Anti-oxidants
Submitted by Rameshwar Reddy on Sat, 05/03/2008 - 12:53.
in
- Rameshwar Reddy's blog
- Login or register to post comments
They are the chemical compounds used to preent the oxidation process and thus contribute to the stabi;ity of the preparation.
Presence of unsaturated fatty acids in fats and oils causes the phenomenon of auto-oxidation in which no third factor is required for oxidation to take place. Hence extra care should be taken for preservation of substance containing self-oxidizing substances.
Environmental factors affecting oxidation:
The factors are amount of oxygen type of container, presence of enzymes like peroxidases and environmental pH.
The uptake of oxygen by the inorganic packing materials is as follows.
Cu>Pb>Zn>Sn>AI
Materials with least uptake of oxygen are preferred.
It is better to avoid auto-oxidisable substances in the preparation as far as possible.
Mechanism of action of antioxidants:
1. Antioxidants are preferably more susceptible to oxidation and thus prevent the product from being oxidized.
2. They prevent or reduce the uptake of oxygen by the preparation.
The amount of antioxidant is selected such that it protects the preparation throughout its shelf life.
Class H :
Preventol BP, Irgasam, Tricholoracarbanilide, Chloroacetanilide, Bromophene, Dichlorophene, Hexachlorophene, Vecide 889, p-chloro-m-cresol, Dichloro-m-xylenol. Tribromosalicylanilide, Chloroxyenol and chlorhexidene.
Class Ph:
P-Thymol, o-Phenyl phenol, 8-hydroxy quinoline sulphate, phenol, cresol, chlorbuto.
Class F:
Hexitidine, Bronidox Bronopol, Dowiel 200, Chlorophenesin, Formaldenyde, p-Formaldehyde and Hexamethylene tetramine.
Class Py:
2-Hydroxy pyridine-N-oxide, Omadine MDS, Sodium omadine, Zinc omadine,Cetyl pyridinium chloride.
Class Am:
Dibromo propamidine, hexamidene.
Class Q:
Quaternary ammonium compounds.
Bacfor, Onyonide, Cetride, kankoh, Hyamine, CTAB, CPTB Benzenenium and benzalkonium chloride.
Class Hg: Phenylmercuric acetate, Sodium methiolate. Phenyl mercuric nitrate.
Class M: Benzyl alcohol, Dodione, 2-phenoxy ethanol, prophylene phenoxetol.
No antioxidant can prevent oxidation of the preparation for ever. It is tim bound phenomenon and the time can only be prolonged.
Free radical formation is the first step in auto-oxidation process
Natural anti-oxidants....
Would you throw some light on natural anti-oxidants found in plants??? Because, many natural anti-oxidants pose even more potent activity than synthetic chemical anti-oxidants...
e.g.- punicalgin found in punica granatum peel...