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Carvalho AM, Fernandes E, Gonçalves H, Giner-Casares JJ, Bernstorff S, Nieder JB, Real Oliveira MECD, Lúcio M. Prediction of paclitaxel pharmacokinetic based on in vitro studies: Interaction with membrane models and human serum albumin. Int J Pharm 2020; 580:119222. [PMID: 32194209 DOI: 10.1016/j.ijpharm.2020.119222] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 01/10/2023]
Abstract
Interactions of paclitaxel (PTX) with models mimicking biological interfaces (lipid membranes and serum albumin, HSA) were investigated to test the hypothesis that the set of in vitro assays proposed can be used to predict some aspects of drug pharmacokinetics (PK). PTX membrane partitioning was studied by derivative spectrophotometry; PTX effect on membrane biophysics was evaluated by dynamic light scattering, fluorescence anisotropy, atomic force microscopy and synchrotron small/wide-angle X-ray scattering; PTX distribution/molecular orientation in membranes was assessed by steady-state/time-resolved fluorescence and computer simulations. PTX binding to HSA was studied by fluorescence quenching, derivative spectrophotometry and dynamic/electrophoretic light scattering. PTX high membrane partitioning is consistent with its efficacy crossing cellular membranes and its off-target distribution. PTX is closely located in the membrane phospholipids headgroups, also interacting with the hydrophobic chains, and causes a major distortion of the alignment of the membrane phospholipids, which, together with its fluidizing effect, justifies some of its cellular toxic effects. PTX binds strongly to HSA, which is consistent with its reduced distribution in target tissues and toxicity by bioaccumulation. In conclusion, the described set of biomimetic models and techniques has the potential for early prediction of PK issues, alerting for the required drug optimizations, potentially minimizing the number of animal tests used in the drug development process.
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Affiliation(s)
- Ana M Carvalho
- CF-UM-UP, Centro de Física das Universidades do Minho e Porto, Departamento de Física da Universidade do Minho, Campus of Gualtar, 4710-057 Braga, Portugal; Nanophotonics Department, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Eduarda Fernandes
- CF-UM-UP, Centro de Física das Universidades do Minho e Porto, Departamento de Física da Universidade do Minho, Campus of Gualtar, 4710-057 Braga, Portugal
| | | | - Juan J Giner-Casares
- Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus de Rabanales, Edificio Marie Curie, Córdoba E-14014, Spain.
| | - Sigrid Bernstorff
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, in Area Science Park, I-34149 Basovizza, Trieste, Italy.
| | - Jana B Nieder
- Nanophotonics Department, Ultrafast Bio- and Nanophotonics Group, INL - International Iberian Nanotechnology Laboratory, Braga, Portugal.
| | - M Elisabete C D Real Oliveira
- CF-UM-UP, Centro de Física das Universidades do Minho e Porto, Departamento de Física da Universidade do Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
| | - Marlene Lúcio
- CF-UM-UP, Centro de Física das Universidades do Minho e Porto, Departamento de Física da Universidade do Minho, Campus of Gualtar, 4710-057 Braga, Portugal; CBMA, Centro de Biologia Molecular e Ambiental, Departamento de Biologia, Universidade do Minho, 4710-057 Braga, Portugal.
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Paál K, Müller J, Hegedûs L. High affinity binding of paclitaxel to human serum albumin. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:2187-91. [PMID: 11277943 DOI: 10.1046/j.1432-1327.2001.02107.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Paclitaxel, a very potent antitumor agent is a hydrophobic molecule with low aqueous solubility. Its currently used formula (Taxol) contains the drug in a 1 : 1 (v/v) mixture of ethanol and Cremophor EL. To minimize vehicle-related toxicity, we developed a novel, water-soluble formulation in which paclitaxel is bound noncovalently to human serum albumin. For this purpose, studies of the paclitaxel-albumin binding equilibrium were performed. Paclitaxel dissolved in ethanol was added to the aqueous solution of human serum albumin. Precipitated paclitaxel was removed and unbound drug was separated by ultrafiltration. Paclitaxel concentration was measured by RP-HPLC. Binding data were evaluated based both on the Scatchard plot and the general binding equation describing binding equilibria with the stepwise stoichiometric binding constants. The Scatchard plot was found to be curvilinear with a slight positive slope of the final part. Parameters of high affinity specific binding were determined from the initial part of the curve (nsp = 1.3 and Ksp = 1.7 x 10(6) M(-1)). Stoichiometric binding constants were estimated by fitting the general binding equation to the experimental data (K1 = 2.4 x 10(6) M(-1) and K2 = 1.0 x 10(5) M(-1)). Saturation of the protein with paclitaxel, similarly to other ligands of albumin, could not be reached. The greatest observed value of r (number of paclitaxel molecules bound to one albumin molecule) was 6.6.
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Affiliation(s)
- K Paál
- Department of Pharmaceutical Research and Development, HUMAN Co. Ltd, Gödöllõ, Hungary.
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Pedersen JB, Pedersen SM, Lindup WE. Contamination by a competitive ligand as an explanation for the inverse dependence of HABA binding parameters upon the protein concentration. Biochem Pharmacol 1989; 38:3485-90. [PMID: 2818639 DOI: 10.1016/0006-2952(89)90118-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
There is evidence that the apparent association constant (K) and/or the number of binding sites (n) are inversely dependent upon protein concentration for a number and variety of ligands with no obvious structure-activity relationships. A model recently shown to explain this effect with an inorganic ligand has now been applied to 2-(4'-hydroxybenzeneazo) benzoic acid (HABA) and also explains the inverse protein dependence of the binding of this compound to human albumin. The model explains this inverse dependence on the basis of a highly bound contaminant which competes with the ligand for the high affinity site. HABA was found to interact with human albumin at three or more sites, the high affinity site which was about 95% contaminated had an association constant of 2 x 10(5)/M, an order of magnitude higher than that found previously when the effect of a contaminant was not considered. The association constant of the competitive contaminant was estimated to be about 5 x 10(6)/M. Since the model accounts for the phenomenon in terms of a property of the protein, rather than of the ligand, it could provide a general explanation for this effect with other ligand-acceptor combinations including a wide variety of drug and hormone receptor preparations.
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