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Younes M, Aquilina G, Engel K, Fowler P, Frutos Fernandez MJ, Fürst P, Gürtler R, Gundert‐Remy U, Husøy T, Manco M, Mennes W, Passamonti S, Moldeus P, Shah R, Waalkens‐Berendsen I, Wölfle D, Wright M, Barat Baviera JM, Degen G, Leblanc J, Herman L, Civitella C, Giarola A, Smeraldi C, Tard A, Vianello G, Castle L. Safety evaluation of crosslinked polyacrylic acid polymers (carbomer) as a new food additive. EFSA J 2021; 19:e06693. [PMID: 34400972 PMCID: PMC8356569 DOI: 10.2903/j.efsa.2021.6693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The EFSA Panel on Food Additives and Flavourings (FAF) provides a scientific opinion on the safety of crosslinked polyacrylic acid polymers (carbomer) proposed for use as food additive in solid and liquid food supplements. Carbomer is formed from the monomer, acrylic acid, which is polymerised and crosslinked with allyl pentaerythritol (APE). The polymers are synthesised in ethyl acetate using ■■■■■ as free-radical polymerisation initiator. In vivo data showed no evidence for systemic availability or biotransformation of carbomer. Carbomer does not raise a concern regarding genotoxicity. Considering the available data set, the Panel derived an acceptable daily intake (ADI) of 190 mg/kg body weight (bw) per day based on a no observed adverse effect level (NOAEL) of 1,500 mg/kg bw per day from a sub-chronic 13-week study in rat, applying a compound specific uncertainty factor (UF) of 8. At the proposed maximum use levels, the exposure estimates ranged at the mean from 1.1 to 90.2 mg/kg bw per day and at the p95 from 12.5 to 237.4 mg/kg bw per day. At the proposed typical use level, the exposure estimates ranged at the mean from 0.7 to 60.2 mg/kg bw per day and at the p95 from 10.3 to 159.5 mg/kg bw per day. The Panel noted that the maximum proposed use levels would result in exposure estimates close to or above the ADI. The Panel also noted that level of exposure to carbomer from its proposed use is likely to be an overestimation. Taking a conservative approach, the Panel considered that exposure to carbomer would not give rise to a safety concern if the proposed maximum use level for solid food supplements is lowered to the typical use level reported by the applicant.
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Sedláček O, Černoch P, Kučka J, Konefal R, Štěpánek P, Vetrík M, Lodge TP, Hrubý M. Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:6115-6122. [PMID: 27238593 DOI: 10.1021/acs.langmuir.6b01527] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ≪ poly[N-(2,2-difluoroethyl)acrylamide] (DFP) < poly(N-isopropylacrylamide) (PNIPAM) ≪ poly(2-isopropyl-2-oxazoline-co-2-n-butyl-2-oxazoline) (POX). Even low doses of β radiation (1 kGy), which are highly relevant to the storage of polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands.
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Affiliation(s)
- Ondřej Sedláček
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Peter Černoch
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Jan Kučka
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Rafał Konefal
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Petr Štěpánek
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Miroslav Vetrík
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Timothy P Lodge
- Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Martin Hrubý
- Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
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Wolf JR. Review: radiolabeled polymers containing covalently bound3H and14C. J Labelled Comp Radiopharm 2016; 59:38-47. [DOI: 10.1002/jlcr.3359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 10/11/2015] [Accepted: 11/08/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Jeremy R. Wolf
- Synthesis Department; ABC Laboratories; Columbia MO 65202 USA
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Garcia Cordeiro Tessarolli F, Gomes De Carvalho Queirós Y, Regina Elias Mansur C. Evaluation of pH-sensitive hydrogels to control the permeability anisotropy of oil reservoirs. J Appl Polym Sci 2014. [DOI: 10.1002/app.40665] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Yure Gomes De Carvalho Queirós
- Laboratory of Macromolecules and Colloids Applied to Petroleum Production (LMCP); Institute of Macromolecules (IMA); Federal University of Rio de Janeiro (UFRJ); 2030 Horácio Macedo Avenue-Ilha do Fundão, Rio de Janeiro RJ 21941-598 Brazil
| | - Claudia Regina Elias Mansur
- Laboratory of Macromolecules and Colloids Applied to Petroleum Production (LMCP); Institute of Macromolecules (IMA); Federal University of Rio de Janeiro (UFRJ); 2030 Horácio Macedo Avenue-Ilha do Fundão, Rio de Janeiro RJ 21941-598 Brazil
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Long M, Rogers SH, Thornthwaite DW, Livens FR, Rannard SP. Monitoring Atom Transfer Radical Polymerisation using14C-radiolabelled initiators. Polym Chem 2011. [DOI: 10.1039/c0py00275e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Alakhov V, Pietrzynski G, Patel K, Kabanov A, Bromberg L, Hatton TA. Pluronic block copolymers and Pluronic poly(acrylic acid) microgels in oral delivery of megestrol acetate. J Pharm Pharmacol 2010; 56:1233-41. [PMID: 15482637 DOI: 10.1211/0022357044427] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Several Pluronic-based formulations were studied in-vitro and in a rat model with respect to the release and bioavailability of megestrol acetate (MA) after oral administration. It was demonstrated that an aqueous, micellar formulation comprising a mixture of a hydrophobic (L61) and a hydrophilic (F127) Pluronic copolymer, significantly enhanced the bioavailability of MA administered orally at relatively low doses (1–7 mg kg−1). Pluronic-based microgels (spherical gel particles of sub-millimetre size) were introduced as MA vehicles. The microgels comprised a cross-linked network of poly(acrylic acid) onto which the Pluronic chains were covalently attached. Microgels of Pluronic L92 and poly(acrylic acid) fabricated into tablet dosage forms exhibited dramatically lowered MA initial burst release. The MA release was pH-dependent owing to the pH sensitivity of the microgel swelling, with the drug retained by the microgel at pH 1.8 and released slowly at pH 6.8. In the rat model, a significant increase in MA bioavailability was observed when the microgel-formulated MA was administered orally at a high dose of 10 mg kg−1, owing to the enhanced retention of the microgel. The study of the microgel passage through the gastrointestinal tract demonstrated the microgel retention characteristic of a very high molecular weight polymer and the absence of any systemic absorption of the polymer.
