title: Analysis of a new fluoroquinolone derivative (Q-35) in human scalp hair as an index of drug exposure and as a time marker in hair.
abstract: Scalp hair samples were obtained every month for three months after administration from healthy male volunteers who participated in the phase I study of a new antimicrobial fluoroquinolone derivative (Q-35). Hairs were cut into 1 cm long pieces successively from the scalp end. Corresponding pieces of 5 hair strands were dissolved in 1 M NaOH and assessed for Q-35 by HPLC. The drug was detectable in the hairs of all subjects taking either a single (400 mg, n = 6) or repeated oral doses of Q-35 (400 mg/day for 6.5 days, total 2600 mg, n = 6). The hair portions containing the drug were shown in most subjects to move outwards along the hair shafts month by month in proportion to the hair growth rate of about 1 cm/month. Q-35 (600 mg/day) was also given to 6 healthy male volunteers for 6.5 days (total 3900 mg) and hair samples were obtained 1 and 3 months after administration. When Q-35 was analyzed along a single hair shaft, the drug was detectable only in 1-2 consecutive 1 cm long pieces, which were also shown to move outwards along the hair shaft with time. A detailed analysis revealed that the drug was contained only in 2-4 consecutive 2.5 mm long pieces of a single hair collected after 3 months, showing that there was no significant axial diffusion of the drug along the hair shaft with time.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pharmacology, Hamamatsu University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uematsu
authors.forename: Y
authors.initials: Y
authors.lastname: Ohsawa
authors.forename: A
authors.initials: A
authors.lastname: Mizuno
authors.forename: M
authors.initials: M
authors.lastname: Nakashima
mesh_terms: D000328:Adult; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000032:analysis* / Q000493:pharmacokinetics; D004781:Environmental Exposure / Q000032:analysis*; D024841:Fluoroquinolones; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015363:Quinolones / Q000008:administration & dosage / Q000032:analysis* / Q000493:pharmacokinetics; D012016:Reference Values; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; C077155:balofloxacin