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Silva PUJ, Oliveira MB, Vieira W, Cardoso SV, Blumenberg C, Franco A, Siqueira WL, Paranhos LR. Oral pigmentation as an adverse effect of chloroquine and hydroxychloroquine use: A scoping review. Medicine (Baltimore) 2022; 101:e29044. [PMID: 35356915 PMCID: PMC10684193 DOI: 10.1097/md.0000000000029044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/23/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Chloroquine and hydroxychloroquine are 2 medications used to treat some systemic diseases. OBJECTIVE The aim of this scoping review was to assess the occurrence of oral pigmentation induced by chloroquine or hydroxychloroquine and to understand the pathogenic mechanism behind this phenomenon. METHODS The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. MEDLINE (PubMed), Scopus, EMBASE, SciELO, Web of Science, Lilacs, and LIVIVO were primary sources, and "gray literature" was searched in OpenThesis and Open Access Thesis and Dissertations (OATD). Studies that screened the occurrence of oral pigmentation associated to the use of chloroquine or hydroxychloroquine were considered eligible. No restrictions of year and language of publication were applied. Study selection and data extraction were performed by 2 independent reviewers. The risk of bias was assessed through the JBI tool, depending on the design of the selected studies. RESULTS The initial search resulted in 2238 studies, of which 19 were eligible. Sixteen studies were case reports, 2 had case-control design and 1 was cross-sectional. Throughout the studies, 44 cases of oral pigmentation were reported. The hard palate was the anatomic region most affected with pigmentation (66%). According to the case reports, most of the lesions (44%) were bluish-gray. The minimum time from the beginning of treatment (chloroquine or hydroxychloroquine) to the occurrence of pigmentation was 6 months. The mean treatment time with the medications was 4.9 years, and the mean drug dosage was 244 mg. Most of the studies (63.1%) had low risk of bias (high methodological quality). CONCLUSIONS The outcomes of this study suggest that hyperpigmentation depend on drug dosage and treatment length. Hyperpigmentation was detected after a long period of treatment with chloroquine or hydroxychloroquine.
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Affiliation(s)
| | | | | | | | | | | | - Walter Luiz Siqueira
- Correspondence: Walter Luiz Siqueira, University of Saskatchewan, College of Dentistry, Saskatoon, Canada (e-mail: ).
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Abstract
Introduction: A century-long history in 8-aminoquinolines, the only anti-malaria drug class preventing malaria relapse, has resulted in the approval of tafenoquine by the U.S. Food and Drug Administration (FDA) and the Australian Therapeutic Goods Administration (TGA) and to date registration in Brazil and Thailand. Tafenoquine is an alternative anti-relapse treatment for vivax malaria and malaria prophylaxis. It should not be given in pregnancy, during lactation of infants with glucose-6-phosphate dehydrogenase (G6PD) unknown or deficient status, and in those with G6PD deficiency or psychiatric illness.Areas covered: This systematic review assesses tafenoquine associated adverse events in English-language, human clinical trials. Meta-analysis of commonly reported adverse events was conducted and grouped by comparison arms.Expert opinion: Tafenoquine, either for radical cure or prophylaxis, is generally well tolerated in adults. There is no convincing evidence for neurologic, ophthalmic, and cardiac toxicities. Psychotic disorder which has been attributed to higher doses is a contraindication for the chemoprophylaxis indication and psychiatric illness is a warning for the radical cure indication. Pregnancy assessment and quantitative G6PD testing are required. The optimal radical curative regimen including the tafenoquine dose along with its safety for parts of Southeast Asia, South America, and Oceania needs further assessment.
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Affiliation(s)
- Cindy S. Chu
- Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, UK
| | - Jimee Hwang
- U.S. President’s Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Global Health Group, University of California San Francisco, San Francisco, CA, USA
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van Onselen R, Downing T. BMAA-protein interactions: A possible new mechanism of toxicity. Toxicon 2018; 143:74-80. [DOI: 10.1016/j.toxicon.2018.01.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 01/16/2018] [Accepted: 01/18/2018] [Indexed: 02/08/2023]
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Rimpelä AK, Reinisalo M, Hellinen L, Grazhdankin E, Kidron H, Urtti A, del Amo EM. Implications of melanin binding in ocular drug delivery. Adv Drug Deliv Rev 2018; 126:23-43. [PMID: 29247767 DOI: 10.1016/j.addr.2017.12.008] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 10/04/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022]
Abstract
Pigmented ocular tissues contain melanin within the intracellular melanosomes. Drugs bind to melanin at varying extent that ranges from no binding to extensive binding. Binding may lead to drug accumulation to the pigmented tissues and prolonged drug retention in the melanin containing cells. Therefore, melanin binding is an important feature that affects ocular drug delivery and biodistribution, but this topic has not been reviewed since 1998. In this review, we present current knowledge on ocular melanin, melanosomes and binding of drugs to pigmented cells and tissues. In vitro, in vivo and in silico methods in the field were critically evaluated, because the literature in this field can be confusing if the reader does not properly understand the methodological aspects. Literature analysis includes a comprehensive table of literature data on melanin binding of drugs. Furthermore, we aimed to give some insights beyond the current literature by making a chemical structure based classification model for melanin binding of drugs and kinetic simulations that revealed significant interplay between melanin binding and drug permeability across the melanosomal and plasma membranes. Overall, more mechanistic and systematic research is needed before the impact of melanin binding on ocular drug delivery can be properly understood and predicted.
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Shinno K, Kurokawa K, Kozai S, Kawamura A, Inada K, Tokushige H. The Relationship of Brimonidine Concentration in Vitreous Body to the Free Concentration in Retina/Choroid Following Topical Administration in Pigmented Rabbits. Curr Eye Res 2016; 42:748-753. [DOI: 10.1080/02713683.2016.1238941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | | | - Seiko Kozai
- Senju Pharmaceutical Co., Ltd., Osaka, Japan
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Roberts JK, Cook SF, Stockmann C, Rollins DE, Wilkins DG, Sherwin CMT. A Population Pharmacokinetic Analysis of Dextroamphetamine in the Plasma and Hair of Healthy Adults. Clin Drug Investig 2016; 35:633-43. [PMID: 26329917 DOI: 10.1007/s40261-015-0323-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND AND OBJECTIVE Hair is an attractive matrix for amphetamine drug testing; however, little is known about the rate at which amphetamines are deposited into hair. Therefore, the purpose of this study was to determine the pharmacokinetics of oral dextroamphetamine in plasma and quantify the rate of deposition into hair in healthy adults using a linked population pharmacokinetic model. METHODS Healthy adults >18 years of age received dextroamphetamine 10 mg orally for 7 days. Plasma samples were collected over 48 h following the final dose, and hair was collected 5 weeks following the first dose. NONMEM 7.2 was used to estimate dextroamphetamine oral absorption rate constant, apparent clearance and volume of distribution of the plasma compartment, the plasma to hair incorporation rate constant, and the apparent volume of distribution in the hair compartment. RESULTS Dextroamphetamine pharmacokinetics were well-described by a one-compartment model with combined additive and proportional error for the plasma compartment, which was linked to a single compartment for the hair. Apparent clearance and volume of distribution in the plasma compartment were scaled by current body weight (centered on the mean). Melanin hair concentration was included as a significant covariate on the hair compartment. Absorption rate constant, clearance, and volume of distribution for the plasma compartment were estimated as 0.527 h(-1) (95% CI 0.467-0.586), 28.7 L/h (95% CI 27.1-30.3), and 377 L (95% CI 326-428), respectively. The incorporation rate constant from plasma to hair was 1.60e(-6) h(-1) (95% CI 1.06e(-6)-2.14e(-6)) and apparent volume of distribution in hair was 17.7 mg (95% CI 12.5-22.8). CONCLUSIONS A one-compartment plasma model linked to a single compartment for hair successfully described the pharmacokinetics of dextroamphetamine in healthy adults. The volume of distribution and clearance of dextroamphetamine increased with weight, and the volume of distribution of the hair compartment increased with greater melanin concentrations.
