This document discusses pharmaceutical incompatibilities that can occur when multiple ingredients are mixed together in a prescription. It defines incompatibility as an undesired change in the physical, chemical, or therapeutic properties of medications. There are three main types of incompatibilities: physical, chemical, and therapeutic. Physical incompatibilities involve changes in properties like color, odor, taste, viscosity or morphology due to insolubility, immiscibility, precipitation, or liquefaction. Chemical incompatibilities involve reactions like oxidation, hydrolysis, polymerization, isomerization, or decarboxylation. Therapeutic incompatibilities modify a drug's intended therapeutic effect and can result in overdose, improper dose, wrong dose, or drug interactions like

1. INCOMPATIBILITIES
YOGESH
D.PHARM
PHARMACEUTICS -II
Q1-: Incompatibilities in prescription.
Definition of prescription-: prescription is an
order written by physician or dentist or any
other registered medical practitioner to a
pharmacist to compound and dispense a specific
medication for the patient.
Definition of incompatibility-: The
undesired change taking place in the physical
chemical and therapeutic property of the
medicaments. when two or more ingredient of

2. prescription are mixed together is terms called
incompatibility.
OR
Incompatibility refers to interaction between
two or more substance which lead to change in
chemical physical therapeutic form of property
of the Pharmaceutical dosage form.
OR
It is defined as when two or more ingredient of a
prescription are mixed together the undesirable
changes that made it takes place in the physical
chemical and therapeutic property of the
medication.
Type of incompatibility
The incompatibility mainly found in three types which
are given as below.

3. Incompatibility
1.Physical 2.Chemical 3.Therapeutic
Insolubility Oxidation Overdose
Immiscibility Hydrolysis Improper Dose
Liquefication Polymerization Wrong Dose
Precipitation Iso-merization Contraindicated drug
De-carboxylation Drug interaction
Absorption of co2 Synergism
Combination Antagonism
DESCRIPTION
1.Physical Incompatibility-:Interaction
between two or more substances which lead to
change in colour, odour, taste, viscosity and
morphology. It is also called Pharmaceutical
incompatibility.
Insolubility-:Insolubility of prescribed agent in
vehicle.
Immiscibility-: When two or more liquid
ingredient in a prescription are not miscible with
each other.
for example-: castor oil not mix in aqua solution

4. Precipitation-:When two or more substance are
mixed together they form precipitation due to
presence of substance negative and positive
charge.
Example-: Benzalkonium chloride , Sodium lauryl sulphate
They are not much together because Benzalkonium chloride
is positive and sodium lauryl sulphate is negative.
They form a precipitate
Liquefication-:It means when two or more solid
substance are mixed together. conversion in a
liquid state
2.Therapeutic Incompatibility-:It is a
modification of the therapeutic effect of one
drug by the prior concomitant
administration of another It is also called
“drug interaction”
Overdose-:Doge is calculated on the basis of
age, sex, weight of the patient. It occur due to
errors in calculation of amount of dose specially
in case of children and older age.

5. NOTE-: Dose of NSAID’S need to half in case of Children
Improper Dose-:It occur when patient is unable
to take the drug due to bad on nauseous taste of
drug large size of drug.
Wrong Dose-:Some time there are changes of
dispensing wrong drug having similar name
For Example-: Digitoxin----------Digoxin
Acidin-------------Apidin
Contraindicated Drug-:There are certain drug
that are incompatible with normal body function
of the patient.
For Example -: Aspirin
(Aspirin is contraindicated in patient with gastric ulcer as
Aspirin in case of Gastro-intestinal bleeding)
Drug Interaction-: Alteration of the therapeutic
effect of one drug by prior concomitant
administration of another.

6. Synergism-:Two drug have Same
pharmacological action give together they
increase therapeutic activity.
For Example -:Combination of Aspirin & Paracetamol Increase = Analgesic effects.
Antagonism-:When two drug having opposite
Pharmacological action are prescribed together.
for example-: purgative and antidiarrheal
3.Chemical Incompatibility-:Reaction
between two or more substances which lead to
change in chemical property of Pharmaceutical
dosage form.
Oxidation-:Oxidation is defined as loss of
electron or gain of oxygen.
Hydrolysis-:A chemical reaction in which water
is used to break down a compound.
Polymerization-:In polymerization small
repeating unit called monomers are bonded to
form a long chain polymer.
For Example -:Formaldehyde-------Heat-------Para Formaldehyde

7. Iso-Merization-:It means conversion of drug to
its isomer.
 Optical Iso-Merization
 Geomatric Iso-Merization
Decarboxylation-:Decarboxylation is a
chemical reaction that removes a carboxyl group
and release carbon dioxide CO2.
For Example-: NaHCO3 ------Auto claving-----Na +CO2
Combination-:Take Palace when the
Pharmaceutical dosage form contain substance
with different charges.
For Example-: Surfactants with Positive &
Negative charges
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