Standard for diazinon active constituent

Version: 
1
Effective Date: 
1 August 2004
1. Description: 
the material shall consist of diazinon together with related manufacturing impurities and shall be in the form of yellow to brown liquid, free from visible extraneous matter and added modifying agents, other than the stabilizer.
2. Common Name: 
Diazinon
3. Chemical Name (IUPAC): 
O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate
4. CAS Number: 
333-41-5
5. Identity test: 
identity of the active constituent must be established by one or more of the following methods: spectroscopic tests (IR spectrum, NMR, mass spectra), Chromatography (HPLC or GC retention time with reference compound) or any other suitable test method
6. Composition: 

6.1 Active Constituent: 950 g/kg minimum (excluding any added stabilizer)

6.2 Toxicological Significant Impurities:

0,0,0',0'-tetraethyl thiopyrophosphate (0,S-TEPP): maximum: 0.2 g/kg

0,0,0',0'-tetraethyl dithiopyrophosphate (S,S-TEPP): maximum: 2.5 g/kg

Water: 0.6 g/kg maximum

Acidity: Not higher than 0.3 g/kg calculated as H2SO4 (CIPAC method MT 31).
7. Analytical methods: 
  • The analytical method used for the determination of the active constituent and toxicological significant impurities must be validated in accordance with the APVMA guidelines for the validation of analytical methods.
  • The APVMA guidelines on validation of analytical methods state that “Analytical methods described in CIPAC handbooks and AOAC International Manual, and in recognized pharmacopoeias [BP, BP (Vet), Ph Eur and USP] for a particular active constituent or formulation are regarded as validated and do not require revalidation. However, the suitability of these methods must be verified under actual conditions of use i.e., the selectivity and accuracy of the method should be demonstrated for the published method when applied to the relevant sample matrix and laboratory conditions.
  • When a CIPAC or AOAC method is used for the assay of an active constituent in a bulk active constituent, there is no matrix. The registrants need to check the specificity of the method to ensure there is no interference from impurities or degradation products. However, determination of accuracy of the method is not required as there is no matrix effect. However, when a CIPAC or AOAC method is used for the assay of an active constituent in a formulated product, determination of both specificity and accuracy is required as the matrix is relevant in formulated products (formulated products have different composition and quantities of excipients).
  • Refer to Guidelines for the Validation of Analytical Methods for Active Constituent, Agricultural And Veterinary Chemical Products (PDF, 164kb).
  • Unless the scope of the collaborative method (CIPAC and AOAC) also includes toxicological significant impurities in the active constituent, validation data for impurities are required.