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Pires PC, Santos LT, Rodrigues M, Alves G, Santos AO. Intranasal fosphenytoin: The promise of phosphate esters in nose-to-brain delivery of poorly soluble drugs. Int J Pharm 2020; 592:120040. [PMID: 33157214 DOI: 10.1016/j.ijpharm.2020.120040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/28/2020] [Accepted: 10/29/2020] [Indexed: 10/23/2022]
Abstract
Intranasal administration could increase both safety and efficacy of drugs acting on the central nervous system, but low solubility severely limits administration through this route. Phenytoin's prodrug, fosphenytoin, is hydrophilic and freely soluble in water, but less permeable since it is dianionic. We aimed to assess whether this phosphoester prodrug could be a suitable alternative to phenytoin in intranasal delivery. Secondly, we aimed to compare simple formulation strategies in fosphenytoin delivery. Fosphenytoin formulations containing thermosensitive and/or mucoadhesive (hydroxypropyl methylcellulose, HPMC) polymers were developed, guided by viscosity, gelling temperatures, osmolality, and in vitro drug release tests. Then, a pharmacokinetic study was performed, comparing an intravenous fosphenytoin solution, an intranasal fosphenytoin solution, and intranasal fosphenytoin mucoadhesive formulations with or without albumin. Formulations containing HPMC allowed high drug strengths, and had a relatively fast release profile, which was not changed by albumin. Intranasal administration of a formulation with HPMC and albumin prolonged drug concentration over time and led to complete or even increased absolute bioavailability. Moreover, phenytoin's blood levels did not reach the high peak obtained with intravenous administration. In conclusion, the use of phosphate ester prodrugs could be an efficient and safe strategy to increase the intranasal bioavailability of poorly soluble drugs.
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Affiliation(s)
- Patrícia C Pires
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Liliana T Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Márcio Rodrigues
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Research Unit for Inland Development (UDI-IPG), Polytechnic Institute of Guarda, 6300-559 Guarda, Portugal.
| | - Gilberto Alves
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Adriana O Santos
- Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal; Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
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Kiang TK, Schmitt V, Ensom MH, Chua B, Häfeli UO. Therapeutic Drug Monitoring in Interstitial Fluid: A Feasibility Study Using a Comprehensive Panel of Drugs. J Pharm Sci 2012; 101:4642-52. [DOI: 10.1002/jps.23309] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 07/23/2012] [Accepted: 08/10/2012] [Indexed: 11/09/2022]
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Zsila F, Nadolski G, Lockwood SF. Association studies of aggregated aqueous lutein diphosphate with human serum albumin and α1-acid glycoprotein in vitro: Evidence from circular dichroism and electronic absorption spectroscopy. Bioorg Med Chem Lett 2006; 16:3797-801. [PMID: 16678417 DOI: 10.1016/j.bmcl.2006.04.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 04/12/2006] [Accepted: 04/12/2006] [Indexed: 11/25/2022]
Abstract
Water-dispersible C40 carotenoid derivatives, with increased utility in mammalian therapeutic applications, include natural stereoisomer-based (3R,3'R,6'R)-lutein (beta,epsilon-carotene-3,3'-diol) derivatives. Esterification with inorganic phosphate and conversion to the sodium salt produced compounds (lutein diphosphate sodium salt; 'LdP') capable of forming red-orange aqueous suspensions after addition to USP-purified water. The aqueous dispersibility of this diphosphate salt reached 29 mg/mL without the addition of heat, detergents, co-solvents, or other additives, and was a potent direct scavenger of superoxide anion (by EPR spectroscopy) in an isolated human neutrophil assay. In the current study, preliminary evidence of the aqueous aggregation of this compound in EPR studies was confirmed using circular dichroism (CD) and electronic absorption (UV-vis) spectroscopy. Evidence for H-type ('card-pack') and J-type ('head-to-tail') self-assemblies was obtained. In vitro analysis of the potential binding interaction between LdP and human serum albumin (HSA) and alpha1-acid glycoprotein (AGP) revealed only non-specific binding with HSA (and none with AGP), contrasting with previous reports of direct interaction between astaxanthin-based soft drugs and the major plasma protein albumin. The rapid in vivo cleavage of this phosphodiester by promiscuous mammalian phosphatases may overcome the aqueous aggregation of the formulated compound. This difference in potential plasma protein interaction with prior reports reflects the subtle structural differences inherent in either the parent carotenoid scaffolds and/or the esterifying moieties.
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Affiliation(s)
- Ferenc Zsila
- Department of Molecular Pharmacology, Institute of Biomolecular Chemistry, Chemical Research Center, H-1525 Budapest, PO Box 17, Hungary
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