Preparation of Solutions (cont.) Universal solvent – water Diluent –Substance used to dilute...
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Transcript of Preparation of Solutions (cont.) Universal solvent – water Diluent –Substance used to dilute...
Preparation of Solutions (cont.)
• Universal solvent – water
• Diluent – Substance used to dilute– Solvent
Preparation of Solutions (cont.)
• Percent concentration
– Expression of the concentration
– Amount of solute per 100 mL solution• Milliliters/100 mL for liquid
solutes• Grams/100 mL if solute is a
solid or semisolid
Preparation of Solutions (cont.)
What is the amount of hydrocortisone powder in 300 mL of 2% hydrocortisone lotion?
2% hydrocortisone lotion contains 2 g of hydrocortisone powder per each 100 mL.
Therefore, 300 mL will contain (2 g x 3) 6 g hydrocortisone powder.
ExampleExample
Preparation of Solutions (cont.)
What is the amount of isopropyl alcohol in 100 mL of a 70% isopropyl alcohol solution?
Percent strength = 70 so a 70% isopropyl alcohol solution has 70 mL isopropyl alcohol per each 100 mL solution.
100 mL has 70 mL isopropyl alcohol with enough water added to make a total of 100 mL.
ExampleExample
Preparation of Solutions (cont.)
Rule 16-2Rule 16-2
For solid or semisolid mixtures prepared
with a dry medication, percent strength
represents the number of grams of
medication in 100 g of the mixture.
Preparation of Solutions (cont.)
Rule 16-2 Rule 16-2 (cont.)
For solid or semisolid mixtures prepared
with a liquid medication, percent strength
represents the number of milliliters of
medication in 100 g of the mixture.
Preparation of Solutions (cont.)
Determine the amount of hydrocortisone in 2% hydrocortisone ointment.
Each 100 mL of ointment contains 2 g of hydrocortisone.
2 g hydrocortisone would be mixed with 98 g petroleum jelly.
ExampleExample
Preparation of Solutions (cont.)
• When preparing percent solutions and solids
– measure the solute;
– add a sufficient quantity of solvent to bring the total to the desired volume;
– know qsad – a sufficient quantity to adjust the dimensions to….
Preparation of Solutions (cont.)
A “recipe” for preparing 100 mL of 2% lidocaine solution:
ExampleExample
2% Lidocaine Solution
Lidocaine 2g
Water qsad 100 mL
Preparation of Solutions (cont.)
A “recipe” for preparing 100 g of 10% zinc oxide ointment from zinc oxide powder and petroleum jelly
ExampleExample
10% Zinc Oxide Ointment
Zinc Oxide 10g
Petroleum jelly 90 g
Preparation of Solutions (cont.)
Procedure Checklist 6-1:Procedure Checklist 6-1: Calculating by the Proportion Method
1. Write a conversion factor with the • units needed in the numerator or
before the colon;
• units converting from in the denominator or after the colon.
Preparation of Solutions (cont.)
Procedure Checklist 6-1: Procedure Checklist 6-1: (cont.)(cont.)
2. Write a factor • with the unknown, “X,” in the numerator or
before the colon .
• with the number to convert in the denominator or after the colon.
X/B or X:B
Procedure Checklist 6-1:Procedure Checklist 6-1: (cont.)(cont.)
3. Set the two factors up as a proportion.
4. Cancel units.
5. Cross-multiply or multiply the means and extremes and solve for the unknown value.
Using Conversion Factors: Proportion Method (cont.)
X/B = C/D or X:B = C:D
Preparation of Solutions (cont.)
Calculate the amount of NaCl needed for for 250 mL of 0.9% sodium chloride.
0.9 g NaCl in 100 mL solution
Step A Convert
No conversion is needed.
ExampleExample
Preparation of Solutions (cont.)
0.9 g NaCl in 100 mL solution
Step B Calculate using the proportion method.
0.9 g /100 mL = X/250 mL
0.9 g x 250 = 100 x X
225 g/100 = 100X/100
2.25 g NaCl = X
ExampleExample
Preparation of Solutions (cont.)
Step C Think!...Is It Reasonable?
Since there is 0.9 g of NaCl in 100 mL, there should be more than 2 times that amount in 250 mL, so 2.25 g is a reasonable answer.
ExampleExample
Preparation of Solutions (cont.)
Procedure Checklist 6-2:Procedure Checklist 6-2: Calculating by Dimensional Analysis
1. Write the unknown “X” on one side of the equation.
X =
Preparation of Solutions (cont.)
