by Chaad » Fri Aug 04, 2006 6:31 am
ginnymarie_1999 asked:
A doctor orders 10 drops of a medication, how many drops are in 1 cc? . Is a drop and a mm the same?
For most pharmaceutical applications, 1 cc (cubic centimeter) is expected to yield 20 drops.
Shill is quite correct in saying :
1 cc = 1 cmÂ³ (cubic centimeter) = 1 ml (1 mili liter or one one-thousandth of a liter.) . This is by definition.
There are approximately 20 drops in 1 cc (cmÂ³ or ml).
Inversely, there are 0.04 cc in 1 drop (1Ã·20). .
This is an average figure, determined by experiment, using water-based solutions.
This not an exact conversion because there is no precise definition of a drop; Drops will vary slightly depending upon the viscosity and density of the fluid. The size of the dropper makes little difference, since the drop size depends primarily upon weight or gravity (which is constant, for all practical purposes).
Fluids of higher viscosity require more force to separate a droplet, but in aqueous (water-based) solutions, the weight or density of the fluid generally increases along with the viscosity. (In other words, thicker solutions are also heavier, so it all "equals out.")
Your follow-up question is a bit confusing (" Is a drop and a mm the same? ") since mm (milimeter) is a measurement of distance, not volume.
â€¢ If you meant ml your question is answered, since one ml equals one cc, or ≈ 20 drops.
â€¢ If you meant one mmÂ³ (cubic milimeter), there are 1000 mmÂ³ in one cc, therefore there are 50 mmÂ³ in one drop (1000 Ã·20).
â€¢ If you meant one minim ... One minim (abbreviated min.) is defined as 1/60th of a Dram, and is about 1/16th of a cc, or about 1.55 drops.
RICHARD then asked:
For a container of 15ml, with a Rx as follows: 2 Gtts. (drops) EACH EYE, 3x PER DAY... HOW LONG SHOULD the CONTAINER LAST?
Assuming Richard has 2 eyes, the consumption rate would be 12 drops per day (2 x 2 x 3). His supply is about 300 drops (15 x 20) and should last 25 days (300Ã·12)
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