The current BSC guidance issued by the FDA allows for biowaivers based on conservative criteria. Possible new criteria and class boundaries are proposed for additional biowaivers based on the underlying physiology of the gastrointestinal tract. The proposed changes in new class boundaries for solubility and permeability are as follows: 1. Narrow the required solubility pH range from 1.0-7.5 to 1.0-6.8. 2. Reduce the high permeability requirement from 90% to 85%. The following new criterion and potential biowaiver extension require more research: 1. Define a new intermediate permeability class boundary. 2. Allow biowaivers for highly soluble and intermediately permeable drugs in IR solid oral dosage forms with no less than 85% dissolved in 15 min in all physiologically relevant dissolution media, provided these IR products contain only known excipients that do not affect the oral drug absorption. The following areas require more extensive research: 1. Increase the dose volume for solubility classification to 500 mL. 2. Include bile salt in the solubility measurement. 3. Use the intrinsic dissolution method for solubility classification. 4. Define an intermediate solubility class for BCS Class II drugs. 5. Include surfactants in in vitro dissolution testing.

/pdf/biopharmaceutics-classification-system-the-scientific-basis-1vvr50wd2i.pdf

Biopharmaceutics Classification System: The Scientific Basis for Biowaiver Extensions

Contributors Jean-Marc Aiache, Nobuo Aoyagi, Dennis Bashaw, Cynthia Brown, William Brown, Diane Burgess, John Crison, Patrick DeLuca, Ruzica Djerki, Jennifer Dressman, Thomas Foster, Kirsti Gjellan, Vivian Gray, Ajaz Hussain, Tom Ingallinera, James Klancke, Johannes Kraemer, Henning Kristensen, Kofi Kumi, Christian Leuner, Jobst Limberg, Petra Loos, Lenny Margulis, Patrick Marroum, Helga Moeller, Bernd Mueller, Martin Mueller-Zsigmondy, Ngozi Okafo, Larry Ouderkirk, Shravan Parsi, Saeed Qureshi, Joseph Robinson, Vinod Shah, Martin Siewert, Ramana Uppoor, and Roger Williams. Aventis, Frankfurt, Germany JW Goethe University, Frankfurt, Germany Eli Lilly and Company, Indianapolis, IN Office of Pharmaceutical Science, Center for Drug Evaluation and Research, US Food and Drug Administration, Rockville, MD Universite d'Auvergne, Clermont-Ferrand Cedex, France National Institute of Health Sciences, Division of Drugs, Tokyo, Japan US Pharmacopeia, Rockville, MD University of Connecticut, Storrs Mansfield, CT Pfizer, Inc, La Jolla, CA University of Kentucky, Lexington, KY Novartis Pharma, Basel, Switzerland AstraZeneca, Sodertalje, Sweden V.A. Gray Consulting, Inc, Hockessin, DE AAI International, Charleston, SC CIMA Laboratories, Inc, Minneapolis, MN Laboratory and Quality Services, Eschborn, Germany University of Copenhagen, Denmark Bundesinstitut fur Arzneimittel, Bonn, Germany Aventis Pharmaceuticals, Bridgewater, NJ Pfizer, Groton, CT Zentrallaboratorium Deutscher Apotheker, Eschborn, Germany Kiel University, Kiel, Germany Alza Corporation, Mountain View, CA DPT Laboratories, Ltd, San Antonio, TX Health Protection Branch, Ottawa, Canada University of Wisconsin, WI

/pdf/fip-aaps-guidelines-to-dissolution-in-vitro-release-testing-2cp52c25iq.pdf

FIP/AAPS guidelines to dissolution/in vitro release testing of novel/special dosage forms

