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1.5 gm to mg: 1.5 = 1.500, move decimal 3 places to right AND change the units: 1500 mg
50 gm to mg: 50 = 50.00, move decimal 3 places to right AND change the units: 50, 000 mg
150 gm to mg: 150 = 150.00, move decimal 3 places to right AND change the units: 150, 000 mg
Or mulBply by 1000
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359 mg to gm: 359.00,move decimal 3 places to leG AND change the units: 0.359 gm
25 mg to gm: 25.00, move decimal 3 places to leG AND change the units: 0.025 gm
9.5 mg to gm: 9.5, move decimal 3 places to leG AND change the units: 0.0095 gm
Or divide by 1000
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2 mg to mcg: 2.0, move the decimal 3 places to right AND change the units: 2000 mcg
39 mg to mcg: 39.0, move the decimal 3 places to right AND change the units: 39,000 mcg
125 mg to mcg: 125.0, move the decimal 3 places to right AND change the units: 125,000 mcg
Or mul8ply by 1000
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9 mcg to mg: 9.0, move decimal 3 places to leG AND change the units: 0.009 mg
42.5 mcg to mg: 42.5, move decimal 3 places to leG AND change the units: 0.0425 mg
199 mcg to mg: 199.0, move decimal 3 places to leG AND change the units: 0.199 mg
Or divide by 1000
10
50 mg is wri=en as 0.05 gm therefore :
1 mg is wri=en as = 0.001 gm
37.5 mg is wri=en as 0.0375 gm
795 mg is wri=en as 0.795 gm
1.035 mg is wri=en as 0.001035 gm
80 mcg is wri=en as 0.08 mg
100 mcg is wri=en as 0.0001 gm
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Doctor prescribes the following: HydrocorBsone 2 % cream 20 grams mixed with Diphenhydramine hcl 6 % cream 30 grams mixed with Pramoxine hcl 3% cream 30 grams
1. What are the total grams dispensed? a.30 grams b.90 grams c.60 grams d.80 gram
2.How many milligrams of hydrocorBsone is in the final preparaBons? a.600 mg b.400 mg c.6000 mg d.4000 mg
3.What is the concentraBon of hydrocorBsone in the final product? a.1 % b.2% c.0.5% d.5%
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4.How many milligrams of diphenhydramine hcl is in the final preparaBon? a.180 mg b.18 mg c.1800 mg d.8,000 mg
5.What is the concentraBon of diphenhydramine hcl in the final product? a.2% b.2.25 % c.0.0225% d.3%
6.How many milligrams of pramoxine hcl in the final product? a.300 mg b.600 mg c.90 mg d.900 mg
7.What is the concentraBon of pramoxine hcl in the final product? a.0.01125% b.3 % c.1.125 % d.0.3% e.1%
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8.Progesterone 2% cream, dispense30 grams. How much progesterone is needed?
Hint: change percent to decimal, then mulBply it by the volume needed. a.60 mg b.600 mg c. 6 mg d.6000 mg
9.What is 5% of 20 ? a.10 b.0.1 c.0.01 d.1
10.Rx for: Testosterone 1 % cream, dispense 30 grams, How much testosterone is needed? a.0.03 gm b.0.3 gm c.0.003 gm d.3 gm
11.How much testosterone is in 1 gram of cream if the concentraBon is 1%? a.0.001 gm b.0.1 gm c.0.01 gm d.None of the above 15
Use the above Equa8on for Specific Gravity
If 100 mLs of D5W weighs 117 grams, what is its specific gravity?
SG= 117 gms (weight of D5W 100mL soluBon = 1.17 100 gms(weight of 100 mLs of water)
If weight of 100 mL of an alcohol solu8on is 85 grams, what is its specific gravity?
SG= 85 grams = 0.85 100 gm
If a liquid has a specific gravity of 0.85, how much does 125 mLs weigh?
0.85 = X/125ml → 125(0.85) = X → X = 106.25 grams When specific gravity is known, you can determine the weight of a volume of liquid. This will be helpful in compounding.
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13. Formula: AceBc acid 0.5 %, making 100 mL SoluBon. The amount needed by weight is 500 mg. How many milliliters is needed? Density is 1.04
A) 0.5ml
B) 0.48ml
C) 1ml
D) None of the above
14. Formula: Calcium chloride 22 % w/v stock soluBon, making 100 mL. Calcium chloride is a powder. How much by weight is needed for a volume of 100 mL?
