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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

Pamoic acid (Embonic acid) | CAS 130-85-8

An aromatic dicarboxylic acid used to form pamoate salts, with acid equivalents, counterion identity and solid-form requirements central to pharmaceutical development.

CAS130-85-8
Molecular formulaC23H16O6
Molecular weight388.4 g/mol

Product overview

Pamoic acid joins two hydroxynaphthoic acid units through a methylene bridge. It provides two carboxylic acid groups on a substantial aromatic framework and is also known as embonic acid. Its main procurement distinction is the free acid versus preformed pamoate salts, including alkali-metal forms. The assay basis and water content should support accurate acid-to-base calculations in salt screening or preparation.

Chemical identity

Chemical name
Pamoic acid (Embonic acid)
CAS number
130-85-8
Molecular formula
C23H16O6
Molecular weight
388.4 g/mol

Application context

Pamoic acid is used in pharmaceutical salt formation, where the pamoate counterion can alter the physical behavior of a basic compound. Published development work includes cinnarizine–pamoate nanocarriers and studies distinguishing salts from cocrystals. The selected base, composition and crystallization conditions determine the resulting solid form. A pamoic acid purchase specification should therefore connect chemical purity and acid equivalents with the target salt study, while dissolution and solid-state behavior are evaluated on the resulting material.

Chemistry and synthetic role

The methylene-linked bis-naphthol structure carries two carboxylic acid sites; phenolic hydroxyls are also present. Neutral acid, monoanion and dianion are distinct charge states.

Quality review

Free acid and counterions

Confirm free pamoic acid and assess unintended alkali-metal content where it affects salt stoichiometry.

Acid-equivalent basis

Agree assay method, water correction and the basis used for acid-to-base ratios.

Related aromatic species

Review chromatographic related substances and any residual solvents relevant to solid-form development.

Preparing a specification

Specify free pamoic acid, assay and water basis, counterion limits where necessary, and impurity requirements appropriate to the intended salt or solid-form study.

Packaging and storage

Confirm container compatibility, closure and net weight for the selected grade and destination. Follow the actual supplier SDS and batch label for storage and transport.

Documentation

Request the batch COA, SDS and analytical methods covering the agreed purchasing specification. Confirm which supporting chromatograms and application-specific records are available from the selected manufacturer.

Procurement questions

Are pamoic and embonic acid the same?

Yes, these are names for the same free acid under CAS 130-85-8.

Is disodium pamoate interchangeable by mass?

No. Counterion content and molecular mass change the calculation and chemical form.

Does pamoate formation guarantee a particular release profile?

The specific salt, particle characteristics and formulation must be evaluated.

Technical sources
  1. PubChem CAS identity lookupNCBI / PubChem
  2. Pamoic AcidTCI
  3. Salt or Cocrystal Puzzle Solved by Mechanochemistry: The Role of Solvent in the Pamoic Acid Case StudyPrimary research indexed by PubMed
  4. Formation of stable nanocarriers by in situ ion pairing during block-copolymer-directed rapid precipitationPrimary research / PMC