Jerome P. Skelly

Quantitative Bioanalytical Methods Validation and Implementation: Best Practices for Chromatographic and Ligand Binding Assays

AbstractThe Third AAPS/FDA Bioanalytical Workshop, entitled “Quantitative Bioanalytical Methods Validation and Implementation: Best Practices for Chromatographic and Ligand Binding Assays” was held on May 1–3, 2006 in Arlington, VA. The format of this workshop consisted of presentations on bioanalytical topics, followed by discussion sessions where these topics could be debated, with the goal of reaching consensus, or identifying subjects where addition input or clarification was required. The discussion also addressed bioanalytical validation requirements of regulatory agencies, with the purpose of clarifying expectations for regulatory submissions. The proceedings from each day were reviewed and summarized in the evening sessions among the speakers and moderators of the day. The consensus summary was presented back to the workshop on the last day and was further debated. This communication represents the distillate of the workshop proceedings and provides the summary of consensus reached and also contains the validation topics where no consensus was reached.ConclusionFor quantitative bioanalytical method validation procedure and requirements, there was a relatively good agreement between chromatographic assays and ligand-binding assays. It was realized that the quantitative and qualitative aspects of bioanalytical method validation should be reviewed and applied appropriately.1.Some of the major concerns between the 2 methodologies related to the acceptable total error for precision and accuracy determination and acceptance criteria for an analytical run. The acceptable total error for precision and accuracy for both the methodologies is less than 30. The 4–6–15 rule for accepting an analytical run by a chromatographic method remained acceptable while a 4–6–20 rule was recommended for ligand-binding methodology.2.The 3rd AAPS/FDA Bioanalytical Workshop clarified the issues related to placement of QC samples, determination of matrix effect, stability considerations, use of internal standards, and system suitability tests.3.There was a major concern and issues raised with respect to stability and reproducibility of incurred samples. This should be addressed for all analytical methods employed. It was left to the investigators to use their scientific judgment to address the issue.4.In general, the 3rd AAPS/FDA Bioanalytical Workshop provided a forum to discuss and clarify regulatory concerns regarding bioanalytical method validation issues.

Determination of in vitro drug release from hydrocortisone creams

Abstract A method for the determination of in vitro release of hydrocortisone from creams using Franz diffusion cell system and synthetic membranes has been developed. The use of synthetic membrane minimizes the variability observed with skin membranes. The method can be employed as a quality control procedure for assuring batch-to-batch uniformity of topical products.

In vitro dissolution profile of transdermal nitroglycerin patches using paddle method

Abstract A dissolution test procedure using an adaptation of the FDA paddle method (USP Apparatus 2) has been developed for the purpose of assuring uniform batch to batch release. The patch is held in position in the dissolution vessel by sandwiching it between a watchglass and an aluminum wire screen. The dissolution profiles of the three marketed brands (10 dosage forms) of transdermal nitroglycerin patches were determined over a 24-h period. All samples, were analyzed by HPLC. The results of patches manufactured by each firm indicate dose proportional release. While there is a qualitative difference in the dissolution pattern among manufacturers, the dissolution procedure was found to be simple, reliable and reproducible, suggesting this technique can be used as a quality control tool for assuring product uniformity.

In vitro/in vivo correlations in biopharmaceutics: scientific and regulatory implications.

SummaryThis paper explains the regulatory and scientific reasons for the regulatory authorities employing dissolution as a key variable for regulatory approval of batch to batch bioequivalence assurance, site of manufacture change, formulation changes, and batch size scale-up for immediate release dosage forms. It also explains the scientific and regulatory reasons why either an in vivo/in vitro correlation using USP’s Level ‘A’, ‘B’ or ‘C’, or a newly proposed ‘mapping’ approach will be required for allowing such changes for controlled-release dosage forms.

