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% w/w(weight)----------active ingredient and base have same unit of weight. 1%=1gm of active ingred per 100gm total product. 1% w/w= 1gm/100gm %v/v(volume)-------solute(active drug) and solvent(inactive base) have same unit of volume. 1% v/v=1ml/100ml
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% w/w(weight)----------active ingredient and base have same unit of weight. 1%=1gm of active ingred per 100gm total product. 1% w/w= 1gm/100gm %v/v(volume)-------solute(active drug) and solvent(inactive base) have same unit of volume. 1% v/v=1ml/100ml %w/v(weight/volume)-------solute is in the weight grams and solvent is in volume ml. 1% w/v=1gm/100ml Percentage concentration
1.4g of phenol mixed with 9g of glycerin. What is % concentration of phenol in this product? 1.4+ 9g =10.4g part/whole x 100=% 1.4/10.4*100=13% w/w 4g KCL is dissolved in base to make total of 25ml. What is per concentration of final product?4/25*100=16%w/v 10ml glycerin is dissolved in enough water to make 73ml of final solution. Calc % of strength of glycerin. 10/73*100=14% v/v
How much KCL is needed to make 240ml of a 10% solution? • 10% mix assumes 10mg mixed into 100ml of fluid • 10mg/100ml=x mg/240ml • X=24mg of kcl • 5g is how many mg? • 1000mg/1gx 5g/1=5000mg • 120mg to g • 1000mg/1g x 120mg/x= g • x=1000x/120=.120g
alligations • Using 2 different concentrations of a drug to arrive at final concentration somewhere between the 2 in stock. • Dr orders 30g of 15% hydrocortisone cream. Pharmacy has cream in 20% and also 2%. Alligation will combine these to get 30gm, of 15%. • See board pg158-------
Ratio concentrations Normally this uses epinephrine or potassium permanganate. You must memorize------- 1:1000------1mg/ml 1:100--------10mg/ml 1:10---------100mg/ml Rx is 3mg of epi. Pharm stock is 1:100 solution. How may ml will be given? 10mg/ml= 3mg/xml 10x mg=3mg X=.3ml
Rx 2.5ml inj of 1:1000 epi is given. How much drug did pt get? • 1:1000=1mg/ml • 1mg/ml=x mg/2.5ml • X =2.5mg
Parenteral calculation • Done for IV drips. This has greater risk of immediate pt harm if wrong. • Flow rate=vol/time • Pt gets 1L of IV sol over 3 hours. What is flow rate? • Flow rate=1000ml/3hrs • Fr=333ml/hr --- this means 5.55ml/min
How many hours will 1L of D5W last when flow rate is 125ml/hr? • Time=vol/rate • time=1000ml/125ml • Time=8hr • Vol=time *rate • How many ml needed to run IV at 60ml/hr for 12 hours? • Vol=12hrs*60mlper hour • Vol=720ml
Gtt/min=volume to be infused *drip set rate/infusion time in minutes • Rx is d5w at 125ml/hr. admin set is 10gtt/ml. How many gtt/min should we use? • Gtt/min= 125ml*10gtt/60min • Gtt/min=1250/60 • Gtt/min=20.8 ~21gtt/min
Gtt/min=volume to be infused *drip set rate/infusion time in minutes • 300ml of d5w given at rate of 75ml/hr. admin set gives 10gtt/ml.how many gtt/min should we use? • Gtt/min=vol infused*drip rate/infusion time(min) • Gtt/min= 75ml*10/60 • Gtt/min=750/60 • Gtt/min=12.5gtt/min ~13ggt/min
https://www.youtube.com/watch?v=CujuVNn7ROY • alligations • https://youtu.be/765wpMCEy6c • Drip rate • https://youtu.be/8qDVEtrQ8a4 • Percents • https://youtu.be/xWw2pQrnztU • Powder volume • https://youtu.be/mm6jeTZV1Z0 • mEq