Dang.....drama drama
Imma take your advice and try and filter out all that static and stick with the legit info thats available. Soooo.... anyway:
Jim,
I haven't gotten a response on those 4 samples (BioP) still out for testing. I'm assuming it won't be until after the holidays when I'll get the results
This is some info I got from another lab I recently reached out to
It seems that formulation is important and Glycine seems to be a potential issue with the data and results (depending on testing methods)
It doesn't seem that the Seros sample contained Glycine, but quite a few of the Chinese generics do (JINTROPIN and OMNITROPE did aswell)
Protein concentration in my sample
The appropriate analysis depends on the sample complexity and if the quantification needs to be absolute in picomoles & micrograms or just relative to other proteins & samples.
We offer a range of quantification services including:
- Absolute quantification of the purified protein batch.
- Relative quantification of multiple proteins in complex samples.
- Absolute quantification of single, individual proteins in complex samples.
We follow the principles for analysis of identity, purity, quantity, as well as product- and process-related impurities as described in the
ICH Q6B guidelines: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products.
Analysis Details
This Amino acid analysis refers to the method used to quantify proteins and peptides.
Sixteen amino acids are quantified – the normal 20 amino acids except tryptophan and cysteine. Asparagine is determined as aspartic acid and glutamine as glutamic acid. The analysis process includes:
- Protein hydrolysis
- HPLC analysis
- Data calculation
(Ph. Eur and USP.)
Apparatus
The analysis is performed on a BioChrom 30 amino acid analyser by ion-exchange chromatography with post-column derivatization using ninhydrin. All amino acids except Proline (440 nm) are monitored at 570 nm.
Protein hydrolysis – Vapour phase
The sample is placed in a 0.5 mL hydrolysis tube and dried down. The tube is placed in a vessel containing an acid hydrolysis solution (6M HCl containing, 0.1% phenol, 0.1% thioglycolic acid). The vessel is flushed with argon and after evacuation (<10 mBar) the vessel is placed at 110°C for 24 hours. After hydrolysis the test sample is dried in vacuum and the sample is dissolved in loading buffer (sodium citrate pH 2.20) including a fixed amount of sarcosine (Sar). This is used as an internal standard to correct for changes in reagent stability and flow rates, and the variation for each sample should not exceed 5%.
Calibration of Instrument
A standard mixture of amino acids is analyzed at 3 different concentrations levels (double determination) to show linearity within the measurement range (700 to 2800 pmol). A plot is made showing peak area versus known concentration of each standard solution. The r-value of the calibration has to be better than 0.999 (proline is accepted at 0.995 due to lower signal/noise). The instrument is linear to 5600 pmol and usually up to ~20 nmol. Depending on the amino acid residue, the signal goes into saturation around 25-35 nmol.
Accuracy & Precision
For each batch run we include a duplicate analysis of a NIST BSA quality control standard. The results are used to determine the precision and the accuracy of the test. The precision should be below 5% and the accuracy within 15%.
Data calculations
A standard amino acid solution is analyzed for each 5 samples, and based on at least two runs, a compensation factor is calculated to correct for ninhydrin activity. Each amino acid in the sample is corrected by this compensation factor.
Unknown protein samples: If a protein sequence is not given, the total protein amount is calculated based on the amount of each amino acid (in pmol) multiplied by the mass of the given amino acid residue. Please note that as the content of cysteine and tryptophan is not included, the obtained value is underestimated by approximately 2.7% (average Cys and Trp content in proteins in the Swiss-Prot database).
Known protein samples: If the protein sequence is known, the measured AA amount in pmol is divided by the number of each specific amino acid in the sequence providing a pmol protein. The average of these numbers in pmol is used to calculate the amount of protein in µg using the molecular weight of the protein.
The calculations against known amino acid sequence is done using a best linear fit based on all detected amino acids, but will be modified for each experiment not to include amino acids with greater than 5 per cent variation.
Lab states they have experience testing pharmaceutical formulated Somatropin
Depending on the results from BioP, I would like to try sending a few samples here
Just wanting your opinion.....this test is a bit more expensive and extensive than the $200-250 AAA
What I'm looking for is a lab I (we) can trust to produce accurate results
As you can see with the comparison results I've posted....all labs are not created equal (as you've correctly pointed out)
Even some of the SIMEC GH results have inconsistent results
The SIMEC results I've post here seem to be a bit more accurate than PMs results
Thanks
(I can always PM the lab info also)