PPT-Calculating the amount of substance in a concentration expressed as a percentage strength

Example 1 How much chloroform is contained in 500mL of a 2 vv concentration Method Step 1 A percentage is a fraction with a base of 100   Step 2 By multiplication Remember this is a . Alligations. Yewande Dayo. Student Pharmacist. Objectives. Upon completion of this chapter, the student will be able to:. Perform calculations for altering product strength by dilution, concentration, or fortification.. Yewande Dayo. Student Pharmacist. Objectives. Define percent weight-in-volume, percent volume-in-volume, and percent weight-in-weight.. Define ratio strength.. Convert percent strength to ratio strength and ratio strength to percent strength.. Danielle DelVillano, Pharm.D.. Objectives. Define the expressions percent weight-in-volume, percent volume-in-volume, percent weight-in-weight, ratio strength. Convert percent strength to ratio strength and vice versa. Dr. . Amani. . Elsayed. Ratio Strength. The concentration of weak solutions or liquid preparations . is frequently . expressed in terms of ratio strength.. Ratio . strength is . another . way of expressing . Concentration. The amount of a specific substance in a known volume of solution. Concentrated Solutions. The amount of substance dissolved in solution is very high . It is difficult to dissolve more substance into solution. Example 1. Calculate the amount of each ingredient required for 1225mL of the formula listed below.. AT A GLANCE/. PHARMACY CALCULATIONS. FORMULATIONS. Ingredient. Master formula. Substance A. 175g. Substance B. AT A GLANCE/. PHARMACY CALCULATIONS. CONCENTRATED WATERS. 13. Concentrated Waters. Concentrated water is diluted to produce single- or double-strength water.. NB:. The pharmaceutical definition of concentrated water is one that is . Calculating the amount of substance needed in an initial concentration to produce a final desired dilution and volume. Example 1 What amount of a substance is required to make 1500mL of a product such that 50mL diluted to 1000mL will give a 1% v/v concentration? Calculating how much base to add to a product to achieve a lower desired concentration. Example 1 How much water should you add to 100mL of a 10% v/v solution to reduce it in strength to a 4% v/v solution? Example 1. How much ingredient A should you add to 100mL of a 10% v/v solution to increase it in strength to a 20% v/v solution?. Method. . AT A GLANCE/. PHARMACY CALCULATIONS. INCREASING A % SOLUTION. Example 1. How much bismuth subsalicylate is contained in a 236mL bottle of 17.6mg/mL concentration?. Method. Step 1: . An amount strength is a fraction..  . Step 2: . By multiplication.  . 20. 2. Example 2. Altering product strength, use of stock solutions, and problem solving by allegation. The strength of a pharmaceutical preparation may be increased or decreased by changing the proportion of active ingredient to the whole. A preparation may be strengthened or made more concentrated by the addition of active ingredient, by admixture with a like preparation of greater strength, or through the evaporation of its vehicle, if liquid. The strength of a preparation may be decreased or diluted by the addition of diluent or by admixture with a like preparation of lesser strength.. Example 1. What amount of a substance is required to make 1500mL of a product such that 50mL diluted to 1000mL will give a 1% v/v concentration?. Method. Step 1: . Calculate the quantity of substance in the final dilution. MIXING CONCENTRATIONS. Calculating the strength of a mixture of two different concentrations.. Example 1. If you mix 100mL of a 5% v/v concentration of drug A with 200mL of a 20% v/v concentration of drug A, what will the final % strength be?.