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Affiliation(s)
- Jessica K Roberts
- Division of Clinical Pharmacology, Department of Pediatrics, School of Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, 84108, USA
| | - Sarah F Cook
- Center for Human Toxicology, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Chris Stockmann
- Division of Clinical Pharmacology, Department of Pediatrics, School of Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, 84108, USA.,Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Douglas E Rollins
- Center for Human Toxicology, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Diana G Wilkins
- Center for Human Toxicology, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA.,Division of Medical Laboratory Sciences, Department of Pathology, School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Catherine M T Sherwin
- Division of Clinical Pharmacology, Department of Pediatrics, School of Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, 84108, USA.
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Reilly J, Williams SL, Forster CJ, Kansara V, End P, Serrano-Wu MH. High-Throughput Melanin-Binding Affinity and In Silico Methods to Aid in the Prediction of Drug Exposure in Ocular Tissue. J Pharm Sci 2015; 104:3997-4001. [PMID: 26524700 DOI: 10.1002/jps.24680] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/02/2015] [Accepted: 09/17/2015] [Indexed: 11/11/2022]
Abstract
Drugs possessing the ability to bind to melanin-rich tissue, such as the eye, are linked with higher ocular exposure, and therefore have the potential to affect the efficacy and safety profiles of therapeutics. A high-throughput melanin chromatographic affinity assay has been developed and validated, which has allowed the rapid melanin affinity assessment for a large number of compounds. Melanin affinity of compounds can be quickly assigned as low, medium, or high melanin binders. A high-throughput chromatographic method has been developed and fully validated to assess melanin affinity of pharmaceuticals and has been useful in predicting ocular tissue distribution in vivo studies. The high-throughput experimental approach has also allowed for a specific training set of 263 molecules for a quantitative structure-affinity relationships (QSAR) method to be developed, which has also been shown to be a predictor of ocular tissue exposure. Previous studies have reported the development of in silico QSAR models based on training sets of relatively small and mostly similar compounds; this model covers a broader range of melanin-binding affinities than what has been previously published and identified several physiochemical descriptors to be considered in the design of compounds where melanin-binding modulation is desired.
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Affiliation(s)
- John Reilly
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Cambridge, Massachusetts 02139.
| | - Sarah L Williams
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Cambridge, Massachusetts 02139
| | - Cornelia J Forster
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Cambridge, Massachusetts 02139
| | - Viral Kansara
- Novartis Institutes for BioMedical Research, Ophthalmology, Cambridge, Massachusetts 02139
| | - Peter End
- Novartis Institutes for BioMedical Research, DMPK, Basel, Switzerland
| | - Michael H Serrano-Wu
- Novartis Institutes for BioMedical Research, Global Discovery Chemistry, Cambridge, Massachusetts 02139
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Schroeder R, Pendleton P, Gerber J. Physical factors affecting chloroquine binding to melanin. Colloids Surf B Biointerfaces 2015; 134:8-16. [DOI: 10.1016/j.colsurfb.2015.06.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 02/02/2023]
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Rainsford KD, Parke AL, Clifford-Rashotte M, Kean WF. Therapy and pharmacological properties of hydroxychloroquine and chloroquine in treatment of systemic lupus erythematosus, rheumatoid arthritis and related diseases. Inflammopharmacology 2015; 23:231-69. [PMID: 26246395 DOI: 10.1007/s10787-015-0239-y] [Citation(s) in RCA: 349] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/23/2015] [Indexed: 12/15/2022]
Abstract
OBJECTIVES This review examines the pharmacokinetics, modes of action and therapeutic properties of the anti-malarial drugs, hydroxychloroquine (HCQ) and chloroquine (CQ), in the treatment of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and related conditions, as well as osteoarthritis (OA). KEY FINDINGS Both HCQ and CQ have historically been employed successfully for the treatment of SLE and RA for over 70 years. HCQ has been used extensively for SLE where it has a good reputation for controlling the dermatological complications in SLE. It has also been reported to effectively control the symptoms of Sjøgren's syndrome, as well as preventing thrombosis in phospholipid antibody (aPL) syndrome. In RA and SLE, HCQ is preferred because of the lower incidence of gastrointestinal adverse reactions compared with CQ and it might have a lower risk of ocular adverse reactions. There is increasing evidence that HCQ may reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients. Both HCQ and CQ have been shown to improve glycaemia and reduce the risks of type II diabetes mellitus. Although both HCQ and CQ are effective in low-moderate RA, HCQ is now preferred as part of combination therapy for more severe disease. The advantages of combination therapy are that the doses of the individual drugs may be lowered so reducing adverse reactions. Both HCQ and CQ are diastereoisomers, have basic properties and are given as the sulphate and phosphate salts. While being relatively well absorbed orally and with good bioavailability, they have long and variable plasma terminal elimination half-lives (approximately 40-60 days). This reflects their high volume of distribution, V D (HCQ 44,000L; CQ 65,000L) which extends into aqueous compartments, long mean residence time (HCQ 1300 h; CQ 900 h) and with about half the drugs (metabolites) undergoing renal clearance. The strong binding to melanin reflects the ocular injury and dermatological properties of these drugs. The consensus is that the occurrence of ocular adverse reactions can be minimised by close attention to the dose (which should be set on a body weight basis) with regular (e.g. quarterly) retinal examination. Although HCQ and CQ can pass through the placenta, the use of these drugs during pregnancy does not appear to risk harm to the baby and might be beneficial to the mother with SLE and her child by controlling the SLE disease activity, which is known to be an important factor affecting pregnancy outcome. The modes of action of HCQ and CQ in these arthritides represent somewhat of an enigma. Undoubtedly, these drugs have multiple actions related, in part, their ability to accumulate in lysosomes and autophagosomes of phagocytic cells as well as affecting MHC Class II expression and antigen presentation; actions of the production of pro-inflammatory cytokines [e.g. interleukin-1 (IL-1) tumour necrosis factor-α (TNFα)]; control of toll-like receptor-9 activation; and leucocyte generation of reactive oxygen species (ROS); i.e. antioxidant activity. The actions of these drugs on T and B cells are less clear but may depend on these leucocyte-mediated actions. Anti-malarials also protect against cytokine-mediated cartilage resorption. This and other actions may underlie the potential benefits in treating OA. The exact relationships of these various actions, mostly determined in vitro, have not been specifically defined in vivo or ex vivo in relation to clinical efficacy. OUTCOMES HCQ and CQ have a good reputation for being effective and relatively safe treatments in SLE, mild-moderate RA and Sjøgren's syndrome. There is need for (a) more information on their mode of action in relation to the control of these diseases, (b) scope for developing formulations that have improved pharmacokinetic and therapeutic properties and safety, and (c) further exploring their use in drug combinations not only with other disease modifying agents but also with biologics.
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Affiliation(s)
- K D Rainsford
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - Ann L Parke
- Department of Rheumatology, St Francis Hospital and Medical Center, Hartford, CT, 06105, USA
| | | | - W F Kean
- Department of Medicine (Rheumatology), McMaster University Faculty of Health Sciences, Hamilton, ON, L8S 4K9, Canada.
- Department of Medicine (Rheumatology), McMaster University Faculty of Health Sciences, Suite #708, 1 Young Street, Hamilton, ON, L8N 1T8, Canada.
