A Comparative Study on the Skin Penetration of Pure Tryptanthrin and Tryptanthrin in Isatis tinctoria Extract by Dermal Microdialysis Coupled with Isotope Dilution ESI-LC-MS

Abstract

The indolo[2,1-b]quinazoline alkaloid tryptanthrin has recently been identified as a pharmacologically active compound in Isatis tinctoria, with potent dual inhibitory activity on prostaglandin and leukotriene synthesis. To investigate the skin penetration of tryptanthrin from solutions of pure compound and Isatis extracts, we developed and validated a cutaneous microdialysis model using ex vivo pig foreleg. Microdialysis was performed by placing linear probes in the dermis of the skin in situ, and tryptanthrin concentrations in the dialysates were determined by isotope dilution electrospray ionization LC-MS in the selected ion mode. Measurable concentrations of tryptanthrin were detected 30 min after application. A dose-dependent increase in tryptanthrin concentrations in the dialysate was observed for the Isatis extracts, but not for pure tryptanthrin. Microscopic analysis showed that the pure compound crystallized from the solution but remained in an amorphous state in the extracts.

References

• 1 Hamburger M, Danz H. Medicament for inhibiting NF-κB. WO 00/61 159. 
• 2 Danz H, Stoyanova S, Hamburger M, Brattström A. Identification and isolation of the COX-2 inhibitory principle in Isatis tinctoria L. (Brassicaceae).  Arch Pharm. 2000;  333 (Suppl. 1) 11
• 3 Danz H, Stoyanova S, Wippich P, Brattström A, Hamburger M. Identification and isolation of the cyclooxygenase-2 inhibitory principle in Isatis tinctoria .  Planta Med. 2001;  67 411-6
• 4 Danz H, Baumann D, Hamburger M. Quantitative determination of the dual COX-2/5-LOX inhibitor tryptanthrin in Isatis tinctoria by ESI-LC-MS.  Planta Med. 2002;  68 152-7
• 5 Danz H, Stoyanova S, Thomet O, Simon H U, Dannhardt G, Ulbrich H, Hamburger M. Inhibitory activity of tryptanthrin on prostaglandin and leukotriene synthesis.  Planta Med. 2002;  68 875-80
• 6 Ishihara T, Kohno K, Ushio S, Iwaki K, Ikeda M, Kurimoto M. Tryptanthrin inhibits nitric oxide and prostaglandin E₂ synthesis by murine macrophages.  Eur J Pharmacol. 2000;  407 197-204
• 7 Recio M C, Hamburger M, Rios J L. In vivo anti-inflammatory activity of Isatis tinctoria extracts and tryptanthrin. Abstract book 50^th Annual Congress of Society of Medicinal Plant Research 2002. Canigueral S, editor Carlet (Valencia); CITA Publicaciones y Documentacion 2002: p. 94
• 8 Heinemann C, Schliemann-Willers S, Oberthür C, Hamburger M, Elsner P. Prevention of experimentally induced irritant contact dermatitis by Isatis tinctoria and tryptanthrin and its impact on UVB-induced erythema. Brit J Dermatol, submitted
• 9 Bronaugh R L, Maibach H I. editors Topical Absorption of Dermatological Products. New York, Basel; Marcel Dekker 2002
• 10 Anderson C, Anderson T, Molander M. Ethanol absorption across human skin measured by in vivo microdialysis technique.  Acta Derm Venerol. 1991;  71 389-93
• 11 Benfeldt E. In vivo microdialysis for the investigation of drug levels in the dermis and the effect of barrier perturbation on cutaneous drug penetration. Studies in hairless rats and human subjects.  Acta Derm Venereol. 1999;  206 (Suppl) 1-59
• 12 Schnetz E, Fartasch M. Microdialysis for the evaluation of penetration through the human skin barrier - a promising tool for future research?.  Eur J Pharm Sci. 2000;  1 1-9
• 13 Riviere J E, Monteiro-Riviere N, Williams P. Isolated perfused porcine skin flap as in vitro model for predicting transdermal pharmacokinetics.  Eur J Pharm Biopharm. 1995;  41 152-62
• 14 Oberthür C, Hoffmann B, Hamburger M. Synthesis of d-tryptanthrin. Pharmazie 2002: 586-7
• 15 Martinez M S, Gutierrez Hurtado B, Colino Gandarillas C I, Martinez Lanao J, Sanchez Navarro A. In vitro study of experimental factors affecting the microdialysis results.  Anal Chim Acta. 2002;  459 143-50
• 16 Benfeldt E, Groth L. Feasibility of measuring lipophilic or protein-bound drugs in the dermis by in vivo microdialysis after topical or systemic drug administration.  Acta Derm Venereol. 1998;  78 274-8
• 17 Friedländer P, Roschdestwensky N. Über ein Oxidationsprodukt des Indigoblaus.  Ber dtsch chem Ges. 1915;  48 1841-7