Oseltamivir Phosphate API Manufacturers and Suppliers in India

Oseltamivir Phosphate API

Oseltamivir phosphate is the phosphate salt of oseltamivir, an ethyl ester prodrug that the body converts to oseltamivir carboxylate, a selective inhibitor of influenza neuraminidase. We manufacture it as an active pharmaceutical ingredient at our Balanagar site in Hyderabad for formulators producing influenza A and influenza B treatments. The product data below is what ships on the technical package.

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Product Description

Product Description

Product: Oseltamivir Phosphate API

CAS Number: 204255-11-8

Chemical Name: Ethyl (3R,4R,5S)-5-amino-4-acetamido-3-(pentan-3-yloxy)-cyclohex-1-ene-1-carboxylate, phosphate (1:1)

Molecular Formula: C16H31N2O8P

Molecular Weight: 410.40 g/mol

Category: Neuraminidase inhibitor

Therapeutic Use: Treatment of infection caused by influenza A and influenza B

Physical Form: Powder

Colour: White to off-white

Solubility: Freely soluble in water, soluble in DMSO, slightly soluble in DMF

Pharmacopoeial Grade: USP

Packing: As per requirement

Synonyms: Oseltamivir; (3R,4R,5S)-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylic acid ethyl ester phosphate salt

Bio-synth offers IP, EP and BP grades as well.

One thing to check before you compare two quotations side by side. The figures above describe the phosphate salt. Oseltamivir free base is CAS 196618-13-0, C16H28N2O4 at 312.41 g/mol, so a kilogram of the phosphate salt carries roughly 761 g of oseltamivir base. Quotations that omit the salt form are not comparable on price per kilogram, and the confusion is live in the market: one of the larger Indian marketplace listings for oseltamivir phosphate is headed with the free base formula C16H28N2O4. Ask every supplier which species the price and the assay refer to.

Oseltamivir Phosphate API Specification

Three limits are published for this product, and they are the ones that decide whether a batch releases.

Test

Limit

Assay (HPLC)

Not less than 98.0% w/w and not more than 101.5% w/w

Water content by KF

Not more than 0.5% w/w

Any unspecified impurity

Not more than 0.1% 

Total impurities

Not more than 0.7% 

A batch certificate of analysis is issued against each production lot. Beyond assay and related substances, a pharmacopoeial oseltamivir phosphate monograph calls for description, identification by infrared absorption and HPLC retention, water content, residue on ignition, elemental impurities under ICH Q3D, and residual solvents controlled to ICH Q3C class limits. Chiral purity deserves particular attention here: oseltamivir has three defined stereocentres and only the (3R,4R,5S) configuration is active, so the enantiomeric and diastereomeric controls are the ones a formulator should read first.

Oseltamivir Phosphate API Manufacturers in India

We trade as Biochemical and Synthetic Products Private Limited and have been making bulk drugs since 1943. The plant sits at Plot No. 11/6/2029, Phase-2, SVCIE, Balanagar, in the Medchal-Malkajgiri district of Hyderabad, and holds manufacturing licence 118/HD/AP/96/B/R under Form 25, currently valid to 31 December 2026.

This is an unforgiving molecule to run. The route builds a densely functionalised cyclohexene carrying an amino group, an acetamido group and a 3-pentyloxy ether around a trisubstituted double bond, and every one of those centres has to arrive with the right configuration. Salt formation with phosphoric acid is then a crystallisation step, not an afterthought: stoichiometry, solvent system and cooling profile decide the crystal habit, the water content and the flow properties the formulator inherits. Getting one batch to assay is comparatively easy. Getting consecutive batches to the same particle size and residual solvent profile is where process control earns its keep.

So the questions worth asking a manufacturer are about change control, not capacity. Has the route changed since the batches you last qualified? Is the crystallisation solvent the same? How are deviations trended between campaigns? Our reaction capabilities page sets out the chemistry the site runs.

Oseltamivir Phosphate API Suppliers in India

Packing is built to the order rather than sold from a standard list, so pack size, liner specification and labelling can be set to your receiving procedure. Agree these in writing before the first shipment: changing a liner mid-contract usually triggers a fresh qualification on your side.

Documents travelling with a commercial order are the batch certificate of analysis, the safety data sheet, and the declarations your regulatory group needs for the destination market. A certificate of pharmaceutical product can be applied for where the importing authority requires one.