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Chloroquine and hydroxychloroquine binding to melanin: Some possible consequences for pathologies. Toxicol Rep 2014; 1:963-968. [PMID: 28962308 PMCID: PMC5598414 DOI: 10.1016/j.toxrep.2014.10.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/25/2014] [Accepted: 10/27/2014] [Indexed: 11/23/2022] Open
Abstract
For many years chloroquine was used as a prophylactic agent against malaria, and more recently as a mild immunosuppressive. However, due to lengthy treatment periods, adverse effects have become apparent, which included retinopathy. The structurally related hydroxychloroquine is less toxic, thought to be owing to a lower tissue accumulation in melanin rich areas. This study primarily focused on quantifying melanin binding between chloroquine and hydroxychloroquine at physiological pH to investigate the potential link between binding and reported toxicity. In addition, for the first time this study quantified the actual extent of adsorption of chloroquine and hydroxychloroquine to melanin and examined the desorption profile of both drugs from melanin to demonstrate the affinity between the pigment and the solutes. The results suggest that there is a difference between the adsorption affinities of chloroquine and hydroxychloroquine, potentially explaining the differences in bioaccumulation in retinal tissue. In addition, both solutes displayed a strong physical attraction to the absorbent.
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Abstract
The 4-aminoquinolines are weak bases that are completely absorbed from the gastrointestinal tract, sequestered in peripheral tissues, metabolized in the liver to pharmacologically active by-products, and excreted via the kidneys and the feces. The parent drugs and metabolites are excreted with a half-life of elimination of approximately 40 days. However, slow release from sequestered stores of the drugs means that after discontinuation, they continue to be released into the plasma for years. Correct dosing is based on the ideal body weight of the patient, which depends on height. The 4AQs diminish autoimmunity without compromising immunity to infections.
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Affiliation(s)
- David J. Browning
- grid.490463.cCharlotte Eye Ear Nose & Throat Associates, Charlotte, NC USA
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Small molecule modulators of aggregation in synthetic melanin polymerizations. Bioorg Med Chem Lett 2012; 22:5503-7. [PMID: 22835871 DOI: 10.1016/j.bmcl.2012.07.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/06/2012] [Accepted: 07/06/2012] [Indexed: 11/23/2022]
Abstract
There are numerous potential applications for melanin-binding compounds, and new methods are of interest to identify melanin-binding agents. A portion of the polymerization to eumelanin, the black to brown pigment in humans, is thought to be supramolecular aggregation of nanoparticles derived from dihydroxyindoles. Starting with chloroquine, a known eumelanin-binding compound, the ability of small molecules to influence aggregation in synthetic eumelanin polymerizations was investigated. Twenty-eight compounds were tested, including pharmaceuticals, dyes, aromatics, and amines. Compounds that either accelerate or delay the appearance of macroscopic particles in synthetic eumelanin polymerizations were uncovered.
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Investigation by imaging mass spectrometry of biomarker candidates for aging in the hair cortex. PLoS One 2011; 6:e26721. [PMID: 22039541 PMCID: PMC3200353 DOI: 10.1371/journal.pone.0026721] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 10/02/2011] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Human hair is one of the essential components that define appearance and is a useful source of samples for non-invasive biomonitoring. We describe a novel application of imaging mass spectrometry (IMS) of hair biomolecules for advanced molecular characterization and a better understanding of hair aging. As a cosmetic and biomedical application, molecules whose levels in hair altered with aging were comprehensively investigated. METHODS Human hair was collected from 15 young (20±5 years old) and 15 older (50±5 years old) volunteers. Matrix-free laser desorption/ionization IMS was used to visualize molecular distribution in the hair sections. Hair-specific ions displaying a significant difference in the intensities between the 2 age groups were extracted as candidate markers for aging. Tissue localization of the molecules and alterations in their levels in the cortex and medulla in the young and old groups were determined. RESULTS Among the 31 molecules detected specifically in hair sections, 2--one at m/z 153.00, tentatively assigned to be dihydrouracil, and the other at m/z 207.04, identified to be 3,4-dihydroxymandelic acid (DHMA)--exhibited a higher signal intensity in the young group than in the old, and 1 molecule at m/z 164.00, presumed to be O-phosphoethanolamine, displayed a higher intensity in the old group. Among the 3, putative O-phosphoethanolamine showed a cortex-specific distribution. The 3 molecules in cortex presented the same pattern of alteration in signal intensity with aging, whereas those in medulla did not exhibit significant alteration. CONCLUSION Three molecules whose levels in hair altered with age were extracted. While they are all possible markers for aging, putative dihydrouracil and DHMA, are also suspected to play a role in maintaining hair properties and could be targets for cosmetic supplementation. Mapping of ion localization in hair by IMS is a powerful method to extract biomolecules in specified regions and determine their tissue distribution.
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Kadam RS, Kompella UB. Influence of lipophilicity on drug partitioning into sclera, choroid-retinal pigment epithelium, retina, trabecular meshwork, and optic nerve. J Pharmacol Exp Ther 2010; 332:1107-20. [PMID: 19926800 PMCID: PMC2835449 DOI: 10.1124/jpet.109.161570] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/18/2009] [Indexed: 11/22/2022] Open
Abstract
In vitro bovine eye tissue/phosphate-buffered saline, pH 7.4, partition coefficients (Kt:b), in vitro binding to natural melanin, and in vivo delivery at 1 h after posterior subconjunctival injection in Brown Norway rats were determined for eight beta-blockers. The Kt:b was in the order intact tissue, dry weight method >or= intact tissue, wet weight method corrected for tissue water and drug in tissue water >> intact tissue, wet weight method > homogenized tissue. In intact tissue methods, Kt:b followed the order choroid-retinal pigment epithelium (RPE) > trabecular meshwork > retina > sclera approximately optic nerve; propranolol > betaxolol > pindolol approximately timolol approximately metoprolol > sotalol approximately atenolol approximately nadolol. Intact tissue, wet weight log (Kt:b) correlated positively with log D for all tissues (R(2) of 0.7-0.9). Log (melanin binding capacity) correlated positively with choroid-RPE log (Kt:b) (R(2) of 0.5). With an increase in concentration, Kt:b decreased in trabecular meshwork for all beta-blockers and for some lipophilic beta-blockers in choroid-RPE and sclera. With an increase in drug lipophilicity, in vivo tissue distribution increased in choroid-RPE, iris-ciliary body, sclera, and cornea but exhibited a declining trend in retina, vitreous, and lens. In vitro bovine intact tissue, wet weight Kt:b correlated positively with rat in vivo tissue/vitreous humor distribution for sclera, choroid-RPE, and retina (R(2) of 0.985-0.993). In vitro tissue partition coefficients might be useful in predicting in vivo drug distribution after trans-scleral delivery. Less lipophilic solutes exhibiting limited nonproductive binding in choroid-RPE might exhibit greater trans-scleral delivery to the retina and vitreous.
