Fast off-line FPSE-HPLC-PDA determination of six NSAIDs in saliva samples.

A fast off-line FPSE-HPLC-PDA method has been reported that allows simultaneous clean up and determination of six non-steroidal anti-inflammatory drugs (NSAIDs) in saliva samples from healthy volunteers. Particularly, furprofen, indoprofen, ketoprofen, fenbufen, flurbiprofen, and ibuprofen were chromatographically resolved. Benzyl paraben was chosen as the internal standard (BzPB, IS). These target compounds were successfully extracted from human saliva using fabric phase sorptive extraction (FPSE) and then analysed in the liquid chromatographic system by means of a short analytical column (Symmetry C18, 75 × 4.6 mm, 3.5 µm) using acetonitrile (AcN) and phosphate buffer (PBS, 30 mM; pH = 2.5) as the mobile phases. The method, validated through the calculation of all analytical parameters in accordance of International Guidelines, was applied to real saliva sample analysis collected from informed volunteers. The proposed approach that included the use of sol-gel polytetrahydrofuran (sol-gel PTHF) sorbent immobilized on cellulose support and C18 stationary phase used in HPLC, showed high potential as a fast tool for future clinical and forensic applications. The herein reported results encourage potential future application of FPSE in the forensic field. Furthermore, the FPSE membrane was tested in dried saliva spot mode (DSS) in order to check its potential use as a sampling device, also for forensic applications.

The health controversies of parabens.

Parabens are preservatives used in a variety of personal care, cosmetic, pharmaceutical and food products. Studies have confirmed the ubiquitous presence of parabens, with levels detected in wastewater, rivers, soil and house dust. Parabens have also been detected in human tissues and bodily fluids, but it is the discovery of these chemical compounds in the breast tissue of patients with breast cancer that has raised public concern over their use. It is hypothesized that the estrogenic properties of parabens may play a role in breast cancer development. However, studies investigating the health effects of parabens are conflicting. At this point, there is an insufficient amount of data suggesting serious consequences from paraben use and exposure to warrant drastic avoidance measures or government regulations.

Do placebo based validation standards mimic real batch products behaviour? Case studies.

Analytical methods validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application. Validation usually involves validation standards or quality control samples that are prepared in placebo or reconstituted matrix made of a mixture of all the ingredients composing the drug product except the active substance or the analyte under investigation. However, one of the main concerns that can be made with this approach is that it may lack an important source of variability that come from the manufacturing process. The question that remains at the end of the validation step is about the transferability of the quantitative performance from validation standards to real authentic drug product samples. In this work, this topic is investigated through three case studies. Three analytical methods were validated using the commonly spiked placebo validation standards at several concentration levels as well as using samples coming from authentic batch samples (tablets and syrups). The results showed that, depending on the type of response function used as calibration curve, there were various degrees of differences in the results accuracy obtained with the two types of samples. Nonetheless the use of spiked placebo validation standards was showed to mimic relatively well the quantitative behaviour of the analytical methods with authentic batch samples. Adding these authentic batch samples into the validation design may help the analyst to select and confirm the most fit for purpose calibration curve and thus increase the accuracy and reliability of the results generated by the method in routine application.

Degradation of parabens by Pseudomonas beteli and Burkholderia latens.

p-Hydroxybenzoic acid esters (parabens) are commonly used antimicrobial preservatives in pharmaceutical formulations. Two microorganisms, isolated from non-sterile methyl paraben (MP) and propyl paraben (PP) solutions, were found to degrade the respective parabens. Identification by 16S rRNA partial gene sequencing revealed them to be Pseudomonas beteli and Burkholderia latens, respectively. The present work describes a previously unreported interaction of the parabens with P. beteli and B. latens. Degradation of MP at various concentrations by P. beteli, followed a logarithmic pattern, while that of PP by B. latens was found to be linear. It was subsequently observed that P. beteli could degrade only MP, while B. latens could degrade both the parabens. Absence of HPLC chromatogram peaks of expected degradation products indicated that the parabens were used up as a carbon source. The behaviour of pathogens (Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus niger) of the pharmacopoeial preservative effectiveness test (PET), towards MP, showed that none had the ability to degrade the paraben. It was concluded that, for a paraben-preserved multi-dose ophthalmic formulation, the sole use of the four pathogens that are recommended by the pharmacopoeia for PET can falsely indicate the formulation to be effective against 'in-use' contamination.