(BQ) Part 1 book “Current topics in medical mycology” has contents: The infection of human skin and nail by scytalidium species, the use of molecular techniques for epidemiologic typing of candida species, skin kinetics ofazole antifungal drugs,… and other contents.
Current Topics in Medical Mycology Editorial Board LIBERO AJELLO, Ph.D., Emory University Eye Center, Ophthalmic Research, 3rd Floor, 1327 Clifton Road, N.E Atlanta, Georgia 30322, U.S.A GARRY T COLE, Ph D., Department of Botany, The University of Texas at Austin, Austin, Texas 78712, U.S.A REBECCA A Cox, Ph D., Research Immunology, San Antonio State Chest Hospital, San Antonio, Texas 78223, U.S.A DAVID J DRUTZ, M.D., Biological Sciences, Smith Kline and French Laboratories, Swedeland, Pennsylvania 19479, U S A KAzuo IWATA, M.D., Hattori Seiko C Ltd., 1-10 Kajicho 2-chome, Chiyoda-ku, Tokyo 101, Japan GEORGE S KOBAYASHI, Ph.D., Division of Dermatology, Washington University School of Medicine, St Louis, Missouri 63110, U.S.A C.P KURTZMAN, Ph.D., Culture Collection Research, Fermentation Laboratory, USDA-ARS, Northern Regional Research Center, 1815 Northern University Street, Peora, Illinois 61604, U.S.A THOMAS G MITCHELL, Ph.D., Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710, U.S.A RICARDO NEGRONI, M D., Catedra de Microbiologica, Parasitologia e Immunologia, Centro de Micologia, Buenos Aires, Argentina DEMOSTHENES PAPPAGIANIS, M D., Department of Medical Mycology, University of California, School of Medicine, Davis CA 95616, U S A ERROL REISS, Ph.D., Division of Mycotic Diseases, Centers for Disease Control, Atlanta, Georgia 30333, U.S.A JOHN L RICHARD, Ph D., USDA-ARS, Northern Regional Research Center, 1815 Northern University Street, Peora, Illinois 61604, U.S.A HISASHI TAKAHASHI, M.D., Department of Dermatology, Teikyo University, School of Medicine, 11 Kaga-2, Itabahiku, Tokyo 173, Japan H UGO VANDEN BOSSCHE, Department of Comparative Biochemistry, Janssen Research Foundation, B-2340 Beerse, Belgium Marcel Borgers Roderick Hay Michael C Rinaldi Editors Current Topics in Medical Mycology VOLUME With 94 Illustrations Springer-Verlag New York Berlin Heidelberg London Paris Tokyo Hong Kong Barcelona Budapest Marcel Borgers, Ph.D Life Sciences Janssen Research Foundation B-2340 Beerse Belgium Roderick Hay, M.D Department of Dermatology Guy's Hospital London Bridge, London SEl 9RT, UK Michael G Rinaldi, Ph.D University of Texas Health Science Center at San Antonio San Antonio, Texas 78284-7750 USA Series Editor: Michael R McGinnis ISSN 0177-4204 © 1992 by Springer-Verlag New York Inc Softcover reprint of the hardcover I st edition 1992 All rights reserved This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag, 175 Fifth Avenue, New York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly analysis Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden The use of general descriptive names, trade names, trademarks, etc in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone While the advice and information in this book are believed to be true and accurate at the date of going to press, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made The publisher makes no warranty, express or implied, with respect to the material contained herein Typeset by Asco Trade Typesetting Ltd., Quarry Bay, Hong Kong ISBN-I3: 978-1-4612-7657-9 DOl: 10.1007/978-1-4612-2762-5 e-ISBN-13: 978-1-4612-2762-5 Series Preface Current Topics in Medical Mycology is intended to summarize current research areas in medical mycology for medical mycologists and other scientists who are working in microbiology and immunology Topics to be included in each volume will serve as contemporary reviews, summaries of current advancements and future directions, and mechanisms to enhance the interdisciplinary use of medically important fungi in understanding pathogenesis, epidemiology, mycotoxins, taxonomy, and other areas where basic, applied, and clinical sciences are used Marcel Borgers Roderick Hay Michael G Rinaldi Contents Series Preface Contributors The Infection of Human Skin and Nail by Scytalidium Species v ix MARY K MOORE The Use of Molecular Techniques for Epidemiologic Typing of Candida Species 43 MICHAEL A PFALLER Bronchopulmonary Aspergillosis: Diagnostic and Therapeutic Considerations HIDEO IKEMOTO Skin Kinetics of Azole Antifungal Drugs 64 88 GEERT CAUWENBERGH Killer System Interactions 137 L POLONELLI, G MORACE, S CONTI, M GERLONI, L CAMPANI, AND C CHEZZI Allylamine Antifungal Drugs 159 NEIL S RYDER AND HUBERT MIETH The Treatment of Superficial Skin Infections Caused by Dermatophytes HUGO DEGREEF 189 vii Contents viii Molecular Approach to the Toxic Action of Quinone Mycotoxins-Chemical Structure and Biochemistry KIYOSHI KAWAI, KAZUO HISADA, HIDEKI MORI, AND YOSHINORI NOZAWA Fusarium-Caused Hyalohyphomycosis: An Overview E ANAISSIE, P NELSON, M BEREMAND, D KONTOYIANNIS, AND M RINALDI 10 (I) Teaching Medical Mycology in Latin America 