Products
Methyl 4-hydroxybenzoate (methylparaben) is present in many drugs as an excipient, especially in liquid and semisolid dosage forms.
Structure and properties
Methyl 4-hydroxybenzoate (C8H8O3, Mr = 152.1 g/mol) exists as a white crystalline powder that is very sparingly soluble in water (about 1.8 g per liter at 20°C). The melting point is about 125°C. Methyl 4-hydroxybenzoate is the methyl ester of -hydroxybenzoic acid and, like ethyl or propyl paraben, belongs to the group of so-called parabens. Furthermore, the sodium salt sodium methyl 4-hydroxybenzoate also exists, which is more soluble in water (E 219).
Effects
Methyl 4-hydroxybenzoate has antimicrobial properties against bacteria and fungi such as molds and yeasts.
Indications for use
Methyl 4-hydroxybenzoate is used as a preservative for pharmaceuticals, foods, and cosmetics, among others.
Dosage
Methyl 4-hydroxybenzoate is often combined with propyl 4-hydroxybenzoate.
Adverse effects
Potential adverse effects include allergic reactions. Methyl 4-hydroxybenzoate has GRAS status and is well tolerated according to the literature (Soni et al., 2002). However, parabens generally have a poor reputation among consumers.
