Its with great sadness that we announce the recent death of our founder, long time Managing Director and Chair Doris Butterworth.  She died peacefully at home.

Doris was a pioneer who started and ran her own scientific company in a time when being both a prominent woman in science and a business woman were not without their challenges.

In 1974 Doris founded what was then the Butterworth Microanalytical Consultancy Ltd.  The company’s name was changed in 1977 to Butterworth Laboratories Ltd and became the laboratory we know today.  She stepped back from the front-line management of the laboratories in 2017 with the appointment of a new Managing Director.  However, she remained as Chair of the Board and, with her tireless work ethic and enthusiasm never waning, remained active in the running of the company right up until her death.

During her 43 years as Managing Director, she took an active interest in all her staff, also performing the role HR Manager, creating a company culture which endures to this day. Her lab was, without a doubt, her life, her soul and reason for being.  It was always at the forefront of her thoughts and right up the end the first thing she would always ask was how the lab was getting on. She will be fondly remembered and highly respected by all employees and colleagues, past and present. Her legacy continues in Butterworth Laboratories Ltd with her sole shareholding being passed to a trust with the employees as beneficiaries.

The following article has been published on Pharmaceutical Technology website. in which John Welch our Associate Director – Business Operations has been quoted.

Click to read article

Frank Judge our Consultant Chemist – Chromatography has worked at Butterworth for nearly 30 years and built up a wealth of experience in analytical chemistry.  He has agreed to write a series of Blogs in which he shares his vast experience on a number of current issues.  Please look out for these in the coming weeks.

Butterworth have just completed the validation of an ICP-MS Method to show equivalence to Graphite Furnace Monograph tests for Lead, Cadmium and Nickel.  ICP-MS analysis is routinely used to meet ICH Q3D requirements for Elemental Impurities in accordance with the Ph Eur and USP. It was a logical move to show the equivalence of this test to the established Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) outlined in the monographs for Magnesium Stearate.

The reason for this methodology shift is prompted by a reduction in requests for analysis using GFAAS and AAS, especially following the introduction of ICP-MS in the Elemental Impurities general chapters.  As such it is becoming harder for contact laboratories to justify the replacement of Atomic Absorption Spectrophotometers (AAS) as they come to the end of their life cycle.

There are already signs that the pharmacopoeias are replacing older metallic methodologies with elemental impurities analysis and this trend is likely to continue. Validation and verification will be something that outsourcers will need to consider as this change gathers pace. Butterworth are perfectly placed with the right experience and knowledge to help you get one step ahead and to provide more robust methodology.

For more information on this analysis: More information

Frank Judge has just published an article on the Pharmaceutical Technology website, which has been used to produce are latest Whitepaper. To download the whitepaper, see Whitepapers

The main complication with the analysis of amino acids and related substances is due to their low volatility and inability to form active chromophores when in a solution. This means that GC and HPLC using UV/Vis detection are not applicable and other common HPLC detectors lack the required sensitivity.

Historically, the Ph. Eur. Amino Acid monographs took advantage of these reactions to determine the levels of ninhydrin-positive substances present as contaminants in various Amino Acid samples using a Thin Layer Chromatography (TLC) procedure. This involved separating sample components by development of the TLC plate, then visualising the analytes by spraying the plate with ninhydrin which reacts with any ninhydrin-positive substances on the plate to give coloured spots. The major problem with this procedure was that it did not resolve all possible ninhydrin-positive substances. The method was also very subjective since quantitation was based on a simple visual comparison of the relative intensity of sample and standard derived spots. To address the problems with TLC, the Ph. Eur. started revising amino acid monograms in 2014, replacing the TLC requirement with a procedure based on High Performance Liquid Chromatography (HPLC). The new test employed the separation of amino acids on an ion-exchange column with different ionic strength and pH eluents. The resulting stream of separated Amino Acid sample components eluting from the column are mixed with ninhydrin supplied from a secondary pump. The mixed sample and ninhydrin stream is then passed through a heated reaction coil to promote derivatisation of any ninhydrin-positive substances, these can then be detected using a photometer at the wavelengths already specified above. This process is known as ‘post-column ninhydrin derivatisation’. Dedicated instruments capable of post-column ninhydrin derivatisation are commercially available and are known as Amino Acid Analysers (AAA).