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Affiliation(s)
- Rajendra S Kadam
- Department of Pharmaceutical Sciences, University of Colorado Denver, 12700 E 19th Ave., Aurora, CO 80045, USA
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Tanaka M, Ono C, Yamada M. Absorption, distribution and excretion of 14C-levofloxacin after single oral administration in albino and pigmented rats: binding characteristics of levofloxacin-related radioactivity to melanin in vivo. J Pharm Pharmacol 2010; 56:463-9. [PMID: 15099441 DOI: 10.1211/0022357023141] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
After single oral administration of 14C-levofloxacin at a dose of 20 mg kg−1 under non-fasting conditions, the absorption, distribution and excretion of radioactivity were studied in albino and pigmented rats. Good penetration of radioactivity into tissues was indicated by higher concentrations in most tissues compared with serum and there were no quantitative differences in the distribution of radioactivity between albino and pigmented rats except for melanin-containing tissues such as the uveal tract of eyes and hair follicles. There was selective and strong binding of drug-related radioactivity to these tissues in pigmented rats. The uveal tract concentrations reached the maximum value (Cmax) of 26.33 + 0.75 μg eq.g−1 at 24 h after dosing and declined slowly with a terminal half-life of 468.1 h (19.5 days). The uveal tract concentration at 12 weeks was 0.73 + 0.12 μg eq.g−1, which is c. 1/36 of Cmax. The AUC0-∞ for the uveal tract was 12.58 mg h−1 g−1. The uveal tracts separated from one eye of each rat were extracted with 0.067 m phosphate buffer (pH 7.4) and 1m HCl/EtOH (30:70), successively. In pigmented rats, approximately 85–48% of radioactivity bound to the uveal tract was released from the tissue by the washing procedures. Most of the eluted radioactivity was released with 1m HCl/EtOH (30:70), indicating that the binding to melanin is reversible, and hydrophobic and electrostatic interactions play an important role in the binding of levofloxacin and/or its metabolites with melanin-containing ocular tissues. Only unchanged drug was detected in the extracts of the uveal tracts. The concentrations and half-life of radioactivity in the uveal tract after dosing of 14C-levofloxacin were found to be much lower and shorter than those after dosing of 14C-chloroquine. It is unlikely that levofloxacin causes toxicity because of its much lower affinity to melanin-containing ocular tissues and shorter duration of therapy compared to chloroquine.
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Affiliation(s)
- Makoto Tanaka
- Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co. Ltd, 16-13, Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan
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Scott K, Kronstrand R. Drug Incorporation into Hair. ANALYTICAL AND PRACTICAL ASPECTS OF DRUG TESTING IN HAIR 2006. [DOI: 10.1201/9781420006193.ch1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Tanaka M, Takashina H, Tsutsumi S. Comparative assessment of ocular tissue distribution of drug-related radioactivity after chronic oral administration of 14C-levofloxacin and 14C-chloroquine in pigmented rats. J Pharm Pharmacol 2004; 56:977-83. [PMID: 15285841 DOI: 10.1211/0022357043932] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Fluoroquinolones have been reported to have a high affinity for melanin. The ocular tissue distribution and accumulation of radioactivity was compared after repeated oral administration of 14C-levofloxacin and 14C-chloroquine at daily doses of 20 mg (0.054 mmol) kg(-1) and 28 mg (0.054 mmol) kg(-1), respectively, in pigmented rats for 84 days. The mean serum level at 24 h following each dose of 14C-levofloxacin was almost constant in the range of 0.33-0.45 nmol equiv mL(-1) after the 14th dose and thereafter. The melanin-containing ocular tissues, such as iris ciliary body and stratum pigment chorioides sclera, showed a much higher concentration of radioactivity than other non-pigmented ocular tissues. The respective concentration in iris ciliary body and stratum pigment chorioides sclera after the 1st dose was 126.47 and 74.91 nmol equiv g(-1), and gradually increased with increasing dose number, reaching 1261.81 and 447.45 nmol equiv g(-1) after the 84th dose, which was ca. 10 and 6 times higher, respectively, than after the 1st dose. The mean serum level following each dose of 14C-chloroquine was almost constant in the range 0.51-0.87 nmol equiv mL(-1) after the 7th dose and thereafter. The respective concentration in iris ciliary body and stratum pigment chorioides sclera after the 1st dose was 572.10 and 709.41 nmol equiv g(-1), and gradually increased with increasing dose number, reaching 33 317.92 and 12 322.90 nmol equiv g(-1) after the 84th dose, which was ca. 58 and 17 times higher, respectively, than after the 1st dose. The concentration in aqueous humour, cornea, lens, vitreous body and retina after the 84th dose was 1.84, 6.33, 0.48, 5.60 and 11.42 nmol equiv g(-1) for 14C-levofloxacin and 18.84, 264.99, 27.26, 158.43 and 1020.89 nmol equiv g(-1) for 14C-chloroquine (ca. 10, 42, 57, 28 and 89 times higher, respectively, than for 14C-levofloxacin). Especially, the concentration in the retina was markedly higher after 14C-chloroquine administration than after 14C-levofloxacin administration. The concentration and the extent of accumulation of radioactivity not only in melanin-containing ocular tissues but also in other non-pigmented ocular tissues, such as retina, after chronic oral administration of 14C-levofloxacin once daily for 84 days were much lower than those after multiple dosing with 14C-chloroquine under the same conditions. These results indicate that levofloxacin would have a much lower risk for ocular toxicity than chloroquine after chronic dosing.
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Affiliation(s)
- Makoto Tanaka
- Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co. Ltd, 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
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18
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Ono C, Yamada M, Tanaka M. Absorption, distribution and excretion of 14C-chloroquine after single oral administration in albino and pigmented rats: binding characteristics of chloroquine-related radioactivity to melanin in-vivo. J Pharm Pharmacol 2004; 55:1647-54. [PMID: 14738591 DOI: 10.1211/0022357022340] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Chloroquine is an antimalarial agent that has been reported to have distinct affinity to melanin. After single oral administration of 14C-chloroquine at a dose of 20mg kg-1 under non-fasting conditions, the absorption, distribution and excretion of 14C-chloroquine-related radioactivity were studied in albino and pigmented rats. The objectives of the study were to investigate differences in the disposition of chloroquine between albino and pigmented rats and to define its in-vivo binding characteristics to melanin-containing ocular tissues. Extensive uptake of radioactivity into tissues was indicated by higher concentrations in most tissues compared with serum and there was no quantitative differences in the distribution of radioactivity found between albino and pigmented rats except for melanin-containing tissues, such as the uveal tract of the eye and perhaps hair follicles. There was selective and strong binding of drug-related compounds to these tissues in pigmented rats. The uveal tract concentrations reached the maximum value of 158.42 +/- 7.86 micrograms equiv g-1 (mean+/-s.e.) at 1 week and decreased very slowly with a terminal half life of 4476 h (187 day). The uveal tract concentrations at 24 weeks were still high (67.75 +/- 6.19 micrograms equiv g-1). The AUC for uveal tract was 842.3 mg.h g-1. A relatively high concentration was still determined in the uveal tract even at 48 weeks after single oral dosing by whole-body autoradiography. The uveal tracts separated from one eye of each rat were extracted with 0.067 M phosphate buffer (pH 7.4) and 1 M HCl-EtOH (30:70) successively. In pigmented rats, almost all radioactivity was released from the tissue with 1 M HCl-EtOH (30:70), indicating that the strong binding by melanin was reversible, and that hydrophobic or electrostatic interaction would play a critical role in the binding of chloroquine and its metabolites with the melanin-containing ocular tissues. Approximately 70% of the radioactivity given was recovered in urine and faeces up to 144 h after dosing both in pigmented and albino rats. The excretion pattern in pigmented rats was similar to that seen in albino rats.
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Affiliation(s)
- Chiho Ono
- Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co. Ltd, 16-13, Kita-Kasai 1-Chome, Edogawaku, Tokyo 134-8630, Japan
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19
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Kawashima H, Iida Y, Kitamura Y, Saji H. Binding of 4-(4-chlorophenyl)-1-[4-(4-fluorophenyl)-4-oxobutyl]pyridinium ion (HPP+), a metabolite of haloperidol, to synthetic melanin: Implications for the dopaminergic neurotoxicity of HPP+. Neurotox Res 2004; 6:535-42. [PMID: 15639785 DOI: 10.1007/bf03033449] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The toxicity of 4-(4-chlorophenyl)-1-[4-(4-fluorophenyl)-4-oxobutyl]pyridinium ion (HPP+), a metabolite of haloperidol, toward dopaminergic neurons was investigated. When HPP+ (approximately 100 microM) was added to primary cultures prepared from rat embryonic mesencephalon for 1 h, the survivability of dopaminergic neurons decreased significantly, and this effect was not inhibited by the dopamine transporter (DAT) inhibitor GBR 12909. In addition, HPP+ bound to neuromelanin, which is abundant in dopaminergic neurons. A binding analysis using the Scatchard method showed that there are two classes of binding sites: high affinity sites with a dissociation constant K(d1) of 20.2 nM, and low affinity sites with a K(d2) of 4.0 microM. HPP+ was released easily from synthetic melanin using phosphate buffer (pH 7.0), suggesting that this binding is reversible. The results suggest that the toxicity of HPP+ in dopaminergic neurons is due not to DAT-mediated uptake, but to the binding to neuromelanin.
