Sources and types of impurities: Pharmaceutical Inorganic Chemistry

Following are the sources of contamination of any drug product:

Raw materials.

Pharmaceutical chemicals may be obtained from plant or animal sources or can be synthesized from chemical materials. But complete separation is not possible so unwanted products cause contamination.

Reaction vessels

Modern vessels are usually made up of stainless steel, grass, plastic. But in some of the reactions, metallic vessels are still used. Some metal ions might leave the container and end the material thus containing it.

Chemical instability

The impurity may also arise during storage and result in chemical instability and a number of pharmaceutically important substances are known to undergo chemical decomposition when stored under non-ideal solutions.

Physical changes

Changes in the physical form of drugs take place causing changes in size, shape, agglomeration, and caring of suspended particles, which cannot be prevented from causing contamination.

Reaction with container material

The possibility of reaction between container and contents constitutes a hazard that cannot be ignored.

Creams and ointments are liable to react with metal surfaces.

Temperature effects

The changes in the material taking place depends on the temperature.A slight increase in temperature causes decomposition causing degradation of materials

Particulate contamination

These include accidental inclusion of atmospheric pollutants such as aluminum oxide, silica, sulfur, etc

Non-particulate contamination

These include gaseous atmospheric pollutants such as sulfur dioxide, hydrogen sulfide, arsenic, and CO2. These constitute a hazard to products manufactured or stored under less than ideal condition

Cross-contamination

The handling powders, granules, and tablets in large bulk frequently creates a considerable amount of our borne dust, which if not controlled can lead to cross-contamination of products

Microbial contamination

Many products especially topical agents which are applied as injured skin, open wounds should be away from contamination caused by bacteria, molds, fungal contaminants from the atmosphere.