TPN Solutions Flashcards Preview

824 > TPN Solutions > Flashcards

Flashcards in TPN Solutions Deck (16):
1

TPN Admixtures

-TPN = Total parenteral nutrition
-Need to consider what salts form which have low water solubility
EX: CaHPO4

2

Is pH or temperature more important when it comes to salt solubility?

pH

3

Ksp Formula Example (CaHPO4)

Ksp = [Ca+2] * ([Phosphate]total / (1 + [H30+]/Ka2))

**If this Ksp is larger than the standard Ksp of the compound at that temperature, precipitates will form**

4

[H3o+] Calculation

[H3o+] = 10 ^ -pH (answer in moles)

5

Ka2 Calculation

Ka2 = 10 ^ -pKa (answer in moles)

6

[Ca+2] Calculation

mEq = mg * valence / MW

mg = mEq * MW / valence

[Ca+2] = mg/MW/1L (answer in moles)

7

Acidic Drugs

-Aspirin
-Ibuprofen
-Penicillins

8

Basic Drugs

-Atropine
-Codeine
-Epinephrine

9

Amphoteric Drug

Morphine

10

pH Effects on Ionization

-Solubility
-Absorption
-Distribution
-Elimination
-Formulation (stability)

11

pH + Formulation

-Ophthalmic - less irritation
-Stability of drug in aqueous media
-Enteric coatings
-Gel formation
-Topical emulsions - partitioning of preservatives which need to be in an unionized state to function (more soluble in organic phase)

12

Carbopol Resin - Gelatin

-Soluble in polar substances (water)
-Increase pH of water to ionize carboxylic acid groups
-Gel formation - electrostatic repulsion between anionic groups

13

Ionization of Weak Acid Equations

K[H2O] = [H3O+][Ac-]/[HAc]

-c = molar [HAc]
-Amount of HAc remaining at equilibrium = c-x
-Amount of H3O+ = x and the amount of Ac- = x

SO, if c >> x, then c-x = ~c and Ka = x^2/c and x^2 = Ka *c

Therefore,
x = [H3O+] = Square root of (Ka * c)

14

Ionization of Weak Bases

-Same idea as acids

Kb = [BH+][OH-]/[B]

x = [OH-] = Square root of (Kb * c)

15

Ionization of Water Equations

Kw = 1 * 10^-14
Kb = Kw/Ka
Ka = Kw/Kb

Kw = [H3O+][OH-]/[H2O]^2

16

Ionization of Polyprotic Compounds

-For acids (electrolytes) and bases, every deprotonated version has its own individual pKa
-For example, H3PO4 has 3 different pKas since it can lose 3 protons (H+)