Exam 4

Strength

relative amount of API in the formulation (how much drug is there).

Drug amount per volume- concentration

Potency

 drug’s ability to produce a pharmacologic effect

What does NOT change when use use this equation: C₁V₁ = C₂V₂

the drug amount stays the same unless you physically add or remove drug.

used for dilution

Product Strength formula

API / Whole (total mixture).

What does Dilution do?

decrease relative amount of API (decreases strength)

• Usually by adding diluent (most common in pharmacy).

• Can also remove API (e.g., filter a suspension).

• lowers concentration

a. What math NOT to do for dilutions and fortifications

b. what math can you use do for dilutions

a. Do NOT use proportions (C₁/V₁ = C₂/V₂) for whole problems—it’s not an equivalence after you change total volume.

b. C₁V₁ = C₂V₂ (volumes/concentrations)

What does fortification do?

• Concept: increase relative API.

  • Usually add active (e.g., powder) → increases numerator and total mass.

  • Or remove diluent (e.g., evaporation) → lowers denominator.

• increases concenttraion

What is stock solution?

• Make a concentrated stock to use repeatedly to make to make weaker solutions by dilution 

• plan concentrations so later dilutions are easy.

• Used for APIs and functional excipients (flavors, sweeteners, suspending agents, etc.).

IV compounding logic:

when mixing two solutions, ask “what happens to each solute’s concentration?

a. allegation define

Allegation is used when combining already-prepared formulations, not pure API powder.

Two methods in allegation 

a. Alligation Medial - weighted average

b. Alligation Alternate - shortcut table used only when mixing TWO components. “parts” represent ratio units, not grams.

Anytime you mix two strengths — whether you use:

• weighted average (allegation medial), or

• parts method (allegation alternate),

the resulting strength must be WHAT?

must fall between the two strengths being mixed.

When one component is “0%” in allegation, what does it act like?

It acts like a it acts as a diluent (contributes no drug), only volume/mass. petrolatum = 0% drug

What happens to final strength when both components have the same API strength in allegation?

mixing does NOT change final strength.

mian difference between dilution used equation (C₁V₁=C₂V₂) and allegation? 

C₁V₁=C₂V₂ assumes API amount is constant; allegation does not assume that — it calculates it.

however you can use c1V1 = c2 v2 in alligation in this situation: 

Situation	Does drug amount change?	Use this
Only adding diluent (0%)	❌ Drug stays same	C₁V₁=C₂V₂

Define alligation alternative

define Scaling factor

(Desired batch) / (Recipe batch); multiply every ingredient by this factor.

Reducing/enlarging can be solved by any what 3 methods 

factor, proportion, dimensional analysis

when are Aliquots are required

• when the weighed amount is below MWQ (~20 mg).

• make a bigger mix with diluent, then take a portion.

• use other math (ratio / C₁V₁=C₂V₂)

Aliquots do NOT change WHAT

the target strength

In proportional parts formulas, each part is a…

is a relative unit, not a fixed volume or weight

When all parts are liquids and compatible, we asume what

volumes are assumed to be additive

give me the different USP

• USP <795> = non-sterile compounding

• USP <797> = sterile compounding

• USP <800> = hazardous handling

• USP <1160> = pharmaceutical calculations in compounding

What is the official written recipe + math called; It must be followed exactly & documented

Master Formulation Record (MFR)

a. When do you know their power volume

b. how to find PV? 

a. when label says “add X to make Y

b. PV = Y − X

Reconstitution

may contain more total drug than label dose — you withdraw the labeled dose only

Capsules:

size chosen by bulk density,

lactose used as

diluent,

tablets ≠

pure API

Suppositories

base = diluent, calibrate mold, usually prepare excess

how Capsules and suppositories connected 

Mainly large mass that contains drug in a certain amount - THEN portioned into individual units.

qs ad

quantity sufficient to make total final volume/weight (not “add that amount”)

difference between ELIXIR and SPIRIT

ELIXIR = Medicinal “drink” base

• Has water + low alcohol mixed

• Often sweet (has syrup)

• Used as something you could give to a patient directly or use to make another liquid

SPIRIT = Strong alcohol extract

• Almost all alcohol, little/no water

• Very strong concentration of oils/flavor or drug

• NOT usually given directly — mostly used as an ingredient to mix into other things

Talc

filter aid (does not remain)

Alcohol + water contract

treat premixed 50/50 as single ingredient in problems.