Butylparaben

Butylparaben, also known as butyl p-hydroxybenzoate and Nipabutyl, is the ester of p-hydroxybenzoic acid and n-butanol, with molecular formula C11H14O3, molecular weight 194.23 and CAS number 94-26-8. It is a white or off-white crystalline powder at room temperature with an assay (on dried basis) of 98.0-102.0% (see specifications); its melting point of 68-71°C sits in the lower range among the four paraben esters (methyl, ethyl, propyl and butyl). Published literature reports that paraben antimicrobial activity and oil solubility both increase with carbon chain length (order methyl < ethyl < propyl < butyl), and butylparaben has the longest chain of the four; it covers molds, yeasts and certain bacteria, is commonly used in semi-solid topical preparations with oily bases (subject to formulation verification) and is often combined with methylparaben, propylparaben and other parabens. These are factory control items; this product is not registered as a pharmaceutical excipient - suitability for pharmaceutical use is assessed by the buyer under applicable drug regulations.

A raw material for antimicrobial preservatives in pharmaceutical formulations. Published literature reports that paraben bacteriostatic activity and oil solubility both increase with carbon chain length (order methyl < ethyl < propyl < butyl), with activity against molds, yeasts and certain bacteria. Downstream applications include topical ointments, creams, gels and suppositories, commonly semi-solid preparations with oily bases (based on its oil solubility, subject to formulation verification). Often combined with other parabens (such as methylparaben and propylparaben) to balance water solubility and antimicrobial efficacy.

Per published literature, paraben oil solubility increases with carbon chain length and butylparaben has the longest chain of the four esters, with comparatively good oil solubility (see Usage); it is commonly used in semi-solid topical preparations with oily bases such as ointments and creams, subject to formulation verification. In systems with a high oil phase, dissolution and dispersion of the preservative component is a typical formulation concern. Specification review points include assay (98.0-102.0%), melting point (68-71°C) and heavy metals (≤20 ppm) on this page.

In gels and suppositories, butylparaben serves as an antimicrobial preservative; base materials and processes differ across these dosage forms, and selection is confirmed through formulation verification, with impurity and heavy-metal limits checked against this page's specifications (related substances individual ≤0.4%, total ≤0.8%).

Butylparaben is often combined with other parabens such as methylparaben and propylparaben to balance water solubility and antimicrobial efficacy; blend ratios are set by the formulation owner and verified in the actual system.