Methods and Options for in vitro Dialyzability; Benefits and Limitations

2005 ◽  
Vol 75 (6) ◽  
pp. 395-404 ◽  
Author(s):  
Ann-Sofie Sandberg
Keyword(s):  
Mineral Absorption ◽  
Permeable Membrane ◽  
Large Molecules ◽  
Transit Times ◽  
Absorption Studies ◽  
Iron And Zinc ◽  
Computer Controlled ◽  
Dialyzable Iron ◽  
Zinc Determination

In vitro dialyzability methods involve a two-step digestion process simulating the gastric and intestinal phase, and dialysis through a semi-permeable membrane with a selected molecular weight cut-off. Dialyzable iron/zinc is used as an estimation of available mineral. Final pH adjustment and use of a strict time schedule were found to be critical factors for standardization. In addition the selected cut-off of the dialysis membrane and the method used for iron and zinc determination influence the results. For screening purposes, simple solubility or dialyzability methods seem preferable to the more sophisticated computer-controlled gastrointestinal model. This is likely more valuable in studies of different transit times and sites of dialyzability. In vitro solubility/dialyzability methods correlate in most cases with human absorption studies in ranking iron and zinc availability from different meals. Exceptions may be that effects of milk, certain proteins, tea, and organic acids cannot be predicted. The dialyzability methods exclude iron bound to large molecules, which in some cases is available and include iron bound to small molecules, which is not always available. In vitro experiments based on solubility/dialyzability are tools to understand factors that may affect subsequent mineral absorption.

scholarly journals An In Vivo Predictive Dissolution Methodology (iPD Methodology) with a BCS Class IIb Drug Can Predict the In Vivo Bioequivalence Results: Etoricoxib Products

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 507
Author(s):  
Isabel Gonzalez-Alvarez ◽  
Marival Bermejo ◽  
Yasuhiro Tsume ◽  
Alejandro Ruiz-Picazo ◽  
Marta Gonzalez-Alvarez ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
In Vitro Dissolution ◽  
Case Examples ◽  
Dissolution Studies ◽  
Weak Bases ◽  
Transit Times ◽  
Class Iib ◽  
The Impact

The purpose of this study was to predict in vivo performance of three oral products of Etoricoxib (Arcoxia® as reference and two generic formulations in development) by conducting in vivo predictive dissolution with GIS (Gastro Intestinal Simulator) and computational analysis. Those predictions were compared with the results from previous bioequivalence (BE) human studies. Product dissolution studies were performed using a computer-controlled multicompartmental dissolution device (GIS) equipped with three dissolution chambers, representing stomach, duodenum, and jejunum, with integrated transit times and secretion rates. The measured dissolved amounts were modelled in each compartment with a set of differential equations representing transit, dissolution, and precipitation processes. The observed drug concentration by in vitro dissolution studies were directly convoluted with permeability and disposition parameters from literature to generate the predicted plasma concentrations. The GIS was able to detect the dissolution differences among reference and generic formulations in the gastric chamber where the drug solubility is high (pH 2) while the USP 2 standard dissolution test at pH 2 did not show any difference. Therefore, the current study confirms the importance of multicompartmental dissolution testing for weak bases as observed for other case examples but also the impact of excipients on duodenal and jejunal in vivo behavior.

scholarly journals EFFECT OF POLYMERS ON THE PHYSICOCHEMICAL AND DRUG RELEASE PROPERTIES OF TRANSDERMAL PATCHES OF ATENOLOL

2018 ◽  
Vol 10 (4) ◽  
pp. 68
Author(s):  
Manish Kumar ◽  
Vishal Trivedi ◽  
Ajay Kumar Shukla ◽  
Suresh Kumar Dev
Keyword(s):  
Drug Release ◽  
Hydroxypropyl Methylcellulose ◽  
Research Work ◽  
High Moisture ◽  
Transdermal Drug Delivery System ◽  
Permeable Membrane ◽  
Transdermal Patches ◽  
Egg Membrane ◽  
Hydrophilicity And Hydrophobicity

