reconstitution of solutions chapter 12. 2 parts of solutions

Reconstitution of Solutions

Chapter 12

2

Parts of Solutions

3

Reconstitution Drug

4

Parenteral Solution from a Solid Solute

Solvent or diluent4.8 mL sterile water

Solid soluteZithromax 500 mg

5 mL reconstituted solutionZithromax 100 mg per mL

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Reconstitution Label for Zithromax

1/10/xx, 0800, reconstituted as 100 mg per mL

Expires 1/17/xx, 0800.

Keep refrigerated. G.D.P.

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Parenteral Solution Reconstitution Procedure

Order: Kefzol 225 mg IM every 6 hours

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Parenteral Reconstitution Procedure

Inject 2 mL air into sterile water

diluent vial

Withdraw 2 mL

sterile water

Add 2 mL sterile water to Kefzol 500 mg powder

Make Kefzol 500 mg in 2.2 mL

reconstituted solution for Kefzol 225

mg/mL

Withdraw 1 mL Kefzol solution for dosage of

225 mg

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Multiple-StrengthReconstitution Drug

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Different IM and IVReconstitution Instructions

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Reconstitution Drug Order

• Order: Solu-Medrol 200 mg IV every 6 hours

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Reconstitution Drug Order • Supply:

– 500 mg vial of powdered Solu-Medrol for IM or IV injection

– Directions on left side of label

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Reconstitution Drug Order • Each 8 mL contains

– “Reconstitute with 8 mL Bacteriostatic Water for Injection with Benzyl Alcohol

– Methylprednisolone sodium succinate equivalent to 500 mg methylprednisolone (62.5 mg per mL)”

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Reconstitution Dosage Calculation

• What do we know?– First, to fill the order, how much and what type

of diluent must you add? – Directions state to add 8 mL of bacteriostatic

water for injection with benzyl alcohol.

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Reconstitution Dosage Calculation

• What do we know?– Second, what is supply dosage of

reconstituted Solu-Medrol? – When adding 8 mL of diluent, the supply

dosage is 62.5 mg per mL

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Reconstitution Dosage Calculation

• What do we know?– Third, what is resulting total volume of this

reconstituted solution? – Total volume is 8 mL – You know this because

• 62.5 mg per mL × 8 mL = 500 mg

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Reconstitution Dosage Calculation

• What do we know?– Finally, how many full doses of Solu-Medrol

are available in this vial? – Vial contains 500 mg and order is for 200 mg – There are two full doses in the vial – Reconstitution label is needed

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Reconstitution Dosage Calculation

• Now you have a vial of 500 mg of Solu-Medrol – Add 8 mL of diluent

• Final yield of the solution is 62.5 mg per mL, your supply dosage.

• Calculate one dose

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Reconstitution Dosage Calculation • Step 1. Convert

– No conversion is necessary– Order: Solu-Medrol 200 mg IV every 6 hours– Supply: 62.5 mg per mL

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Reconstitution Dosage Calculation

• Step 2. Think– You want to give more than 1 mL– You want to give more than three times 1 mL

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Reconstitution Dosage Calculation

• Step 3. Calculate

62.5 mg

1 mL

200 mg

X

62. 5 X

200

X = 3.2 mL

• Given intravenously every 6 hours

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Solution Strength• A fraction expresses strength of a solution

made from a liquid concentrate:– Numerator is number of parts of solute– Denominator is number of parts of solution– Difference between denominator (final

solution) and numerator (parts of solute) is number of parts of solvent

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Solution Strength• Example: strength nutritional formula

– 1 part concentrate– 3 parts of total solution– 3 - 1 = 2 parts solvent (water)

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Calculating Solutions• To prepare solutions:

– Apply ratio-proportion to find amount

– Quantity of desired solution • Amount of liquid solute = Amount of solvent

Ratio for desired solution strength = Amount of solute

Quantity of desired solution

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Solution Calculation• Example:

– A physician orders a patient’s wound irrigated with strength hydrogen peroxide and normal saline solution every 4 hours while awake.

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Solution Calculation• 60 mL per irrigation for 3 irrigations during

your 12 hour shift– Prepare 60 mL × 3 irrigations = 180 mL total

solution

• How much stock hydrogen peroxide and normal saline will you need?

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Solution Calculation

• Step 1. Convert– No conversion is necessary

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Solution Calculation• Step 2. Think

– You want to make strength• 2 parts solute (concentrated hydrogen peroxide) to

3 total parts solution

• Amount of solvent is 3 – 2 = 1 part saline

• For 180 mL of solution, you will need of it as solute (120 mL) and of it as solvent (60 mL)

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Solution Calculation• Step 3. Calculate

2

3

X mL

180 mL(solute)

(solution)

3X 360

3X

3

360

3X 120 mL of solute (hydrogen peroxide)