AOAC is developing a general validation guideline for qualitative identification methods for botanical ingredients in response to the ever-increasing need for identity testing (Final GMP Rule requires 100% testing for identity of incoming botanical ingredients). Developed by the Working Group for Validation of Identity Methods for Botanical Raw Materials and its subgroup, the draft validation guideline provides technical guidance for the validation of botanical identification methods and includes sections on Scope, Applicability, Terms and Definitions, and Validation Study Protocols (Single-Laboratory Validation, Independent Validation Study, and Collaborative Study).

In the past several years, botanical ingredients were deemed high priority by the AOAC Ingredient Ranking Subgroup (IRS) that required identification methods, i.e., methods to differentiate one botanical from another botanical or adulterant(s). At the time, no guidelines existed for the validation of qualitative identification methods for botanicals. As a result, a working group, comprising members with a wide range of technical knowledge, including botany, dietary supplement manufacturing, analytical chemistry, statistics, microbiology, and methods validation, was developed to establish a guideline for validating these types of methods for botanicals.

The AOAC guideline for validation of microbiological methods, which has recently been revised and is currently under review, was adapted for qualitative botanical identity methods, as decided by the working group. The Probability of Detection (POD) model, which was originally developed for validation of microbiological methods, is being considered for application to validation of botanical identification methods.

In addition to the POD model, inclusivity and exclusivity testing were identified as critical performance characteristics in the validation of qualitative identity methods. To illustrate how the POD model, inclusivity, and exclusivity might be incorporated in the validation of botanical identity methods, a subgroup of the working group was formed to develop an example protocol.

The Validation Protocol Development Subgroup focused its effort on one botanical identification method, and selected a TLC method for the identification of Panax ginseng to further develop a validation study design. The subgroup determined that a validation study design for Panax ginseng, or any botanical identification method for that matter, should include the following studies: method detection response, specificity (exclusivity), inclusivity, repeatability, environmental materials effects, and reproducibility (collaborative study).

After additional review by the subgroup and working group, which is expected by year-end, the validation guideline will be posted on the AOAC Web site for public comment. The guideline will then be reviewed by the AOAC Presidential Task Force on Dietary Supplements. Final approval of the guideline will be based on review by the AOAC Official Methods Board and Board of Directors. If successful, it is expected that the AOAC validation guideline for botanical identification methods will be available by fall 2011.

For more information, contact Scott Coates, chief scientific officer, at scoates@aoac.org or Bob Rathbone, senior director, methods validation and publications at rrathbone@aoac.org. Full coverage is scheduled for the July/August 2010 issue of Inside Laboratory Management

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