Butyl 4-hydroxybenzoate sodium salt

Synonyms butyl-4-hydroxybenzoate sodium salt sodium butyl hydroxybenzoate. 

CAS 36457-20-2 EINECS/ELINCS 253-049-7 Synonyms Butylparaben, sodium salt p-Hydroxybenzoic acid, butyl ester, sodium salt Sodium butyl 4-hydroxybenzoate Sodium n-butyl-4-hydroxybenzoate Sodium butyl-p-hydroxybenzoate... 

Applications. In many countries the methyl, ethyl and n-propyl esters of p-hydroxybenzoic acid, as well as their sodium salts, are permitted for preservation of some foods. The maximum permissible quantity is around 0.1%. In the USA methyl- and propyl-paraben are considered GRAS. The maximum permissible quantity is 0.1%. Their main field of use is not food preservation but the preservation of pharmaceutical and cosmetic fat emulsions. The usage of the butyl ester is not allowed in food applications. 

Buffers can also be provided in parenteral formulations to ensure the required pH needed for solubility and/or stability considerations. Other excipients included in parenteral products are preservatives (e.g., benzyl alcohol, p-hydroxybenzoate esters, and phenol), antioxidants (e.g., ascorbic acid, sodium bisulfite, sodium metabisulfite, cysteine, and butyl hydroxy anisole), surfactants (e.g., polyoxyethylene sorbitan monooleate), and emulsifying agents (e.g., polysorbates). An inert gas (such as nitrogen) can also be used to enhance drug stability. Stability and solubility can also be enhanced by the addition of complexation and chelating agents such as the ethylenediaminetetraacetic acid salts. For a more detailed list of approved excipients in parenteral products, the reader should consult the monographs within the USP. 

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