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To determine if an IVIVC model can predict PK profiles of varying formulations of a BCS Class 1 drug that is a salt of a weak base. An IVIVC model (Level A) was created by correlating deconvoluted in vivo absorption data obtained from oral administration of 50 mg, 100 mg, and 200 mg fast and slow extended release formulations with in vitro percent dissolved using residual regression analysis. The model was then used to predict the in vivo profile of five test products that varied in formulation characteristics. The model passed internal validation for predicted Cmax and AUC. For external validation, in vitro data of five different test formulations was utilized. The model passed external validation for two test formulations that were different but belonging to the same release mechanism as that of the reference formulation. Three formulations failed external validation because they belonged to either a mixed or different release mechanism. The model and results were further confirmed using GatstroPlus™ simulation software. These observations indicate that an IVIVC model for a BCS class I drug may be applicable to varying formulations if the principle of the drug release is similar.

This is a summary report of the workshop entitled "Dissolution Testing for the Twenty-first Century: Linking Critical Quality Attributes and Critical Process Parameters to Clinically Relevant Dissolution," organized by the In Vitro Release and Dissolution Testing Focus Group of the American Association of Pharmaceutical Scientists. Participants from the pharmaceutical industry, regulatory authorities, and academia in the US, Europe, and Japan attended this workshop to review, discuss, and explore the role of traditional dissolution testing in the new arena of Quality by Design (QbD) and Process Analytical Technology (PAT). Other areas of discussion were the use of the dissolution test to evaluate drug release from novel dosage forms, challenges in dissolution testing and specification setting, and dissolution apparatus calibration using performance verification tablets versus mechanical calibration. The workshop identified areas where further research and collaboration are needed to advance knowledge and understanding of the science of dissolution. Views expressed in this report are those of the authors and do not necessarily reflect those of the FDA and USP.

There has been a growing interest during the past decade in the use of fiber optics dissolution testing. Use of this novel technology is mainly confined to research and development laboratories. It has not yet emerged as a tool for end product release testing despite its ability to generate in situ results and efficiency improvement. One potential reason may be the lack of clear validation guidelines that can be applied for the assessment of suitability of fiber optics. This article describes a comprehensive validation scheme and development of a reliable, robust, reproducible and cost-effective dissolution test using fiber optics technology. The test was successfully applied for characterizing the dissolution behavior of a 40-mg immediate-release tablet dosage form that is under development at Novartis Pharmaceuticals, East Hanover, New Jersey. The method was validated for the following parameters: linearity, precision, accuracy, specificity, and robustness. In particular, robustness was evaluated in terms of probe sampling depth and probe orientation. The in situ fiber optic method was found to be comparable to the existing manual sampling dissolution method. Finally, the fiber optic dissolution test was successfully performed by different operators on different days, to further enhance the validity of the method. The results demonstrate that the fiber optics technology can be successfully validated for end product dissolution/release testing.

A simple and rapid stability-indicating HPLC assay procedure has been developed and validated for metronidazole benzoate. The HPLC conditions were as follows, column: Waters Symmetry C8, 5 microm packing, 4.6 mm x 250 mm; detection: UV at 271 nm; injection volume: 20 microl; mobile phase: acetonitrile-0.1% glacial acetic acid in monobasic potassium phosphate (0.01 M) (40:60, v/v); isocratic elution under ambient temperature at 2.0 ml min(-1). The procedure separated metronidazole benzoate and its potential degradation products, metronidazole and benzoic acid, in an overall analysis time of about 6 min with metronidazole benzoate eluting at about 5 min. The injection repeatability was 0.03%, and the intraday and interday repeatability were 0.4 and 0.7%, respectively. The procedure provided a linear response over the concentration range 0.2-800 microg ml(-1) (r=1.0000) with the limits of detection and quantitation 0.03 and 0.2 microg ml(-1), respectively. The solubilities of metronidazole benzoate in water, 0.01 M hydrochloric acid and 0.05 M phosphate buffer, pH 6.8, determined each in triplicate using the procedure, were 0.2 mg ml(-1) (R.S.D. 7%), 0.4 mg ml(-1) (R.S.D. 2%) and 0.2 mg ml(-1) (R.S.D. 8%), respectively. The results show no detectable hydrolysis of metronidazole benzoate in 0.01 M hydrochloric acid at 37 degrees C or in the mobile phase at ambient temperature in 10 h.