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Method Review Form

AOAC INTERNATIONAL Standards Development

Name of Reviewer:

Nour Eddine ES-SAFI

Title of Method:

Quantification of Mitragynine in Kratom Raw Materials and Finished Products by

High-Performance Liquid Chromatography: Singly Laboratory Validation

AOAC Candidate Method Number

: KRA-02

Applicable SMPR:

AOAC SMPR 2015.008

I. SUMMARY OF METHOD

The method entitled "Quantification of Mitragynine in Kratom Raw Materials and Finished

Products by High-Performance Liquid Chromatography: Singly Laboratory Validation" presents

results dealing with the quantitative analysis of mitragynine in 8 matrixes including dried

leaves, extract, capsule and beverages which were purchased from commercial vendors. The

method used separation through an analytical HPLC with detection at 226 nm. Example of the

obtained results showed the separation of various compounds with this method. The

quantitative analysis of mitragynine in the studied samples was determined after calibration

using a commercial mitragynine sample.

II. REVIEW OF THE METHOD ONLY:

1. Does the applicability of the method support the applicability of the SMPR? If no, please explain

what is missing.

The applicability of the method does not support the applicability of the SMPR. Thus, the

AOAC SMPR 2015.008

stated that “the Methods must be able to quantitate mitragynine, 7-

hydroxymitragynine, and separate other relevant indole alkaloids of

Mitragyna speciosa

, in a

broad range of matrices, including plant material, extracts, and finished products”. The

proposed KRA-02 method was tested on various different samples including dried leaves,

extract, capsule and beverages. However, only mitragynine was quantified in the studied

samples while the quantitative analysis of other analytes such as 7-hydroxymitragynine was

not done The authors indicated that the content of 7-hydroxymitragynine was below the

quantitation limit for all the explored samples, therefore this method is only valid for the

detection and quantitation of mitragynine in raw materials, bulk extracts and finished

products.