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Affiliation(s)
- Valery Alakhov
- Supratek Pharma, Inc., 215, Boulevard Bouchard, Suite 1315, Dorval, Quebec H9S 1A9, Canada.
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Long M, Thornthwaite DW, Rogers SH, Bonzi G, Livens FR, Rannard SP. Utilising 14C-radiolabelled atom transfer radical polymerisation initiators. Chem Commun (Camb) 2009:6406-8. [DOI: 10.1039/b913294e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Riley RG, Smart JD, Tsibouklis J, Young SA, Hampson F, Davis A, Kelly G, Dettmar PW, Wilber WR. An in vitro model for investigating the gastric mucosal retention of 14C-labelled poly(acrylic acid) dispersions. Int J Pharm 2002; 236:87-96. [PMID: 11891073 DOI: 10.1016/s0378-5173(02)00014-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Polymers that bind from solution onto gastric mucosae can be used as a means of facilitating localised drug delivery, or act as therapeutic agents in their own right (e.g. by forming a protective layer or by inhibiting enzymes). Previous workers have used semi-quantitative methods to identify the ability of commercially available poly(acrylic acid)s to bind to gastric mucosa. In this study, the binding and retention of labelled poly(acrylic acid)s to sections of gastric mucosa from the pyloric region of pigs stomach were evaluated using 'static' and 'dynamic flow' test systems. Dispersions (3%) of 'low', 'high' and 'ultra high' (cross-linked) polymers were seen to adhere to porcine pyloric mucosa after exposure and rinsing in the 'static' system. The high molecular weight polymer showed the greatest retention in the 'dynamic' test system when washing continuously with simulated gastric acid. Changing the pH of the dispersions from 4.3 to 6.2 had little effect on polymer retention. It was concluded that polymers that were sufficiently mobile in solution to spread on, and interact with, the mucosal surface, but had a sufficiently high molecular weight to form viscous solutions and/or bioadhere to the mucosa, may be retained on the mucosal surface for the longest periods.
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Affiliation(s)
- Robert G Riley
- Biomaterials and Drug Delivery Group, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael's Building, White Swan Road, PO1 2DT, Portsmouth, UK
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Riley RG, Green KL, Smart JD, Tsibouklis J, Davis JA, Hampson F, Dettmar PW, Wilber WR. The gastrointestinal transit profile of 14C-labelled poly(acrylic acids): an in vivo study. Biomaterials 2001; 22:1861-7. [PMID: 11396891 DOI: 10.1016/s0142-9612(00)00369-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The gastrointestinal distribution profiles for three 14C-labelled poly(acrylic acid)s of different average molecular weights and degrees of cross-linking have been established using the rat model. Despite initial differences in transit times and retention characteristics, these structural features were found to be of little influence to the overall gastrointestinal transit of the materials under consideration. No evidence for the systemic absorption of any of the polymers could be identified.
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Affiliation(s)
- R G Riley
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
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Riley RG, Smart JD, Tsibouklis J, Dettmar PW, Hampson F, Davis JA, Kelly G, Wilber WR. An investigation of mucus/polymer rheological synergism using synthesised and characterised poly(acrylic acid)s. Int J Pharm 2001; 217:87-100. [PMID: 11292545 DOI: 10.1016/s0378-5173(01)00592-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A range of poly(acrylic acid)s with different average degrees of polymerisation and cross-linking densities were synthesised using a solution polymerisation process. The rheological characteristics of aqueous dispersions of these materials and those of mixtures with homogenised pigs gastric mucus were investigated using dynamic oscillatory rheology, and compared to the known mucoadhesive Carbopol 934P. From the storage moduli, the rheological synergy and relative rheological synergy were calculated, and the effects of concentration and pH on this considered. Generally, the larger the molecular weight (and degree of cross-linking), the greater the rheological synergy, with Carbopol 934P giving the most pronounced effect. Rheological synergy was seen to be concentration-dependent, and a maximum concentration to produce an optimum effect was evident. Acid pHs were seen to favour synergy, although in marked contrast to previous literature reports, the optimum mucus-polymer interaction was not observed at the half ionised value (pH = pKa) but at pH regimes that were unique to each polymer type. This could be influenced by the structural constrains imposed on potential hydrogen bonded interactions. It was concluded that synthesising poly(acrylic acid)s with better defined physicochemical properties than commercially available polymers will advance the study of the phenomenon of rheological synergy.
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Affiliation(s)
- R G Riley
- Biomaterials and Drug Delivery Group, Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, White Swan Road, PO1 2DT, Portsmouth, UK
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