207 231 251 RICARDO NEGRONI 10 (II) The' Need for a National Mycoses Reporting System CARLYN HALDE, MIRIAM VALESCO, AND MARTHA FLORES Index 259 267 Contributors E ANAISSIE, M.D The University of Texas, M.D Anderson Cancer Center, Houston, TX 77030, USA M BEREMAND, Ph.D The United States Department of Agriculture, Peoria, IL 61604, USA L CAMPANI, M.D Istituto di Microbiologia, Universita degli Studi di Parma, Parma, Italy GEERT CAUWENBERGH, Ph D Department of Clinical Research and Development, Janssen Research Foundation, Beerse, Belgium C CHEZZI, M.D Istituto di Microbiologia, Universita degli Studi di Parma, Parma, Italy S CONTI, M D Istituto di Microbiologia, Universita degli Studi di Parma, Parma, Italy H DEGREEF, M.D Department of Dermatology, Catholic University Leuven, Leuven, Belgium MARTHA FLORES, B.S Microbial Diseases Laboratory, California State Department of Health Services, Berkeley, CA 94701, USA M GERLONI, M.D Istituto di Microbiologia, Universita degli Studi di Parma, Parma, Italy ix x CARLYN HALDE, Ph.D Department of Microbiology, University of California, San Francisco, CA 94143-0414, USA KAzuo HISADA, Ph.D Department of Biochemistry, Gifu University School of Medicine, Gifu, Japan HIDEOIKEMOTO, M.D Department ofInternal Medicine, Juntendo University School of Medicine, Tokyo, Japan KIYOSHI KAWAI, Ph.D Department of Food and Nutrition, Chukyo Women's University, Aichi, Japan D KONTOYIANNIS, M.D The University of Texas, M D Anderson Cancer Center, Houston, TX 77030, USA HUBERT MIETH, D.V.M Department of Dermatology, Sandoz Forschungsinstitut, Vienna, Austria MARY K MOORE, Ph.D Mycology Department, Institute of Dermatology, United Medical and Dental Schools of Guy's and St Thomas' Hospitals (University of London); Mycology Unit, Department of Microbial Diseases, St Thomas' Hospital, London, England, United Kingdom G MORACE, M.D Istituto di Microbiologia, Universibi Cattolica del Sacro Cuore, Rome, Italy HIDEKI MORI, M.D Department of Pathology, Gifu University School of Medicine, Gifu, Japan RICARDO NEGRONI, M D Faculty of Medicine, Centro de Micologia del Departamento de Microbiologia, Buenos Aires, Argentina P NELSON, Ph.D The Fusarium Research Center, Pennsylvania State University, University Park, PA, USA YOSHINORI NozAwA, Ph.D Department of Biochemistry, Gifu University School of Medicine, Gifu, Japan Contributors Geert Cauwenbergh 122 4-3 Ketoconazole serum and stratum corneum levels after 10 days' administration of200 mg daily TABLE Day 10 (end of intake) 15 20 Serum level (JLg/ml) Stratum corneum level (JLg/ml) 0-7.4 1.4-11.9 o o 2.6 1.3 different dermatopharmacological studies, four possible routes of ketoconazole delivery to the skin after oral administration should be considered: Excretion in the eccrine sweat (rapid route) When one considers the role of the sweat gland in the excretion of ketoconazole, the potential role of the sweat gland in heat regulation should also be considered Indeed, as described by Thiele et al 24 the follOwing process is going on in and around the resting sweat glands: a Water is evaporated, taking up latent heat, in or near the secretory coil of the glands b The water vapor passes outward along the duct c Because of a difference in temperature between the deeper parts of the sweat glands and the upper epidermal duct, the bulk of the water vapor recondenses on the walls of the duct d The condensed water returns via the mUcilaginous lining of the duct by capillary attraction This becomes important when differences in responses to ketoconazole in pityriasis versicolor have to be explained Indeed, in an individual at rest (i.e., with resting sweat glands), the mechanism described above will induce a cyclic recuperation of sweat-excreted ketoconazole before it can reach the stratum corneum This will result in lower drug levels on the skin surface However, during exercise or under sauna conditions heat production is such that water loss cannot be stopped by this system As a consequence, large amounts of ketoconazole are excreted under these conditions, resulting in higher drug levels on the skin surface This is probably the underlying reason why Borelli25 and Jacobs 26 have advocated short courses of ketoconazole combined with physical exercise as therapy for pityriasis versicolor In the study by Borelli, the fact that patients were living in a tropical environment (Venezuela) may also have contributed to the extensive excretion of the drug through the sweat glands Evidence that this mechanism does not recycle ketoconazole during physical exercise is given by the fact that the highest ketoconazole concentrations are found in the sediment fraction of sweat collected on the surface of the skin and by the observation that under sauna conditions, the sweat levels follow a parallel course to the plasma levels This would not be the case when recycling occurs 4-Skin Kinetics of Azole Antifungal Drugs 123 Excretion in the sebum (slow route) The