PRESERVATIVES (Pharmaceutics | Chapter-3): Latest D Pharma 1st year Notes

Preservatives

Preservative are the chemical agent which prevents the product contamination or product decomposition by the action of any contaminant (environmental or biological).
Preservative commonly add in the pharmaceutical and various food products for enhancing their stability and shelf life. Phenolic compounds like sodium benzoate are highly used as preservative during the manufacturing.

On the basis of mechanism of action it is divided into three categories-

Antimicrobial agents- Agent which prevents the contamination (gram positive and gram negative) and degradation by microbes is called as antimicrobial agents. These agents are active in low concentration. Example– phenolic compounds, parabens, propylene glycol, BHT, BHA.
- On the basis of their activity it is further divided into two parts:
  - Microbiostatic- that inhibits the growth and multiplication of the microbes.
  - Microbiocidal- that agent direct kills the microbes.
Antioxidants agents-those agents which prevents the products oxidation or degradation in the presence of molecular oxygen. Generally API is more reactive towards the oxygen, so antioxidants are mix with the product and overcome the product reactivity. Example- ascorbic acid, citric acid, tocoferols, BHA, BHT.
Chelating agents-those agents which form the cyclic compounds or complexes with the pharmaceutical ingredients and prevent the degradation of pharmaceutical formulation Example-EDT A, polyphosphates.
- On the basis of sources it is divided into two parts-
  - Natural preservatives-vinegar, honey, castor oil, salt, sugar.
  - Synthetic preservatives-sodium benzoate, BHA,BHT.

Preservative enhance the stability and shelf life of the products, so it maintain the product activity for long time.
It prevents the product by any microbial contamination increase their resistance power against the microbial growth.
Many environmental factors effect the products property, for overcoming this activity preservative are also used.
It also mixes with the food preparation for prevention their oxidation.