API Synthesis

Active Pharmaceutical Ingredients (APIs) are compounds with therapeutic or prophylactic properties that are key ingredients in the therapeutic efficacy of a drug. Protheragen-ING specializes in the custom synthesis of high-quality APIs. Our scientists have expertise in organic chemistry, process optimization, and experience in designing efficient and cost-effective synthetic pathways for these molecules, and are well versed in modern We are well-versed in modern compound synthesis and synthetic pathway troubleshooting. We strictly respect various international manufacturing standards to ensure the safety, efficacy, and quality of the final drug product.

Fig.1 API Synthesis.

Common Types of APIs

Synthesis Methods for APIs

Protheragen-ING's API synthesis methods are diverse, depending on the structure and chemistry of the target compound.

Organic Synthesis It involves the conversion of feedstock molecules into target molecules using organic chemical reactions and techniques. Organic synthesis methods include substitution reactions, addition reactions, condensation reactions, redox reactions, and cyclization reactions. These methods are usually carried out in organic solvents and are controlled using catalysts and reaction conditions.
Inorganic Synthesis Methods include solution methods, precipitation methods, thermal decomposition methods, and vapor phase deposition methods. These methods usually involve inorganic reactions such as acid-base neutralization, coordination reactions, and redox reactions to form the target compound.
Biosynthesis This method involves the use of microorganisms, cell culture, fermentation, and genetic recombination techniques to produce proteins, peptides, antibodies, and other biomolecules. Biosynthetic methods typically utilize enzymes, metabolic pathways, and biological reactions in organisms to synthesize target molecules.

Synthesis scheme for chlorthalidone APIFig 1. Synthesis scheme for chlorthalidone API[1].

Our API Synthesis Service Flow

1. Synthesis Route Design

Before starting the synthesis of an API, Protheragen-ING's chemical scientists design the synthetic route. This includes determining the appropriate reaction steps and conditions from the starting material to the final product. Synthetic route design requires consideration of the structure of the product, the selectivity and yield of the reaction, as well as possible side reactions and waste disposal.

2. Feedstock preparation and handling

Before starting the synthesis, we prepare and handle the raw materials and reagents, including material procurement, storage, and pre-treatment.

3. Reaction steps

Depending on the synthetic route, a series of reaction steps are executed, which may include esterification, alkylation, oxidation, reduction, substitution, cyclization, and so on. Each reaction step optimizes the reaction conditions, such as temperature, pressure, reaction time, and catalyst usage, to achieve high yields and selectivity.

4. Purification

After the completion of the reaction, we get the crude product, followed by the purification step. Methods of purification include crystallization, distillation, extraction, adsorbent column chromatography, and solvent extraction.

5. Quality Control

We conduct stringent quality control and analytical tests at all stages of API synthesis to ensure the purity, identification, and potency of APIs. Through the use of various analytical techniques, such as mass spectrometry, nuclear magnetic resonance, high-performance liquid chromatography, and gas chromatography, APIs are quality tested and ensured to meet the required quality standards.

If you are interested in this service and need more information, contact us and we will arrange for professionals to provide you with more information and discuss your specific requirements.


  1. Kharat C, et al. "A Validated RP-HPLC Stability Method for the Estimation of Chlorthalidone and Its Process-Related Impurities in an API and Tablet Formulation." International Journal of Analytical Chemistry. 2020, 7, 1-11.


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