Week 6 pharmaceutical calculations 1 Flashcards
One tablet, eye drop etc…
i
Two tablets, eye drops etc…
ii
Three tablets, eye drops etc…
iii
Morning
om, mane, am
Night / evening
on, nocte, pm
When required / if nessecary
prn, sos
As directed / use as directed
mdu, ud
Once daily
od, q1d
Twice a day
bd, bds, bid
Three times a day
tds, tid
Four times a day
qds, qid
On alternate days
qod, altd
Hourly
qh, q1h
Every two hours
q2h
Every four hours
q4h or qqh
Every twelve hours
q12h
Immediately
stat.
To be used as directed
mdu
Total quantity
mitt., mitte, send
Weight
-1 kilogram (kg) = 1000 grams (g)
-1g = 1000 milligrams (mg)
-1mg = 1000 micrograms (mcg or μg)
-1mcg = 1000 nanograms (ng)
Volume
-1 litre (l) = 1000 millilitres (ml)
-1ml = 1000 microlitres (μl)
Strength of pharmaceutical preparations
In general, the physical nature of the ingredients will determine how the strength of a preparation is expressed.
Solid dosage forms
g / mg / micrograms
Non - solid dosage forms, oral liquids
For oral liquids, most commonly:
milligrams per x ml e.g., 100mg/5ml
Non - solid dosage forms
%, expressed in quantity per quantity
e.g.,
concentration in % = mass / volume
% w/v
Weight in volume, g per 100ml
% w/w
Weight in weight, g per 100g
% v/v
Volume in volume, ml per 100ml
Pharmacoepias
Parts per million, ppm
e.g., 1ppm contains 1 part of solute per 1,000,000 parts of solution
Non - solid dosage forms, ratios
Where strengths are given as ratios, this means g per number of ml
e.g., 1:1000 means 1g per 1000ml
Making products to formulae
Sometimes formulae and dilutions are expressed as “parts”
“parts”
-calamine powder 1 part
-aqueous cream 10 parts
Equivalent to:
1g
10g
Total: 11g and (1g/11g) x 100% = 9.09% w/w
“to parts”
alamine powder 1 part
aqueous cream
to 10 parts
Equivalent to:
1g
9g
Total: 10g and (1g/10g) x 100% = 10% w/w