absence of drug in the sebum after 14 days and the high concentrations in sebum after longer treatments with ketoconazole indicate that it probably takes to weeks before ketoconazole from the sebaceous glands becomes available on the skin in measurable amounts Indeed, after incorporation in the basal layer of the sebaceous gland, it takes about 14 days before the sebocytes open into the sebaceous gland A further to days are needed, under normal circumstances, for the sebum to be excreted on the skin surface Further studies should be initiated with tritium labeled ketoconazole, to investigate the incorporation into the sebaceous gland, using the hamster Hank model Incorporation into the basal layer (slow route) Ketoconazole is still detectable in the stratum corneum and 10 days after discontinuation of therapy This is too early to be caused by excretion in the sebum and too late to be caused by sweat excretion Therefore, a mechanism of drug incorporation in the basal layer should be considered (captured intracellular) Recent studies by Wilkinson and Jacobs on keratinocytes have shown that ketoconazole can slow down keratinocyte proliferation by 20% when concentrations of to 10 JLglml are reached in the culture medium 27 This finding suggests that ketoconazole is capable of penetrating into the keratinocyte, thus making the existence of this third route also probable Note: Apart from incorporation in and delivery onto the skin, incorporation of ketoconazole in hair and nails is also of importance Studies have been initiated to determine whether the drug is passively incorporated into this keratinous material or whether a more active mechanism exists, consisting of absorption by sweat and sebum and reabsorption by hair or nails by nutrition through the nail bed A fourth route could be diffusion from the bloodstream across the dermalepidermal barrier through the nonvascular layers of the epidermis, up to the stratum corneum This relatively rapid route of delivery should also be considered, since ketoconazole has been detected in blister Huid induced by suction or contact with cantharidine as early as a few hours after oral administration ofketoconazole 28 Itraconazole The qualitative pharmacokinetic profile of oral itraconazole has been studied as a part of a whole-body autoradiographic study in rats Autoradiographic pictures were taken 1, 4, and 24 h after a single oral dose of 10 mglkg (Figs 4-33 to 4-35) After h, very high levels of radioactiVity occurred in the liver and the contents of the stomach and small intestines High levels could also be observed in the uterine wall and the salivary gland Lower uniform levels occurred in the remaining tissues; radioactivity in the skeletal muscle was 124 Geert Cauwenbergh FIG 4-33 Autoradiogram showing the distribution of radioactivity in a pregnant Wistar rat, at the day 18 of gestation, h after oral administration of H -itraconazole at 10 mg/kg S, salivary glands; L, liver; I, intestine; a, adrenal; K, kidney; i, small intestine; pI, placenta; F, fetus; m, muscle FIG 4-34 Autoradiogram showing the distribution of radioactivity in a pregnant female Wistar rat, at day 18 of gestation, h after oral administration of 3H_ itraconazole at 10 mg/kg S, salivary glands; H, heart; F, fetus; m, muscle; M, mammary gland; I, intestine; i, small intestine; E, eyeball; b, brain; h, pituitary gland; S, salivary gland; bf, brown fat; T, thymus; H, heart; L, liver; St, stomach; s, spleen; a, adrenal; i, small intestine; f, fat; pI, placenta; u, urinary tract; R, rectum; F, fetus; v, vulva; I, intestine 4-Skin Kinetics of Azole Antifungal Drugs 125 FIG 4-35 Autoradiogram showing the distribution of radioactivity in a pregnant female Wistar rat, at day 18 of gestation, 24 h after oral administration of 3H_ itraconazole at 10 mglkg E, eyeball; I, intestine; i, small intestine; f, fat; F, fetus; R, rectum; V, vulva; M, mammary gland; b, brain; h, pituitary gland; S, salivary gland; bf, brown fat; T, thymus; H, heart; L, liver; St, stomach; s, spleen; a, adrenal; K, kidney; I, intestine; i, small intestine; F, fetus; pi, placenta; m, muscle; f, feces similar to that in placenta or most glandular tissues but was virtually absent in the brain and fetal tissue Table 4-4 shows the quantitative levels compared with plasma levels Tissue levels appeared maximal at about h after administration The highest levels were detected in the liver, stomach, and small intestine The adrenal cortex showed high levels, but the medulla contained background radioactivity only Very high levels were present in the mucosa of the gastrointestinal tract, uterus, and vaginal fluid The mammary gland, salivary gland, brown fat, heart muscle, and tongue were also clearly positive Other organs with appreciable levels of radioactivity included subcutaneous fat, pilosebaceous units, lung, kidney, and skeletal muscle The lowest radioactivity occurred in blood, brain, and fetal tissue The placental