This document discusses pharmaceutical incompatibilities, which are undesirable changes that occur when two or more substances are combined, affecting safety, efficacy, appearance, and stability. There are three main types of incompatibilities: physical, chemical, and therapeutic. Physical incompatibilities involve a physical change when substances are combined, such as changes in color, odor, taste, viscosity or morphology. One example given is insolubility - when one substance is insoluble in the vehicle it is being added to, such as chalk powder precipitating out of an aqueous solution due to its insolubility in water. Suspending agents can be added to prevent precipitation in such cases.

1. Pharmaceutical
Incompatibilities.
Presented by
Prof. Sudipta Roy

2. Definition of Incompatibility.
Incompatibility:
Formation of Changed and Undesirable product.
There are three types of Pharmaceutical
Incompatibilities seen due to changes and
undesirable effects-Physical,Chemical and
therapeutic incompatibilities to affect the
safety,efficacy, appearance and stability of the
product.

3. Reasons of Pharmaceutical
Incompatibilities.
• Formation of Undesirable product are due to
• Compounding
• Formulation
• Manufacturing
• Packaging
• Dispensing
• Storage
• Administration of drugs

4. The pharmaeutical incompatibilities may be changed
due to physical, chemical, and therapeutic qualities
of the medicine.

5. Physical incompatibilities.
• Two or more than two substances are combined, a
physical change takes place and unacceptable
product is formed.
• Interaction between two or more substances lead
to change in color, odor , taste , viscosity and
morphology.

6. Reasons of Physical
Incompatibility.
Insolubility:-Insolubility of prescribed agents in
vehicle.
Immiscibility:-Immiscibility of two or more liquids.
Precipitation:-It occurs due to solvent is insoluble
when it is added to solution.
Liquefaction:-Liquefaction of solids mixed in a dry
state (called eutexia).

7. • INSOLUBILITY
• Materials are not dissolved in particular solvent system.
• Incompatibilities are due to insolubility of the inoeganic and
organic compounds in particular solvent.
• These are factors that affect insolubility.
• Change in PH
• Milling
• Surfactant
• Chemical reaction
• Complex formation
• Co-solvent

8. Common Examples of Diffusible Solids:
Substances like chalk, acetyl salicylic acid ,succinyl
sulphothiazzole, zinc oxide, and calamine etc.

9. Tinctures containing resins or chlorophyll gets
precipitated when added to the aqueous system.
E.g.:-Mixture of prepared chalk
Rx
Chalk powder –2g
Tincture catechu – 2ml
Cinnamon water – 2ml

10. Causes: - Chalk powder is insoluble in water , due to
this It gets precipitated into aqueous
medium,diffusible in nature which results in physical
incompatibility.
Remedy: - Use of suspending agents are necessary to
suspend the precipitated chalk particles.

11. Generally 2% W/V of compound tragacanth powder
is recommended as suspending agent.
• The corrected prescription is Mixture of prepared
chalk
• Rx
• Chalk powder –2g
• Tragacanth – 0.4g
• Tincture catechu – 2ml
• Cinnamon water up to 30ml