Methyl 4-hydroxybenzoate has antimicrobial characteristics and is used as preservative in pharmaceutical formulations and cosmetics. It can be combined with other parabens like propyl 4-hydroxybenzoate or ethyl 4-hydroxybenzoate. Methylparaben is a type of paraben. Parabens are chemicals that are often used as preservatives to give products a longer shelf life. They're added to food or cosmetics to prevent the growth of mold and other harmful bacteria.
sodium methyl para-hydroxybenzoate is a compound with formula Na(CH3(C6H4COO)O). It is the sodium salt of methylparaben. It is a food additive with the E number E219 which is used as a preservative.
METHYL hydroxybenzoate and its sodium derivative are recommended by the B.P.C. and by Martin-dale1 as preservatives for creams, emulsions, lotions and ophthalmic solutions, and they are used to preserve local anaesthetics.