This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Here are the answers to Question 3 and Question 4: Question 3 a. Discuss two advantages of using a powdered dosage form (2 marks) Faster dissolution and absorption: Powders have a larger surface area compared to tablets or capsules, which allows for quicker dissolution in the gastrointestinal tract and thus faster absorption into the bloodstream. Ease of dose adjustment: Powdered forms allow for more flexible and precise dose adjustments for individual patients, especially in compounding, making them suitable for pediatric or geriatric patients who may require specific dosages. b. i. Outline two methods that can be used to determine the flowability of the powder? (2 marks) Angle of Repose: This method measures the maximum angle at which a pile of powder can stand without slumping. A smaller angle of repose indicates better flowability. Carr's Index (Compressibility Index) or Hausner Ratio: These are calculated from the bulk density and tapped density of the powder. They provide an indication of the powder's compressibility and, indirectly, its flow characteristics. b. ii. Determine the flowability of the powder. Given: Bulk density = 0.72 g/mL, Tapped density = 0.88 g/mL. Step 1: Calculate Carr's Index. Carr's Index = Tapped Density - Bulk DensityTapped Density × 100\% Carr's Index = 0.88 g/mL - 0.72 g/mL0.88 g/mL × 100\% Carr's Index = (0.16)/(0.88) × 100\% ≈ 18.18\% Step 2: Calculate Hausner Ratio. Hausner Ratio = Tapped DensityBulk Density Hausner Ratio = 0.88 g/mL0.72 g/mL ≈ 1.22 Step 3: Interpret the flowability based on the calculated values. A Carr's Index of 18.18\% and a Hausner Ratio of 1.22 both indicate that the powder has Fair flowability. b. iii. How does poor flowability of a powder affects the formulation of tablets? (2 marks) Poor flowability significantly impacts tablet formulation by causing inconsistent filling of tablet dies. This leads to weight variation among tablets, which in turn results in content uniformity issues, meaning each tablet may contain a different amount of the active pharmaceutical ingredient. It can also cause manufacturing problems such as bridging in hoppers or sticking to punch faces. b. iv. What can be done to improve powder flowability? (2 marks) Granulation: This process converts fine powders into larger, denser granules, which generally flow better and reduce dustiness. Addition of Glidants: Incorporating small amounts of flow-enhancing agents, such as colloidal silicon dioxide or talc, can reduce inter-particulate friction and improve powder flow. Question 4 a. If the adult dose of Allopurinol is 100mg, calculate a dose for a child with a body surface area of 0.45m² (2 marks) Step 1: Use the Body Surface Area (BSA) formula for pediatric dosing, assuming a standard adult BSA of 1.73 m^2. Child's dose = Child's BSA (m^2)Adult BSA (m^2) × Adult dose Child's dose = 0.45 m^21.73 m^2 × 100 mg Child's dose ≈ 0.2601 × 100 mg ≈ 26.01 mg The dose for the child is approximately 26 mg. b. The initial maintenance dose of vancomycin for infants less than 1 week old is 17mg/kg every 18hours. i. What would be the dose, in milligram, for an infant weighing 2500g? (2 marks) Step 1: Convert the infant's weight from grams to kilograms. Weight in kg = 2500 g1000 g/kg = 2.5 kg Step 2: Calculate the dose in milligrams. Dose = 17 mgkg × 2.5 kg = 42.5 mg The dose for the infant would be 42.5 mg. ii. How many milliliters of an injection containing 500mg per 25ml should be administered to obtain this dose? (2 marks) Step 1: Determine the concentration of the injection. Concentration = 500 mg25 mL = 20 mgmL Step 2: Calculate the volume needed for the dose. Volume = Dose requiredConcentration Volume = 42.5 mg20 mgmL = 2.125 mL 2.125 mL of the injection should be administered. c. A physician orders 2g of an antibiotic to be placed in 1000ml of D5W. Using an injection that contains 200mg of the antibiotic per 2ml, how many milliliters should be added to the medication order? (2 marks) Step 1: Convert the ordered dose from grams to milligrams. Ordered dose = 2 g × 1000 mgg = 2000 mg Step 2: Determine the concentration of the antibiotic injection. Concentration = 200 mg2