Haemolysis Effect Estimation of Doxycycline Hyclate 150 mgDelay Release Tablet in Bio-analysis (Human Plasma) by LiquidChromatography-Tandem Mass Spectrometry
A fast, simple and particular method for estimation of Doxycycline in healthy human plasma was validated using Minocycline as IS. The analyte and IS were extracted from plasma using SPE. The compound was estranged on a RP column with an isocratic mobile phase consisting of 0.1% formic acid in water and acetonitrile (12:88, v/v), and detected by tandem mass spectrometry in positive ion mode. The ion transition recorded in several reaction monitoring mode were m/z 294.1→225.1 for Doxycycline and m/z 286.1→217.1 for IS. Linearity in plasma was observed over the concentration range 0.3-30 ng/mL for Doxycycline. The mean recovery for Doxycycline was 83.7%, with a lower limit of quantification of 0.3 ng/mL. The coefficient of variation of the assay was less than 6.8%, and accuracy of 96.1% to 102.2%. The validated method was applied to bioequivalence study of 150 mg Doxycycline Hyclate tablet in healthy human volunteers. The validated method was used to expose study samples of bioequivalence study of 150 mg Doxycycline Hyclate delay release tablet in 36 healthy human volunteers. Total 50 samples from individual volunteers identified as Haemolyzed, which were analyze initial and repeat again to cross check the method reproducibity for Haeamolysis effect and compared which found acceptable range. Bioequivalence was prove for test and reference using validated method to experimental samples (Figure 1).
A Novel and Rapid Method to Determine Doxycycline in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry
A simple, rapid, specific and sensitive liquid chromatography tandem mass spectrometric method has been developed and validated for the determination of doxycycline from the human plasma. Doxycycline is extracted from human plasma by solid phase extraction. Demeclocycline was used as an internal standard. Detection was performed at transitions of 444.800→428.200 for doxycycline and 464.700→448.100 for demeclocycline using mass spectrometry. Chromatographic separation of analyte and internal standard were carried out using a reverse phase C18, column at 0.500 ml/min flow. The assay of doxycycline is linear over the range of 0.055-7.612 μg/ml, with a precision <14.83%, regression coefficient (r2)=0.9961 and the limit of quantification in plasma for doxycycline was 0.055 μg/ml. Mean extraction recovery obtained was 95.55%. Samples are stable at room temperature for 6 h, processed samples were stable at least for 30.20 h and also stable at three freeze-thaw cycles. The method has been used to perform pharmacokinetic and bioequivalence studies in human plasma.
Locally delivered doxycycline as an adjunct to mechanical debridement at retreatment of periodontal pockets: outcome at furcation sites.
BACKGROUND
The goal was to evaluate the clinical outcome of non-surgical retreatment at molar furcation sites by ultrasonic debridement with or without adjunctive application of locally delivered doxycycline, and to explore factors affecting the healing results.


METHODS
This study involves 32 patients with chronic periodontitis, who received initial pocket/root debridement by ultrasonic instrumentation, followed by random assignment to retreatment of remaining pathologic sites at 3 months by ultrasonic instrumentation with or without adjunctive local application of an 8.8% doxycycline gel. Clinical examinations of plaque, probing depth (PD), relative attachment level, furcation involvement, and bleeding after furcation probing were performed initially, before retreatment at 3 months (baseline), and 3 and 9 months after retreatment. The primary efficacy variable was reduction in the degree of furcation involvement. A multilevel logistic model was used to evaluate the impact of patient and tooth site related factors on the main outcome variable.


RESULTS
The retreatment including locally delivered doxycycline resulted in closure of 50% of degree I furcation sites, compared to 29% for sites treated with mechanical debridement only (P >0.05). Of the degree II furcation sites, 17% in the test and 11% in the control group were reduced in depth (P >0.05). The logistic multilevel model with "furcation improvement" as the dichotomous outcome variable revealed that local application of doxycycline had no statistically significant effect. The odds ratio for ?furcation improvement? was 0.80 (95% confidence interval [CI], 0.65 to 0.99) for 1-mm increase of initial vertical PD, 0.36 (95% CI, 0.17 to 0.80) for initial furcation involvement degree II compared to degree I, and 0.24 (95% CI, 0.08 to 0.72) for smokers compared to non-smokers.


CONCLUSION
Improvement in molar furcation involvement after non-surgical periodontal therapy was not enhanced by adjunctive locally applied doxycycline and negatively affected by increased vertical PD and tobacco smoking.