Automated dissolution systems HPLC analysis

Fortunately, automated fiber-optic probe-based dissolution systems have begun to appear for these solid dosage-form applications. One such system uses dip-type UV transflectance fiber-optic probes, each coupled to a miniature photodiode array (PDA) spectrophotometer to measure drug release in real time. This fiber-optic dissolution system can analyze immediate- and controlled-release formulations. The system is more accurate and precise than conventional dissolution test systems, and it is easier to set up than conventional manual sampling or automated sipper-sampling systems with analysis by spectrophotometry or HPLC. 

For 12-hour controlled-release tablets, the accuracy of the 12-hour dissolution profile obtained from in situ measurements was assessed by comparison with measurements obtained by manual withdrawal and analysis by HPLC. The results (Fig. 22) obtained by two analysts on different days show that the 12-hour dissolution profile obtained from in situ fiber-optic-probe-based measurements is as accurate as that obtained by the automated withdrawal of the sample and analysis by HPLC. In addition, in situ measurements were obtained with fiber-optic probes placed in the medium at the USP sampling position throughout the test, whereas the cannulas used to manually withdraw medium were inserted and removed at each measurement interval. The fiber-optic dissolution system displays excellent stability and validation char-... 

Most manufacturers of dissolution testing devices offer semi-automated systems that can perform sampling, filtration, and UV reading or data collection. These systems automate only a single test at a time. Fully automated systems typically automate entire processes including media preparation, media dispensing, tablet or capsule drop, sample removal, filtration, sample collection or analysis (via direct connection to spectrophotometers or HPLCs), and wash cycles. A fully automated system allows automatic performance of a series of tests to fully utilize unused night and weekend instrument availability. 

Many of the techniques described above, excipient compatibility, blend uniformity by HPLC dissolution, and content uniformity/assay by HPLC can be effectively automated by robotic sample preparation. Each of these techniques requires that the sample under study be dissolved in an appropriate solvent and fully extracted from any excipients. There are a number of commercially available products that have proven to be effective and robust in this sample preparation role. This robotic process can reduce both the analyst hours required to prepare a number of samples, and turnaround time on the sample analysis, since the robotic systems will operate unattended over night and on weekends. There is of course a cost to pay for laboratory automation. There is a significant capital cost, and then an ongoing maintenance cost for the continued operation of the system. Also it is critical that a specialist be available in-house to care for the system, develop the methods, and troubleshoot any issues with the system. The cost of the system and specialist must be weighed against the advantages of speed and lab capacity enhancement realized with a successful automation implementation. 

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