a) An intravenous solution of sodium chloride 0.2% requires to be made isotonic by the addition of anhydrous glucose. What weight of anhydrous glucose is required in the preparation of 1L of the intravenous solution? (A 1% solution of sodium chloride depresses the freezing point of water by 0.576°C. A 1% solution of anhydrous glucose depresses the freezing point of water by 0.1037°C.) (4 marks)
b) A pharmacist has to make a batch of one hundred lg suppositories, each containing 75mg of drug X. Mould calibration is 1. Drug X has a displacement value of 2.1. Assuming the pharmacist makes a 20% excess to allow for losses in preparation and the base is theobroma oil, calculate the quantity of theobroma oil required. What is the final weight of each suppository? (3marks)
c) A pharmacist is requested to use three lots of ointment containing 30%, 20% and 5% ichthammol, respectively, to prepare 500g of a ointment containing 15% ichthammol. In what proportion should they be mixed to prepare 200g of a 15% ichthammol ointment? (3 marks)
d) You receive a prescription for a 6-year-old boy (weight: 34kg) for intravenous immunoglobulin (‘IVIG’) 2g/kg X 1 dose.
Your institution carries Bivigam 10%. The manufacturer recommends this medication to be administered at an initial rate of 0.5mg/kg/minute for 10 minutes. If tolerated, the solution may be titrated up every 20 minutes in increments of 0.8mg/kg/minute up to a maximum of 6mg/kg/minute. Your institution carries Bivigam 5g/50mL as stock solution.
- How many vials of stock solution would you need to fulfil the above medication order?
- What is the initial rate of infusion for this patient’s prescription?
- What is the minimum duration for infusion for the prescription assuming the patient is able to tolerate this medication?
e) Calculate the osmolarity of 8.45% Sodium Bicarbonate solution (molecular weight of sodium bicarbonate = 84g/mol). (2 marks)
f) How many milliliters of 1:700 Benzalkonium Chloride are required to prepare 30mL of 0.01% w/v Benzalkonium Chloride ophthalmic solution? (2 marks)