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Affiliation(s)
- Hidekazu Kawashima
- Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501
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20
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Abstract
To define the binding characteristics of fluoroquinolones to synthetic levodopa melanin, the binding of various drugs, including levofloxacin and ofloxacin, and positive controls (timolol and chloroquine), was investigated in-vitro. The affinity and capacity of the drug binding were calculated by Langmuir's adsorption isotherm. The affinity constant (K) and the binding capacity (r(max)) of levofloxacin were similar to those of timolol and much lower than those of chloroquine. Racemic ofloxacin and its enantiomers showed similar K and r(max), suggesting that the binding lacked stereoselectivity. The binding experiment with levofloxacin derivatives indicated that the basic nitrogen atom at position 7 of the quinolone ring, but not carboxyl group at position 3, would play a critical role in the interaction of fluoroquinolones with melanin. The melanin-drug complexes of levofloxacin and chloroquine were washed with neutral phosphate buffer, ethanol and 1 M HCl solution to explain the nature of the interaction of melanin with the drugs. Electrostatic forces mainly participate in the formation of the chloroquine-melanin complex, whereas van der Waals' and hydrophobic interactions are involved in the levofloxacin-melanin complex in addition to electrostatic forces. The interactions of various fluoroquinolones such as norfloxacin, enoxacin, sparfloxacin, ciprofloxacin and lomefloxacin with melanin were also studied. The results showed that the relative K value was: chloroquine approximately ciprofloxacin, sparfloxacin >/= lomefloxacin > timolol, levofloxacin approximately enoxacin, norfloxacin, and that the relative r(max) value was: norfloxacin, enoxacin >/= chloroquine, sparfloxacin > levofloxacin, ciprofloxacin, timolol, lomefloxacin. The fluoroquinolones vary in their affinity and capacity to bind with melanin, and ciprofloxacin and sparfloxacin showed a stronger interaction with melanin than the other fluoroquinolones studied.
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Affiliation(s)
- Chiho Ono
- Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co., Ltd, 16-13, Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan
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21
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Abstract
Ocular morphology is specifically directed at facilitating the transmittance of visible light to the retina for the purposes of photoreceptor absorption and phototransduction, thereby initiating the process of vision. By absorbing excess radiation, melanin significantly enhances this process. It can also act as a photoprotector by quenching reactive oxygen species and other radicals produced as a result of the high oxygen dependency of the retina for its metabolism. However, melanin also binds numerous pharmaceuticals, a process that can result in ocular toxicity. Although our understanding of this binding remains somewhat limited, melanin chemistry, its distribution, and other factors influencing binding appear to play a significant role in predisposing ocular tissues, such as the choroid and retinal pigment epithelium, to toxicological insult. Many of the drugs that have been identified as causing these effects are known photosensitizers in which radiation plays a significant role in eliciting the pathologies. The phototoxic effects range from minor histological/chemical changes, which do not impact the quality of vision, to pigmentary retinopathies, which could potentially involve the loss of sight. Such effects, resulting from photosensitizer-drug binding to melanin, are to be separated from toxic effects, such as some ganglion cell abnormalities, that result from pharmaceuticals affecting ocular tissues directly.
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Affiliation(s)
- Pierrette Dayhaw-Barker
- Hafter Light and Laser Institute, Pennsylvania College of Optometry, Elkins Park, Pennsylvania 19027, USA.
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22
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Borges CR, Martin SD, Meyer LJ, Wilkins DG, Rollins DE. Influx and efflux of amphetamine and N-acetylamphetamine in keratinocytes, pigmented melanocytes, and nonpigmented melanocytes. J Pharm Sci 2002; 91:1523-35. [PMID: 12115851 DOI: 10.1002/jps.10144] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To establish an in vitro model of drug incorporation into hair and to elucidate the potential roles of hair cell selectivity and hair color in the incorporation of certain drugs into hair, the basic drug amphetamine and its nonbasic analog N-acetylamphetamine (N-AcAp) were analyzed for influx and efflux into and out of keratinocytes, pigmented melanocytes (PM), and nonpigmented melanocytes (NPM) as a model for incorporation and efflux of these drugs from hair cells. NPM were of the same melan-a cell line as PM, but cultured in the presence of the tyrosinase inhibitor phenylthiocarbamide. Results show that PM take up large amounts of the basic drug amphetamine (levels of uptake dependent on melanin content), whereas keratinocytes and NPM take up only small amounts of amphetamine. None of the cells take up N-AcAp above background levels. Interestingly, whereas keratinocytes and NPM quickly efflux most of the influxed drug, PM are slow to efflux and only efflux approximately 65% of influxed drug, if efflux media is not refreshed. (If efflux media is periodically refreshed, PM will eventually redistribute essentially all influxed drug back into the media.) These results demonstrate that pigmented cells take up greater amounts of the basic drug amphetamine, and efflux it more slowly than nonpigmented cells. Also, these results are consistent with previous data for in vivo incorporation of amphetamine in animal hair. In combination with previous data, an overall comparison of the amphetamine and N-AcAp incorporation data support a non-diffusion mediated model for drug incorporation into hair cells.
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Affiliation(s)
- Chad R Borges
- Department of Pharmacology and Toxicology, University of Utah, 20 South 2030 East, Room 490, Salt Lake City 84112, USA.
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23
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Labarre P, Papon J, Moreau MF, Moins N, Bayle M, Veyre A, Madelmont JC. Melanin affinity of N-(2-diethylaminoethyl)-4-iodobenzamide, an effective melanoma imaging agent. Melanoma Res 2002; 12:115-21. [PMID: 11930107 DOI: 10.1097/00008390-200204000-00003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The cellular uptake and incorporation in macromolecules of iodine-125 labelled N-(2-diethylaminoethyl)-4-iodobenzamide ([125I]BZA), a melanoma imaging agent, was studied using human melanoma cells M3Dau (amelanotic) and M4Beu (melanotic). The interaction between [125I]BZA and synthetic melanin was examined in various conditions of incubation. The results showed that uptake was high only for M4Beu, whereas the incorporation in trichloroacetic acid-precipitable proteins was very low for both model cell lines, with no correlation with melanin content. Experiments with synthetic melanin showed that BZA binding to melanin was saturable and reversible, and involved several types of interaction. The influence of the ionic environment indicated that electrostatic forces play a role in the affinity, and the decrease in binding produced by the presence of an alcohol in the medium suggested that hydrophobic interactions may be involved in the binding mechanism. This was supported by the Scatchard analysis, which revealed two classes of binding sites, and the determination of two association constants (K1 = 3.9 +/- 1.9 x 106/M and K2 = 2.9 +/- 0.9 x 104/M). The affinity of BZA for melanin might explain the good results obtained in a phase II clinical trial for the diagnosis of malignant melanoma metastases, in which the specificity was 100%.
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Affiliation(s)
- P Labarre
- INSERM U484, rue Montalembert, BP 184, 63005 Clermont-Ferrand Cedex, France.
