RX 351 – Basic Pharmaceutics Nandita G. Das, Ph.D., R.Ph. Page 1 of 4 M2.B3 Practice Challenge Level Problems with % w/w Applications The following problem set is for your practice...

M2 B3


RX 351 – Basic Pharmaceutics Nandita G. Das, Ph.D., R.Ph. Page 1 of 4 M2.B3 Practice Challenge Level Problems with % w/w Applications The following problem set is for your practice and self-assessment. You may use any resource you wish to in order to work the problems.This assignment will not be graded, and is designed for self-directed learning. Completion of the assignment is not mandatory, and your progress will not be monitored. There are no points associated with this assignment. The solutions are provided – you may compare your answers against the given solution sheet to check your work and identify areas where you need more work and/or help from your instructors or peers. The instructor is available to answer any questions you may have, either by e-mail, during the live synchronous sessions, or meetings set up via Zoom. 1. How many grams of sorbitol powder will be required to prepare a 20% w/w sorbitol solution using 100 mL of water as solvent? Molecular weight of sorbitol = 182.17 g/mol; Density of sorbitol = 1.49 g/mL 2. Prepare 500 mL of 5% w/w sucrose syrup (default vehicle for syrup = water). Perform calculations, and write a brief procedure as if you were executing this task in the laboratory. RX 351 – Basic Pharmaceutics Nandita G. Das, Ph.D., R.Ph. Page 2 of 4 3. One kilogram of sucrose was added to one liter of water to prepare a syrup. What is the %w/w strength of the syrup? A) 0.1 % w/w B) 1 % w/w C) 10 % w/w D) 50 % w/w E) 100% w/w 4. Consider the following formula: Sorbitol 10 % w/v Water qs ad 100 mL How many milliliters of commercially available Sorbitol Solution USP (70% w/w, SG 1.28 at 25°C) will be required to compound the Rx? RX 351 – Basic Pharmaceutics Nandita G. Das, Ph.D., R.Ph. Page 3 of 4 5. Given the information that the specific gravity of glycerin is 1.25 at 25°C, you will need to add _______ g calamine powder to 100 mL glycerin to prepare a 20% w/w calamine lotion. 6. What is the % w/v strength of the calamine lotion in the previous problem? Density of calamine powder is 5.610 g/cm3. 7. A 4.00 gram sample of NaOH (solid) is dissolved in enough water to make 0.50 liter of solution. What is the normality of this solution? FW of NaOH = 40 g/mol RX 351 – Basic Pharmaceutics Nandita G. Das, Ph.D., R.Ph. Page 4 of 4 8. A solution of hydrochloric acid has a density of 1.15 grams per milliliter and is 30% by mass HCl. (a) What is the molarity of this solution of HCl? (b) What volume of this solution should be taken in order to prepare 5 liters of 0.2 M hydrochloric acid by dilution with water?