Goal
Provide an efficient, environmentally friendly method for preparing and refining hydroxychloroquine and its sulfate with high purity and controlled impurity levels.
Problem
Existing hydroxychloroquine synthesis methods suffer from low yields, high impurity levels, use of toxic solvents (e.g., phenol, chloroform), hazardous high-pressure equipment, and large amounts of hazardous waste.
Concept Summary
The invention discloses a purification process that crystallizes crude hydroxychloroquine in a mixed solvent of a ketone (e.g., acetone, methyl ethyl ketone) and an ester (e.g., ethyl acetate). The process includes controlled temperature crystallization, filtration, washing, and optional pH-adjusted extraction steps using sodium hydroxide. The method yields hydroxychloroquine of >99.9 % purity and hydroxychloroquine sulfate of >99.8 % purity while minimizing toxic solvents and waste.
Principles
- Crystallization
- Solvent extraction
- pH adjustment
- Inert-gas protection
- Temperature control
Scientific Domains
Materials
- acetone
- methyl ethyl ketone
- methyl isobutyl ketone
- 2-pentanone
- methyl acetate
- ethyl acetate
- propyl acetate
- isopropyl acetate
- butyl acetate
- acetic acid
- 4,7-dichloroquinoline
- 5-(N-ethyl-N-2-hydroxyethylenediylamino)-2-pentylamine (hydroxychloroquine side-chain compound)
- sodium hydroxide
- sodium carbonate
- potassium hydroxide
- water
- nitrogen
- argon
- helium
- carbon dioxide
Mechanisms of Action
- Crystallization from mixed ketone/ester solvent
- Filtration and washing of crystals
- Alkaline extraction of crude product
- pH-controlled precipitation
Applications
- Production of antimalarial drug hydroxychloroquine
- Manufacture of hydroxychloroquine sulfate tablets for lupus erythematosus and rheumatoid arthritis
Claimed Performance
Purity of refined hydroxychloroquine >99.9 %; single impurity <=0.06 %; total impurities <0.04 %. Purity of hydroxychloroquine sulfate >=99.8 %; single impurity <=0.06 %.
Experimental Evidence
The abstract states that the refined product can reach 99.9 % purity with impurity limits as described, but no quantitative experimental data or independent replication is provided.
Limitations
- Requires handling of organic solvents (ketones, esters) that are flammable
- Needs inert-gas atmosphere and precise temperature control
- Scale-up may be limited by solvent recovery infrastructure