Objective: The objective of this research work was to develop a transdermal drug delivery system containing atenolol with different ratios of hydrophilic and hydrophobic polymeric combinations, using solvent evaporation technique and to examine the effect of hydrophilicity and hydrophobicity of polymers on the physicochemical and drug release properties of transdermal patches.Methods: Solvent casting method has been used to formulate transdermal patches. Hydroxypropyl methylcellulose (HPMC), Polyvinylpyrrolidone (PVP), Ethylcellulose (EC) in different combination ratios were used as the polymer. Propylene glycol was used as a plasticizer. Permeation enhancers such as span 80 were used to enhance permeation through the skin. In vitro diffusion study was carried out by franz diffusion cell using egg membrane as a semi-permeable membrane for diffusion.Results: Result showed that the thickness of the all batch of patches varied from 0.32 to 0.39 mm with uniformity of thickness in each formulation. Formulations F1 to F3 had high moisture content varied from 2.07±0.09 to 2.56±0.15 and high moisture uptake value varied from 3.21±0.35 to 4.09±0.38, due to a higher concentration of hydrophilic polymers. Drug content of all batches was ranged between 85.92±1.32 to 95.71±1.42. Folding endurance values off all batches were more than 75. Formulation batches F1 to F3 showed higher cumulative drug release varied from 61.34% to 68.11% as compared to formulation batches F4 to F6.Conclusion: Higher proportion of hydrophilic polymer in the formulation of transdermal patches, gives higher percentage drug release from prepared patches. The finding of the study indicates that hydrophilicity and hydrophobicity of polymer effects the physicochemical and drug release properties of transdermal patches and an optimum proportion of hydrophilic and hydrophobic polymer is required for the preparation of effective transdermal patches. 

scholarly journals A Validated HPLC-PDA-HRMS Method to Investigate the Biological Stability and Metabolism of Antiparasitic Triterpenic Esters

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7154
Author(s):  
Laura Schioppa ◽  
Fanta Fall ◽  
Sergio Ortiz ◽  
Jacques H. Poupaert ◽  
Joelle Quetin-Leclercq
Keyword(s):  
Medicinal Plants ◽  
Degradation Products ◽  
Biological Stability ◽  
Acidic Media ◽  
Microsomal Metabolism ◽  
Plasma Enzymes ◽  
Absorption Studies ◽  
H 30

Pentacyclic triterpenes (PTs) are commonly found in medicinal plants with well-known antiparasitic effects. Previous research on C-3 and C-27 triterpenic esters showed effective and selective in vitro antiparasitic activities and in vivo effectiveness by parenteral routes. The aim of this study was to determine triterpenic esters’ stability in different biological-like media and the main microsomal degradation products. An HPLC-PDA method was developed and validated to simultaneously analyze and quantify bioactive triterpenic esters in methanol (LOQ: 2.5 and 1.25–100 µg/mL) and plasma (LOQ: 5–125 µg/mL). Overall, both triterpenic esters showed a stable profile in aqueous and buffered solutions as well as in entire plasma, suggesting gaining access to the ester function is difficult for plasma enzymes. Conversely, after 1 h, 30% esters degradation in acidic media was observed with potential different hydrolysis mechanisms. C-3 (15 and 150 µM) and C-27 esters (150 µM) showed a relatively low hepatic microsomal metabolism (<23%) after 1 h, which was significantly higher in the lowest concentration of C-27 esters (15 µM) (>40% degradation). Metabolic HPLC-PDA-HRMS studies suggested hydrolysis, hydroxylation, dehydration, O-methylation, hydroxylation and/or the reduction of hydrolyzed derivatives, depending on the concentration and the position of the ester link. Further permeability and absorption studies are required to better define triterpenic esters pharmacokinetic and specific formulations designed to increase their oral bioavailability.

Preparation and in vitro absorption studies of a novel polysaccharide‑iron (III) complex from Flammulina velutipes

2019 ◽  
Vol 132 ◽  
pp. 801-810 ◽  
Author(s):  
Chen Cheng ◽  
De-chun Huang ◽  
Li-yan Zhao ◽  
Chong-jiang Cao ◽  
Gui-tang Chen
Keyword(s):  
Flammulina Velutipes ◽  
Absorption Studies

The Precision of in vitro Methods and Algorithms for Predicting the Bioavailability of Dietary Iron

