Chemical Properties of IV Solutions

 pH Value – the degree of acidity or alkalinity of a solution.

• Less than 7.0 = acidic
• Greater than 7.0 = basic (alkaline)
• Blood plasma pH 7.4

IV solutions should have a pH that is neutral (near 7.0) so they don’t adversely affect the pH of the blood.

Hypotonic solution – hypoosmolar solution; fewer number of dissolved particles than blood cells; water is drawn into cells, causing cells to swell.

• 0.45% normal saline (NS)

Hypertonic solution – hyperosmolar solution; greater number of dissolved particles than blood cells; water is drawn out of cells, causing cells to shrivel.

• 50% dextrose or 3% sodium chloride

Isotonic solution – similar number of dissolve particles as blood.

• 0.9% NS

Compatibility – the ability to combine two or more base components or additives within a solution, without resulting in changes to the physical or chemical properties of the additives.

Stability – is affected by storage conditions; some IV medications need to be refrigerated or frozen after compounding; amber-colored bags protect the drug from exposure to light.

• Osmolarity and Osmolality

• Osmolarity – a measure of the number of milliosmoles of solute per liter of solution (mOsm/L).

  • Blood plasma = 285 mOsm/L

  Osmotic pressure – the pressure required to maintain equilibrium, with no net movement of solution across body membranes.

  Osmolality – a measure of the number of milliosmoles of solute per kilogram of solvent.

  An IV preparation must be isoosmotic, meaning the solution should have the same number of particles in solution per unit volume and the same osmotic pressure as blood.

  
  

• Types of IV Solutions

• Multiple IV solutions are available. Most common used IV infusions are dextrose in water, normal saline, or dextrose in saline.

  Technicians typically compound two types of CSPs:
  
• • Large-volume parenterals
     • Primary source of hydration
  • Small-volume parenterals
     • “piggybacked”
  •