Sodium Phenylacetate

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Cat Number

API0231642

CAS Number

114-70-5

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Product Detail Description Scientific Support Customer Q&A

CAS Number

114-70-5

EINECS

204-052-7

Storage

Store at room temperature

Synonyms

Phenylacetic acid sodium salt; Sodium benzeneacetate; Sodium phenylacetate [USAN]; Phenylacetate sodium salt

Molecular Formula

C8H7NaO2

Molecular Weight

158.13

Smiles

C1=CC=C(C=C1)CC(=O)[O-].[Na+]

Appearance

White to off-white crystalline powder

Boiling Point

265.5℃

Relative Density

1.164

General Description

Sodium phenylacetate is a nitrogen-binding agent used intravenously, in combination with sodium benzoate, for the treatment of acute hyperammonemia in urea cycle disorders. The drug is metabolically converted to phenylacetylglutamine, which acts as an alternative nitrogen sink.

Mechanism of Action

Phenylacetate conjugates with glutamine in the liver and kidneys via the enzyme phenylacetyl-CoA:glutamine acyltransferase, forming phenylacetylglutamine. This compound contains two nitrogen atoms (derived from ammonia via glutamine synthesis) and is rapidly excreted in the urine. Each mole of phenylacetate removes two moles of nitrogen, effectively reducing plasma ammonia levels.

Application

Sodium phenylacetate (with sodium benzoate) is FDA-approved as an adjunctive therapy for acute hyperammonemia in patients with urea cycle enzyme deficiencies. It is administered intravenously as a loading dose followed by continuous infusion.

In maple syrup urine disease (MSUD), dietary modification and extracorporeal removal of toxic metabolites are standard. Sodium phenylbutyrate, used in urea cycle disorders, has been anecdotally associated with reduced branched‑chain amino acid (BCAA) levels in MSUD patients on adequate protein intake. This case report describes an MSUD patient during an acute attack where technical difficulties prevented dialysis; treatment with sodium phenylbutyrate led to clinical improvement and BCAA reduction. The authors suggest that when extracorporeal procedures are not feasible, sodium phenylbutyrate may serve as an alternative pharmacological intervention to lower BCAA levels, though more studies are needed.

Fig. 1 Hemodialysis and Na phenylacetate/benzoate and phenylbutyrate treatment during attack management. (Köse M, et al., 2017)

References

Köse M, et al. A Patient with MSUD: Acute Management with Sodium Phenylacetate/Sodium Benzoate and Sodium Phenylbutyrate. Case Rep Pediatr. 2017;2017:1045031.

Does Sodium Phenylacetate require protection from moisture during storage?

Yes, it is highly hygroscopic and rapidly absorbs moisture, leading to deliquescence. Store in tightly sealed, moisture-proof containers with desiccant.

What is the recommended storage temperature for Sodium Phenylacetate?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can accelerate decomposition and caking.

Is Sodium Phenylacetate stable in solution for intravenous use?

Aqueous solutions are stable when stored at room temperature, but we recommend use within 48 hours to prevent microbial growth. Provide in-use data.

How is the impurity phenylacetic acid (free acid) monitored during stability?

This potential degradation product is quantified using a validated HPLC method, ensuring it remains below specified limits for parenteral use.