Phosmet can also be obtained through the condensation of phthalimide with formaldehyde and conversion of the product to chloride which is reacted with sodium dimethylphosphorodithioate.

[4] As an organophosphate, phosmet competitively inhibits pseudocholinesterase and acetylcholinesterase (AChE), preventing hydrolysis and inactivation of acetylcholine.

Its inhibitory effects on the AChE enzyme leads to a pathological excess of acetylcholine in the body.

[6][7] The mechanism of inhibition consists of phosmet blocking the active site of the enzyme that binds the ester portion of acetylcholine.

The first phase corresponds with the distribution of the compound to tissues and has an observed half life of 0.2 to 6 hours.

The second phase corresponds with the direct elimination of the compound and has a significantly longer half life of 41 to 1543 hours.

The areas that display the highest level of activity can be found in the liver and the whole blood as this is where the major metabolic process takes place.

In addition, analysis of both rat and cockroach faeces and urine in live animal studies showed that phosmet is metabolized in the liver, oxidizing the compound into phosmet-oxon.

Nicotinic symptoms result from the accumulation of acetylcholine at motor nerve endings in skeletal muscle and ganglia.

Accumulation of acetylcholine in the CNS leads to a variety of signs and symptoms, including tension, anxiety, ataxia, convulsions, restlessness, insomnia and coma.

It acts in place of the serine hydroxyl group in the enzyme and forming a complex with the organophosphorus moiety.

The primary toxicological endpoint of concern to the EPA is cholinesterase inhibition; a common toxic effect of organophosphate poisoning.

In vitro studies have shown phosmet induces apoptosis in trophoblasts, through oxidative stress.

More research is needed to find the physiological effects of aromatase inhibition and androgen receptor binding.

There are however concerns for workers who are in contact with Phosmet through mixing, handling and loading who are at risk for inhalation or dermal exposure.