Every generic drug that reaches a pharmacy shelf in India or abroad has to answer one question first: does it behave in the body the same way as the innovator product it copies? Bioavailability and bioequivalence (BA/BE) studies are how that question gets answered, and in India the Central Drugs Standard Control Organisation (CDSCO) decides when they are required, how they are approved and where they may be conducted. This guide walks through the requirements, the forms, the BE NOC pathway for export studies and the timelines sponsors should plan around in 2026.
What Are Bioavailability and Bioequivalence Studies?
Bioavailability (BA) describes the rate and extent to which the active ingredient of a drug is absorbed and becomes available in systemic circulation. A BA study measures this directly in human volunteers, typically through serial blood sampling and pharmacokinetic analysis.
A bioequivalence (BE) study is comparative. It doses a test product (usually a generic) and a reference product (the approved innovator brand) in the same subjects and compares their pharmacokinetic profiles. If the two products deliver the drug at a statistically equivalent rate and extent, they can be treated as therapeutically interchangeable without repeating full clinical trials.
The acceptance criterion regulators apply
The near-universal standard, followed by CDSCO as well as the US FDA and EMA, is that the 90 percent confidence interval of the test-to-reference geometric mean ratio for Cmax and AUC must fall within 80.00 to 125.00 percent. Most studies use a crossover design in which each volunteer receives both products, separated by a washout period of at least five half-lives of the drug, commonly around two weeks.
Because a failed pivotal study is expensive, many sponsors first run a small pilot bioequivalence study of around 12 subjects to estimate variability and check the formulation before committing to a pivotal design of 18 to 36 subjects.
When Does CDSCO Require a BE Study?
Three regulatory triggers account for most BE work in India.
- New drugs and investigational new drugs. Under the New Drugs and Clinical Trials (NDCT) Rules 2019, any BA or BE study of a new drug or investigational new drug in human subjects needs prior permission from the Central Licensing Authority. A drug generally retains "new drug" status for four years from its first approval in India, so generics of recently approved molecules fall in this bucket.
- Domestic manufacturing licences for BCS Class II and IV oral generics. Gazette notification G.S.R. 327(E) of 3 April 2017 amended the Drugs and Cosmetics Rules so that State Licensing Authorities cannot grant a manufacturing licence for oral dosage forms of drugs in Biopharmaceutics Classification System (BCS) Class II (low solubility, high permeability) or Class IV (low solubility, low permeability) unless bioequivalence data is submitted. This closed a long-standing gap where older generics could be licensed on quality testing alone.
- Export dossiers. Regulators in the US, EU, Brazil, and most other markets require BE data in generic (ANDA-type) submissions. Studies conducted in India purely to support foreign filings follow their own streamlined pathway, described below.
Regulatory Pathways at a Glance
| Scenario | Governing provision | What you file | Outcome and timeline |
|---|---|---|---|
| BA/BE study of a new drug or IND for the Indian market | NDCT Rules 2019 | Form CT-05 application to CDSCO | Permission granted in Form CT-07; decision within 90 working days |
| BE study for export only, of a drug approved in India, US, UK, EU, Japan, Australia or Canada (single-dose crossover, oral form, healthy adults) | NDCT Rules 2019, Rule 31(2) | Prior intimation via the SUGAM portal with ethics committee approval | Study may start on CDSCO acknowledgment (the BE NOC route) |
| Manufacturing licence for oral BCS Class II or IV generics | G.S.R. 327(E), 2017 amendment to the Drugs and Cosmetics Rules | BE data with the State Licensing Authority application | Licence is not granted without bioequivalence evidence |
| Operating a BA/BE study centre | NDCT Rules 2019 | Form CT-08 application | Registration certificate in Form CT-09 |
| Importing test or reference product for a study | NDCT Rules 2019 | Form CT-16 application | Import licence for study quantities |
The BE NOC Pathway for Export Studies
India runs a large share of the world's bioequivalence studies for foreign generic filings, and CDSCO maintains a deliberately lighter route for them, commonly called the BE NOC (no objection certificate) pathway.
Under Rule 31(2) of the NDCT Rules 2019, a BE study conducted solely for export does not need full CDSCO permission when it meets a defined profile: a single-dose, two-period, two-sequence, two-treatment crossover study in normal healthy adult volunteers, using an oral dosage form of a drug already approved in India or in the United States, United Kingdom, European Union, Japan, Australia or Canada. For these studies the applicant submits a prior intimation through CDSCO's SUGAM portal, together with the ethics committee approval, and may begin the study once CDSCO acknowledges the intimation.