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24
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Markuszewski M, Kaliszan R. Quantitative structure-retention relationships in affinity high-performance liquid chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 768:55-66. [PMID: 11939558 DOI: 10.1016/s0378-4347(01)00485-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In this report the affinity high-performance liquid chromatography data, which were determined on silica-based human serum albumin, alpha1-acid glycoprotein, keratin, collagen, melanin, amylose tris(3,5-dimethylphenylcarbamate), and basic fatty acid binding protein columns, are discussed. Using a quantitative structure-retention relationship (QSRR) approach the affinity data were interpreted in terms of structural requirements of specific binding sites on biomacromolecules. The unique chromatographic properties of immobilized artificial membrane and cholesterol stationary phases were also analyzed from the point of view of mimicking biological processes. It has been demonstrated that chemometric processing of appropriately designed sets of chromatographic data derived in systems comprising biomolecules provides information of relevance for molecular pharmacology and rational drug design.
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Affiliation(s)
- Michal Markuszewski
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Poland
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25
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Fukuda M, Morita Y, Sasaki K, Yamamoto Y. Studies on the binding mechanism of fluoroquinolones to melanin. J Infect Chemother 2000; 6:72-6. [PMID: 11810538 DOI: 10.1007/pl00012154] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/1999] [Accepted: 03/15/2000] [Indexed: 10/25/2022]
Abstract
In order to elucidate the binding mechanism of melanin and fluoroquinolones (ofloxacin, norfloxacin, ciprofloxacin, lomefloxacin, levofloxacin), we investigated the interaction of fluoroquinolones with compounds such as l-beta-(3,4-dihydroxyphenyl) alanine (l-DOPA), l-tyrosine, 5-hydroxy-l-tryptophan, l-tryptophan, and l-phenylalanine, which possess the kind of functional groups that melanin does and are closely related to melanin. The recovery of drugs from the melanin-drug complexes by metal ions of Li, Na, Ka, Mg, Ca, Ba, Cu, Ni, and Fe was demonstrated. Smaller and highly charged cations were found to be more effective for this recovery, and magnesium ions were the most effective of all the ions investigated.
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Affiliation(s)
- M Fukuda
- Department of Ophthalmology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa 920-0293, Japan.
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26
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Abstract
Certain drugs and chemicals, such as chloroquine, chlorpromazine, and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), are bound to melanin and retained in pigment cells for long periods. This specific retention in pigmented tissues can cause adverse effects in the skin, eye, inner ear, and pigmented nerve cells of the substantia nigra of the brain. To date, all studies have been focused on eu- and neuromelanin. In the present study, we show that chloroquine, chlorpromazine, chlomipramine, paraquat, acridine orange, and nickel, which are bound to eumelanin, also bind to synthetic pheomelanin, but the binding to pheomelanin is lower. The binding varied with the cysteine content and pH, and the results indicate that the binding is complex and includes ionic interactions. In addition, we have shown that these substances also bind to synthetic thiourea-containing melanin, but to quite a low extent. We also present a microautoradiographic study on the binding of 14C-chloroquine to natural pheomelanin in vivo in yellow mice C57BL (Ay/a). Black (C57/BL) and albino (NMRI) mice were used as controls. The autoradiography demonstrated a pronounced uptake of chloroquine in the hair follicles and the dermal melanocytes in the ear of yellow mice, which was comparable to the corresponding accumulation of label in black mice. In the albino mouse, the uptake was lower and more homogeneously distributed in the skin. These results suggest that the toxicological risks of melanin-related adverse effects are applicable to persons with a high content of pheomelanin in the skin and hair.
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Affiliation(s)
- U Mårs
- Department of Pharmaceutical Biosciences, Biomedical Center, Uppsala University, Sweden.
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27
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Kaliszan R. Retention data from affinity high-performance liquid chromatography in view of chemometrics. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 715:229-44. [PMID: 9792513 DOI: 10.1016/s0378-4347(98)00175-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A combination of affinity chromatography and chemometrics is demonstrated to provide information on drug analytes and on biomacromolecules forming stationary phases, which is of relevance to molecular pharmacology and to rational drug design. The approach can also be applied to elucidate the molecular mechanism of enantioseparation on natural biopolymer stationary phases. Affinity high-performance liquid chromatographic data, which were determined on silica-based human serum albumin, alpha1-acid glycoprotein, keratin, collagen, melanin and amylose tris(3,5-dimethylphenylcarbamate) stationary phases, are discussed. Quantitative structure-retention relationships (QSRRs) derived for test series of drug analytes are interpreted in terms of structural requirements of specific binding sites on biomacromolecules. A means to quantify the differences in drug-biomacromolecule binding among the members of analyte families is demonstrated based on hydrophobicity and structural descriptors from molecular modeling. Chemometric processing of appropriately designed sets of affinity chromatographic data may increase the speed and efficiency of a search for new drugs, providing at the same time a chance to reduce the number of in vivo screenings. It can also be of help in rational selection of chiral columns for specific analytical separations.
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Affiliation(s)
- R Kaliszan
- Medical University of Gdańsk, Department of Biopharmaceutics and Pharmacodynamics, Poland
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28
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Lowrey AH, Famini GR, Loumbev V, Wilson LY, Tosk JM. Modeling drug-melanin interaction with theoretical linear solvation energy relationships. PIGMENT CELL RESEARCH 1997; 10:251-6. [PMID: 9359620 DOI: 10.1111/j.1600-0749.1997.tb00684.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The affinity of drugs and other xenobiotic agents for melanin is a well-known phenomenon, often occurring with serious physiological consequences. For example, the interaction of anti-psychotic drugs with neuromelanin may play a pivotal role in the induction of extrapyramidal movement disorders associated with the chronic administration of phenothiazine and other neuroleptic agents. Little, however, is known about the complete nature of melanin-drug binding and the impact of these interactions on the physico-chemical properties of melanin. Data, such as binding affinities, can be analyzed using recently developed computational methods that combine mathematical models of chemical structure with statistical analysis. In particular, theoretical linear solvation energy relationships provide a convenient model for understanding and predicting biological, chemical, and physical properties. By using this modeling technique, drug-melanin binding of a set of 16 compounds has been analyzed with correlation analysis and a set of theoretical molecular parameters in order to better understand and characterize drug-melanin interactions. The resulting correlation equation supports a charge transfer model for drug-melanin complex formation and can also be used to estimate binding constants for related compounds.
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Affiliation(s)
- A H Lowrey
- The Laboratory for Structure and Matter, U.S. Naval Research Laboratory, Washington, D.C. 20375, USA
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29
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Gygi SP, Wilkins DG, Rollins DE. A comparison of phenobarbital and codeine incorporation into pigmented and nonpigmented rat hair. J Pharm Sci 1997; 86:209-14. [PMID: 9040097 DOI: 10.1021/js960268h] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Drugs and endogenous compounds circulating in the blood may ultimately become incorporated into a growing hair shaft. Hair analysis for drugs of abuse is a growing field in the area of forensic and clinical toxicology. However, the underlying principles that govern drug incorporation into hair are not known. In this study, we examined the incorporation of a weak acid, phenobarbital, and a weak base, codeine, into Sprague-Dawley (SD) rat hair. Codeine or phenobarbital was administered to male SD rats at 40 mg/kg/day for 5 days by intraperitoneal (ip) injection. Hair was collected from the back 14 days after beginning the 5-day dosing protocol and analyzed by gas chromatography/mass spectrometry (GC/MS) for codeine and phenobarbital. The time-courses of phenobarbital and codeine in plasma were also obtained after a single ip injection (40 mg/kg). Concentrations of codeine and phenobarbital in SD hair samples were 0.98 +/- 0.10 and 17.01 +/- 1.40 ng/mg hair. respectively. The areas under the curve (AUC) of plasma concentration versus time for codeine and phenobarbital were 1.58 and 414.50 micrograms h/microL, respectively. Notwithstanding the greater phenobarbital concentrations in hair, when plasma concentrations were considered, codeine was apparently incorporated to a 15-fold greater extent than phenobarbital. Because hair pigmentation may be important in drug incorporation, the incorporation of these two drugs was also studied in Long-Evans (LE; produces both black and white hair on the same animal) rats after 40 mg/kg/day of ip drug administration for 5 days. Hair was collected at the same time as the previous experiment. Concentrations of codeine in hair were 44-times greater in pigmented than nonpigmented hair from the same animals. In contrast, hair concentrations of phenobarbital were identical in both pigmented and nonpigmented hair. These data suggest that hair pigmentation greatly affects weak base incorporation but not weak acid incorporation into hair. Because hair concentrations of phenobarbital are not affected by pigmentation, phenobarbital may be an ideal drug to separate out factors other than pigmentation involved in incorporation of drugs into hair.
