Asymmetrical Flow Field-Flow Fractionation (AF4)

Method Introduction

Asymmetrical flow field-flow fractionation (AF4) is a well-established and highly versatile technique for sizing and quantifying aggregates and particles in protein formulations.
AF4 separates the various species in a channel consisting of a non-permeable plexiglass upper wall and a semipermeable accumulation wall at the bottom made of an ultrafiltration membrane and a solid frit. In AF4, the so-called cross-flow, the underlying force to separate the species is a physical field directed perpendicular to the laminar flow of the mobile phase.

Similar to HP-SEC analysis, in AF4 analysis, UV, refractive index, and fluorescence detectors are usually used as concentration-determining/quantifying detection systems. Additionally, multi-angle laser light scattering (MALLS) detection is used to determine the molecular weight and size of separated species.

Applications

Because of its wide separation range from a few nanometers to several micrometers, AF4 has been found appropriate for analyzing colloidal systems, such as liposomes, nanoparticles, polymers and virus-like particles.

AF4 can be used in all stages of pharmaceutical development and manufacturing – from early research to late-stage release testing under GMP, serving as a valuable tool for the orthogonal cross-validation of high-performance size-exclusion chromatography (HP-SEC) and analytical ultracentrifugation (AUC). AF4 is often used in the context of forced degradation studies and real-time stability studies since those often imply the formation of relatively large amounts of aggregates in the size range covered by AF4.

Quality and Biosafety Level

We provide all our analytical services with the highest quality standards. Experienced scientists carry out each project, and a scientific reviewer comprehensively checks every report or data presentation.

We offer this technology with the following quality and biosafety levels:

R&D level

We offer this method under R&D. Our GRP system assures the highest-quality research standards.

Up to biosafety level 2

This method can be applied to nucleic acids, viruses, cells, viral vectors, including lentiviruses, and more.

Analytical Method Development, Qualification and Validation

For common sample types, we can often apply standardized methods with little setup effort. However, when needed, our experienced analytical experts create or optimize custom methods tailored to your active pharmaceutical ingredient, product type and development phase.

Method Development

Our method development approach tailors sample preparation, method settings and data analysis to the needs of your project and sample.

We include representative samples and, where available, suitable reference standards and stressed/degraded materials, allowing our analytical scientists to design a highly suitable, stability-indicating, robust and repeatable method. Upon request, we will compile a detailed description of the method for your records.

Method Qualification

Method qualification is the initial assessment of an analytical procedure’s performance to show its suitability for its intended purpose.

During method qualification, our analytical scientists perform documented testing demonstrating that the analytical procedure meets criteria in several categories. Criteria may include factors such as repeatability, specificity and robustness. We compile a qualification plan and report, including all relevant data.

Method Validation

Under GMP conditions, method validation confirms that an analytical procedure’s performance suits its intended purpose. Depending on the method’s scope, a broad range of method characteristics, such as specificity, accuracy, precision, limit of detection/limit of quantification (LOD/LOQ), linearity and range, is considered.

During method validation, our analytical scientists perform documented testing demonstrating that the analytical procedure consistently produces a result that meets the predetermined acceptance criteria. We compile a validation plan and report that includes all relevant data.

Depending on the development phase, a fit-for-purpose validation approach can be offered, adjusting the validation required efforts in a phase-appropriate way to meet the method’s needs.

Method Verification

Compendial method verification confirms that a compendial method (e.g., from Ph. Eur. or USP) is suitable and reliable for its intended purpose under the specific conditions of the laboratory.

Unlike full method validation, compendial method verification is often considered a partial validation since the method has already undergone extensive testing and validation during its inclusion in the compendium. The extent of method verification depends on the type of method.

During method verification, our analytical scientists perform documented testing demonstrating that the developed analytical method performs adequately for the specific product or matrix being tested and within the specific laboratory where the method will be employed.

Talk to Our Experts or Request a Quote

Our expert team is ready to answer your questions and guide you to the services best suited to your program’s modality, stage and challenge. If your needs are well-defined, we’ll begin the quotation process.

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