CAS Number: 121-75-5


pK Chemicals manufactures Malathion in accordance with current Good Manufacturing Practice (cGMP).

Purified Malathion

    •   is used as an API in lice shampoo
    •   is highly effective, safe, and has been used for decades all over the world
    •   is approved by FDA and EMEA for treatment of head lice infestation

Malathion, an organophosphate, is both pediculicidal (kills live lice) and partially ovicidal (kills lice eggs). Organophosphates acts by inhibiting the enzyme acethylcholine esterase, which breaks down the neurotransmitter acetylcholine, the primary neurotransmitter in muscle tissue. The accumulation of acetylcholine causes muscle spasms and death of the lice and bugs by suffocation.



For additional information about the Certificate of Suitability to the monographs of the European Pharmacopoeia (CEP) for Malathion, please visit EDQM's website: Malathion EP, Monograph Details

The Danish Medicines Agency has issued a GMP certificate for Malathion. Our certificate number is DK API-H 00091117.
GMP certificate from the EudraGMDP database operated by the European Medicines Agency can be downloaded here: EudraGMDP.

Pack sizes

Item number Weight Packaging
31-6177-04 100 g 125 mL aluminium container
31-6177-00 Bulk 25 L aluminium container



Test/Characteristic Limit Test Method
Appearance Colourless to pale yellow liquid Visual (Ph.Eur.)
Identification As Malathion CRS IR (2.2.24)
Relative Density 1.220 to 1.240 Relative Density (2.2.5)
Optical Rotation - 0.1 to + 0.1 º Polarimetry (2.2.7)
Water NMT 0.1 w/w % Karl Fischer (2.5.12)
Assay 98.0 - 102.0 % HPLC (2.2.29)
Impurity A (Isomalathion) NMT 0.3 w/w % HPLC (2.2.29)
Impurity B (Maloxon) NMT 0.1 w/w % HPLC (2.2.29)
Impurity C NMT 0.25 % HPLC (2.2.29)
Any single unspecified impurity NMT 0.1 % HPLC (2.2.29)
Total impurities NMT 1 % HPLC (2.2.29)
Ethanol NMT 5000 ppm GC (Ph.Eur)
TAMC NMT 1000 Cfu/g (2.6.12)
TYMC NMT 100 Cfu/g (2.6.12)

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