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Affiliation(s)
- S P Gygi
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112, USA
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30
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Radwańska A, Frackowiak T, Ibrahim H, Aubry AF, Kaliszan R. Chromatographic modelling of interactions between melanin and phenothiazine and dibenzazepine drugs. Biomed Chromatogr 1995; 9:233-7. [PMID: 8593425 DOI: 10.1002/bmc.1130090509] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Differences in drug-melanin interactions were determined for 13 phenothiazine neuroleptics and 2 dibenzazepine thymoleptics by means of high-performance liquid chromatography. The chromatographic column was packed with a stationary phase obtained by chemical immobilization of synthetic L-dopa melanin on silica particles. For six phenothiazines the melanin-binding parameters were also determined by an ultrafiltration method. Correlation between measures of drug-melanin interaction determined chromatographically and by the standard slow-equilibrium method was significant, however moderate. The chromatographic method of assessing interactions between drugs and melanin permitted reliable and quantitatively comparable data for representative series of solutes to be readily obtained. Such data were subjected to the analysis of quantitative structure-retention relationships (QSRR). It was found that retention of the agents on the immobilized melanin column could be described by two-parameter regression equations comprising the energy of the lowest unoccupied molecular orbital and either the water-accessible surface area of a drug molecule or its hydrophobicity parameter, determined chromatographically on an immobilized artificial membrane column. The QSRR equation derived allows for the estimation of melanin binding based on the structure of a compound candidate, and thus rationalizes predictions of potential toxicity of drugs or drug candidates.
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Affiliation(s)
- A Radwańska
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Poland
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31
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Kaliszan R, Kaliszan A, Wainer IW. Prediction of drug binding to melanin using a melanin-based high-performance liquid chromatographic stationary phase and chemometric analysis of the chromatographic data. JOURNAL OF CHROMATOGRAPHY 1993; 615:281-8. [PMID: 8335705 DOI: 10.1016/0378-4347(93)80342-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The high-performance liquid chromatographic retention parameters (k) have been determined for a series of 29 phenothiazines and related drugs. The k values were obtained on a hydrocarbon-bound silica stationary phase, an aminopropyl stationary phase and an aminopropyl phase coated with melanin. Polycratic retention data determined on a hydrocarbonaceous column were extrapolated to 0% of organic modifier in binary aqueous eluent yielding the chromatographic hydrophobicity parameter, log k'w. Logarithms of capacity factors determined isocratically on the aminopropyl column were subtracted from analogous values obtained with the same column loaded with melanin. The resulting parameter, log k'm-a, in combination with log k'w produced a regression equation (correlation coefficient r = 0.9531, significance level p = 10(-6)) which could be used to describe drug-melanin binding efficiency, EB. Theoretical EB values were calculated by means of the derived equation for the whole series of 29 drugs chromatographed. The efficiency of binding EB to synthetic melanin was also determined by an ultrafiltration method for fifteen members of the series. No statistically significant differences were observed between the EB values calculated using the chromatographic and ultrafiltration approaches. The results indicate that chemometric analysis of the appropriate chromatographic data is a practical method for the evaluation of melanin binding.
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Affiliation(s)
- R Kaliszan
- Department of Oncology, McGill University, Montreal General Hospital, Quebec, Canada
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32
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Abstract
Various drugs and other chemicals, such as organic amines, metals, polycyclic aromatic hydrocarbons, etc., are bound to melanin and retained in pigmented tissues for long periods. The physiological significance of the binding is not evident, but it has been suggested that the melanin protects the pigmented cells and adjacent tissues by adsorbing potentially harmful substances, which then are slowly released in nontoxic concentrations. Long-term exposure, on the other hand, may build up high levels of noxious chemicals, stored on the melanin, which ultimately may cause degeneration in the melanin-containing cells, and secondary lesions in surrounding tissues. In the eye, e.g., and in the inner ear, the pigmented cells are located close to the receptor cells, and melanin binding may be an important factor in the development of some ocular and inner ear lesions. In the brain, neuromelanin is present in nerve cells in the extrapyramidal system, and the melanin affinity of certain neurotoxic agents may be involved in the development of parkinsonism, and possibly tardive dyskinesia. In recent years, various carcinogenic compounds have been found to accumulate selectively in the pigment cells of experimental animals, and there are many indications of a connection between the melanin affinity of these agents and the induction of malignant melanoma.
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Affiliation(s)
- B S Larsson
- Department of Pharmaceutical Biosciences, Uppsala University, Sweden
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Salazar-Bookaman M, Fowble J, Patil P. Stoichiometry of interaction between soluble (?)-dopa melanin and enantiomers of ephedrine by NMR spectroscopy. Chirality 1992. [DOI: 10.1002/chir.530040704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kozik A, Korytowski W, Sarna T, Bloom AS. Interactions of flavins with melanin. Studies on equilibrium binding of riboflavin to dopa-melanin and some spectroscopic characteristics of flavin-melanin complex. Biophys Chem 1990; 38:39-48. [PMID: 2128193 DOI: 10.1016/0301-4622(90)80038-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Natural melanins are photoprotective pigments that in mammals are principally found in the skin, hair, and eyes. Although the molecular mechanism of photoprotection of pigmented cells has not yet been established, several hypotheses have been proposed with melanin acting as a light filter, free radical scavenger, and quencher of electronically excited states of reactive intermediates. It can be expected that the detoxicating efficiency of melanin should be enhanced if the melanin and potentially cytotoxic species are brought close together. Such a situation may occur for a number of photosensitizing dyes that have the ability to bind to melanin. The interaction of melanin with flavins has been studied under strictly controlled experimental conditions. The equilibrium dialysis method has been employed to determine dissociation constants and the number of binding sites in melanin at pH 5-9. The data reveal that synthetic DOPA-melanin has two different classes of binding sites with dissociation constants of 10(-6) and 10(-5) M, respectively. The overall binding capacity of melanin, at pH 7, is 250 nmol RF/mg melanin. The amount of bound-to-melanin RF increases with pH. The absorption spectra of melanin complexes with RF and lumiflavin indicate that hydrophobic interaction may be involved in the binding of these flavins by melanin. No changes in flavin fluorescence have been detected after binding of flavin to melanin. It appears that, contrary to cationic photosensitizing dyes, the singlet excited state of flavin molecules is not quenched by melanin.
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Affiliation(s)
- A Kozik
- Department of Animal Biochemistry, Jagiellonian University, Krakow, Poland
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Wilczok T, Stepień K, Buszman E, Porebska-Budny M. Interaction of methotrexate with melanins and melanosomes from B16 melanoma. Biophys Chem 1990; 35:265-70. [PMID: 2118811 DOI: 10.1016/0301-4622(90)80014-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It has been demonstrated that methotrexate forms stable complexes with melanin and melanosomes isolated from B16 melanoma. The number of binding sites and binding constants for methotrexate binding by intact melanosomes and melanin were n = 0.046 mumol/mg, K = 0.32 x 10(4) M-1 and n = 0.063 mumol/mg, K = 1.08 x 10(4) M-1, respectively. Binding of methotrexate to synthetic DOPA-melanin used for comparison also shows a single class of binding sites, n = 0.060 mumol/mg with binding constant K = 2.34 x 10(4) M-1. The possibility of side effects caused by methotrexate-melanin interactions after treatment of neoplasms is discussed.
