NPIcenter.com : Industry Blogs - Chondroitin Testing Methods (cont)

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Posted by: jhildreth	1/27/2007 10:16 PM
Thank you all for your wonderful comments and input regarding the enzymatic method and AOAC in general. The next question I would like to address is "Is this method an approved or official AOAC method?". The answer to this question is "no" and any lab claiming to be using an approved AOAC method is clearly in the dark as to what that means. I suppose it would be appropriate at this point to define what constitutes an "approved" AOACmethod. AOAC basically has two types of "approved" methods that pertain to our industry. The first AOAC approved method level is what is termed the "Peer Verified Method" (PVM). This is a method that has undergone a single-lab validation and its performance has been checked in at least one other, independent laboratory. It is expected (at least by AOAC) that most PVMs will eventually undergo full interlaboratory collaborative studies (usually 10-12 labs) and obtain "Official Method" status which is the second or highest level of approval.

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Comments (6)

Re: Chondroitin Testing Methods (cont)

By mroman123 on 1/29/2007 4:21 PM

I'd like to clarify the AOAC process a bit so there isn't any confusion. There is a big difference between an AOAC "approved" method and an AOAC "official" method. A PVM has been "approved" by a general or technical referee, and there is no official status to this type of method (in reality, very few methods go through the PVM process - the last one was approved in 1999). An "official" method has successfully completed a full collaborative study, and been reviewed and approved by the AOAC methods committee and the official methods board. It is published in the AOAC's Official Methods of Analysis book.

The chondroitin method is mid-way through the validation process. The proposed method was developed by David Ji at Analytical Labs in Anaheim and Joseph Zhou at NOW Foods. It was selected over other "competing" methods, including the CPC titration method, by an AOAC Expert Review Panel. A complete single-laboratory validation of the method was performed at Analytical Labs in Anaheim to determine the accuracy, within-lab precision (repeatability), linearity/range, selectivity, and ruggedness. That method and the validation data has been submitted to the Journal of AOAC for publication. The method must now go into a collaborative study to determine the between-laboratory reproducibility. A minimum of 8 laboratories must successfully complete this study. The collaborative study protocol is being reviewed by the AOAC method committee on dietary supplements as I write this. Once the collaborative study has been completed, the method committee and general referee will review the data and vote on whether to approve the method for "Official First Action." Assuming it is approved, it becomes "official," but still it is not a final method - the method must sit out in the public domain for 2 years to give users a chance to comment. If no serious problems are encountered in that time, the committee can recommend to the Official Methods Board that it be adopted "Final Action." If the method board agrees, then it is a final action.

As you can see, there are a lot of steps involved, and this is why an "official" method is given such a high status.

Re: Chondroitin Testing Methods (cont)

By pnbrown on 1/31/2007 3:32 PM

Thanks Jana for that great overview of the AOAC process. People have a tendency to throw around the word "validation" but I think it is important to understand that everyone's definition is not the same. AOAC has extremely rigorous protocols and the infrastructure to ensure all stages, whether single lab validation or full inter-collaborative study, undergoes peer-review by both Dietary Supplement Method Committee members and independently by the General Referee.

Undertaking the validation of a method is the only way to ensure it is fit for its intended purpose. I bring this up because I keep seeing the same improprieties when it comes to method use over and over, in particular:

1. AOAC Official Method (modified)
If an AOAC official method is in any way modified, it is no longer an official method, period. It has been changed or tampered with and as such you cannot be sure it is still fit for purpose. If a laboratory is trying to claim they are using an Official AOAC method, but have modified the method, it is important to ensure they have validated their modification appropriately.

2. Improper use of a method.
The scope and applicability of a method is a statement of how and when the method can be used. If a method has not been validated for a particular matrix then the method can not be reliably employed for that analysis without conducting another validation. For example a method developed and validated to test heavy metals in sea water would not be applicable to heavy metal analysis in a dietary supplement unless the method was validated for use with the new matrix. That is not a subtle example but the same principal applies to the use of a method validated for a raw material being applied to a finished product of the same material.

Official Test (modified)

By jamesnealk on 2/1/2007 2:13 AM

Back in the early gun slinging days of dietary supplements testing when SJW was in its heyday, it was very hard to get any two laboratories to come up with the same test results for total dianthrones. Our laboratory consistently found that we were lower than two other laboratories. All laboratories claimed that they were doing the DAC 86, 91 revision Spectrophotometric Assay.

The method was for St. John's Wort Herb only. Nowhere did the method specify that it was for spray dried extract. However, we were all using it for that as well. Most labs eliminated the chlorophyll removal step and some labs were exposing the extracts for several minutes to strong light to convert proto-hypericin and proto-pseudohypericin into hypericin and pseduohypericin respectively. We were following the DAC which did not specify to eliminate the chlorophyl clean up step or to perform the light exposure step. These were undeclared modifications to the methods. Much of the confusion came from the fact that the laboratories failed to indicate that the method referenced was modified for the assay.
Our laboratory began adding the word "modified" to methodologies used when appropriate to help customers understand that the method we used was based on the referenced method but that we had made departures in order to provide them with more valid data for the sample type.
Much has changed since then and we have all collectively come to a better understanding of what the curent state of validation and quality in testing mean. Today, we still use the term modified when we change an official method becuase we don't want the client to be misinformed about what we were doing. However, in no way did we imply or say that we were using official methods at that point. We were using modifications of official methods that were modified by our laboratory to apply to the unique issues faced with the client's matrix. Keep in mind that USP allows scientists to modify or use entirely different methods providing that they can demonstrate equivalent or better performance in compliance with the validation requirements of USP<1225>. One the other hand, AOAC does not have this policy and is currently in an extensive dialogue about the concept of metod extension and when a change requires a new collabortive study. This is ongoing.
Our current method for testing benzene is based on the USP<467> method and we use the term "modified" because we made changes to enchance sensitivity and reliability. For instance, instead of using an FID detector, we use a mass spec detector. In addition, we have added an internal stanard that is deuterated to increase accuracy and precision. Further, we have changed the sample preparation method to prevent the formation of added benzene which would happen if you ran the USP method as is in the current volume. So, we have modified, very extensively, the method. However, we have also validated those modifications using the guidelines of USP<1225> on the sample matrices we are testing.
So, although modified can sometimes be a bad word, it can also be a sign of integrity. Laboratories that use this term to help customers understand that departures have been made from the method that was written in the monograph are often doing so to attempt to honestly communicate what is going on to help avoid confusion later on. In some cases, you are allowed to modify methods as long as you can document equivalent or better performance. In other cases you can't. It is important to be clear about what changes have been made so that clients are able to compare data between laboratories. It is unfortunate when we encounter laboratories that don't advise clients of modifications and say they are following the method literally. That, to me, is a much more serious problem. I feel that this topic has raised enough concern and caused enough confusion that an industry guidance document would be a great idea that laboratories can agree to so that companies know what they mean when they say modified. is that something we can tackel as an industry?

Re: Chondroitin Testing Methods (cont)	By steveblank on 2/12/2007 3:35 PM
Where can I get a copy?

Re: Chondroitin Testing Methods (cont)	By jhildreth on 2/12/2007 3:37 PM
If anyone is interested in more information on the method please call me directly at 310-920-4517 so I can get your contact information.

Re: Chondroitin Testing Methods (cont)	By Resveratrol on 3/29/2007 9:37 AM
I woder how can we get the difference of Chondroitin from Bovin and Shark? If you have interests in discuss this please contact me by: Changsha organic Herb inc. E-mail: steve0805@21cn.com sales@organic-herb.com