A rapid spectrophotometric assay for tetracycline in gingival crevicular fluid

Abstract

Aim: The aim of this study was to investigate a rapid spectrophotometric assay for its potential to measure tetracycline levels in gingival crevicular fluid (GCF). Materials and methods: The technique involves complexation of tetracycline with molybdenum in order to shift the absorbance spectrum away from that region where interference with plasma proteins is a problem. The sensitivity of the assay and reproducibility of elution were examined together with an assessment of the effect of plasma proteins. The assay was also tested in a small pilot clinical project, measuring tetracycline levels in GCF following placement of a test gel formulation in 25 periodontal pockets in 5 patients. Results: The in vitro results showed good sensitivity of the assay over the concentration range tested (0.5–200 μg tetracycline) and with little effect of plasma proteins. Elution from the paper strips was reproducible with a good linear correlation between direct and filter absorbed assays (r=0.9989, p<0.01). The pilot clinical study indicated a mean half‐time of tetracycline in GCF of 28 min with confidence intervals of 21 to 34 min, although wide variation between the drug levels of individual periodontal pockets was seen. Conclusions: The results indicate good sensitivity for this assay to measure tetracycline hydrochloride in vivo. The potential for rapidly processing large numbers of samples contrasts with the assay time and limited sample throughput of other methods such as high pressure liquid chromatography (HPLC) and suggests that the technique may be a useful addition to current techniques for measuring tetracycline hydrochloride in vivo.

Analise da farmacocinetica e dos indices PK/PD da doxiciclina no plasma, fluido gengival e saliva e avaliação de seu efeito sobre a osteoclastogenese mediada por RANKL

“…A successful periodontitis therapy requires a reduction in the number of bacteria responsible for periodontal infections (Kim et al, 2004). In this context, systemically administered antibiotics, such as doxycycline (a semi-synthetic tetracycline), have been widely used as adjuncts to the treatment of different forms of periodontitis (Feres et al, 1999;Needleman et al, 2001;. Doxycycline (Dox) is a broad-spectrum antibiotic with activity against a wide range of gram-positive and gram-negative microorganisms (Zhanel et al, 2004).…”

“…The volume of GCF was estimated by the difference between the weight of strips before and after fluid collection by using an analytical microbalance. The density of the GCF was considered 1.02(Needleman et al, 2001). The samples were stored at -70°C until the analyses.…”