I recently became a member of the Dietary Supplement Laboratory Quality Assurance Program (DSQAP) Advisory Board. DSQAP is a collaboration between the U.S. National Institutes of Health (NIH) Office of Dietary Supplements (ODS) and the National Institute of Standards and Technology (NIST) that enables participants to improve the accuracy and precision of their measurements for nutrients, marker compounds, toxic elements and/or pesticides in dietary ingredients and finished products.

Demand for Validated Methods & Materials
U.S. Congress recognized the lack of publicly available, validated analytical methods for dietary supplements—and a lack of reference materials for validation of analytical methods—in 1994 when the Dietary Supplement Health and Education Act (DSHEA) was passed. As part of DSHEA, NIH/ODS was directed to fund development of analytical methods and reference materials for dietary supplements.

NIST’s dietary supplement program began in 2001 as a collaborative effort between NIST and NIH/ODS to underpin the then-anticipated current good manufacturing practice (cGMP) requirements.

Subparts E and J of the cGMP regulation require supplement manufacturers to establish specifications for identity, purity, strength and composition; to set limits on contaminants and adulterants for every ingredient in their products; and to analyze both “materials in process” and finished products to determine whether specifications are met. The validity of analytical methods must be verified and then routinely used for monitoring against the manufacturer’s specifications.

Over the past eight years, DSQAP has administered 11 exercises with more than 150 participating laboratories in 22 countries. Participants include academic, government and third-party testing laboratories as well as instrument, standards and dietary supplement manufacturers. Test samples have been distributed in the areas of nutritional elements, toxic elements, water-soluble vitamins, fat-soluble vitamins, fatty acids, botanical marker compounds, organic contaminants and recently, botanical identity.

SRMs for Botanical Dietary Supplements
NIST is developing Standard Reference Materials (SRMs) for botanical dietary supplements as part of a multi-year interagency agreement among NIST, NIH/ODS, the Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition (CFSAN) and the FDA Center for Drug Evaluation and Research (CDER).

SRMs with assigned values for concentrations of active and/or marker compounds, pesticides and toxic elements assist in the verification of manufacturers’ label claims and are used for quality control during the manufacturing process in support of cGMP requirements.

In most cases, these SRMs are provided as suites of materials (plant, extract, finished product) that represent different analytical challenges. The constituents for which values are assigned are also listed. The constituents in all of these materials have been determined by multiple independent methods with measurements performed by NIST and collaborating laboratories.

The methods utilized different sample extraction and cleanup steps in addition to different instrumental analytical techniques and approaches to quantification. These materials are provided primarily for use in method development and as control materials to support the measurement of these constituents in other similar products.

To date, more than 20 natural-matrix SRMs have been produced and suites of materials based on black cohosh, soy, kudzu and red clover are currently in progress. Certificates of analysis for these materials can be found at www.nist.gov/srm. In addition, analytical methods have been developed for the measurement of citrus alkaloids, flavonoids, catechins, phytosterols, xanthines and organic acids.

The first DSQAP Advisory Board meeting is scheduled for Sep. 27 at the AOAC International Annual Meeting in Los Angeles, CA. During this meeting the board will discuss how to maximize the benefits of the DSQAP, measurement challenges facing participating laboratories, best ways to provide methodology information to participants and future directions for the program.

I look forward to working with DSQAP to help herbal and dietary supplement manufacturers meet regulatory requirements efficiently and effectively.

---

Maged Sharaf, PhD
American Herbal Products Association (AHPA)

Maged Sharaf, PhD, is the chief science officer of the American Herbal Products Association (AHPA), the national trade association with a focus primarily on herbs and herbal products. AHPA’s membership represents U.S. and international growers, processors, manufacturers, marketers and institutes specializing in botanicals and herbal products. Before AHPA, Dr. Sharaf was the director, Foods, Dietary Supplements and Herbal Medicines at the United States Pharmacopeial Convention (USP). Before USP he was pharmacy associate professor and has preceding experience conducting bioanalytical assay development and validation, and human bioequivalence studies in support of the pharmaceutical industry; and quality control and manufacturing of pharmaceutical dosage forms. He can be reached at 301-588-1171; E-mail: msharaf@ahpa.org; Website: www.ahpa.org.