[Pharmacokinetic study of percutaneous absorption of salicylic acid from baths with salicylate methyl ester and salicylic acid].

Percutaneous uptake of methyl salicylate was investigated by use of Leukona-Rheumabad (Dr. Atzinger) in 10 volunteers. Percutaneous uptake of salicylic acid was investigated by use of Contrheuma-Bad (Spitzner) in 15 volunteers. By use of bathing concentration of 0.03 g/l of methyl salicylate, plasma levels of 220-820 ng/ml were found 1 h after beginning, and 46-193 ng/ml after 6 h. 2.3-8.7 mg of salicyluric acid was eliminated on the first day, and 0.47 to 1.48 mg on the second day. By use of bathing concentration of 0.33 g/l of salicylic acid constant plasma levels of 10 +/- 1.27 ng/ml were found in a period of 24 h. The renal elimination of 0.92 +/- 0.14 at first day, 0.72 +/- 0.11 at second day, and 0.50 +/- 0.08 mg salicyluric acid at third day was found. Salicylic acid was eliminated 0.086 +/- 0.009 resp. 0.079 +/- 0.007 resp. 0.043 +/- 0.011 mg by those days. The half-time of elimination in urine after methyl salicylate bathing is (as with injected salicylic acid) between 2.4 to 4 h. Conversely half-time of elimination in urine by salicylic acid bathing is between 30 to 50 h, and is greater with salicylic acid bathing than with other application forms. This is in agreement with earlier examinations and results which point out the deposition of salicylic acid in skin. Any definitive deposition of salicylic acid in skin by methyl salicylate bathing was not found.(ABSTRACT TRUNCATED AT 250 WORDS)