A first order runs the same way each time. You send the molecule, grade, quantity and destination country; we confirm what we can release against and quote; you qualify a sample, raise the purchase order, and the batch is scheduled into a campaign. State the destination market in the first enquiry, because finding out at quotation stage that a document is missing costs less than finding out after qualification. The quality systems page describes how batches are controlled and released.

Oseltamivir Phosphate API Price in India

Published figures for this product are catalogue rates for gram quantities, not bulk prices, and we do not publish a list price. Four things move the number.

Salt form and assay basis. A price on the free base is not the same price on the phosphate salt. Fix the basis before comparing.

Grade and specification. A tighter unspecified impurity limit, or an added particle size requirement, cuts yield and raises the price.

Order volume and campaign scheduling. A quantity that fits an existing campaign prices differently from one needing a dedicated run.

Packing, documentation and destination. Specialised liners, extra stability data and market-specific paperwork all carry cost.

Send the specification you intend to buy against and the annual volume, and the quotation will reflect what you actually need. Our API manufacturing process overview explains where cost sits in a multi-step synthesis.

Quality and Compliance

Stated precisely, because the scope of each document matters.

ISO 9001:2015. Certificate 156792-2014-AQ-IND-UKAS, issued by DNV Business Assurance UK Limited under UKAS accreditation, first certified 20 August 2002. The scope reads “Development, manufacture and sale of active pharmaceutical ingredients (APIs), drug intermediates, biological products & liver injectable”.

ICH Q7. Manufacturing follows ICH Q7 principles, the international GMP guideline for active pharmaceutical ingredients. The document on file is a declaration made by the company. It is not a third-party certificate, and this page does not describe it as one.

WHO-GMP. We hold a WHO-GMP certificate from the Drugs Control Administration, Government of Telangana, L.Dis.No. 150458/TS/2024, valid to 5 June 2027.

CEP registration is under process as well.

How Oseltamivir Phosphate Works and Where It Is Used

Oseltamivir phosphate is a prodrug. After absorption it is hydrolysed to oseltamivir carboxylate, which blocks the neuraminidase glycoprotein on the influenza virion surface. Neuraminidase cleaves newly formed virus particles free of the host cell, so inhibiting it leaves progeny virus tethered and limits spread through the respiratory tract. The effect covers neuraminidases of influenza A, including pandemic H1N1 strains, and influenza B.

Finished products made from this API treat and prevent influenza. Clinical benefit depends heavily on early dosing, which is why API demand is seasonal and why buyers contract ahead of the northern hemisphere winter rather than order against immediate need. Our oseltamivir phosphate API sourcing guide covers how to plan around that cycle.

Oseltamivir Phosphate API FAQs

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Please write in your queries and we will get back to you.


    204255-11-8 for the phosphate salt. The free base carries a different number, 196618-13-0, and the two are frequently mixed up in supplier listings.

    C16H31N2O8P, 410.40 g/mol. If a datasheet shows C16H28N2O4 at 312.41 g/mol, that is oseltamivir free base, not the phosphate salt.

    Several Indian producers supply it, and public directories such as PharmaCompass and Pharmaoffer list them alongside Chinese and European sources. We manufacture it at Balanagar, Hyderabad.

    It is the active ingredient in medicines that treat and prevent influenza A and influenza B infection.

    seltamivir phosphate has monographs in the USP and the Ph.Eur/BP. We release against the specification agreed with the customer, and the certificate of analysis states the tests and limits applied. Confirm the grade you need when you enquire. We offer IP, EP, BP and USP grades.

    Ask for one. Send the specification you intend to qualify against with your enquiry and our sales team will confirm sample availability, quantity and charge.

    A batch certificate of analysis and a safety data sheet as standard, with a certificate of pharmaceutical product available where the importing authority asks for one.

    No. We hold no DMF for oseltamivir phosphate. If your market requires one, raise it at the quotation stage.

    Request a Quotation

    Tell us the grade, the quantity, the packing you need and the destination market. Where you have a specification of your own, send it, because it is faster to tell you at the outset whether a limit is achievable than to discover it during qualification.

    You will get back a written quotation, the current specification, and a clear statement of which documents we hold for this product and which we do not. Start at the contact page.

    If you are running a new-supplier assessment, the company history covers the site’s background.

    The full API portfolio shows what else is made alongside this product.