Background: Patients with ALS commonly exhibit pseudobulbar affect. Methods: The authors conducted a multicenter, randomized, double-blind, controlled, parallel, three-arm study to test a defined combination of dextromethorphan hydrobromide (DM) and quinidine sulfate (Q) (AVP-923) for the treatment of pseudobulbar affect in ALS. Q inhibits the rapid first-pass metabolism of DM. The effects of AVP-923 (30 mg of DM plus 30 mg of Q) given twice daily for 28 days were compared with those of its components. Patients were evaluated on days 1, 15, and 29. The primary efficacy variable was the change from baseline in the Center for Neurologic Study Lability Scale (CNS-LS) score. Secondary efficacy variables were laughing/crying episode rates and changes in Visual Analog Scales for Quality of Life (QOL) and Relationships (QOR). Efficacy was evaluated in intention-to-treat subjects who were not poor metabolizers of DM (n = 65 for AVP-923, n = 30 for DM, and n = 34 for Q). Safety was assessed in all randomized subjects (n = 140). Results: AVP-923 patients experienced 3.3-point greater improvements in CNS-LS than DM patients ( p = 0.001) and 3.7-point greater improvements than Q patients ( p p Conclusions: AVP-923 palliates pseudobulbar affect in ALS. Overall benefits of treatment are reflected in fewer episodes of crying and laughing and improvements in overall quality of life and quality of relationships.

Treatment of pseudobulbar affect in ALS with dextromethorphan/quinidine: a randomized trial.

Objective

To evaluate the efficacy and safety of DM/Q (capsules containing dextromethorphan [DM] and quinidine [Q]) compared with placebo, taken twice daily, for the treatment of pseudobulbar affect over a 12-week period in multiple sclerosis patients.



Methods

A total of 150 patients were randomized in a double-blind, placebo-controlled study to assess pseudobulbar affect with the validated Center for Neurologic Study-Lability Scale. Each patient also recorded the number of episodes experienced between visits, estimated quality of life and quality of relationships on visual analog scales, and completed a pain rating scale.



Results

Patients receiving DM/Q had greater reductions in Center for Neurologic Study-Lability Scale scores than those receiving placebo (p < 0.0001) at all clinic visits (days 15, 29, 57, and 85). All secondary end points also favored DM/Q, including the number of crying or laughing episodes (p ≤ 0.0077), quality of life (p < 0.0001), quality of relationships (p = 0.0001), and pain intensity score (p = 0.0271). DM/Q was well tolerated; only dizziness occurred with greater frequency than with placebo.



Interpretation

Results in multiple sclerosis patients were similar to those of a previous study in amyotrophic lateral sclerosis, demonstrating that DM/Q may be beneficial in treating potentially disabling pseudobulbar affect in a variety of neurological disorders. Ann Neurol 2006;59:780–787

Randomized, controlled trial of dextromethorphan/quinidine for pseudobulbar affect in multiple sclerosis.

Purpose The use of cytochrome P450 2D6–inhibiting drugs (CYP2D6 inhibitors) during tamoxifen treatment leads to a decrease in plasma concentration of endoxifen, the major active tamoxifen metabolite. Concomitant use of CYP2D6 inhibitors, such as selective serotonin reuptake inhibitors, as well as low tamoxifen adherence may negatively impact tamoxifen efficacy in patients with breast cancer. The objectives of this study were to relate concomitant CYP2D6 inhibitor use and tamoxifen adherence to breast cancer event-free time (EFT). Patients and Methods Data were from PHARMO and included a community pharmacy dispensing database; PALGA, a nationwide pathology database; and the Dutch Medical Register in the Netherlands. Patients with breast cancer treated with adjuvant tamoxifen between 1994 and 2006 were included. A Cox proportional hazards model with a time-dependent definition for concomitant CYP2D6 inhibitor exposure was used. Adherence calculated over the first year after tamoxifen initiation was related ...

Effect of Concomitant CYP2D6 Inhibitor Use and Tamoxifen Adherence on Breast Cancer Recurrence in Early-Stage Breast Cancer