radioactivity was markedly higher than that in the fetus The tissue distribution after 24 h was similar to that after h However, somewhat lower levels occurred in the liver Very high radioactivity per- 126 Geert Cauwenbergh FIG 4-36 Autoradiogram showing the distribution of radioactivity in the vagina of a pregnant female Wistar rat, at day 18 of gestation, 24 h after oral administration of 3H-itraconazole at 10 mg/kg (magnification, x5) R, rectum; i, small intestine; ut, uterus; pI, placenta; u, urinary bladder; f, fat; ur, ureter; m, muscle; M, mammary gland; v, vagina sisted in the contents of the small intestine, cecum, and rectum Apart from the gastric mucosa, virtually no radioactivity persisted in the stomach Vaginal secretions showed very high levels at the 24-h time point (Fig 4-36) The other organs showed somewhat lower radioactivity than at the h time point, but the general distribution pattern had not changed In terms of quantitative amounts of radiolabeled drug, the highest tissue levels, after repeated dosing with 10 mg of itraconazole per kg of body weight in rats over 28 days, are observed in liver, pancreas, and adrenals Most other tissues, including the skin, had higher drug levels (measured by HPLC) than the corresponding plasma levels It is also interesting to note that in skin (whole skin after removal of subcutaneous fat), itraconazole levels persist at the same level 24 h after the last dose This is in contrast with other tissues, where tissue concentrations follow the same curve as the corresponding plasma concentrations All of these results for animals suggest29 that (1) itraconazole has a higher TABLE 4-4 Itraconazole plasma and tissue levels after weeks' administration of 10 mg/kg/day to rats Time after last dose (h) 24 Itraconazole concn (p.g/ml or g of wet tissue) Plasma Brain Liver Lung Kidney Pancreas 0.16 0.05 0.30 0.11 4.95 1.71 0.78 0.25 0.84 0.47 4.0 0.98 Skin Fat Muscle 0.37 0.4 0.40 0.15 0.11 0.08 4-Skin Kinetics of Azole Antifungal Drugs 127 affinity for most tissues than for blood or plasma and (2) a difference exists in tissue levels after single or long term dosing; e.g., after a single dose brain levels were virtually absent, but after 28 days of dosing they were higher than the corresponding plasma levels This suggests that some organs will slowly build up a depot of the drug during long term administration Stratum corneum levels of itraconazole have been measured in material taken from human volunteers 14 The methodology followed in this study has been described earlier The weights of the various samples are given in Table 4-5 The itraconazole levels in the plasma (peak levels) and in the other samples are given in Table 4-6 (IOO-mg dose) and Table 4-7 (200-mg dose) The evolution of the itraconazole levels is shown in Figs 4-37 and 4-38 TABLE 4-5 Weight of sebum, sweat, hair, nail, and stratum corneum samples Source Wt (mg) No of samples Minimum Maximum Median Mean 11 11 12 12 2.0 940 481 61 11.7 2,990 561 1,189 5.4 2,130 507 66 5.8 2,050 512 79.3 31 20 20 14 14 168 131 36 83 40 18 Sebum Sweat Hair Nails Strateum corneum Palms Beard Back 85.1 52.6 19.9 TABLE 4-6 Mean plasma and tissue levels of itraconazole after weeks' administration of 100 mg daily (two volunteers) Level (ng/ml or ng/g)a Time of sampling Plasma (peak) Palms Beard Back Hair Day Day Day Day 14 Day 21 Day 28 54 285 382 274 337 0 53 47 98 132 0 444 912 1,462 1,467 0 389 427 553 587 0 19 24 73 41 0 56 67 121 128 Post days Post 14 days Post 21 days Post 28 days ND ND ND 67 70 37 ND 846 258 56 15 132 ND ND ND NA NA NA NA NA NA NA NA aND, Not detectable by the HPLC method (s; 1.0 ng per sample); NA, not available Nails Geert Cauwenbergh 128 ng/ml 10000 1000 plasma -0- _ palms beard -0- back 100 10 o days 14 28 21 35 42 49 56 end therapy FIG 4-37 Mean itraconazole plasma levels and tissue levels after weeks' administration of 100 mg daily ng/ml 10000 1000 ""*" -m- 100 -B- plasma sebum sweat palms 10 o~~ ~ ~ . -~ days end therapy FIG 4-38 Itraconazole plasma, tissue, and fluid levels after week of therapy with 200 mg daily 4-Skin Kinetics of Azole Antifungal Drugs 129 TABLE 4-7 Plasma, tissue, and fluid levels of itraconazole after week administration of200 mg daily (one volunteer) Time of sampling Level (ng/ml or ng/g)a Time postintake Plasma Sebum Sweat Start 3h 5h 7h 24h 3h 3h day days days 14 days ND 125 198 169 40 646 498 246 175 15 ND ND ND ND ND ND 2,410 4,640 3,640 3,510 271 ND ND ND ND ND 32 72 17 29 ND Day Day Day Post Post Post Post Palms ND ND ND ND ND ND 77 60 78 72 50 aND, Not detectable In the volunteers who had taken 100 mg of itraconazole daily for weeks, steady-state was reached within days after the start of therapy Steady state peak plasma levels ranged from 274 to 382 ng/ml During that same period a slow buildup of itraconazole occurred in the stratum corneum, with a maximum of 132 ng/g at the end of the 4-week therapy In the beard region, stratum corneum levels were