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Affiliation(s)
- T Wilczok
- Department of Biochemistry and Biophysics, Silesian Medical Academy, Katowice, Poland
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Stepień KB, Dworzański JP, Bilińska B, Porebska-Budny M, Hollek AM, Wilczok T. Catecholamine melanins. Structural changes induced by copper ions. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 997:49-54. [PMID: 2546609 DOI: 10.1016/0167-4838(89)90134-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Melanins synthesized from adrenaline and dopamine in the presence or absence of copper ions were characterized by pyrolysis-gas chromatography-mass spectrometry and by IR and ESR methods. It was shown that Cu2+ are able to induce changes in the melanin structure. Melanins obtained from adrenaline-Cu2+ and dopamine-Cu2+ complexes are composed mainly from monomeric units of the indole type. Melanins synthesized from these catecholamines without Cu2+ contain additionally large amounts of unindolized monomeric units. The structure differences in both types of melanins are reflected in their sorptive abilities and spectroscopic characteristics.
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Affiliation(s)
- K B Stepień
- Department of Biochemistry and Biophysics, Silesian Medical Academy, Sosnowiec, Poland
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Abrahamsson T, Boström S, Bräutigam J, Lagerström PO, Regårdh CG, Vauqelin G. Binding of the beta-blockers timolol and H 216/44 to ocular melanin. Exp Eye Res 1988; 47:565-77. [PMID: 2903066 DOI: 10.1016/0014-4835(88)90095-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The eyes from pigmented rabbits were instilled with the beta-adrenoceptor antagonists H 216/44 or timolol. After a single instillation (1.9 mumol), the iris and ciliary body contained H 216/44, which decreased with a half-life of approx. 43 days. Daily instillation caused a gradual increase in the content of H 216/44 and timolol in the iris and ciliary body, the steady-state concentration of timolol being 10 times higher than that of H 216/44. The concentrations of H 216/44 were seven times higher in the iris and ciliary body of pigmented rabbits than in albino animals. H 216/44 was reversibly bound to the melanosomes from the iris and ciliary body and not metabolized in this tissue. In vitro binding of timolol and H 216/44 to bovine melanosomes showed comparable multi-site binding curves. The binding of chlorpromazine was substantially higher. The beta-blockers could be more readily released from the melanosomes with aqueous solutions of salt and ethanol than with distilled water. It is concluded that both H 216/44 and timolol bind reversibly to ocular melanin. The differences in binding characteristics in vitro may only partly explain the differences in the in vivo binding to ocular melanin in the rabbit eye.
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Abstract
Whole-body autoradiography of pigmented C57BL mice injected with 3H-labelled aflatoxin B1 (AFB1) showed a high degree of labelling of melanin-containing tissues, such as the melanin of eyes and hair follicles. The corresponding tissues in albino NMRI mice contained only low amounts of the label. Liquid chromatography of extracts of pigmented mouse eyes showed the presence of only non-metabolized AFB1. Analysis of the binding of AFB1 to melanin from bovine eyes using the method of Scatchard revealed two classes of binding sites. Incubations in the presence of metallic cations did not affect the binding, indicating that ionic forces play no role in the affinity. Comparisons of the binding of AFB1 to the bovine-eye pigment in media containing n-propanol, ethanol or methanol indicated that hydrophobic interactions play a role in the affinity. Apposition of the aromatic rings in AFB1 and the indole nuclei of the melanin may also result in van der Waals' forces, and the combination of these two types of forces may underly the binding of AFB1 to melanin. The melanin binding implies that AFB1 is retained in pigmented tissues at higher concentrations than in any other tissue of the body. The biological implication of this accumulation is now known, but the possibility that there may be an increased risk for the induction of melanomas is discussed.
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Affiliation(s)
- P Larsson
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala Biomedical Center
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D'Amato RJ, Benham DF, Snyder SH. Characterization of the binding of N-methyl-4-phenylpyridine, the toxic metabolite of the parkinsonian neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, to neuromelanin. J Neurochem 1987; 48:653-8. [PMID: 3491879 DOI: 10.1111/j.1471-4159.1987.tb04142.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) selectively destroys neuronal cell bodies in the neuromelanin-containing substantia nigra of humans and primates. We show that N-methyl-4-phenylpyridine (MPP+), the active metabolite of MPTP, binds to neuromelanin with high affinity. This binding increases at higher pH and is displaced most potently by divalent cations and antimalarial drugs. MPP+ bound intracellularly to neuromelanin may be stored and released gradually, resulting in subsequent damage to neurons of the substantia nigra.
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Savage NW, Barber MT, Adkins KF. Pigmentary changes in rat oral mucosa following antimalarial therapy. JOURNAL OF ORAL PATHOLOGY 1986; 15:468-71. [PMID: 3027287 DOI: 10.1111/j.1600-0714.1986.tb00660.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pharmacogenic pigmentation of the oral mucosa has been reported following the use of a number of anti-malarial drugs. The nature and distribution of the pigment is inconclusive in the literature. The aim of the present study was to document pigment deposition within the oral mucosa of DA rats following prolonged chloroquine and pyrimethamine administration. The drugs were given as a combined dosage and separately to different groups via stomach gavage tube. After 12 weekly administrations the palatal mucosa was examined histochemically and ultrastructurally for changes in numbers and size of active melanocytes using the dopa-oxidase technique. The serum was analysed for changes in ACTH and testosterone levels. Morphometric analysis of cells incubated for dopa-oxidase showed a significant increase in the size of dopa positive cells with both drugs but an increase in the number of active melanocytes with chloroquine only. Serum levels of ACTH remained unchanged with both drugs but pyrimethamine caused an elevation in testosterone.
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Ames JR, Ryan MD, Klayman DL, Kovacic P. Charge transfer and oxy radicals in antimalarial action. Quinones, dapsone metabolites, metal complexes, iminium ions, and peroxides. JOURNAL OF FREE RADICALS IN BIOLOGY & MEDICINE 1985; 1:353-61. [PMID: 3837802 DOI: 10.1016/0748-5514(85)90147-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A mechanism of action is proposed that encompasses almost all of the main categories of antimalarial agents: quinones and precursors, dapsone metabolites, metal complexes of thiosemicarbazones and biguanides, iminium-type ions from acridines and quinolines, and peroxides. The toxic effect of the drugs is believed to result from the generation of reactive oxygen radicals that usually arise via charge transfer. Electrochemical studies (reduction potential and reversibility) were performed on a number of these agents. Reduction potentials range from -0.23 to -1.52 V. It is likely that the in vivo values are appreciably more positive in certain cases.
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Buszman E, Kopera M, Wilczok T. Electron spin resonance studies of chloroquine-melanin complexes. Biochem Pharmacol 1984; 33:7-11. [PMID: 6322795 DOI: 10.1016/0006-2952(84)90363-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Electron spin resonance (ESR) studies of chloroquine complexes with synthetic DOPA-melanin, synthetic catechol-melanin, melanin isolated from bananas and humic acid were performed. Two chloroquine concentrations (5 X 10(-5) M and 1 X 10(-3) M) were used for chloroquine-melanin complex formation. ESR studies showed differences in free radicals concentration depending on melanin origin. It was demonstrated that addition of chloroquine to melanin results in broadening of the melanin ESR signal and is accompanied by changes in the integrated intensity of the analyzed melanin samples.
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