Guest guest Posted July 15, 2004 Report Share Posted July 15, 2004 Dear Hemali, Here is the way that I do the math in my tutorials which is set up in ratio/proportions: " 1. A patient weighing 110 lbs is to recive 5mcg/kg/min of a IV solution containing dopamine 600mg in 250ml D5W.The calculated IV dose rate is a.125mcg/min b.0.125 mg/min c.0.250 mg/min d.25mcg/min " Jeanetta's Answer is: " C " However it should be 0.25 mg/min as `trailer zeros' are not acceptable in pharmacy. 2.2 lbs---110 lbs ------ = ------- 1 Kg--------X Kg 50 Kg = X Kg Pt wt = 50 KG Rx order is 5 mcg/Kg/ min 5 mcg/1 Kg x 50 Kg = 250 mcg Therefore the answer would be 250 mcg/min. But that answer does not exist. We must then try to convert the 250 mcg to mg by dividing the 250mcg by 1000 mcg/1mg. 1000 mcg----250 mcg -------- = -------- 1 mg--------X mg 0.25 mg = X mg Therefore the answer is : 0.25 mg / min " 2.What is the resultant percentage conc when 30 gms of codeine phospate is dissolved in 2 litres of solution? a.1% b.10% c.1.5% d.15% " Jeanetta's answer: " C " (Be careful not to use the `periods' in front of the numbers which may appear to look like `decimals'.) First You must realize that % in pharmacy is X gm / 100 ml solution. You will find the complete `explanation' in my Math Tutorials: 30 gm codeine phosphate-------X grams Codeine ------------------------ = ------------------ 2 Liter solution-------------100 ml 30 gm codeine phosphate-------X grams Codeine ----------------------- = ------------------- 2000 ml solution-------------100 ml 30 x 100 -------- = 1.5% 2000 " I want to know whether percentage strength and percentage concentration means the same thing or is it different. " Percent strength will be represented with a percent sign. Example: 45% water Percent concentration is the same thing: 34% oil Concentration is written with two units, one in the numerator and the other in the denominator. Example: 45% calcium = 45 grams calcium in 100 ml of solution and written as the following ratio: 45 gm calcium ------------------------ 100 ml calcium solution " Thanks in advance " You are most welcome! Respectfully, Jeanetta Mastron CPhT BS Chemistry Founder/Owner > Hi, > I need help in solving these problems.I did them but I don't where I am going wrong as the answers are not tallying with the book's. > > 1.A patient weighing 110 lbs is to recive 5mcg/kg/min of a IV solution containing dopamine 600mg in 250ml D5W.The calculated IV dose rate is > a.125mcg/min > b.0.125 mg/min > c.0.250 mg/min > d.25mcg/min > > 2.What is the resultant percentage conc when 30 gms of codeine phospate is dissolved in 2 litres of solution? > a.1% > b.10% > c.1.5% > d.15% > I want to know whether percentage strength and percentage concentration means the same thing or is it different. > > Thanks in advance > Hemali > > > > Quote Link to comment Share on other sites More sharing options...
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