higher than the corresponding peak plasma levels from day of therapy onward A significant further increase could be observed between weeks and of treatment From week onward, a steady-state level in the beard region was observed The stratum-corneum of the back also had higher itraconazole levels than the corresponding peak plasma levels These levels also showed a slow buildup during therapy, almost reaching the steady-state situation after weeks of treatment The hair tips contained detectable itraconazole levels after week of treatment (19 ng/g of hair) These levels increased gradually but were consistently lower than the corresponding peak plasma levels Finally, distal fingernail clippings contained measurable levels of itraconazole after week (56 ng/g) These levels gradually increased during continued therapy (128 ng/g at week 4) After the end of the treatment, plasma levels of itraconazole decreased to almost undetectable levels within days (3 ng/ml) Palmar stratum corneum, however, contained drug levels which persisted for at least weeks after the end of treatment and was no longer detectable after weeks The beard region showed a gradual decrease of itraconazole levels, but the drug was still measurable weeks after the end of therapy (15 ng/g) Finally, the stratum corneum of the back still had therapeutic levels week after the end of therapy, but no itraconazole could be detected weeks after the end of the treatment 130 Geert Cauwenbergh In the volunteer who took 200 mg of itraconazole daily for week, steady state was reached within days after the start of therapy Steady-state peak plasma levels ranged between 498 and 646 ng/ml Itraconazole levels in the palmar stratum corneum became detectable for the first time after days of therapy (77 ng/g), and they persisted during the 2-week follow-up after the end of therapy Itraconazole became detectable in sweat (5 ng/ml) 24 h after the first dose of medication Drug levels in the sweat were measurable as long as plasma levels of itraconazole were measurable (i e., untill week after the end of therapy) Itraconazole levels in the sebum became measurable after days of drug intake and were to 10 times higher than the corresponding peak plasma levels One week after the end of therapy the sebum still contained therapeutic levels of itraconazole (271 ng/g), but sebum levels were no longer detectable weeks after the end of therapy Discussion Topical Administration As demonstrated, 2% ketoconazole cream shows rapid penetration into the stratum corneum but only a limited penetration into the deeper layers of the epidermis An almost identical epidermal distribution profile is observed with itraconazole in cream This suggests that for azole antifungals, the role of the chemical structure on the enhancement of penetration of the drug into the epidermis is limited The repeat study with 2% ketoconazole cream in a DMSO excipient, on the other hand, has clearly demonstrated that azole derivatives may show a different penetration profile when a different cream or ointment base is used Indeed, with DMSO, depending on the contact time, the azole derivative may penetrate to the basal layer of the epidermis and even into the dermis For this reason it is possible that application of an azole in DMSO to the skin may result in systemic absorption of the drug, provided the contact time between the epidermis and the drug-vehicle has been sufficiently long Finally, careful observation of unstained histological sections suggests that the damage caused by the DMSO vehicle to the initially intact stratum corneum is significant This damaging effect on the corneal layer may well be the primary cause of the penetration enhancing effect of DMSO, since it apparently disturbs the barrier function of the stratum corneum The relative amounts of ketoconazole and itraconazole available in the stratum corneum can easily be calculated from histograms Using these histograms, it can be extrapolated that when of a 2% ketoconazole cream is evenly applied to 10 cm of epidermis, the total amount of drug in the stratum corneum after h of contact time is 6.8 mg This means that 0.68 mg of ketoconazole per cm can be measured in the stratum corneum Indeed, the epidermis has been divided into different segments, and the percentage of 131 4-Skin Kinetics of Azole Antifungal Drugs TABLE 4-8 Comparison of the skin kinetics of three orally active antifungals Property Keratin adherence Excretion in sweat Excretion in sebum Uptake in basal layer Griseofulvin Ketoconazole Itraconazole Weak Extensive Limited Limited Strong Extensive Limited Limited Strong Moderate Extensive Moderate total radioactivity per segment is given One gram of 2% ketoconazole contains 20 mg of drug, which is spread over a surface of 10 cm (or mg/cm ) The total amount of radioactive drug available in the horny layer is approximately 34% of the total radioactive drug applied on the skin (i.e., 34% of2 mg, or 0.68 mg) Also, the