Hydrodynamic, mass transfer, and dissolution effects induced by tablet location during dissolution testing

Bai, Ge; Armenante, Piero M.

doi:10.1002/jps.21512

Cited by 53 publications

(91 citation statements)

References 19 publications

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“…In order to maintain the continuity of the pH monitoring and adjustment processes, both the pH electrode and the diffuser have to be continuously immersed in the dissolution medium during the test. Apparently, the placement of the pH electrode and the gas diffuser in the upper part of the dissolution vessel (∼3 cm below media surface) do not influence the hydrodynamic conditions at the bottom part of the vessel, where the dosage form is supposed to stay during the dissolution experiment in the paddle apparatus (20,21). However, the changes in the hydrodynamics caused by the gas diffuser as well as the electrode were not studied in the present work and require further investigations.…”

Section: Discussionmentioning

confidence: 85%

An Automated System for Monitoring and Regulating the pH of Bicarbonate Buffers

et al. 2013

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Abstract. The bicarbonate buffer is considered as the most biorelevant buffer system for the simulation of intestinal conditions. However, its use in dissolution testing of solid oral dosage forms is very limited. The reason for this is the thermodynamic instability of the solution containing hydrogen carbonate ions and carbonic acid. The spontaneous loss of carbon dioxide (CO 2 ) from the solution results in an uncontrolled increase of the pH. In order to maintain the pH on the desired level, either a CO 2 loss must be completely avoided or the escaped CO 2 has to be replaced by quantitative substitution, i.e. feeding the solution with the respective amount of gas, which re-acidifies the buffer after dissociation. The present work aimed at the development of a device enabling an automatic pH monitoring and regulation of hydrogen carbonate buffers during dissolution tests.

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Section: Discussionmentioning

confidence: 85%

An Automated System for Monitoring and Regulating the pH of Bicarbonate Buffers

et al. 2013

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“…On the other hand, synergistic effects are observed for the films containing nanoparticles as an increase in flow rate also helps in the disaggregation of the nanoparticles, consequently producing an enhancement in dissolution. It has been shown that the sample location has an impact on dissolution (45,46). During the basket rotation, the strip-film is randomly moving inside the basket or could also be sticking to the basket wall, resulting in an uncontrolled strain rate on the film and therefore on the drug particles.…”

Section: Dissolution Testing Using the Flow-through Cell Dissolution mentioning

confidence: 99%

Using USP I and USP IV for Discriminating Dissolution Rates of Nano- and Microparticle-Loaded Pharmaceutical Strip-Films

et al. 2012

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Abstract. Recent interest in the development of drug particle-laden strip-films suggests the need for establishing standard regulatory tests for their dissolution. In this work, we consider the dissolution testing of griseofulvin (GF) particles, a poorly water-soluble compound, incorporated into a strip-film dosage form. The basket apparatus (USP I) and the flow-through cell dissolution apparatus (USP IV) were employed using 0.54% sodium dodecyl sulfate as the dissolution medium as per USP standard. Different rotational speeds and dissolution volumes were tested for the basket method while different cell patterns/ strip-film position and dissolution media flow rate were tested using the flow-through cell dissolution method. The USP I was not able to discriminate dissolution of GF particles with respect to particle size. On the other hand, in the USP IV, GF nanoparticles incorporated in strip-films exhibited enhancement in dissolution rates and dissolution extent compared with GF microparticles incorporated in strip-films. Within the range of patterns and flow rates used, the optimal discrimination behavior was obtained when the strip-film was layered between glass beads and a flow rate of 16 ml/min was used. These results demonstrate the superior discriminatory power of the USP IV and suggest that it could be employed as a testing device in the development of strip-films containing drug nanoparticles.

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“…In addition, and to make the system more sensitive to the effect of small geometric differences, tests were also conducted with tablets fixed at several positions in the vessel. As shown in previous studies by this group (25)(26)(27), tablets placed at different locations on the vessel bottom can have different dissolution rates since they experience different flows around them and different shear stresses, especially if the system is nonsymmetrical. Therefore, in this work, dissolution tests were conducted not only with the standard tablet drop technique specified in the USP (28), but also with tablets fixed in place at nine positions on the vessel bottom (i.e., the central position, four positions on the 10° off-center circle, and four other positions on the 20° off-center circle).…”

mentioning

confidence: 82%

Effect of a Fiber-Optic Probe on the Dissolution of Salicylic Acid Tablets in USP Apparatus 2

Bing¹,

Bredael²,

Armenante³

2013

Dissolution Technol.

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Fiber-optic probes permanently inserted in the dissolution medium in dissolution vessels can automate the sampling process but can also potentially affect the hydrodynamics in the vessel, possibly resulting in increased drug dissolution rates. In this work, dissolution experiments with non-disintegrating salicylic acid calibrator tablets were conducted in dissolution testing Apparatus 2 in both the presence and absence of a commercially available fiber-optic probe (Opt-Diss). Tests were conducted using tablets dropped in the medium according to USP guidelines, as well as with tablets fixed at nine positions on the vessel bottom (i.e., either centered in the vessel or placed at different off-center locations with respect to the vessel vertical centerline). The results were compared using statistical tools. In many cases, the presence of the probe resulted in slightly faster dissolution rates. The difference between the results obtained in experimental systems with the probe and those obtained with the control system without the probe depended on tablet position. Larger differences were observed when the tablets were on inner circle positions (10° off-center circle), especially when the tablets were located immediately downstream of the probe. A paired t-test as well as the difference factor (f 1 ) and similarity factor (f 2 ) were used to statistically analyze the results. In most cases, the results obtained with the inserted probe were statistically different, according to the paired t-test, from those obtained without it. It can be concluded that fiber-optic sampling probes can often result in small but measurable enhancements in the dissolution rates, which can produce appreciable variations in test results.

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Hydrodynamic, mass transfer, and dissolution effects induced by tablet location during dissolution testing

Cited by 53 publications

References 19 publications

An Automated System for Monitoring and Regulating the pH of Bicarbonate Buffers

An Automated System for Monitoring and Regulating the pH of Bicarbonate Buffers

Using USP I and USP IV for Discriminating Dissolution Rates of Nano- and Microparticle-Loaded Pharmaceutical Strip-Films

Effect of a Fiber-Optic Probe on the Dissolution of Salicylic Acid Tablets in USP Apparatus 2

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