How a British Covid-19 vaccine went from pole position to troubled start

Re:How a British Covid-19 vaccine went from pole position to... by ggm on Saturday December 26, 2020 @10:12PM (#25548482)

Having done spectrophotometry for water quality analysis 40+ years ago I was somewhat surprised it was being used but it has some advantages: it's mechanistic and easy, without risking the integrity of the sample, but as the story here shows it depends on certainty of the solvents and related conditions under test (we had to use specific optical refractive index glass measurement vials with their own cleansing routine and there was a rigmarole around calibration i still suspect was hugely subjective. I would hope by now the human eyeball is replaced by some digital light sensor, I think my subjective view skewed the sampling method)

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Re:How a British Covid-19 vaccine went from pole position to... by refurb on Saturday December 26, 2020 @11:42PM (#25548904)

UV visible does have all those benefits you mention. What went wrong here is what is called “validation” and is a big part of pharmaceutical analytical analysis.

You not only describe how you measured your drug concentration, but you also test the limits. And those limits should go beyond anything you might encounter in actual manufacturing.

If your aim is to confirm a concentration of 5mg/mL, then you test all the way down to 0mg/mL and then 50mg and 500mg/mL. Then if you have a saline mixture, you test different concentrations of NaCl.

You’re basically trying to break the analysis to show where it doesn’t work.

The fact they did a UV vis and didn’t account for a different emulsifier is a big miss.

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Re:How a British Covid-19 vaccine went from pole position to... by exmadscientist on Saturday December 26, 2020 @11:03PM (#25548711)

> I would hope by now the human eyeball is replaced by some digital light sensor

It has been! But if my lab experience was any guide, it's not necessarily a good light sensor. Spectrophotometry is great for getting coarse accuracy results out of. True precision... that is, and will remain, difficult.

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Re:How a British Covid-19 vaccine went from pole position to... by 5440 on Saturday December 26, 2020 @11:33PM (#25548856)

It works just fine. The samples are tested in the UV-VIS at 280nm.

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