To process a prescription order for a 30% dextrose solution, the pharmacy technician would mix the stock solutions of 50% dextrose and 5% dextrose solutions in which ratio? ------------------------------------------------------------ Using the alligation method: 50 __________ 7.5 ______50_______ 5 ___________ 7.5

7.5 = 7.5 1 : 1 the ratio is 1 to 1

If you prepare 1L of a 7.5% dextrose solution using the stock solutions of 5% (D5W) dextrose and 50% (D20W) dextrose, how many milliliters (mL) of each dextrose solution will be needed? ------------------------------------------------------------ Using the alligation method: 50 __________ 2.5 _______7.5________ 5 ___________ 30

2.5 is the number of parts of the 50% solution. 30 is the number of parts of the 5% solution. 2.5 + 30 = 32.5 parts (total number of parts of the 7.5% solution)

50% dextrose solution: x / 2.5 parts = 1L/32.5 parts x = 42 mL D20W

5% dextrose solution: x / 12.5 parts = 250 mL/15 parts x = 208 mL D5W

Add the volume 42 mL to the volume 208 mL in order to get to the volume of the 7.5% dextrose solution: 42 mL + 208 mL = 250 mL