thickness of the stratum corneum can be measured When a histogram was used (Fig 4-12), the stratum corneum had a thickness of 0.038 mm The total volume of the stratum corneum under the l-cm surface is 100 X 0.038 = 3.8 mm3 , and the ketoconazole concentration is 680/3.8 or 179 JLg/mm (or 179 JLg/g) Similar calculations can be made for itraconazole based on the histograms ofbioavailable radioactivity With a 1% drug concentration, this would mean a drug level in the stratum corneum of about 80 JLg/mm For both ketoconazole and itraconazole, these values are well above the required minimum inhibitory concentrations (MIC's) for dermatophytes Oral Administration Two major features of an antifungal agent determine its therapeutic efficacy: the direct antifungal effect usually expressed as an MIC value and its availability at the site of infection For topical antifungals, this availability is usually adequate provided that the base ensures a steady release of drug into the infected stratum corneum Therefore, antifungal drug levels in the stratum corneum often exceed 100 JLg/g after topical application (see earlier) The situation is slightly different with oral antifungals, which have no direct contact with the fungus immediately after their administration Indeed, an oral drug should be absorbed and will have been through the liver before it becomes available for systemic distribution to all organs For these reasons, an oral antifungal agent will not necessarily produce adequate drug levels in the skin (at the site of infection) The present study of itraconazole skin kinetics suggests some major differences with both griseofulvin and ketoconazole (Table 4-8) It has previously been suggested that griseofulvin is, to some extent, incorporated in the basal layer But Epstein and co-workers demonstrated that sweat is the major route of griseofulvin delivery to the stratum corneum In addition, those authors showed that griseofulvin does not bind avidly to the stratum 132 Geert Cauwenbergh corneum Harris et al demonstrated that sweat is the most important route of delivery of ketoconazole to the skin but also that it has a high binding capacity in the horny layer Excretion in sebum and incorporation in the basal layer were less important 12 The present study suggests that: Sweat does not play a major role in the delivery of itraconazole to the stratum corneum Itraconazole sweat levels are very low 24 h after the first intake of the drug With ketoconazole, peak sweat levels were found to h after intake, and drug levels were measurable in the sweat from h after intake onward Although limited in quantity, sweat levels of itraconazole seem to follow the same kinetics as the plasma levels, similar to the findings with ketoconazole Sebum plays a major role in the delivery of itraconazole to the stratum corneum, as shown by sebum levels to 10 times higher than the corresponding plasma levels These levels remain high for up to days after the end of therapy but are no longer detectable weeks after the end of therapy Incorporation of itraconazole into the basal layer of the epidermis is of less significance, as demonstrated by the levels in the palmar stratum corneum However, in addition, this route of drug delivery continues to give measurable itraconazole levels at a time when plasma, sweat, and sebum levels are undetectable The differing importance of these three drug delivery routes to the skin explains the difference in drug levels in the stratum corneum at different body sites The palms have a fairly thick stratum corneum with no sebum excretion, and excretion through sweat is also limited Itraconazole levels in the palms are relatively low (incorporation in the basal layer) but persist for at least weeks after the end of therapy because of the thickness of the stratum corneum The back has a comparatively thin stratum corneum with an even distribution of sebum and sweat glands This results in levels higher than the corresponding plasma levels, but the drug also disappears within weeks after the end of therapy (parallel to the disappearance of detectable sebum and sweat levels) The beard region produces a much higher contribution of sebum excretion in the delivery of drug to the skin As a consequence, itraconazole levels are extremely high and therefore remain measurable up to weeks after discontinuation of therapy The appearance of itraconazole in the distal part of the fingermails after days demonstrates that itraconazole may act rapidly on fungus in the nail plate Itraconazole seems to reach the nail not only via incorporation into the nail matrix but also by diffusion from the nail bed into the nail plate Skin, hair, and nails act as completely separate compartments Once itraconazole has entered these organs, it will not be redistributed into the systemic circulation This is shown by persistently high levels in these 4-Skin Kinetics of Azole Antifungal Drugs 133 keratinized sites in the absence of measurable