Categories:

Pharmaceutical Excipients

Methylparaben

Alias: Methylparaben / Methyl parahydroxybenzoate / Methyl p-hydroxybenzoate / Methyl 4-hydroxybenzoate / 4-Hydroxybenzoic acid methyl ester / Nipagin
CAS No.
Molecular Formula: C₈H₈O₃

Structure

Product Details

Product Overview

Product Summary

Methylparaben, also known as methyl p-hydroxybenzoate and Nipagin, is the ester of p-hydroxybenzoic acid and methanol, with molecular formula C8H8O3, molecular weight 152.15 and CAS number 99-76-3. It is a white or off-white crystalline powder at room temperature, melting at 125-128°C, with an assay (on dried basis) of 98.0-102.0%, a clear and colorless solution, loss on drying ≤0.5% and heavy metals ≤10 ppm (see specifications). As the methyl ester member of the paraben family, its antimicrobial action targets mainly molds and yeasts, and it is often combined with other parabens such as propylparaben. Among the four paraben esters (methyl, ethyl, propyl and butyl), its melting point sits in the higher range, which can serve as a reference item for batch identification. 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.

Usage

A raw material for antimicrobial preservatives in pharmaceutical formulations; published literature reports inhibitory activity against molds and yeasts. Downstream applications include oral liquid preparations, topical ointments, creams and other pharmaceutical dosage forms. Often combined with other parabens (such as propylparaben) at different ratios. Also used for preservation in syrups and mixtures. This product is not registered as a pharmaceutical excipient; suitability for specific formulations is subject to the pharmaceutical regulatory requirements of the target market, to be confirmed by the buyer.

Applications

Applications by Industry

Pharmaceutical Formulation Preservation

Methylparaben is used as an antimicrobial preservative in pharmaceutical formulations, covering oral liquid preparations, topical ointments and creams, as well as liquid preparations such as syrups and mixtures; suitability for demanding dosage forms is assessed by the buyer, subject to the formulation owner's process requirements. Formulators typically review assay (98.0-102.0%), related substances (individual ≤0.4%, total ≤0.8%, p-hydroxybenzoic acid ≤0.3%) and heavy metals (≤10 ppm) against the specifications on this page.

Reagent and Other Industrial Uses

Methylparaben also serves as a laboratory reagent and as a preservative component in industrial products; reagent uses typically focus on assay and solution clarity (clear and colorless, see specifications), and other specification requirements can be agreed upon during inquiry, with batch data confirmed by our sales team.

Specifications

Technical Specifications

Product Specifications
Appearance	White or off-white crystals or crystalline powder
Content (on dried basis)	98.0%–102.0%
Melting point	125–128°C
Acidity	Compliant (0.1 mol/L NaOH consumption ≤0.1 mL)
Solution clarity and color	Clear and colorless
Chloride (Cl)	≤0.035%
Sulfate (as SO₄)	≤0.024%
Related substances	Individual impurity ≤0.4%, total impurities ≤0.8%; p-hydroxybenzoic acid ≤0.3%
Loss on drying	≤0.5% (silica gel desiccator, vacuum dried to constant weight)
Residue on ignition	≤0.1%
Heavy metals	≤10 ppm
Arsenic	≤0.0001%

Logistics

Packaging, Storage & Transport

Packaging

25 kg fiber drum with double polyethylene liner; custom packaging available upon request. Sample arrangements and order quantities can be discussed during inquiry.

Storage

Store tightly closed in a cool, dry, well-ventilated place

Transport

Transport classification follows the goods transport appraisal report and the carrier's requirements; protect from moisture, sunlight and physical damage; keep packaging intact

FAQ

Frequently Asked Questions

What are the assay and key specifications?

Assay (on dried basis) 98.0-102.0%, melting point 125-128°C, acidity compliant (0.1 mol/L NaOH consumption ≤0.1 mL), loss on drying ≤0.5%, heavy metals ≤10 ppm; related substances controlled at individual ≤0.4%, total ≤0.8% with p-hydroxybenzoic acid ≤0.3% (see specifications). The product is produced and released against the figures on this page; batch data is confirmed with our sales team during inquiry.

What packaging and order quantities are available?

Standard packaging is a 25 kg fiber drum with a double polyethylene liner, and custom packaging is available. Sample arrangements and order quantities can be discussed during inquiry; regular batches are produced against the order schedule.

Which preservatives is it combined with?

Methylparaben is often combined with other parabens such as propylparaben; the ratio is set by each formulation, and selection should follow verification in the actual system.

How do I avoid naming confusion in procurement?

Common aliases include methyl p-hydroxybenzoate, 4-hydroxybenzoic acid methyl ester and Nipagin; quoting CAS number 99-76-3 in inquiries is recommended. Note the difference between methylparaben (the ester) and p-hydroxybenzoic acid (the free acid, controlled at ≤0.3% under related substances) - they are not the same substance.

What are the storage and transport requirements?

Store tightly closed in a cool, dry, well-ventilated place; transport classification follows the transport identification report and carrier requirements; protect from moisture, sunlight and physical damage. Special packaging or transport conditions can be discussed during inquiry.