A) 22mg B) 0.22gm C) 22gm D) 2gm
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15. AceBc acid 0.921% (w/w) 100 gram. The aceBc acid will be measured by weight. How much is used?
A) 0.921gm B) 921gm C) 921mg D) A and C
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16. Glycerin 50 % v/v oral soluBon. In 100 mLs, how many milliliters is needed of Glycerin?
A) 50ml
B) 0.5ml
C) 5ml
D) None of the above
17. DMSO 6.25 % v/v, Vitamin A 2000 U/mL ophthalmic emulsion. DMSO is a liquid, so for 100 mLs, how many milliliters of DMSO is required?
A) 625ml
B) 2ml C)6.25ml D)62.5ml
20
Some compounding companies have general formulaBons for troches, suppositories, lollipops and rapid dissolve tablets that explain how to calculate displacement for any acBve pharmaceuBcal ingredients that need to be added. Some of these formulaBons have already displaced the other inacBve ingredient (sweeteners, flavors, suspending agents) that may be listed in the formula, so please read the formulas carefully.
All bases labeled faey acids from various vendors may not contain the same ingredients therefore all will not calibrate molds equally. Proprietary bases containing different mixes of ingredients will also needed to be calibrated to the appropriate mold. CalibraBon of the mold with bases is required before performing calculaBons.
22
HOW TO SOLVE What informa8on is needed in order to calculate the formula?
1) The amount of fa=y acid base that the mold holds for 1 suppository stated above in the example: 1.28 gm
2) Total powders added for 1 suppository Calculate: Add up all powders necessary for 1 suppository: Aspirin 75 mg Silica gel 15 mg
Total powder burden = 90 mg
3) The displacement factor for the base from the chart on previous page -‐locate fa=y acid base -‐the API is a powder -‐therefore use 70 % is the correct choice
• Solve: 1. calculate displacement: (Total powders) X (displacement factor) = X,
90 mg x 70 % = 63 mg. -‐What does this mean? Adding 90 mg of powder will displace 63 mg of the fa=y acid base.
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2. Subtract the amount of displacement from the amount of base used for 1 suppository:
1.28 gm – 0.063 gm = 1.217 gm. -‐What does this number mean? It’s the amount of base required for the formula for 1 suppository.
3. So formula would be, for ONE suppository:
Aspirin USP 75 mg Silica gel micronized 15 mg Fa=y acid base 1.22 grams
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• Rectal rocket mold holds 6.59 grams total of faey acid base and Paraffin, 50/50 raBo.
• This mold requires 35 mg of silica gel • Calculate for 2 suppositories.. Since percent’s are stated for the acBves, the
calculaBon is: mul8ply the percent required of each drug by the total weight of the bases the mold holds.
• THERAPEUTICS COMMENT: since percent is prescribed, and it is based on the capacity of the mold, always make sure the final dose is appropriate.
How much base is needed for 2 suppositories? Calculate total powders first.
• Lidocaine USP 6.59 gm X 2 % = 0.1318 gm X 2 suppository = 0.2636 gm. • HydrocorBsone USP 6.59 gm X 1 % = 0.0659 gm X 2 suppository = 0.1318 gm • Silica gel, 0.035 gm X 2 suppository = 0.07 gm
Total powders = 0.4654 gm
How much base is needed? Base: 6.59 gm/suppository X 2 suppositories = 13.18 gm
25
This is split equally between the two bases, paraffin wax and fa=y acid base. Therefore the amount of each base is listed below prior to displacement: 13.18gm of total base/2 (the 2 represents the 2 different bases)
Paraffin wax 6.59 gm Faey acid base 6.59 gm
Please calculate the displacement of the powders using the chart on page 13 for displacement factor. Then calculate the amount of each base needed for the formula, and fill in the amounts needed below to complete the formula.