plasma levels of Itraconazole Probably, the best way to compare systemic ketoconazole and itraconazole is by using stratum corneum plasma level ratios From the available data (palmar stratum corneum), the ratio for ketoconazole, when the drug is given for or 14 days at a daily dose of 400 mg, is 0.7 after days and 0.66 after 14 days (Table 4-1) For itraconazole, however, this picture is completely different Palmar stratum corneum versus plasma levels show a ratio of 1.66 at day After 28 days of treatment at 100 mg daily, this ratio for palmar stratum corneum is about When stratum corneum from the back is considered, even higher ratios are observed (6.1 at day and 9.2 after 28 days) These figures clearly demonstrate that systemic administration of itraconazole results in higher levels in the epidermis than the corresponding plasma levels This is in contrast to ketoconazole Obviously, this reversed tissue level/plasma level ratio has Significant practical consequences with regard to predictability of therapeutic effect If the MIC value for a given strain of Trichophyton rubrum is JLglml for ketoconazole and 0.1 JLglml for itraconazole, it is obvious that a ratio of 0.7 may result in inadequate skin levels of ketoconazole when plasma levels are to 1.5 JLglml In the case of itraconazole, however, a plasma level of 0.1 JLglml would mean that concentrations at the site of infection are higher than the necessary MIC value of 0.1 JLglml Another important clinical implication of the prolonged presence of itraconazole in the epidermis is the potential for a reduction in the duration of drug administration The presence of adequate antifungal drug concentrations in the skin to weeks after the end of treatment would suggest that with a 4-week course of treatment, the site of infection receives a 6- to 8-week exposure to the antifungal, and this without redistribution of the drug into the systemic circulation over the last to weeks It is obvious that this factor is of Significant therapeutic importance when one considers oral treatment for common dermatophyte infections of the skin Conclusions This study of the pharmacokinetic profiles ·')f ketoconazole and itraconazole in the skin has elucidated a number of interesting findings: It appears possible to make an appropriate choice of vehicle (in terms of percutaneous penetration) based on an in vitro model using nude mouse skin Obviously, the nude mouse skin could be replaced by human excised skin if such were available The use of this model has demonstrated significant differences in percutaneous penetration of topically applied ketoconazole depending on the vehicle used By using microautoradiography, it has been possible to locate ketoconazole in different epidermal layers when applied in the formulation 134 Geert Cauwenbergh selected from the in vitro model mentioned above This microautoradiography method has also produced semiquantitave assessments of the amounts ofketoconazole in different epidermal layers The use of a different base (DMSO) has drastically changed the penetration profile of topically applied ketoconazole, as shown by photographs and histograms Both topically applied ketoconazole and itraconazole in the same base result in similar penetration profiles in the epidermis Only after 16 h of contact is there a tendency for itraconazole to shift of its peak binding toward the granular layer Calculations of the amounts of itraconazole and ketoconazole in the stratum corneum after topical application suggest that the quantity of drug available at the site of infection is considerably more than the MIC required for dermatophytes when and 2% creams, respectively are used Significant differences exist in the pharmacokinetic skin profiles of ketoconazole and itraconazole after oral administration Ketoconazole is predominantly excreted via the sweat, while with itraconazole, excretion via the sebaceous glands plays a much more important role Both drugs have a high affinity for keratinized tissue, but overall, the tissue affinity of itraconazole is much greater than that of ketoconazole This is illustrated by the ratios of stratum corneum plasma levels For ketoconazole, this ratio is 0.7 after administration of 400 mg for consecutive days For itraconazole (100 mg for consecutive days), this ratio ranges from 1.66 in palmar stratum corneum to 6.1 in stratum corneum from the back In summary, it appears that topical administration of either ketoconazole or itraconazole results in drug levels at the site of infection which are much higher than the MICs required for dermatophytes As a consequence, any difference in antifungal potency in clinical studies at the drug concentrations used (1 and 2%) may be expected to be minimal For orally administered itraconazole and ketoconazole, the pharmacokinetics in the skin are significantly different in favor of itraconazole, and therefore better results may be expected with itraconazole in the treatment of