Fiber-optic dissolution system

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. 

FIGURE 21 Dissolution profiles for buffered aspirin tablets obtained with the fiber-optic dissolution system (260-350 nm) and manual sampling with HPLC analysis. The dissolution was performed with USP apparatus 2 at 75 revolutions per minute. A second-derivative baseline correction was performed on the fiber-optic raw spectral data to correct for scattering due to the turbid solution. 

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-... 

W. Li, J. Chen, B.-R. Xiang, D.-K. An, Simultaneous on-line dissolution monitoring of multicomponent solid preparations containing vitamins Bi, B2 and B6 by a fiber-optic sensor system, Anal. Chim. Acta 408 (2000) 39. 

L. Liu, G. Fitzgerald, M. Embry, R. Cantu, B. Pack, Technical evaluation of a fiber-optic probe dissolution system, Dissol. TechnoL, 15, 10-20 (2008). 

There are three instrument designs in use with fiber-optic probes. One system makes simultaneous measurements on up to eight dissolution bath probes using a CCD-based spectrophotometer with xenon flash lamp source. The signals from all eight probes are simultaneously imaged onto a single CCD detector and concentrations determined in real... 

Bynum, K.C. Kraft, E. Analytical performance of a fiber optic probe dissolution system. Pharm. Technology 1999, 23, 10. 

Advances in instrumentation have resulted in a wide array of choices for analysts. These include instruments for specific applications with custom sample holders as well as general multiuse types. In the past 10 years, various patents have been issued for sample holders, sample supports, and a fiber optic system for dissolution.f ... 

In addition to the dissolution and identification tests, the ability of the system to perform an assay and a content uniformity determination has been demonstrated. Because there are no fluid transfers, the vessels can be sealed, eliminating the need for volume corrections or fluid replacements. Therefore, with a 12-vessel dissolution apparatus, it is possible to designate 10 of the vessels for the content uniformity test and to average the results from the 10 or 12 vessels for the assay determination. Typical data for a 12-hour controlled-release product are presented in Table 2. Excellent agreement between the fiber-optic- and HPLC-based measurements is evident. 

In a Hrst arrangement the process control system includes automatic sampUng in the hot zone such as an explosion-proof container, the manual or automatic transfer of the sample to the laboratory, a robot to prepare the analysis, and transfer of the solution to be analyzed to an fiber-optic measurement cell [163]. This architecture is most commonly found today if the laboratory is habitually and directly involved in controlling the various steps in the process. It is JustiHed if the samples must also be prepared in a hot zone, or if the analysis requires semiautomatic operations such as dissolution of solid samples, or sophisticated techniques such as chromatography, mass spectrometry, or emission spec-... 

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