Procedure Checklist 6-2Procedure Checklist 6-2 (cont.)(cont.)
2. On the other side of the equation, write a conversion factor with the units of measure for the answer on top and the units you are converting from on the bottom.
mL
g. x
100
90
Preparation of Solutions (cont.)
Procedure Checklist 6-2 Procedure Checklist 6-2 (cont.)(cont.)
3. Multiply the numerator of the conversion factor by the number that is being converted divided by 1.
1
250
100
90 mLX
mL
g.x
Preparation of Solutions (cont.)
Procedure Checklist 6-2 Procedure Checklist 6-2 (cont.) (cont.)
4. Cancel units.
1
250
100
90 mLX
mL
g.x
Preparation of Solutions (cont.)
Procedure Checklist 6-2:Procedure Checklist 6-2:5. Solve the equation.
gX
100
225
g.X 252
Preparation of Solutions (cont.)
Step C Think! … Is It Reasonable?
Regardless of the method used, we find that 2.25 g of NaCl is needed to prepare 250 mL of a 0.9% solution.
ExampleExample
Preparation of Solutions (cont.)
Write the recipe for 250 mL of 0.9% sodium chloride solution.
ExampleExample
0.9% Sodium Chloride Solution
NaCl 2.25 g
Water qsad 250 mL
Practice
Write a recipe for preparing 50 g if a 10% zinc oxide ointment using zinc oxide powder and petrolatum jelly.
ANSWER:
10% Zinc Oxide Ointment
Zinc oxide powder 5g
Petroleum jelly 45 g
Preparing a Dilution from a Concentrate
• When preparing a solution from two solutions of different concentration, know
– Solvent – less concentrated solution
– Solute – more concentrated solution
• To calculate, use
– Formula method
– Alligation
Preparing a Dilution from a Concentrate (cont.)
Procedure Checklist 16-1 Procedure Checklist 16-1 Formula Method
1. Identify information needed:
a. V = volume of solution needed
b. C = concentration of solution needed
c. St = amount of solute
d. Sv = amount of solvent
Preparing a Dilution from a Concentrate (cont.)
Procedure Checklist 16-1 Procedure Checklist 16-1 (cont.)
2. Insert values into formula:
C x V = St
3. Determine the amount of solvent by subtracting the solute from the total volume:
V – St = Sv
Preparing a Dilution from a Concentrate (cont.)
Ordered: 1 oz of ¼ strength hydrogen peroxide in normal saline for wound care TID for 2 days. Write the recipe.
Step A = Convert ounces to mL.
1 oz TID x 2 day = 6 oz
1oz/30 mL = 6 oz/ X
180 mL = X
ExampleExample
Preparing a Dilution from a Concentrate (cont.)
Step B Calculate.
V = 180 mL, C = ¼
C x V = St ¼ x 180 mL = 45 mL of the solute (hydrogen peroxide)
V – St = Sv
180 mL – 45 mL = 135 mL of the solvent (normal saline)
ExampleExample
Preparing a Dilution from a Concentrate (cont.)
The recipe is:
Step C
Since 45 is one fourth of the total volume of solution (180 mL) and 135 + 45 = 180 mL, this answer is reasonable.
ExampleExample
¼ strength Hydrogen Peroxide – 180 mL
H2O2 45 mL
NS 135 mL
Practice
Clean leg wound with 2 oz of ½ strength hydrogen peroxide in normal saline q6 h x 3 days. Write the recipe for total supply needed.
½ hydrogen peroxide – 720 mL
H2O2 360 mL
NS 360 mL
ANSWER:
Patient Education
• Mixing infant formulas
1. Know that most formulas have 20 calories / ounce.
2. Wash hands and top of formula can before starting.
3. Let cold water run for 2 minutes.
Patient Education
4. When using liquid formulas
a. Check that label reads “concentrate”;
b. shake before opening;
c. follow recipe from AP;
d. pour formula concentrate into another container;
e. measure desired amount of water;
f. add to concentrate and mix well.
Patient Education
5. When using powdered formulas
a. follow instruction of AP;
b. measure desired amount of water;
c. check liquid level at eye level;
d. add level measures of formula powder;
e. use scoop provided;
f. mix or shake well.
Patient Education
6. When storing formula
a. refrigerate in a covered container;
b. throw away unused prepared formula after 48 hours;
c. throw away unused formula powder one month after opening the can.
Patient Education
7. When feeding with formula
a. shake formula well;
b. warm bottle;
c. do not use microwave;
d. shake bottle after warming;
e. test temperature of formula;
f. discard formula left in bottle after feeding.