Short answer — it depends on what you need (finished formulations vs APIs/excipients vs packaging vs contract manufacturing). Below are widely used, reputable B2B options in India grouped by primary use-case, with a quick note on when each is most useful.

General B2B marketplaces with strong pharma sections

• IndiaMART — largest Indian B2B marketplace often used to find manufacturers, distributors and exporters across pharma categories. (en.wikipedia.org)
• TradeIndia — another large, long‑running B2B directory used by many pharma suppliers and exporters. (en.wikipedia.org)

Pharma / chemical‑specialist marketplaces (APIs, intermediates, excipients, lab supplies)

• ChemDmart / ChemDmart marketplace — purpose‑built for chemicals and pharma ingredient sourcing (APIs, intermediates, excipients). Good for procurement and RFQs. (chemdmart.com)
• BidChemz / other chemical marketplaces — marketplaces that list pharma APIs and chemical suppliers across India. Good for bulk raw‑material sourcing. (bidchemz.com)

Pharma‑industry directories / B2B portals focused on Indian pharma companies & contract services

• IndiaPharma.com — pharma‑industry B2B directory + news/tenders; useful to find CDMOs, FDF manufacturers and supplier profiles. (indiapharma.com)
• Pharmalytica Digital Marketplace (CPhI/PharmaLytica ecosystem) — event‑backed marketplace for machinery, packaging, APIs and CDMOs; useful when you want curated trade‑show‑grade suppliers. (pharmalytica.in)

Marketplaces that target franchise / third‑party manufacturing / distributors (common in India)

• PharmaVends / PharmaVends.in — B2B pharma directory focused on PCD franchises and third‑party manufacturers. Useful for local franchise/third‑party leads. (pharmavends.com, pharmavends.in)
• PharmaManch / PharmaManch.com — portal listing PCD franchise, third‑party manufacturers and verified leads across India. (pharmamanch.com)
• PharmaHook / PharmaHook.in — B2B pharma leads portal for products, franchises and distributors. (pharmahook.in, pharmahook.com)

Packaging / procurement‑tech for pharma packaging

• Bizongo — tech‑enabled procurement and packaging platform used by large Indian pharma players for packaging procurement and supplier management. (bizongo.com)

How to pick which platform

• Use IndiaMART / TradeIndia when you want maximum reach and many supplier profiles quickly. (en.wikipedia.org)
• Use ChemDmart / BidChemz for APIs, intermediates and regulated chemical sourcing where product‑level filters and supplier verification for chemicals matter. (chemdmart.com, bidchemz.com)
• Use industry directories (IndiaPharma, Pharmalytica) and event marketplaces when you want curated, trade‑show vetted CDMOs, machinery or packaging vendors. (indiapharma.com, pharmalytica.in)
• Use pharma‑franchise portals (PharmaVends, PharmaManch, PharmaHook) when your need is PCD/franchise or local distributor partnerships. (pharmavends.com, pharmamanch.com, pharmahook.in)

Quick supplier‑vetting checklist (musts before placing substantial orders)

• Verify regulatory licences on the CDSCO / state FDA portals (manufacturing/distribution licenses, import licenses where applicable). (cdsco.gov.in, cdscoonline.gov.in)
• Check GMP / WHO‑GMP / ISO certifications and request copies; verify with issuing bodies when possible. (cdscoonline.gov.in)
• Ask for a recent Certificate of Analysis (CoA) for the exact batch or typical batches and confirm that testing aligns with pharmacopeial specs. (gmp-compliance.org)
• Request references, perform a site visit or third‑party audit for large/recurring contracts, and confirm corporate identity (CIN, bank account details). (actizapharma.com, cdsco.gov.in)
• Use staged payments, clear commercial terms (lead times, QC acceptance criteria, penalties), and NDAs when sharing specs.

If you want, I can convert this into a one‑page shortlist tailored to a specific need (APIs vs finished dosage vs packaging vs third‑party manufacturing) and include contact links and what to request from each supplier.