Calculations I & II

Question 1

fl oz to mL

Answer 1

1 fl oz = 29.57 mL

Question 2

oz to g

Answer 2

1 oz = 28.4 g

Question 3

grains to g

Answer 3

1 gr = 64.8 g

Question 4

left ear abbreviation

Answer 4

AS

Question 5

right ear abbreviation

Answer 5

AD

Question 6

both ears abbreviation

Answer 6

AU

Question 7

left eye abbreviation

Answer 7

OS

Question 8

right eye abbreviation

Answer 8

OD

Question 9

both eyes abbreviation

Answer 9

OU

Question 10

steroid equivalents

Answer 10

prednisone 5mg
prednisolone 5mg
methylprednisolone 4mg
triamcinolone 4mg
dexamethasone 0.75mg
betamethasone 0.5mg
hydrocortisone 20mg
cortisone 25mg

Question 11

how to calculate ratio strength from a concentration such as 5mg/mL

Answer 11

convert to % strength (w/w, w/v, v/v) then convert to ratio strength represented as 1/X (1:X) which has NO UNITS

Question 12

does ratio strength have units

Answer 12

no

Question 13

how to convert 0.00022% to ppm

Answer 13

set up proportion
0.00022g = x
100mL 1,000,000
x = # ppm

Question 14

specific gravity
use
equation
SG >1 =
SG <1 =

Answer 14

SG helps convert between volume and weight of the same substance

SG = g/mL
SG >1 = heavier than water
SG <1 = lighter than water

Question 15

what equation is used for dilution of a substance

Answer 15

C1Q1 = C2Q2
* need same units on each side

Question 16

In alligation, what % is in the top left, bottom left, and middle

Answer 16

top left = higher %
bottom left = lower %
middle = desired %

Question 17

In an osmolarity question, how does the equation change if they are asking for mOsm/L vs milliosmoles

Answer 17

for mOsm/L the numerator must be normalized to 1L
ex) have 10g in 200mL = x / 1000mL where x is now the g/L in the numerator
mOsm/L = g in 1 L x # particles x 1000
MW

if asking for mOsm –> can leave as original grams

mOsm = g actual x # particles x 1000
MW

Question 18

How do you determine the # particles for the osmolarity equation
mOsm/L = g in 1 L x # particles x 1000
MW

Answer 18

particles = number of dissociated components if dissolved in water
dextrose, mannitol = 1 (non-ionic, do not dissolve)
KCl, NaCl, NaC2H3O2, MgSO4 = 2 particles each
CaCL2 = 3 particles

Question 19

You can _____ mOm/L (osmolarty) of multiple substances together to get the osmolarity of the solution

A. divide
B. subtract
C. add
D. multiply

Answer 19

C. add

Question 20

For isotonicity, how do you determine the isotonicity factor (i)?

Answer 20

Depends on the number of dissociated ions. Add 0.8 to i each time you increase the # dissoc ions by 1

dissoc ions i value
1 1
2 1.8
3 2.6
4 3.4
5 4.2

Question 21

What substances are isotonic?

Answer 21

bodily fluids, eye drops, nasal solutions, TPN

Question 22

What does isotonic mean

Answer 22

osmotic pressure = that of NaCl 0.9% which is 300 mOsm/kg

Question 23

Define SCE (“E”)

Answer 23

sodium chloride equivalents
Helps determine the relationship between the amount of drug that produces a specific osmolarity and the amount of NaCl that produces the same osmolarity

Question 24

Equation to determine the SCE (“E”) of a drug

Answer 24

SCE aka E = 58.5 x (i)
MW x 1.8

Question 25

How to solve a SCE isotonicity question

Answer 25

1. calculate E with equation
2. g drug x E = g NaCl it will represent
3. use the concentration of NaCl 0.9% to determine how much “total” NaCl is needed for isotonicity
4. subtract. 3-2 = amount of additional NaCl needed to create isotonicity

Question 26

mEq
equation

Answer 26

mEq = mg x valence
MW

valence = # of negatively charged ions

Question 27

i value vs # particles vs valence

Answer 27

i is the isotonicity factor determined by the number of dissociated ions
#particles is the # particles that are dissociated
valence = # negatively charged ions once dissociated