# pharm calc

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1. changing the strength of a pharmaceutical preparation
concentration
• admixture with a like preparation of greater strength
• evaporation of vehicle (if liquid)
2. changing the strength
dilution
• admixture with a like preparation of lesser strength
3. provide a product strength more suitable for use by a particular patient
elderly or young
4. same amount active ingredient
• -diluent=increase concentration
• +diluent=decrease concentration
5. Strengteh and total quantity
if the amount of active ingredient remains constant, any change in the quality of a solution or mixture of solids is inversely proportional to the percentage or ration strength
6. increase quantity
percentage or ration strength decreases
7. decrease quantity
percentage or ratio strength increases
8. Relationship between total quantity and strength
C1Q1=C2Q2
9. Stock solutions
• concentrated solutions of active or inactive sibstances (increase concentrated)
• used as a convenience to prepare solutions of lesser concentrations
need to subtract amount already present from amount found in Q1C1=Q2C2 equation
11. Alligation
arithmetical method of solving problems that involves the mixing of slutions or mixtures of solids possessing different percentage strengths
12. Alligation Medial
• percentage strength of each component is multiplied by its corresponding quantity
• sum of the products is divided by the total quantity of the mixture
• resultant decimal fraction is multiplied by 100 to give percentage strength of mixture
13. Alligation Alternate
calculate the number of parts of 2 or more components of a given strength when they are mixed to prepare a mixture of desired strength
14. Alligation Alternate
• strength of a mixture (desire) must lie somewhere between the strengths of its components
• stronger than its weakest component
• weaker than its strongest component
15. reducing and enlarging formulas
• reduce or enlarge formulas for pharmaceutical preparations
• offical formulas are based on the preparation of 1000 mL or 1000g
16. Smaller quantity
reduce formula
17. greater quantity
• enlarge formula
• maintain the correct proportion of one ingredient to another
18. Step 1
Determine the factor that defines the multiple (enlarge) or the decimal fraction(refuce) of the amount of formula to be prepared
19. Factor=want/have
quantity of formula desired/quantity of formula given
20. Step 2
Multiply the quantity of each ingredient in the formula by the factor to determine the amount of each ingredient required in the reduced or enlarged formula
21. Formulas that specify proportional parts
indicate the relative proportion of each of the ingredients in the formula either by eright or volume
 Author: marinir ID: 51042 Card Set: pharm calc Updated: 2010-11-22 04:56:29 Tags: calc Folders: Description: altering product strengths Show Answers: