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Antimicrobial Effectiveness Testing

USP ⟨51⟩ antimicrobial effectiveness (preservative) testing for multi-dose products.

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Compendial standard this method is validated to.

TAT

Business days from sample receipt to report.

WHY YOU NEED IT

Why Antimicrobial Effectiveness Testing Matters

Prove the antimicrobial preservative works

USP ⟨51⟩ challenges the product with microorganisms to confirm the preservative (e.g. benzyl alcohol) actually suppresses growth over the in-use period (28 days).

Essential for multiple-dose vials

Every needle entry is a contamination opportunity — preservative effectiveness is what protects later doses.

Substantiate in-use dating under USP ⟨797⟩

USP ⟨797⟩ requires aqueous multiple-dose CSPs to pass AET, and those results are what support using the vial for up to 28 days after first entry.

OUR PROCESS

How we run this test for you

Method Suitability

Proving the method first

Before the study runs, we confirm the neutralizer recovers every challenge organism from your product — otherwise the preservative masks growth in the test itself.

3 vials

Support for Multi-Dose Containers

Releasing every batch

For aqueous multiple-dose containers, USP ⟨797⟩ requires AET for both Category 2 and 3 compounded sterile preparations — it's a one-time test for each formulation and container.

Stability Studies

Across your stability timeline

Run at Day 0 and Day 90 alongside the rest of your stability panel, AET shows that the preservative works — and that it still works when the beyond-use date expires.

6 vials

TECHNOLOGY

Challenge the product, then count survivors.

Qualify the method

Method suitability confirms the ability of the assay to measure microbial growth.

Challenge and incubate

The product is inoculated with the five compendial organisms and held under controlled conditions.

Count over 28 days

Survivors are enumerated at Day 0, 7, 14, and 28, and log reduction is compared to the USP ⟨51⟩ category criteria.

OUR SERVICES

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USP <85>

Endotoxin Testing

USP <85> bacterial endotoxin testing (LAL) for compounding pharmacies lot release.

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USP <621>

Potency Testing

HPLC potency testing that confirms each compounded lot falls within ±10% of its label claim.

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USP <1207>

Container Closure Integrity Testing

USP <1207> container closure integrity testing (vacuum decay) for sterile vials.

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18 calendar days

USP <71>

Compendial Sterility Testing

The traditional USP <71> sterility method, accepted by every regulatory body.

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2 business days

USP <788>

Particle Counting

USP <788> sub-visible particulate matter counting for injectable products.

2 business days

USP <790>

Visual Inspection

USP <790> inspection for visible particulates in injectable products.

2 business days

USP <697>

Fill Volume Testing

USP <697> fill-volume verification (container content) for injectable products.

2 business days

USP <791>

pH Testing

pH testing under USP <791> — a fast, low-touch check on each compounded lot.

STABILITY STUDIES

Planning a stability study?

See how this test can support a validated stability program and the data needed for extended beyond-use dating.

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Stability-indicating HPLC methods that separate API from degradation products

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Custom study designs for refrigerated, frozen and room-temperature storage conditions

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Defined pull points with potency, pH, appearance and container-closure assessment

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Documentation packages to support extended beyond-use dating under USP <797>

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Sterility and endotoxin testing integrated at study end points

Guide: USP <797> stability studies & extended beyond-use dating →

Request a Stability Study Quote

Starting at $10,000

CATEGORY 2

CATEGORY 3

These studies generate the stability data required to qualify for the extended beyond-use dates that USP <797> permits for Category 2 and Category 3 CSPs — going well beyond the default short-dating limits.

TYPICAL STUDY OUTLINE

What a stability program covers

Supports

USP <797> Cat 2 & Cat 3 extended BUD

Storage conditions

Refrigerated · Frozen · Controlled RT

Pull points

T0, then defined intervals to BUD

Assays per point

Potency · pH · Appearance

Method type

Stability-indicating HPLC