3. Definition
Chemical interaction between the ingredients in prescription
A toxic / inactive product may be formed
Due to oxidation reduction, acid base hydrolysis
Characterized by precipitation, effervescence, decomposition and
color change/ explosion
5. Types
Tolerated changing the order of mixing or
mixing of solution in dilute form
Adjusted
addition/substitution of reacting
substance with other of equal
therapeutic value
7. Incompatibility may be….
Intentional
• When the prescriber knowingly
prescribe the incompatible drug
Unintentional
• When the prescriber prescribes the
drug unknowingly
9. Precipitates
Diffusible
Reaction between dilute solution proceed at a slower rate
Light precipitates
Diffuse readily in solution
Not soluble in water
Uniformly distributed
Indiffusible
Reaction between Strong solution proceed at a faster rate
Thick precipitates
Do not diffuse readily in solution
Not soluble in water
Not uniformly distributed
11. Precipitate yielding interaction
Method A
Reacting
substance
Reacting
substance
Add one by
one with rapid
stirring
Diffusible
precipitate
Label : Shake well
before use
12. Precipitate yielding interaction
Method B
Smooth
Mucilage
Reacting
substance
Add one by
one with rapid
stirring
Indiffusible
precipitate
Compound
tragacanth
1
2
2nd
portion
+
Reacting
substance Label : Shake well
before use