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Platinum Cobalt Unit #222

Open timbrisc opened 2 years ago

timbrisc commented 2 years ago

Issue migrated from trac ticket # 5824

component: organization | priority: minor | keywords: PT-CO

2022-06-07 21:04:40: william.hess@fda.hhs.gov created the issue

UCUM Board needs to provide input. The Platinum-Cobalt Scale (known as the Pt/Co scale or Apha-Hazen Scale) is a color scale that was introduced in 1892 by chemist Allen Hazen (1869–1930). The index was developed as a way to evaluate pollution levels in waste water. It has since expanded to a common method of comparison of the intensity of yellow-tinted samples. It is specific to the color yellow and is based on dilutions of a 500 ppm platinum cobalt solution. The color produced by one milligram of platinum cobalt dissolved in one liter of water is fixed as one unit of color in platinum-cobalt scale. The scale for APHA color goes from 0 to 500 in units of parts per million of platinum cobalt to water. Zero on this scale represents distilled water, or what is more commonly called white water. The ASTM has detailed description and procedures in ASTM Designation D1209, "Standard Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)". Please see https://en.wikipedia.org/wiki/Pt/Co_scale and https://en.wikipedia.org/wiki/APHA_color.

This new concept is needed to support the U.S. Food and Drug Administration Pharmaceutical Quality Chemistry Manufacturing and Control (PQ/CMC) initiative. Please see https://www.regulations.gov/document/FDA-2022-N-0297-0001, which in part, states:

"PQ/CMC is a term used to describe manufacturing and testing data of pharmaceutical products. PQ/CMC encompasses topics such as drug stability, quality specification, batch formula, and batch analysis, which are important aspects of drug development. PQ/CMC plays an integral part in the regulatory review process and life cycle management of pharmaceutical products. The development of a structured format for PQ/CMC data will enable consistency in the content and format of PQ/CMC data submitted, thus providing a harmonized language for submission content, allowing reviewers to query the data, and, in general, contributing to a more efficient and effective regulatory decision-making process by creating a standardized data dictionary.

The impetus for this standardization effort was the provisions from the 2012 Food and Drug Administration Safety and Innovation Act (Pub. L. 112-144), which authorized the Agency to require certain submissions to be submitted in a specified electronic format. PQ/CMC standardization supports FDA's regulatory needs in receiving structured and standardized data in pharmaceutical quality and includes two objectives: (1) To standardize the pharmaceutical quality data that is currently received by FDA in eCTD Module 3 from the sponsoring organizations, and (2) to use these structured elements and develop a FHIR data exchange solution."

gschadow commented 1 year ago

Sounds like a special kind of extinction coefficient to me, from spectrophotometry.

Would need literature references. There are some from the cited Wikipedia link.

At this point it is TL;DR for me, need to bail out for today to file taxes. But this is a good example where the submitter should try to do some homework and suggest how we might insert this into UCUM.

How does it relate to spectrophotometry, extinction coefficient at wavelength λ , and what are its mathematical properties, i.e., how can we calculate with it?