Following are frequently asked questions regarding the use of osmolality in the pharmaceutical, biotechnology, and sports medicine applications.

In scientific terms, osmolality is a measure of the number of particles in a solution. For example, water has a very low osmolality (close to zero) where cranberry juice cocktail has a very high osmolality because there are a lot of sugar molecules dissolved in it. The osmolality of Gatorade is close to that of our blood, a factor that helps assure rapid absorption. If beverage osmolality becomes too high (e.g. soft drinks and fruit juices), the rate of fluid absorption is slowed.

The osmolality of standard cell growth media for mammalian cells is 300mOsm/kg, an optimal value for most cell lines.

Osmolality is a measure of the number of particles in a solution and can affect the functionality of fluid replacement drink. The osmolality of Accelerade ranges from approximately 345 to 365 mOsm/kg. Data in the literature suggests that beverages in the range of 0 to 400 osmolality do not affect intestinal absorption or fluid homeostasis during moderately intense exercise.

Answer: Most established vertebrate lines will tolerate a rather large variation in osmotic pressure. The useful range of osmolality of cell culture media for vertebrate lines is between 260 to 320 mOSM/kg. Invertebrate lines vary greatly in their sensitivity to osmotic pressure. For example, the snail embryo ATCC CRL-1494 requires medium of about 155 mOSM/kg, while some insect media prefer 360 to 375 mOSM/kg.

PediaSure Enteral Formula has an osmolality of 335 mOsm/kg H20 and PediaSure Enteral Formula with Fiber and scFOS® has an osmolality of 345 mOsm/kg H20.

A2: Freezing-point osmometers measure the number of particles in solution with millimole sensitivity. Osmolality is not affected by the size, shape or charge of particles and is less influenced by suspended particles (i.e. particles not in solution). Therefore, by using osmolality in conjunction with other tests (i.e. specific gravity, etc.) you can often clarify or pinpont a diagnosis more quickly.