YOUR QUESTION :-

                  How can you know that a sample is UV active?

       Please update me- is there any specification on structure basis, that a compound is UV active?As a large molecule, can we make a decision to look into whether the structure of that molecule is UV active or inactive?

Answer - UV/Vis spectroscopy is routinely used in analytical chemistry for the quantitative determination of different analytes, such as transition metal ions, highly conjugated organic compounds, and biological macromolecules. Spectroscopic analysis is commonly carried out in solutions but solids and gases may also be studied.

• Solutions of transition metal ions can be colored (i.e., absorb visible light) because d electrons within the metal atoms can be excited from one electronic state to another. The colour of metal ion solutions is strongly affected by the presence of other species, such as certain anions or ligands. For instance, the colour of a dilute solution of copper sulfate is a very light blue; adding ammonia intensifies the colour and changes the wavelength of maximum absorption (λmax).

• Organic compounds, especially those with a high degree of conjugation, also absorb light in the UV or visible regions of the electromagnetic spectrum. The solvents for these determinations are often water for water-soluble compounds, or ethanol for organic-soluble compounds. (Organic solvents may have significant UV absorption; not all solvents are suitable for use in UV spectroscopy. Ethanol absorbs very weakly at most wavelengths.) Solvent polarity and pH can affect the absorption spectrum of an organic compound. Tyrosine, for example, increases in absorption maxima and molar extinction coefficient when pH increases from 6 to 13 or when solvent polarity decreases.

• While charge transfer complexes also give rise to colours, the colours are often too intense to be used for quantitative measurement.

almost all aromatic compounds are UV active and also compounds with double bonds with extended conjugation. Any basic book on spectroscopy can help you to know whether your molecule will be uv active or not. 

 Your Question :-

How to analyse UV inactive compound on HPLC using UV Detector?

In my research field I got UV inactive compound having one Chiral Center I want to separate the enantiomers on HPLC having UV detector So what can i do to get UV response on HPLC. ?

Answer - 

I suggest to complex the compound with some kind of regents to give a color so you can detect in visible range. For the enantiomer you can modify a mobile phase containing 5% beta-cyclodextrine to enhance selectivity towards enentiomers.Derivatization is one way, but more laborious and expensive. You can try the more straightforward approach of indirect UV detection.  The detection of a UV-Vis-transparent analyte is accomplished by adding light-absorbing species into the mobile phase. The presence of the analyte is monitored by measuring a decrease or The only way you could analyze a UV inactive compound on a UV detector is to derivatize it to add a UV active functionality, such as a phenyl ring.  Otherwise you can't use UV on the compounds in their native state since there is nothing for the UV detector to detect. If you are doing this as a preparative LC than derivatization wouldn't be an option.  Your only recourse would be to use another type of detector.

 Your Question :-

    Can Chloroform degrade C18 reverse phase Silica?

Answer - Chloroform will not damage your C18 RP column. I was hesitant before using it the first time, so I used a really old column that had been used with a lot of lipid-containing samples. The improvement after a {20% Ethanol or Methanol:water(ultra-pure) > 100% Methanol > 100% Acetonitrile > 100% Chloroform > 100% Acetonitrile > 100% Methanol > 20% Methanol:ultra-pure water} progression was very dramatic, restoring the column's theoretical plate number to close to that when it was new. This suggested that a lot of lipid had been accumulating on my column, impairing its performance and maybe introducing a 'lipid partition' into my separations. I have repeated this 'column-stripping' procedure several times since, on old columns that were losing resolution, and it does usually help, depending on the history of the column, and whether it has been used and stored within the limits set by the manufacturer.

I agree, however, that chloroform would not be appropriate in a mobile phase solvent for a Reverse-Phase column.

                                                                                                                                Thank you

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DATA INTEGRITY AND ALCOA +

 

                        DATA INTEGRITY AND ALCOA + 

                        

Your  question ---

Q: I am familiar with the term ALCOA as it relates to data integrity, but lately, I have heard people refer to ALCOA+. Can you explain what impact this new acronym has on my company’s data integrity program?

ANSWER : -  Before we get into the reason for the additions to ALCOA, referred to as ALCOA+, we should review what both of the acronyms mean. The acronym ALCOA requires data be attributable, legible, contemporaneous, original, and accurate. The acronym ALCOA+ adds the concepts that, in addition to ALCOA, data also needs to be complete, consistent, enduring, and available. It is important to understand what each element of ALCOA and ALCOA+ mean in order to apply the concepts appropriately with respect to a company’s records. The following are some general definitions, paraphrased from the Pharmaceutical Inspection Co-operation Scheme (PIC/S) (1), that can be used for understanding the elements of ALCOA and ALCOA+:

• Attributable: The data generated or collected must be traceable back to the individual who generated the information.