skin dermatophytoses than with ketoconazole References Raab WPE The Treatment of Mycosis with Imidazole Derivatives SpringerVerlag, Berlin 1980 Stiittgen G, Bauer E Permeation von markierten Oxiconazol Mykosen 1985; 28(3): 138-147 Wallace SM, Shah VP, Epstein WL, et al Topically applied antifungal agents Percutaneous penetration and prophylactic activity against Trichophyton mentagrophytes infection Arch Dennato11977; 113: 1539-1542 Hoechst AG Batrafenfor Local Therapy of Skin Mycoses AG Hoechst, Frankfurt am Main, 80 Federal Republic of Germany 1982 Weidinger G, Czok R, Mieth H Exoderil (naftifin) Ein neues Antimykotikum zur Behandeling von Dermatomykosen Med Welt 1985; 36:462-467 4-Skin Kinetics of Azole Antifungal Drugs 135 Roberts SOB, Mackenzie DWR Mycology, in Rook A, Wilkinson DS, Ebling FJD (eds), Textbook of Dermatology Blackwell Scientific Publications, London 1973; pp 767-868 Shah VP, Epstein WL, Riegelman S Role of sweat in accumulation of orally administered griseofulvin in skin ] Clin Invest 1974; 53(6): 1673-1678 Epstein WL, Shah VP, Riegelman S Griseofulvin levels in stratum corneum Study after oral administration in man Arch Dermato11972; 106:344-348 Woestenborghs R, Lorreyne W, Heykants J A high-performance liquid chromatographic method for the determination of ketoconazole in human plasma: validation and application to the bioavailability and dose proportionality study in man Preclinical research report on R 41400 No 42, September 1982 10 Young WS, Kuhar MJ A new method for receptor autoradiography (3H) opioid receptors in rat brain Brain Res 1979; 179:255-270 11 Michiels M Zur Pharmakokinetiek von Ketoconazol, in Seeliger HPR, Hauck H (eds), Chemotherapie von Oberfiaechen-, Organ- und Systemmykosen Perimed Fachbuch-Verlagsgesellschaft MBH, Erlangen 1982; pp 36-41 12 Harris R, Jones HE, Artis WM Orally administered ketoconazole: route of delivery to the human Stratum corneum Antimicrob Agents Chemother 1983; 24(6): 876-882 13 Haneke E The efficacy and safety of ketoconazole in treating dermatomycoses, in Meinhof W (ed), Oral Therapy in Dermatomycoses: A Step Forward Proceedings of a symposium The Medicine Publishing Foundation Symposium Series No 16 Oxford, 1985; pp 19-26 14 Cauwenbergh G, DegreefH, Heykants J, et a1 Pharmacokinetic profile of orally administered itraconazole in human skin ] Am Acad Dermato11988; 18(2): 263268 15 Woestenborghs R, Lorreyne W, Heykants J Determination of itraconazole in plasma and animal tissues by high-performance liqUid chromatography ] Chromatogr1987; 413:332-337 16 Rawlins M Systemic absorption ofketoconazole 2% cream and ketoconazole 400 mg vaginal pessaries Clinical research report on R 41400 No 301 Janssen UK August 1982 17 Swanson N Systemic absorption following dermal application of 2% ketoconazole cream Clinical research report on R 41400 March 1984 18 Levine HB Introduction to antifungal imidazoles, In Levine HB (ed), Ketoconazole in the Management of Fungal Disease Adis Press, Hong Kong 1982; pp 47-83 19 Symoens J, Cauwenbergh G Ketoconazole, a new step in the management of fungal disease Prog Drug Res 1983; 27: 63-84 20 Jones HE Ketoconazole Today: A Review of Clinical Experience Adis Press, Manchester 1987 21 Artis WM Final pathway for delivery of oral antifungals to keratinized cornified skin, in Meinhof W (ed), Oral Therapy in Dermatomycoses: A Step Forward Proceedings of a symposium The Medicine Publishing Foundation Symposium Series No 16 Oxford 1985; pp 61-70 22 Haneke E Tissue concentrations ofketoconazole after treatment, in MeinhofW (ed), Oral Therapy in Dermatomycoses: A Step Forward Proceedings of a symposium The Medicine Publishing Foundation Symposium Series No 16 Oxford 1985; pp 71-72 23 Van Cutsem J, Van der Flaes M, Thienpont D, et a1 Quantitative Bestimmung von Ketoconazol in den Haaren oral BehandeIter Ratten und Meerschweinchen Mykosen 1980; 23(8): 418-425 24 Thiele FAJ, Mier PD, Reay RA In Measurements on the Surface of the Skin KU Nijmegen 1974; pp 31-39 136 Geert Cauwenbergh 25 Borelli D Treatment of pityriasis versicolor with ketoconazole Rev Infect Dis 1980; 2(4): 592-595 26 Jacobs PH Evolution in the treatment of pityiasis versicolor, in MeinhofW (ed), Oral therapy in Dermatomycoses: A Step Forward Proceedings of a symposium The Medicine Publishing Foundation Symposium Series No 16 Oxford 1985; pp 119-122 27 Wilkinson DI, Jacobs PH Metabolic effects of ketoconazole on cultured human keratinocytes June 1986 28 Korting HC, Dom M, Schaefer-Korting M Ketoconazole concentrations in human plasma and skin blister fluid XVI Congressus Intemationalis Dermatologiae, Tokyo, 1982 29 Heykants J, Michiels M, Meuldermans W, et al The pharmacokinetics of itraconazole in animals and man: an overview, in Fromtling RA (ed), Recent trends in the discovery, development and evaluation of antifungal agents JR Prous Science Publishers, SA, Barcelona 1987; pp 223-249 ... 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