2005 ◽  
Vol 75 (6) ◽  
pp. 436-445 ◽  
Author(s):  
Sean Lynch
Keyword(s):  
Iron Absorption ◽  
Heme Iron ◽  
Iron Bioavailability ◽  
Cell Uptake ◽  
In Vitro Tests ◽  
Cellular Iron ◽  
Non Heme Iron ◽  
Human Volunteers ◽  
Dialyzable Iron

Three factors determine how much iron will be absorbed from a meal. They are the physiological mechanisms that regulate uptake by and transfer through the enterocytes in the upper small intestine, the quantity of iron in the meal, and its availability to the cellular iron transporters. Established methods exist for predicting the effect of physiological regulation and for measuring or estimating meal iron content. Three approaches to estimating bioavailability have been advocated. Two are in vitro screening procedures: measurement of dialyzable iron and Caco-2 cell uptake, both carried out after in vitro simulated gastric and pancreatic digestion. The third is the use of algorithms based on the predicted effects of specific meal components on absorption derived from isotopic studies in human volunteers. The in vitro procedures have been very useful for identifying and characterizing factors that affect non-heme iron absorption, but direct comparisons between absorption predicted from the in vitro tests and measurements in human volunteers have only been made in a limited number of published studies. The available data indicate that dialysis and Caco-2 cell uptake are useful for ranking meals and single food items in terms of predicted iron bioavailability, but may not reflect the magnitudes of the effects of factors that influence absorption accurately. Algorithms based on estimates of the amounts of heme iron and of enhancers and inhibitors of non-heme iron absorption in foods make it possible to classify meals or diets as being of high, medium, or low bioavailability. The precision with which meal iron bioavailability can be predicted in a population, for which a specific algorithm has been developed, is improved by measuring the content of the most important enhancers and inhibitors. However, the accuracy of such predictions appears to be much lower when the algorithm is applied to meals eaten by different populations.

scholarly journals Human IgA as a heterovalent ligand: switching from the asialoglycoprotein receptor to secretory component during transport across the rat hepatocyte.

1986 ◽  
Vol 102 (3) ◽  
pp. 920-931 ◽  
Author(s):  
J M Schiff ◽  
M M Fisher ◽  
A L Jones ◽  
B J Underdown
Keyword(s):  
Secretory Component ◽  
Binding Activity ◽  
Asialoglycoprotein Receptor ◽  
Galactose Oxidase ◽  
Rat Hepatocyte ◽  
Binding Properties ◽  
Affinity Adsorption ◽  
Switching Event ◽  
Transit Times

Asialoglycoproteins are taken up by the rat liver for degradation; rat polymeric IgA is taken up via a separate receptor, secretory component (SC), for quantitative delivery to bile. There is negligible uptake of these ligands by the converse receptor, and only a low level of missorting of ligands to opposite destinations. The two pathways are not cross-inhibitable and operate independently (Schiff, J.M., M. M. Fisher, and B. J. Underdown, 1984, J. Cell Biol., 98:79-89). We report here that when human IgA is presented as a ligand in the rat, it is processed using elements of both pathways. To study this in detail, different IgA fractions were prepared using two radiolabeling methods that provide separate probes for degradation or re-secretion. Behavior of intravenously injected human polymeric IgA in the rat depended on its binding properties. If deprived of SC binding activity by affinity adsorption or by reduction and alkylation, greater than 80% of human IgA was degraded in hepatic lysosomes; radioactive catabolites were released into bile by a leupeptin-inhibitable process. If prevented from binding to the asialoglycoprotein receptor by competition or by treatment with galactose oxidase, human IgA was cleared and transported to bile directly via SC, but its uptake was about fivefold slower than rat IgA. Untreated human IgA was taken up rapidly by the asialoglycoprotein receptor, but depended on SC binding to get to bile: the proportion secreted correlated 1:1 with SC binding activity determined in vitro, and the IgA was released into bile with SC still attached. These results demonstrate that human IgA is normally heterovalent: it is first captured from blood by the asialoglycoprotein receptor, but escapes the usual fate of asialoglycoproteins by switching to SC during transport. Since the biliary transit times of native human and rat IgA are the same, it is probable that the receptor switching event occurs en route. This implies that the two receptors briefly share a common intracellular compartment.

Sign in / Sign up

Export Citation Format

Share Document