Dextromethorphan (DM) pharmacological properties predict that the widely used cough suppressant could be used to treat several neuronal disorders, but it is rapidly metabolized after oral dosing. To find out whether quinidine (Q), a CYP2D6 inhibitor, could elevate and prolong DM plasma profiles, 2 multiple-dose studies identified the lowest oral dose of Q that could be used in a fixed combination with 3 doses of DM. A multiple-dose study in healthy subjects with an extensive or a poor enzyme metabolizer phenotype evaluated the safety and pharmacokinetic profile of a selected fixed-dose combination (AVP-923). Study 1 randomized 46 healthy subjects, who were extensive CYP2D6 metabolizers, to receive 0, 2.5, 10, 25, 50, or 75 mg Q twice daily in combination with 30 mg DM for 7 days. Plasma and urine samples were collected after the first and last doses for the assay of DM, dextrorphan (DX), and Q. Study 2 randomized 65 healthy extensive CYP2D6 metabolizers to 8 groups given twice-daily 45- or 60-mg DM doses combined with 0, 30, 45, or 60 mg Q for 7 days. The effects of increasing Q were not different with doses greater than 25 mg, whereas lower doses showed a dose-related increase in plasma DM concentrations. Urinary ratios of DM/DX showed a Q dose- and time-related increase in the number of subjects converted to the poor metabolizer phenotype that reached 100% on day 3 of dosing with 25 mg Q. Results from both studies indicated that 25 to 30 mg Q is adequate to maximally suppress O-demethylation of DM. Study 3 evaluated 7 extensive metabolizers and 2 poor metabolizers given an oral capsule every 12 hours containing 30 mg Q combined with 30 mg DM. DM plasma AUC values increased in both groups of subjects during the 8-day study. The mean urinary metabolic ratio (DM/DX) increased at least 27-fold in extensive metabolizers by day 8. There was no effect of Q on urinary metabolic ratios in poor metabolizers. Safety evaluations, including electrocardiograms, indicated that the combination was well tolerated, with no difference between extensive and poor metabolizer phenotypes.

Pharmacokinetics of dextromethorphan after single or multiple dosing in combination with quinidine in extensive and poor metabolizers

The new FDA Guidance for Industry BA and BE Studies for Orally Administered Drug Products - General Considerations and Average, Population, and Individual Approaches to Establishing Bioequivalence imply significant changes in the areas of enrollment, cost, ethics, time, entry, validation applications (EVAs), and statistical and pharmacokinetic methods. The changes from three-period to two-period design for food effect studies, the elimination of most steady state studies, and the analyses of only the active moiety or ingredient are welcome. However, if the current guidances are adopted, additional time will be needed for participants, and more participants will be needed, resulting in higher costs to drug developers. The PK parameters needed to assess BE and the need for replicate designs for drugs with long t 1/2 are still unclear. Finally, the advantages of the aggregate property of the FDA metric versus the disaggregate criteria are challenged, and four bioeauivalence criteria are proposed.

A contract research organization's response to the new FDA guidances for bioequivalence/bioavailability studies for orally administered drug products.

Liquid chromatography–fluorescence (LC–FLS), liquid chromatography–tandem mass spectrometry (LC–MS/MS) and inductively coupled plasma–mass spectrometry (ICP-MS) methods were developed and validated for the evaluation of motexafin gadolinium (MGd, Xcytrin) pharmacokinetics and biodistribution in plasma and tissues. The LC–FLS method exhibited the greatest sensitivity (0.0057 μg mL−1), and was used for pharmacokinetic, biodistribution, and protein binding studies with small sample sizes or low MGd concentrations. The LC–MS/MS method, which exhibited a short run time and excellent selectivity, was used for routine clinical plasma sample analysis. The ICP–MS method, which measured total Gd, was used in conjunction with LC methods to assess MGd stability in plasma. All three methods were validated using human plasma. The LC–FLS method was also validated using plasma, liver and kidneys from mice and rats. All three methods were shown to be accurate, precise and robust for each matrix validated. For three mice, the mean (standard deviation) concentration of MGd in plasma/tissues taken 5 hr after dosing with 23 mg kg−1 MGd was determined by LC–FLS as follows: plasma (0.025±0.002 μg mL−1), liver (2.89±0.45 μg g−1), and kidney (6.09±1.05 μg g−1). Plasma samples from a subset of patients with brain metastases from extracranial tumors were analyzed using both LC–MS/MS and ICP–MS methods. For a representative patient, ≥90% of the total Gd in plasma was accounted for as MGd over the first hour post dosing. By 24 hr post dosing, 63% of total Gd was accounted for as MGd, indicating some metabolism of MGd.

Validation and use of three complementary analytical methods (LC-FLS, LC-MS/MS and ICP-MS) to evaluate the pharmacokinetics, biodistribution and stability of motexafin gadolinium in plasma and tissues.

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Pharmacokinetics of dextromethorphan after single or multiple dosing in combination with quinidine in extensive and poor metabolizers

A contract research organization's response to the new FDA guidances for bioequivalence/bioavailability studies for orally administered drug products.

Validation and use of three complementary analytical methods (LC-FLS, LC-MS/MS and ICP-MS) to evaluate the pharmacokinetics, biodistribution and stability of motexafin gadolinium in plasma and tissues.