1. Concentrations of Drug Products Concentrations are expressions of the strength of drugs in aqueous solutions or suspensions Concentrations of drugs in solid dosage forms like creams or ointments Concentrations are ratios of amount of drug per volume Mg/ml, mcg/ml, mg/L, mg/dl and % w/v for solutions % w/w for solid dosage forms like creams And ppm for gases

2. Concentrations of Drug Products Concentrations are effectively the amount of drug in the total volume or amount of vehicle or product Courtesy of : Westward pharmaceuticals There is 100 mg of morphine in this whole vial of 10 ml of drug product Courtesy of :http://medlibrary.org/lib/rx/meds/triamcinolone- acetonide-29/page/2/ This product has 80 mg of drug in 80 g tube

3. Percentage Concentrations X % w/v is by definition X g of drug/100 ml solution 5% is 5 g/100 ml (very important is pharmacy) 0.9% is 0.9 g/100 ml (NS) X% v/v is by definition X ml of drug/100 ml solution X% w/w is by definition X g of drug/100 g of product

4. Dose Formula C * V= D C= concentration V= volume D= Dose To use this formula make sure all units match i.e. C= mg/ml V must be ml and D is mg

5. Sample Calculations A patient in the hospital develops an acute supraventricular tachycardia with a HR of 130 at rest. MD orders a STAT order of Diltiazem 10 mg IVP. If you have a vial of Diltiazem 50 mg/10 ml, how much do you draw into the syringe to deliver this dose? Courtesy of: http://www.hospira.com/en/products_and_services/dru gs/DILTIAZEM_HYDROCHLORIDE_INJECTION

6. Sample Calculations A patient in the hospital develops an acute supraventricular tachycardia with a HR of 130 at rest. MD orders a STAT order of Diltiazem 10 mg IVP. If you have a vial of Diltiazem 50 mg/10 ml, how much do you draw into the syringe to deliver this dose? Answer: C * V= D C is 50 mg/10 ml or 5 mg/ ml D is 10 mg 5 * V = 10 V= 2 ml Answer 2 you can use ratios and proportions 50 mg/ 10 ml = 10 mg/ X ml; and X=2 ml

7. Sample Calculations A patient is experiencing a DVT and requires a Heparin Drip with a loading dose of 8,000 units. You have a vial of heparin 1,000 units/ml, what volume do you use to deliver this loading dose? Answer C*V=D C= 1000 units/ml D=8,000 units 1000*V=8000 V= 8 ml

8. Sample Calculations A patient required a dose of insulin for hyperkalemia. The dose was supposed to be 10 units. 30 minutes later, patient develops profound hypoglycemia (30 mg/dl) and is comatose. Dextrose was given and patient recovers with no permanent brain damage. (Thank God). It was determined that the order was written as : regular Insulin.1 ml IVP stat. The pharmacist profiled the order as 1 ml IVP stat. If you have Humulin R (which is 1000 units/ 10 ml) and draw this volume what was the dose given? C*V=D C= 1000 unit/10 ml or 100 units/ml V= 1 ml 100 units/ml * 1 ml= 100 units What is the magnitude of the error? Dose given is 100 units Actual dose is 10 units 10 fold overdose How can such error be avoided? Write the order as : regular insulin 10 units IVP or 0.1 ml IVP

9. Sample Calculations A patient requires an amiodarone drip. The concentration of the drip is 450 mg/250 ml in D5W. You are asked to compound this drip. Using a 250 ml D5W and amiodarone 150 mg/ 3 ml vial how do you prepare this drip? http://www.nursingconsult.com/nursing/drugs/monograph?tab=generic&drug_id=25

10. Sample Calculations If C= 150 mg/3 ml it is 50 mg/ml Dose is 450 mg (this is what must be added to the 250 ml bag) 50 * V = 450 V= 9 ml If each vial is 3 ml and you need 9 ml you need 3 vials 1 vial/ 3 ml = x vials/9 ml X= 3 vials This is an example of a dilution, which we will work on in class