Definition, Classification, Physical, Chemical and Therapeutic Incompatibilities with Examples : Pharmaguideline

Online GMP Courses with Certificate


Definition, Classification, Physical, Chemical and Therapeutic Incompatibilities with Examples

Definition, Classification, Physical incompatibility, Chemical incompatibility, Therapeutic incompatibility,
Compatibility is a term used to describe the interaction of two or more substances that results in changes to the medical, physical, or chemical properties of the pharmaceutical dosage form.
There are three types of incompatibilities such as -
  1. Physical incompatibility
  2. Chemical incompatibility
  3. Therapeutic incompatibility
Physico-chemical incompatibility is the combination of physical incompatibility and chemical incompatibility.

1. Physical incompatibilities

Changes in color, taste, texture, odor, viscosity, viscosity, and morphology are caused by the interaction of two or more substances.
  • There is a visible change in the physical world
  • A product is formed that is unpalatable, non-uniform, and unacceptable.
  • Measuring doses accurately is difficult.
  • A pharmaceutical skill can correct the problem.
Physical incompatibility manifests itself in the following ways:
  • A prescription agent cannot be dissolved in a vehicle
  • Liquids that are immiscible with each other
  • In a state of dry mix, solids liquefy
Insolubility/ A prescription agent cannot be dissolved in a vehicle
Prescribed agents can be less soluble in the vehicle as a result of the following factors:
  1. Complex formation
  2. Surfactant
  3. Chemical reaction
  4. Change in pH
  5. Co-solvent
  6. Milling
Insolubility manifests itself in the following ways, among others:
  • Benzalkonium chloride;
  • Sodium lauryl sulfate, etc.
Immiscibility/ Liquids that are immiscible with each other

Incomplete mixing
Example - The oil drops may float on the surface of the water when aqueous preparations containing flavorings such as orange oil or lemon oil, or their alcoholic solutions, are prepared. Their presence makes the solution appear turbid and cloudy.

Liquefaction of solid mix in a dry state / In a state of dry mix, solids liquefy

Mixing of two solid substances results in their transformation into liquids.
Example - Mixed solids with low melting points fall into a liquefaction state due to eutectic mixtures, which result in a soft mass that may disintegrate the chemical structure of the preparation. When ex-menthol, thymol, and aspirin are mixed, they form a eutectic mixture.

Chemical incompatibilities

A change in the chemical properties of pharmaceutical dosage forms as a result of a reaction between more than two substances.
Causes -
  • Carbon dioxide is emitted as a result of chemical incompatibilities.
  • Calcium and magnesium soluble salts with soluble bicarbonate
  • Sodium bicarbonate and bismuth subnitrate
  • Glycerine and sodium bicarbonate with borax. `
Types of chemical changes:
  • Oxidation
  • Isomerization
  • Absorption of Carbon-di-oxide
  • Hydrolysis
  • Formation of insoluble complexes
  • Polymerization
  • Decarboxylation
  • Combination
There are four types of chemical incompatibility:
  1. Tolerated
  2. Adjusted
  3. Intentional
  4. Unintentional
Chemical incompatibility
1. Alkaloidal
  • Alkaloidal salt-containing alkaline substances
  • Iodides soluble in alkaloidal salts
  • Tannin-containing alkaloidal salts
  • Alkaloidal salts that contain salicylate
  • An alkaloidal salt that contains iodides and bromides soluble in water
2. Incompatibility with soluble salicylates
  • Salts of ferric ions soluble in salicylates
  • Alkali bicarbonate soluble in salicylate
3. Iodides are incompatible with soluble forms
  • Using ferric salts to oxidize iodides
  • Incorporation of potassium chlorate into the oxidation of iodides
  • Using quinine sulfate to oxidize iodides

With our naked eyes, we can see these things.
  • Turbidity
  • Precipitation
  • Crystallization/crystal growth
  • Aggregation
  • Solidification
  • Discoloration
  • Thickening
  • Change in color, Odor and tastes, etc.

Therapeutic incompatibilities

In simple terms, it means altering the therapeutic effects of a drug by administering it concurrently with another. Drug interactions are also called interactions between drugs. Therapeutic incompatibility is an unintentional change in pharmacodynamic or pharmacokinetic parameters resulting from the use of medicinal products.

For example, drugs containing amino acids cannot be taken with monothioglycerol oxidase inhibitors.
  • There are several possible causes, including:
  • Overdosing on a single drug or taking the wrong dosage.
  • Using the wrong dosage form.
  • The drug has contraindications.
  • Drugs that work synergistically and antagonistically
There are two main groups of mechanisms:
1. Pharmacokinetics
Analyze the reactions between drugs taken from the vantage point that includes absorption, distribution, metabolism, and excretion.

2. Pharmacodynamics
Associated with the pharmacological activity of the drugs interacting with each other. Synergistic effects, antagonism, altered cellular transport, or effects on receptors.
Get subject wise printable pdf documentsView Here

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
.moc.enilediugamrahp@ofni :liamENeed Help: Ask Question

No comments:

Post a Comment

Please don't spam. Comments having links would not be published.

Popular Categories

QA SOPs QC SOPs Micro SOPs HVAC Production SOPs Stores SOPs Checklists Maintenance SOPs HPLC Sterile GLP Validation Protocols Water System GDP Regulatory Maintenance Calibration Warning Letters Education B.Pharmacy
Online Courses

Follow Pharmaguideline



Editable Pharmaceutical Documents in MS-Word Format. Ready to use SOPs, Protocols, Master Plans, Manuals and more...



Recent Posts