Comparison of Tunable Diode Laser Absorption Spectroscopy and Isothermal Micro-calorimetry for Non-invasive Detection of Microbial Growth in Media Fills.
Two methods were investigated for non-invasive microbial growth-detection in intact glass vials as possible techniques for automated inspection of media-filled units. Tunable diode laser absorption spectroscopy (TDLAS) was used to determine microbially induced changes in O2 and CO2 concentrations within the vial headspaces. Isothermal microcalorimetry (IMC) allowed the detection of metabolic heat production. Bacillus subtilis and Streptococcus salivarius were chosen as test organisms. Parameters as robustness, sensitivity, comparability and time to detection (TtD) were evaluated to assess method adequacy. Both methods robustly detected growth of the tested microorganisms within less than 76 hours using an initial inoculum of <10CFU. TDLA turned out to be less sensitive than TDLA and IMC, as some false negative results were observed. Compared to the visual media-fill examination of spiked samples, the investigated techniques were slightly slower regarding TtD. Although IMC showed shorter TtD than TDLAS the latter is proposed for automating the media-fill inspection, as larger throughput can be achieved. For routine use either TDLA or a combination of TDLA and TDLA should be considered. IMC may be helpful for replacing the sterility assessment of commercial drug products before release.
Center of Biomechanics &Biocalorimetry, University Basel, Gewerbestr. 14, CH-4123 Allschwil, Switzerland.|F. Hoffmann - La Roche, Ltd., Sterile Drug Product Manufacturing, Wurmisweg, CH-4303 Kaiseraugst, Switzerland.
David
D
Brueckner
Novartis Pharma Stein AG, CH-4332 Stein, Switzerland.
David
D
Roesti
F. Hoffmann - La Roche, Ltd., Sterile Drug Product Manufacturing, Wurmisweg, CH-4303 Kaiseraugst, Switzerland.
Ulrich Georg
UG
Zuber
F. Hoffmann - La Roche, Ltd., Sterile Drug Product Manufacturing, Wurmisweg, CH-4303 Kaiseraugst, Switzerland.
Rainer
R
Schmidt
Clinical Pharmacology &Toxicology, Universitätsspital Basel, Markgräflerhof, Hebelstrasse 2, CH-4031 Basel, Switzerland.
Stefan
S
Kraehenbuehl
Center of Biomechanics &Biocalorimetry, University Basel, Gewerbestr. 14, CH-4123 Allschwil, Switzerland.|Department of Urology, Universitätsspital Basel, Spitalstrasse 21, CH-4031 Basel, Switzerland.
Gernot
G
Bonkat
Center of Biomechanics &Biocalorimetry, University Basel, Gewerbestr. 14, CH-4123 Allschwil, Switzerland.|Department of Urology, Universitätsspital Basel, Spitalstrasse 21, CH-4031 Basel, Switzerland.
Olivier
O
Braissant
D001412:Bacillus subtilis / Q000737:chemistry / Q000254:growth & development*; D002151:Calorimetry / Q000379:methods*; D002245:Carbon Dioxide / Q000032:analysis*; D054023:Lasers, Semiconductor; D010100:Oxygen / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods*; D000070001:Streptococcus salivarius / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism*; D013696:Temperature
D002245:Carbon Dioxide; D010100:Oxygen