To negate these and other problems, and reduce uncertainty with analysis reporting times, Butterworth has purchased and validated a Hitachi LA8080 Amino Acid Analyser. The main differences from the previous ad hoc set-up included an increase in sensitivity. The biggest change was the elimination of tubing blocking and increasing analytical column back pressures. At the end of each individual sample analysis, after all amino acids have eluted, a column regeneration mobile phase is pumped prior to a long period of equilibration with initial analytical mobile phase conditions. Another benefit is that the secondary ninhydrin pump operates in 2 channel mode; a start-up and shutdown program is run with every sequence which involves purging the pump and reaction coil with an ethanol solution to dissolve and remove any particulate build-up.

Butterworth has already verified the new system for the analysis of Arginine, Histidine and Tryptophan, and will verify the method for other less frequently requested amino acids when required by clients. In addition our Projects Department are also currently looking at the same testing in the JP Monograph as the result of a client request.

Frank Judge is a consultant chemist at Butterworth Laboratories Limited, an independent contract testing laboratory in the UK. He has worked at Butterworth for almost 30 years and shares his recollections of the past three decades of residual solvent analysis in the Butterworth laboratory.

In 1988, the United States Pharmacopeia first published General Monograph <467>, Organic Volatile Impurities (OVI), which addressed the control of just seven specified Residual Solvents. When Judge joined Butterworth Laboratories in 1994, the chromatography lab was already carrying out OVI testing, utilising both direct injection and headspace procedures of <467>. 

The rise of headspace GC systems

1996 saw the implementation of the first automated headspace GC system in response to increased client demand. Much of this testing was “blind compliance”, since the seven targeted solvents were practically never used in the production of pharmaceutical articles. The end of the decade witnessed a huge increase in headspace residual solvents analysis at Butterworth, both for compliance to <467> and the development of product-specific screening procedures based on the solvents used in production. 

By 2005, Butterworth had six headspace GC systems, just in time for what was to be another period of dramatic increase in requirement for headspace analysis. That year, a completely revised chapter <467> renamed “Residual Solvents” was published which adopted the ICH Q3C classification and limits for residual solvents based on toxicity. The chapter included headspace procedures for the screening of the five Class 1 and 23 Class 2 solvents. 

This was a cause for excitement in the chromatography lab at Butterworth, since the company had already built considerable experience in the headspace analysis of residual solvents. Butterworth now saw a chance not only for an increase in revenue, since the new monograph was much more labour intensive and time consuming, but also for a chance to showcase its chromatography skills in this area.  

However, there was a further inclusion in the 2005 USP which caused panic throughout the industry, caused by perhaps the shortest statement ever made in the USP to have the greatest impact. This was USP General Notices 5.60.20 which stated that “All USP and NF articles are subject to the relevant control of residual solvents, even when no test is specified in the individual monograph.”  This meant that hundreds of pharmaceutical substances previously not prescribed to comply with <467> would now be required to do so.

Since manufacturers tend to have limited GC capabilities, there were many calls to Butterworth seeking assurance that the company would be set up to carry out the new <467> procedure by the 2006 implementation date. Even more calls were made to the USP and FDA asking for more time to prepare, and the implementation was postponed an extra year not once but twice. By the time the revised chapter and general notice were finally implemented in 2008, Butterworth had already verified its use of the new procedure.

The development of residual solvent analysis at Butterworth

With the implementation of the new general chapter, some laboratories were reporting difficulty in demonstrating enough sensitivity to comply with the signal to noise system suitability requirement for the low level Class 1 reference standard. It had already been realised at Butterworth that the problem was not in fact one only of chromatographic sensitivity, but was at least in part due to the solution preparation scheme of <467>, particularly the multi-level aqueous dilution of the hydrophobic Class 1 standard components. 

Butterworth proposed an alternative dilution scheme which involved only a single step. In 2009, Judge was asked by the USP to present Butterworth’s alternative method and experience of <467> at a symposium of the Joint Pharmaceutical Analysis Group, which greatly increased clients’ confidence in Butterworth’s practical application of <467>. 

In 2010, Butterworth issued an in-house GC-headspace procedure for the fully quantitative analysis of named Class 1, 2 and 3 headspace amenable residual solvents. This was used where solvents present were known or targets had been identified by <467> screening. This procedure includes multi-level calibration and demonstration of spike recovery at 50% of the limit.

