Unique construction and calibration techniques used to produce dissolution flow cells dramatically reduce uncertainty due to manufacturing tolerances
With an increasing number of pharmaceutical formulations, the use of short path length flow cells to reduce absorbance levels is often the only alternative to diluting the test media when conducting dissolution studies.
However at very short path lengths, ie less than 0.5mm, manufacturing tolerances begin to add significantly to the uncertainty of the measured path length, and can introduce path length uncertainty of up to 20% at the 0.01mm path length.
According to Optiglass, the unique construction and calibration techniques used to produce its Starna type 583, 584 and 585 series flow cells dramatically reduce uncertainty from this source, and make them the preferred choice of many dissolution system providers.
Cells are available in a comprehensive range of path lengths, from 100mm down to 0.01mm.
Path lengths are verified either by precise mechanical measurement, or, in the case of path lengths below 0.5mm, ie 0.2, 0.1, 0.05, 0.02 and 0.01mm, by interference measurements on a reference spectrophotometer.
This technique can determine path length to a tolerance better than 0.2 microns (0.0002mm), or better than 2% for a 0.01mm cell.
Each cell has its path length and unique serial number engraved on it during manufacture, thereby ensuring traceability.
The fully fused glass or quartz cell body is bonded into a precision CNC engineered aluminium enclosure that provides precise alignment and also makes the complete assembly exceptionally stable and durable.
Another benefit is that the screw connectors can be attached really tightly to achieve leak-free seals - Starna flow cell assemblies are pressure tested during manufacture to over 5bar.