Displacement Factor: 70% 0.4654gm x 0.7 = 0.32578 13.18gm – 0.32578 = 12.85gm of base total (rounded)
12.85gm/2 suppository bases = 6.43gm
Lidocaine USP 0.26 gm Hydrocor8sone USP 0.13 gm Silica gel micronized 0.07 gm Paraffin wax 6.43gm Fa=y Acid Base 6.43gm
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18. PrescripBon for progesterone 100 mg suppository. PracBBoner specified using polyethylene glycol 1450 as the base. Dispense # 50. The formulaBon worksheet includes the use of silica gel at 15 mg per suppository. AGer displacement, the amount of Polyethylene glycol used per suppository is 2.16 gm. Answer the quesBons below:
Based on USP guidelines, how many will the formula be wrieen for to insure that the necessary quanBty of 50 can be dispensed? a. 50 suppositories b. 52 suppositories c. 55 suppositories d. 60 suppositories
19. The displacement factor used for Polyethylene glycol 1450 in this formula is: a.70 % b.100 % c.80 % d.90 %
20. For quality control purposes, 5 suppositories are selected to be weighed, and are removed from the mold. The mold that was used did not need lubricaBon, so there is no other addiBonal weight considered. What should each suppository weigh? a.2 gm b.2.275 gm c.2.045 gm d.1.91 gm 27
How to solve
Equa8on:
Strength of commercial product in milligrams = desired dose in milligrams
Weight of commercial product in milligrams X in milligrams
Cross mulBply, then divide to solve for the value of X, and when solved, X in milligrams represents the amount of commercial produc t( A + E) will contain the desired dose of acBve drug.
31
How to solve:
• Determine how much tablet by weight will equal the required dose. Use above equa8on, plug in known facts:
20 mg tablet strength = 15 mg required dose 100 mg tab weight X mg of tablet to give required dose
(20 mg)(X mg) = (15 mg)(100mg) 20X mg = 1500 mg Divide both sides by 20, in order to solve for X X = 1500 mg = 75 mg
20 mg
What does this mean? it takes 75 mg of ONE crushed tablet to give the required dose of 15 mg of Enalapril
• What volume does this occupy in a size one capsule? Pack stat has been done: 190 mg.
Dose/pack stat X 100 % = % volume, However the dose is NOT 15 mg, but is the weight of the tablet that equal 15 mg, in this case, 75 mg.
75 mg = 0.3947 X 100 % = 39.47 % This means that the dose occupies 190 mg 39.47 % of empty capsule.
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• How much filler is needed? 100 % full – 39.47 % = 60.53 % therefore 60.53 % filler is needed.
Lactose with 420 mg as pack stat, is mul8plied by 60.53 %.
Change 60.53 to decimal by moving decimal 2 places to lek: 0.6053
420 mg X 0.6053 = 254 mg of lactose per capsule is needed.
For 100 capsules: 15 mg/capsule, 1500 mg is needed. (15mg x 100 capsules)
Tablets are 20 mg each, so 1500 mg/20mg per tablet = 75 tablets are needed.
Lactose: 254 mg per capsule X 100 capsules = 25.4 gm of lactose.
This is a theore8cal formula that would be used based on the theore8cal numbers.
34
Remember: 625 mg = 100 mg(API) + 525 mg(E)
21. Vigaro® 37.5 mg been prescribed for energy. Its only available as a 100 mg tablet, and one tablet weighs 625 mg. How many milligrams of the crush tablet of Vigaro will contain the specified dose? Use the equaBon on the previous slide to solve.
a) 234mg b) 2.34gm c) 100mg d) None of the above
35
22. Aker compounding the prescrip8on, what will be the beyond use date be if the Vigaro® tablets have a shelf life of 90 days lek?
a. 14 days from date of compounding b. 30 days from the date pa8ent picked up c. 60 days from date of dispensing d. 90 days from the date of compounding e. 180 days from the date of compounding
23. What would be the beyond use date for the compound if the commercial tablets had an expira8on date 2 years out?
a. 14 days from the date of compounding b. 30 days from the date of compounding c. 90 days from the date of compounding d. 180 days from the date of compounding e. 2 years from the date of compounding
36
24. JerraSolve USP is a new drug designed to enhance problem solving skills. It is available as a raw, graded API, and is stable in water and air. A Rx for 12.5 mg/mL oral soluBon is presented, with a quanBty of 65 mLs to be dispensed, and paBent requests a combinaBon of marshmallow and chocolate flavors. In the flavor notes, its suggested to add 3 % of each flavor plus Steviol glycosides 95 % at a concentraBon of 0.5 %. Preserved water is the vehicle used.
Which of the below formulaBons is correct?
a. Formula for 65 ml JerraSolve USP 0.8125 gm Marshmallow flavor 1.95 mL Chocolate flavor 1.95 mL Steviol glycoside 95 % 0.325 gm Preserved water 65 mL
b. Formula for 65 ml Jerra Solve USP 0.8125 gm Marshmallow flavor 1.95 mL Chocolate flavor 1.95 mL Steviol glycosides 95 % 0.325 gm Preserved wate q.s. 65 mL
40
25. ArielLishes is available as a 50 mg tablet, is not bieer and stable in water, soluble in ethyl alcohol and has been proven to increase humor and wit. One tablet weighs 435 mg. The packing staBsBc of the product in a size # 1 capsule is 525 mg.