Studies that fall outside this profile, such as multiple-dose designs, patient-based BE studies, non-oral dosage forms or molecules not approved in the listed jurisdictions, require a full Form CT-05 application and Form CT-07 permission before dosing can begin.
Two practical points trip up first-time sponsors. The study must still run at a CDSCO-registered BA/BE centre with a registered ethics committee, and any imported reference product needs a Form CT-16 import licence, so procurement lead times belong in the project plan from day one.
Approval Timelines: What to Plan For
The NDCT Rules give CDSCO 90 working days to decide a BA/BE study application, which translates to roughly four to five calendar months at the outer bound. Prior-intimation export studies move much faster because the study can start on acknowledgment rather than waiting for substantive review.
The regulatory clock is only part of the schedule. A realistic end-to-end plan for a standard fasting BE study looks like this:
- Protocol development, reference product procurement and ethics committee review: four to eight weeks
- Regulatory acknowledgment or permission: from days (prior intimation) up to 90 working days (full permission)
- Volunteer screening, housing and dosing across both periods: three to six weeks depending on the washout
- Bioanalysis of plasma samples and pharmacokinetic-statistical analysis: four to six weeks
- Clinical study report writing and quality review: three to four weeks
Where an agency requires both fasting and fed studies, the two are often run back to back with shared screening, which saves several weeks over sequential planning. Fees apply per the Sixth Schedule of the NDCT Rules, and incomplete dossiers are the most common cause of lost time, so a pre-submission review of the application pays for itself.
Choosing a BA/BE Study Partner in India
The facility you choose determines whether your data survives regulatory scrutiny in the destination market. Points worth verifying before contracting:
- CDSCO registration and DCGI mandate. The centre must hold a valid Form CT-09 registration; ask for it rather than assuming.
- International inspection history. If the dossier is headed to Brazil, an ANVISA-approved centre avoids a foreign inspection delay; the same logic applies to US FDA and EMA-facing programmes.
- Bioanalytical depth. Confirm the LC-MS/MS platform, the number of validated methods and whether your molecule (or one like it) has been run before. Method development from scratch adds weeks.
- Clinical capacity. Volunteer recruitment strength, screening infrastructure and medical cover determine how predictably periods complete.
- Reporting and regulatory support. A centre that writes submission-ready reports and can support the DCGI and CDSCO filing work downstream removes a handoff.
Celesta Healthcare's clinical research division operates a 17,000 sq ft dedicated BA/BE centre in Pune that is duly mandated by DCGI, ANVISA approved and designed for US FDA and EMA regulated markets, with LC-MS/MS bioanalysis and a library of validated methods. You can review the full capability set on our BA/BE studies page.
Frequently Asked Questions
What is the difference between a bioavailability and a bioequivalence study? A bioavailability study measures how much of a drug reaches systemic circulation and how fast. A bioequivalence study compares a test product against a reference product in the same subjects to show the two perform equivalently, using the 80.00 to 125.00 percent acceptance window for Cmax and AUC.
How long does CDSCO approval for a BE study take? For studies needing full permission, the NDCT Rules 2019 set a 90-working-day decision timeline on a Form CT-05 application. Export-only studies that qualify under Rule 31(2) can start as soon as CDSCO acknowledges the prior intimation.
Is a BE study mandatory for every generic manufactured in India? No. Since the 2017 amendment (G.S.R. 327(E)), BE data is mandatory for manufacturing licences of oral dosage forms of BCS Class II and IV drugs, and for generics of drugs still within their four-year new drug period. Other categories may be licensed on quality and dissolution data, though export markets almost always require BE evidence regardless.
What is a BE NOC? It is the informal name for CDSCO's acknowledgment that lets a bioequivalence study intended purely for export proceed under the prior-intimation route of Rule 31(2), without a full permission cycle.
Plan Your Next BE Study with Celesta
If you are weighing study designs, timelines or the right regulatory route for a molecule, our clinical research team can help you scope the work before you commit budget. Explore our BA/BE study services, see how a pilot bioequivalence study can de-risk a pivotal programme, or talk to our regulatory group about DCGI and CDSCO approvals for your product. Send us your molecule list and target markets, and we will come back with a study plan and timeline.