0.5
-pH at 25°C (with NaHCO3) :7.40 + 0.5
-Osmolality (without NaHCO3) : 250 + 5%
-Osmolality (with NaHCO3) : 290 + 5%

STORAGE: Store the powder or the final solution at 2 to 6°C. If these conditions are not maintained alterations may be observed, such as:
1. Colour change
2. Grainings
3. Insolubility
4. Alteration of pH
5. Incapacity to maintain its integrity under normal conditions.

PREPARATION: Medium 199 powder is extremely hygroscopic and must not be exposure to the environment. Preparations with higher concentrations are not recommended due to the possibility of precipitate formation.

1. Measure out tridistillate water to approximately 90% of desired total volume of medium (15-20°C).
2. Add the powder and mix gently into equilibrium. DO NOT HEAT THE WATER.
3. After the powder is completely dissolved, add 2.2 g of sodium bicarbonate 5.6% for one liter.
4. Add antibiotics or other components if desired.
5. If necessary, adjust pH with HCl 1N or NaOH 0.1N, or also CO2.

Add tridistillate water to the final volume and filter the medium into sterile container using a 0.22m membrane filter.

PRESENTATION: Powder: bottles with powder for 1, 10 and 50 liters.
Liquid: Bottle with 100 and 500 ml.
STORAGE: 2 to 6°C
SHELF LIFE: 12 months