# Small-molecule APIs: Production route

Why making one kilo of medicine uses hundreds of kilos

Source page: https://www.materialinsights.org/chemicals/apis/routes/

What this tab covers How it is made: the main production routes or, for product families, the main product types and technologies, compared on share of supply, inputs per tonne, plant scale, yield, co-products and unit cost.

APIs are made by three broad routes. Most generics come from batch organic synthesis in multipurpose stainless-steel and glass-lined reactors. Antibiotics, statins and steroids start from fermentation and are finished chemically or with enzymes. A growing share uses biocatalysis or continuous flow to cut solvent use. Plants are rated by reactor volume, not tonnes: Laurus passed 8,200 kL in FY26. The cost of an API is set by the number of steps, yield, solvent recovery and the cost of the KSM.

#### Routes compared

| Route | Share of supply | Inputs per tonne | Typical scale | Yield | Co-products | Unit cost |
|---|---|---|---|---|---|---|
| **Batch chemical synthesis (multipurpose plants)** | most of generic API tonnage (indicative) | PMI typically 168-308 t of materials per t of API, mostly solvents and water (ACS GCI via Kekessie et al. 2024, indicative) | Laurus 8,200 kL reactor volume (FY26); single-product generic blocks 100-5,000 t/yr | overall 20-70% across steps (indicative) | spent solvents, salts, high-COD effluent | generic API prices from about $3/kg (paracetamol) to hundreds of $/kg; raw materials were 39.5% of Divi's Q4 FY26 sales |
| **Fermentation plus semi-synthesis** | dominant for antibiotics; China leads | sugar or starch feed and large electricity for aeration and cooling (see antibiotic_intermediates) | Lyfius (Aurobindo) penicillin G 15,000 t/yr at Kakinada | not published | mycelium biomass, spent broth | scale-driven; Chinese pricing has made sub-scale plants unviable |
| **Biocatalysis and continuous flow** | small but rising (indicative) | can cut PMI by half or more versus batch routes (ACS GCI award cases, indicative) | kilo-lab to a few hundred t/yr | often higher selectivity | less solvent waste | lower operating cost, higher development cost |
| **Highly potent and complex APIs (HPAPI, ADC payloads)** | small tonnage, rising value share | not published | kilograms to a few tonnes a year | not published | cytotoxic waste requiring incineration | very high per kg |

#### How each route works
**Batch chemical synthesis (multipurpose plants)**

Sequential reactions in 2-20 kL reactors with isolation, filtration and drying between steps. The same train makes many products in campaigns. Most generic APIs follow 4-10 steps from a KSM.

flexible and cheap capital; high solvent and waste load
 Laurus Labs FY26 press release; BoB Capital on Divi's Q4 FY26 (May 2026); IMARC Q2 2025 **Fermentation plus semi-synthesis**

Microbes (Penicillium, Acremonium, Streptomyces) produce a natural product in 100-300 m3 fermenters; it is extracted and converted chemically or enzymatically to the API. Used for beta-lactams, macrolides, statins, steroids and some vitamins.

low cost at scale; needs very large capital and cheap power
 Aurobindo press release (Oct 2024); PSU Watch (2026) **Biocatalysis and continuous flow**

Engineered enzymes replace metal catalysts or protecting-group chemistry; flow reactors run hazardous steps (nitration, hydrogenation, azides) in small volumes continuously. Adopted by originators and leading CDMOs.

greener and safer; needs process development early
 ACS GCI Pharmaceutical Roundtable (indicative) **Highly potent and complex APIs (HPAPI, ADC payloads)**

Oncology and hormone APIs made in contained suites with isolators. Small volumes, high margin. Lonza, Piramal Pharma Solutions and Divi's invest here.

high barriers and margins; small markets
 qualitative Unit economics are indicative ranges from the sources named; costs move with feedstock and energy prices, plant size and region.

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/apis/index.md)
- [Overview](https://www.materialinsights.org/chemicals/apis/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/apis/correlation/index.md)
- [Production](https://www.materialinsights.org/chemicals/apis/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/apis/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/apis/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/apis/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/apis/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/apis/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/chemicals/apis/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/apis/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/apis/links/index.md)