A 30 mg dose has been prescribed, how much crushed tablet is needed to give 30 mg of ArielLishes? a. 30 mg b. 261 mg c. 315 mg d. 50 mg e. None of the above
26. Further calculaBons from quesBon 25: what percent volume does the dose occupy in the size # 1 capsule? a. 30 mg/525 mg = 5.71 %
b. 261 mg/525 mg = 49.71 % c. 315 mg / 525 mg = 60 % d. 50 mg / 525 mg = 9.5 % e. none of the above
41
27. JerraSolve can be taken with ArielLishes. Together, no job is impossible and work becomes fun! JerraSolve USP is a bulk API, and has a pack stat of 236 mg in a size 1 capsule. ArielLishes is a tablet. Refer to quesBon 28 for informaBon needed to solve the quesBon. What percent filler is needed if a dose of JerraSolve 20 mg and ArielLishes 30 mg needs to be encapsulated? a. 85. 82 % b. 41.82 % c. 31.53% d. 82.03% e. None of the above
28. Rx calls for three and one half boeles of paregoric for a compound. If each boele has 40 mLs, how many mLs is needed?
a. 140 mL b. 100 mL c. 120 mL d. 200 mL
29. Doctor ordered ArBtoxin 250 mg/dose. It is available as a 3gm/5 mL soluBon. How many mLs is needed per dose? How much would you use to make 125 doses?
a. 0.5 mL/dose; use 62.5 ml for 125 doses b. 0.4166 mL/dose; use 52.08 mL for 125 doses c. 0.25 mL/dose; 31.25 mL for 125 doses d. 1 mL/dose; 125 mL for 125 doses
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30. If epinephrine injecBon is available in a raBo concentraBon of 1:200, how would this concentraBon be expressed in mg/mL?
a. 1 mg/mL b. 2 mg/ml c. 0.5mg/ml d. 5 mg/ml
31. If 90 grams of HC 2.5 % cream is mixed with 60 grams of 1 % HC cream, what is the resultant percentage concentraBon of HC in this cream? a. 1.6% b. 1.7 % c. 1.8 % d. 1.9 %
32. What volume of a 2 % Jayvocillin soluBon can be made from 15 grams of powder?
a. 250 mL b. 500 mL c. 750 mL d. 1000 mL
33. Heparin comes as 20,000 units/mL vial, how many mL are required for a dose of 12,500 units?
a. 0.625 mL b. 0.75 mL c. 0.5 mL d. 0.25 mL
43
34. What is the % equivalent of an 1:8 raBo? a. 0.125% b. 1.25 % c. 12.5 % d. 125 %
35. SebasBanstroid is a Canadian product used to treat tumors and is available as a powder trituraBon, at a 0.1 % concentraBon. How much acBve SebasBanstroid is in 1 gram of powder?
a. 10 mg b. 100 mg c. 1 mg d. 10 mcg
36. To make 15 micrograms capsules, how much of the 0.1 % trituraBon is used for 100 capsules?
a. 15 mcg x 100 capsule = 1500 mcg or 1.5 mg of trituraBon b. 15 mcg x 100 capsule= 1500 mcg or 1.5 mg API; 15,000 mg of trituraBon c. 15 mcg x 100 capsule = 1500 mcg or 1.5 mg API; 1500 mg of trituraBon d. 15 mcg x 100 capsule = 1500 mcg or 1.5 mg API; 150 mg of trituraBon
44
Cheat Sheet
• Percent to decimal, divide the percent by 100 or move decimal point 2 places to lek
• Decimal to percent, mul8ply by 100 and add the “%” sign, or move decimal point 2 places to the right.
• Grams = Milliliters X Specific Gravity **useful to convert the volume of a substance to its weight, therefore you must know volume and specific gravity.
• Milliliters = Grams/ Specific Gravity **Useful to convert the weight of a substance to its volume, therefore you must know weight and specific gravity.
Concept: Substances that have a specific gravity less than 1 are lighter than water Substances that have a specific gravity greater than 1 are heavier than water.
• Gram to milligram move decimal 3 places to right or mul8ply by 1000
• Milligrams to miCrograms move decimal 3 places to right or mul8ply by 1000
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