E2 L2 - Components of Parenteral Products - Vehicles

Question 1

Occurs when, to produce equilibrium, a substance in solution crosses a membrane from an area of lower concentration to an area of higher concentration

Answer 1

Osmolarity

Question 2

Solutions containing the same concentration of particles

Answer 2

Isotonic (water = iso-osmotic)

Question 3

Certain isotonic pH neutral infusates cause

Answer 3

Phlebitis

Question 4

T/F - isotonic is the same as iso-osmotic

Answer 4

FALSE

Question 5

Isotonicity def

Answer 5

Maintaining and possessing a uniform tension or tone (of cell membranes/tissues/blood, endothelial cells)
-Can stretch and contract
-Do not get worn out - flexible but does not get out of shape

Question 6

T/F: concentrations tend to equalize over time

Answer 6

True

Question 7

How do concentrations equalize?

Answer 7

Diffusion
Osmosis

Question 8

Diffusion

Answer 8

Solute moves from the region of higher concentration to the region of lower concentration - Permeable membrane
Same concentration and volume on both sides

Question 9

Osmosis

Answer 9

WATER moves from region of higher concentration to the region of lower concentration
-Travels across SEMI permeable membrane
-some things in, some things not
-water can cross freely, but solutes cannot
Concentrations are the same on both sides, but volume is not the same

Question 10

Isotonicity - vehicle

Answer 10

Parenteral vehicles have the ability to shrink or burst open blood and venous endothelial cells

Question 11

Isotonicity cell membranes

Answer 11

Semipermeable
-impermeable (nothing goes through) - cell starves
-permeable (everything goes through) - cell ends as an empty shell dead again
Semipermeable (some things can cross, others cannot) - viable cell

Question 12

RBC flexibility

Answer 12

It can be flexible and stretch, but cannot expand = too full - Cell bursts open - hemolysis

Question 13

Hemolysis

Answer 13

Different conc. inside and outside the cell membrane
Tendency to equalize concentrations remains A catch: the membrane is semipermeable (living cell)
Only water can go through (not solutes)
water will move to dilute the more concentrated side
Does not have to be water, any hypotonic vehicle can do the same

Question 14

How can we measure the risk of any given preparation?

Answer 14

By knowing the osmolarity or the osmolality of the prep
We use an instrument called an osometer to measure this property
This is a practical use of colligative properties
-Freezing point depression
-Lowering of vapor pressure
-Osmotic pressure

Question 15

Colligative properties

Answer 15

Properties of solutions that depend on the quantity of “molecular particles” (be they molecules or ions, say m particles) in solution, rather than the chemical nature of the dissolved material(s)
-Sodium ion - m particle
molecule of glucose - m particle
count all particles together, no matter what they are, and it will give number we want

Question 16

M particles continued

Answer 16

Any solute (Drug, electrolyte, sugar) m-particle dissolved has the same effect as something else
Osmolarity and osmolality are determined by the total (added up) concentration of solutes dissolved (counted as “m-particles”), including the drug