Chemometric evaluation of the efficacy of locally administered chlorhexidine in patients with periodontal disease.

The process of assessment of drug efficacy produces multivariate data which are difficult to interpret. The interpretation and extraction of relevant data requires application of chemometric algorithms for multivariate data analysis. The aim of our study was evaluation of the efficacy of local treatment with chlorhexidine (CHX) in patients suffering from periodontal disease by chemometric algorithms for multivariate data analysis. Several algorithms were used: principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA). The PCA models identified the examined variables as suitable for monitoring the periodontal disease progression at the same time revealing mutual relationship among them. The developed PLS-DA model successfully distinguished patients treated with CHX from non-treated patients. The OPLS-DA model revealed differences in the mechanism of action of the two widely applied treatments in periodontal disease, local administration of CHX and local administration of doxycycline (DOX). The approach presented in this study opens the possibility of application of chemometric algorithms for multivariate data analysis for assessment of treatment efficacy.

High-Throughput HPLC-MS/MS Method for Quantification of Ibuprofen Enantiomers in Human Plasma: Focus on Investigation of Metabolite Interference.

In this research, as a part of the development of fast and reliable HPLC-MS/MS method for quantification of ibuprofen (IBP) enantiomers in human plasma, the possibility of IBP acylglucoronide (IBP-Glu) back-conversion was assessed. This involved investigation of in source and in vitro back-conversion. The separation of IBP enantiomers, its metabolite and rac-IBP-d3 (internal standard), was achieved within 6 min using Chiracel OJ-RH chromatographic column (150 × 2.1 mm, 5 µm). The followed selected reaction monitoring transitions for IBP-Glu (m/z 381.4 → 205.4, m/z 381.4 → 161.4 and m/z 205.4 → 161.4) implied that under the optimized electrospray ionization parameters, in source back-conversion of IBP-Glu was insignificant. The results obtained after liquid-liquid extraction of plasma samples spiked with IBP-Glu revealed that the amount of IBP enantiomers generated by IBP-Glu back-conversion was far <20% of lower limit of quantification sample. These results indicate that the presence of IBP-Glu in real samples will not affect the quantification of the IBP enantiomers; thereby reliability of the method was improved. Additional advantage of the method is the short analysis time making it suitable for the large number of samples. The method was fully validated according to the EMA guideline and was shown to meet all requirements to be applied in a pharmacokinetic study.

Efficacy assessment of local doxycycline treatment in periodontal patients using multivariate chemometric approach.

The aim of our study was application of chemometric algorithms for multivariate data analysis in efficacy assessment of the local periodontal treatment with doxycycline (DOX). Treatment efficacy was evaluated by monitoring inflammatory biomarkers in gingival crevicular fluid (GCF) samples and clinical indices before and after the local treatment as well as by determination of DOX concentration in GCF after the local treatment. The experimental values from these determinations were submitted to several chemometric algorithms: principal component analysis (PCA), partial least square discriminant analysis (PLS-DA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA). The data structure and the mutual relations of the selected variables were thoroughly investigated by PCA. The PLS-DA model identified variables responsible for discrimination of classes of data, before and after DOX treatment. The OPLS-DA model compared the efficacy of the two commonly used medications in periodontal treatment, chlorhexidine (CHX) and DOX, at the same time providing insight in their mechanism of action. The obtained results indicate that application of multivariate chemometric algorithms can be used as a valuable approach for assessment of treatment efficacy.

Development and validation of RP HPLC method for determination of betamethasone dipropionate in gingival crevicular fluid.

Abstract A simple RP HPLC method for quantification of betamethasone dipropionate (BDP) in gingival crevicular fluid (GCF) has been developed and validated. GCF represents a valuable matrix for therapeutic monitoring of drugs used in the treatment of periodontal disease. The proposed method involves single step extraction for sample preparation. The calibration curve for BDP was linear over the concentration range of 0.10-2.00 µg mL⁻¹ (R² = 0.9971). RSD values of intra- and inter-day precision ranged 2.2-4.5 and 1.6-5.7 %, while accuracy values were higher than 96.6 and 97.0 %, respectively. The described method can be successfully applied for determination of betamethasone concentrations in GCF obtained from patients with chronic periodontitis after local treatment with BDP cream 0.5 mg g⁻¹.