Bioequivalence Testing

Bioequivalence testing is critical to gain regulatory approval for non-NDA submissions. Choosing the right nonclinical test system can help sponsors get their product through the approval process more efficiently by reducing the amount of clinical testing required.

Generic drugs represent over 80% of prescriptions in the US, and can alleviate drug shortages, reduce costs, and enhance patient access to treatment. Regulatory approval of new generics requires proof of bioequivalence (BE). Our suite of BE assays from simple in vitro permeability to in vivo pharmacokinetics provide exceptional, robust data to support these applications.

The Absorption Systems Difference

Absoprtion Systems’ wide range of assays enable us to find the optimal solutions to your bioequivalence needs. We have extensive experience working with different dose routes (e.g. oral, dermal, ocular) as well as with in vitro, ex vivo and in vivo assays. Our scope of expertise allows us to design the optimum studies to address client needs.


What dose routes do Absorption Systems support for bioequivalence studies?

We support a full range of dose routes and have systems of increasing complexity with which to study these. A snapshot of these assays is shown in the table below:


Dose Route In vitro Ex vivo In vivo


Combined dissolution absorption (iDAS)

Intestinal perfusion

Tissue permeability

Standard PK

Ported animals

Intra-oral (Buccal/Subligual) 3D tissue equivalent Tissue permeability

Sublingual dosing


IVRT Skin permeability

Dermal dosing (topical, patches)

Disease models

Ocular MDCK Corneal/Conjunctival tissue permeability

Ocular dosing (topical, intravitreal)

Disease models

Intravaginal 3D tissue equivalent Tissue permeability Vaginal dosing (topical, suppository)











What are complex generic drug products?

Complex generics are drugs with either non-standard active ingredient, formulation or route of delivery. For example, a topical skin product may have multiple formulations based on reactions with the dermis. These differences have important consequences for bioequivalence studies. 



In general, we offer expert guidance and experimental studies to support all regulatory approval routes for drug products. Bioequivalence studies are particularly important for ANDA and 505(b)(2), for which there may already be approved products to be used for reference.


Does the FDA support complex generic drug products (CGDPs)?

The FDA has clearly prioritized the accelerating of CGDPs to market. They recognise that the products ‘ by nature of their formulation, delivery systems or the complexity of their active ingredients, for example, are harder to “genericize” under traditional approaches.’ (FDA, 2019).

Addressing this requires the development of reliable and reproducible scientific tools to help understand chemical and biological complexity and establish bio-relevant assays.

Want to find out more about our multimodal approach to bioequivalence studies?