Identification and quantification of 6β-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man

Identification of 6 beta-hydroxydexamethasone as a major urinary metabolite of dexamethasone in man has been accomplished by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. Mass fragmentographic measurements revealed that more than 30% of the intravenously or orally administered dexamethasone dose was excreted in the 24-h urine as 6 beta-hydroxydexamethasone, while only a small fraction of the dose was excreted as unchanged dexamethasone and its glucuronic acid conjugate.

An in vitro study of possible food-drug interactions of the controlled-release propranolol products

Abstract The pH-dissolution profiles of 4 controlled release (C.R.) propranolol products were investigated. Three of the products were pretreated with peanut oil prior to the dissolution testing to simulate drug administration with a fatty meal. The results were displayed in 3-dimensional graphs utilizing the topographical plotting technique of Skelly et al. The influence of pH on the in vitro drug release from the C.R. formulations was found to be less significant than the effect of lipid. A substantial decrease in dissolution rate that occurs with lipid pretreatment across the entire pH range suggests that lipid may have a significant effect on these C.R. drug products which are subject to a high first-pass effect.

Integration of pharmacokinetics, pharmacodynamics, and toxicokinetics in rational drug development

Twenty-five papers from a conference on [title] held April 1991, in Arlington, Virginia, were edited and updated for presentation in this proceedings volume. Contributions on the topics announced in the title are from academic, governmental, and industrial scientists aiming to identify the roles and

Comparative in vitro release profiles of marketed nitroglycerin patches by different dissolution methods

A simple procedure for determining the in vitro release profile of transdermal patches has been developed. The patch is held in position by sandwiching it between a watch glass and an aluminum wire screen, placed at the bottom of the dissolution flask, and the release profile determined using the USP paddle method (FDAs procedure). Currently there are five brands of conditionally approved nitroglycerin patches, each using a different quality control procedure. Dissolution of all patches was conducted by the firms procedure and FDAs method. The release profiles of all products with both methods are compared and discussed. The FDAs procedure/method was found to be simple, reproducible and applicable for in vitro release characterization of all brands of marketed patches.

THEOPHYLLINE-CONTROLLED RELEASE PREPARATIONS AND FATTY FOOD : AN IN VITRO STUDY USING THE ROTATING DIALYSIS CELL METHOD

The in vitro dissolution behavior of four controlled-release theophylline products was investigated utililzing the rotating dialysis cell method. The effects of pH, oil, and enzymes on the dissolution profiles were studied. The wide range of pH values and the content of oil and enzymes in the dissolution media in the dialysis cell, which functioned as an in vitro model, were simulated to mimic physiological changes due to food along the entire gastrointestinal tract. Treatment with oil affected the dissolution behavior of Uniphyl and especially Theo-Dur Sprinkle but had little or no effect on the dissolution profiles of Theo-Dur tablets and Theo-24 capsules. The in vitro observations of the oil effect were related to the food effect obtained from published in vivo studies. The rotating dialysis cell can be a useful tool in studying factors which may be responsible for dissolution-related food effects on the absorption of controlled-release products.

Analysis of in Vitro Dissolution of Whole vs. Half Controlled-Release Theophylline Tablets

Controlled-release (CR) drug products dissolve more slowly than conventional-release products, reflecting their quality of sustaining a prolonged therapeutic effect. A frequent practice with scored tablets when only half the dosage is desired is to divide the tablet at the score mark and administer only half of the product. The dissolution characteristics of the divided tablets are unknown. It is only an assumption that the halved tablet behaves similarly to the whole tablet both in vitro and in vivo. A series of in vitro dissolution analyses was performed on whole and half CR theophylline tablets from different manufacturers. Statistical tests were carried out between the dissolution results of whole and those of halved tablets to determine whether the mean overall percentages dissolution (averaged over sampling times) were similar and whether the patterns of percentage dissolution over time were similar. The dissolution of halved tablets was slightly faster compared to that of intact (whole) tablets. However, these small differences were not large enough to cause concern or to require bioavailability studies.