In 2015, Butterworth issued another USP-compliant in-house headspace screening procedure (at ICH limits) for all headspace-amenable Class 1, 2 and 3 solvents (64 individual targets) but still excluding the 12 non-volatile problem solvents. This procedure includes the alternative standard preparation schemes developed at Butterworth with reduced number of dilution steps. 

In April 2021, Butterworth issued yet another, USP-compliant, generic screening procedure for the analysis of ten of the 12 non-headspace ICH solvents by direct injection GC. The method includes extensive quality control requirements such as standard repeatability, resolution, signal to noise and spike recovery. Another advantage of this procedure is that it takes into consideration the solubility of the sample material. 

And next?

Things never stand still at Butterworth and the Chromatography Team have started the process of producing a validated generic HPLC based procedure for the residual solvents, Formic and Acetic Acids in Water and Acetonitrile soluble substances. Once completed, Butterworth will be able to screen samples for all 76 ICH target solvents using only three procedures. No doubt there will be future challenges and changes to the Residual Solvents monographs in the USP, EP and other national monographs, which will require further changes and updates to these procedures. But Butterworth is confident, given its record of keeping abreast of the various changes so far, that it will continue to provide this service for the foreseeable future.

Nickel, lead and other metal limit tests have started disappearing from some pharmacopoeial monographs over the past few years. As in the European Pharmacopeia monographs for Mannitol and Erythritol.

This does not mean that analysis of these metals is no longer needed!

There is a requirement for elemental impurities to be assessed in all materials in accordance with European Pharmacopeia chapter 5.20 and United States Pharmacopeia chapter <232>, this covers a total of 24 elements including nickel and lead. This requirement followed the removal of the Heavy Metals limit test some years ago.

Where a monograph contains a metal limit test that overlaps with the Elemental Impurities you can expect that test to be removed in a future versions.

Elemental impurities testing can be challenging with requirements for low limits of detection in sometimes tricky sample matrixes. Butterworth laboratories have extensive experience with elemental impurities testing and offer a material specific validation service should it be required.

If you would like to discuss the requirements please get it touch using our Enquiry Form or Quotation Request Form

In 2018 the USP-NF introduce a Content of Sodium assay to the Sodium hydroxide monograph and a Content of Potassium assay to the Potassium Hydroxide monograph, both performed by Atomic Absorption Spectroscopy (AAS). This was in addition to the Total Alkali titrimetric assay in these monographs.

These newer AAS assays immediately began causing problems generating erroneous results which did not always agree with the titrimetric assay. Investigation demonstrated that poor precision observed was related to the very large sample dilution required. The USP-NF have acknowledged the problems with these methods and are working on alternatives using ICP-OES.

Butterworths have generated alternative methods for the Content Sodium and Potassium using ICP-OES to USP-NF <1225> requirements which are ready go. These methods have demonstrated much improved precision and accuracy resolving the issues seen in the AAS tests.

For more information on these tests or any other pharmacopeia analysis, please use our Enquiry Form or Quotation Request Form

Having developed an HPLC instrument technique for the determination of Ninhydrin-Positive Substances (NPS) back in 2015 to replace the traditional Thin Layer Chromatography method, our laboratories have now completed the commissioning of a dedicated Hitachi LA8080 High-Speed Amino Acid Analyser.

This upgrade equips our lab with a faster and more reliable system for the determination of ninhydrin-positive substances (including ammonium) in amino acid, pharmaceutical and biological samples; helping to ensure that we can meet the increasing needs of our clients.

Furthermore, the use of OpenLab II Chromatography Data System Workstation Plus for instrument control and data processing further strengthens the laboratory’s compliance to data integrity requirements.

The instrument is capable of detecting a range of ninhydrin-positive substances including, but not limited to:

Alanine	Glycine	Proline
Ammonium	Histidine	Serine
Arginine	Isoleucine	Threonine
Aspartic acid	Leucine	Tryptophan
Cysteine	Lysine	Tyrosine
Cystine	Methionine	Valine
Glutamic acid	Phenylalanine

During the upgrade we had to temporarily suspend this testing, but we are pleased to report that a new and improved service is now available.

For more information on our NPS – Amino Acid Analysis analysis, please use our Enquiry Form or Quotation Request Form