• Legible: The data recorded must be readable and permanent.

• Contemporaneous: The results, measurements, etc. must be recorded at the time the work is performed.

• Original: Original or source data are the record, report, notebook etc. where the data point was initially recorded.

• Accurate: The data recorded must be complete, consistent, truthful, and representative of facts.

• Complete: Information that is critical to recreating and understanding an event. This would include any repeat or reanalysis performed on a laboratory test sample.

• Consistent: The data are presented, recorded, dated, or time-stamped in the expected and defined sequence.

• Enduring: The data or information must be maintained, intact, and accessible throughout their defined retention period.

• Available: The data or information must be able to be accessed at any time during the defined retention period.

Data integrity has always concerned regulatory authorities, but it is important to understand what is prompting the renewed discussion of ALCOA and the introduction of ALCOA+ when discussing data integrity issues. Many of the concepts for ALCOA have been captured in the regulations as far back as 1978. Since that time, the industry has changed dramatically. The generic-drug industry has grown and in the United States alone accounts for more than 80% of the prescriptions written today (2). Coupled with the emergence of biosimilars, virtual companies, contract manufacturing organizations, rapid advances in automation and information technology, and the globalization of the industry have resulted in reinterpretation of the attributes associated with maintaining the integrity of data throughout the product lifecycle, whether those data are generated from electronic, paper-based, or hybrid systems. In addition, there has been an increase in citations internationally by the FDA, European Medicines Agency (EMA), Medicines and Healthcare products Regulatory Agency (MHRA), World Health Organization (WHO), and other health authorities. These changes and increased violations have brought about a resurgence and need to reeducate the industry on the basic principles and concepts regarding the proper control of data used to support the quality and safety of medicines.

The ALCOA acronym has been used since the 1990s; however, the requirements governing data elements have been in regulations for a much longer period of time. EudraLex chapter 4 states, “Suitable controls should be implemented to ensure the accuracy, integrity, availability, and legibility of documents. Instruction documents should be free from errors and available in writing” (3). The US Code of Federal Regulations (CFR) refers to these elements in various sections of the regulations (4–8). An example for language speaking to the element of attributable is in 21 CFR 211.194(a)(7), which states, “The initials or signature of the person who performs each test and the date(s) the tests were performed.” Language in 21 CFR 58.130 (e) addresses the elements of contemporaneous and legible by stating, “All data generated during the conduct of a nonclinical laboratory study, except those that are generated by automated data collection systems, shall be recorded directly, promptly, and legibly in ink. All data entries shall be dated on the date of entry and signed or initialed by the person entering the data.”

Recent documents issued by WHO (9) and the PIC/S (1) have added to the original ALCOA attributes as indicated above. The PIC/S document actually states, “Some key concepts of GDocPs are summarized by the acronym ALCOA: Attributable, Legible, Contemporaneous, Original, and Accurate. The following attributes can be added to the list: Complete, Consistent, Enduring, and Available. Together, these expectations ensure that events are properly documented and the data can be used to support informed decisions.” WHO refers to ALCOA+ in the title of Appendix 1 to their 2018 document. The last two documents also address the concept of quality culture (10). The impact to your organization is that the quality culture must ensure that data supporting the quality and safety of your product must now meet the ALCOA+ elements in order to avoid regulatory citations for data integrity issues.

References

1. PIC/S, Draft Guidance: Good Practices for Data Management and Integrity in Regulated GMP/GDP Environments (PIC/S, August 2016).
2. statista.com 2019.
3. EC, EudraLex,The Rules Governing Medicinal Products in the European Union, Volume 4, Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Chapter 4.
4.  21 CFR 11: Electronic Records; Electronic Signatures
5.  21 CFR 58: Good Laboratory Practice for Nonclinical Laboratory Studies
6.  21 CFR 211: Current Good Manufacturing Practice for Finished Pharmaceuticals
7.  21 CFR 212.50: Current Good Manufacturing for Positron Emission Tomography Drugs
8.  21 CFR 820: Quality System Regulation
9.  WHO, Annex 5, Guidance on Good Data and Record Management Practices (WHO, June 2016).
10. S. Schniepp, Pharmaceutical Technology 42 (10) 2018.