B. De Spiegeleer

LC-MS profiling of N-alkylamides in Spilanthes acmella extract and the transmucosal behaviour of its main bio-active spilanthol

N-Alkylamides are a promising group of naturally occurring bio-actives, with evidence for immune stimulating properties, which find applications i.a. in buccal preparations. In Spilanthes extracts, these properties are mainly ascribed to the most abundant N-isobutylamide, spilanthol. Yet, other N-alkylamides present in these extracts may contribute to this effect, as well as to its potential toxicity and physiologic interactions. Therefore, N-alkylamide profiling of an ethanolic Spilanthes extract was performed using a gradient reversed phase high performance liquid chromatography/electrospray ionization ion trap mass spectrometry (HPLC/ESI-MS) method on an embedded polar column. MS(1) and MS(2) fragmentation data were used for identification purposes. Moreover, the transmucosal behaviour of spilanthol, formulated in this ethanolic extract and in two commercially available oral gels, was evaluated using porcine buccal mucosa in a Franz diffusion cell experimental set-up. A high-throughput HPLC-UV method was used for the quantification of spilanthol in the receptor phase. Fundamental permeation characteristics of spilanthol in a solvent-independent way (100% aqueous dose solution) were obtained using different propylene glycol/water ratios. Eight N-isobutylamides, two 2-methylbutylamides and one 2-phenylethylamide were detected, with spilanthol as most abundant N-alkylamide (88.8%). Up till now, two of these N-isobutylamides were not yet described in Spilanthes extracts. We demonstrated for the first time that spilanthol permeates the buccal mucosa. Depending on the formulation, a more pronounced local or systemic effect is achieved, which is important for the regulatory product classification. The purely aqueous permeation coefficient K(p,aq) (+/-SEM) was found to be 11.3 (+/-0.403)10(-3)cm/h.

Transdermal behaviour of the N-alkylamide spilanthol (affinin) from Spilanthes acmella (Compositae) extracts

AIM OF THE STUDY N-Alkylamides are a large group of bioactive molecules found in several plants from the genera Echinacea, Xanthoxylum and Spilanthes. Extracts and formulations derived from these plants are not only orally used, but also applied on the skin as well. However, there is currently no specific information available about the intrinsic local pharmacokinetics of N-alkylamides after topical application on human skin, questioning the role of this mode of administration. The present study investigates the transdermal behaviour of spilanthol, a prominent N-alkylamide. MATERIALS AND METHODS Two pharmaceutically accepted dose solutions (ethanol and propylene glycol based aqueous donor vehicles), combined with three different receptor fluids (PBS, PBS+0.5% HPbetaCD, EtOH/H(2)O (30:70, v/v)), were applied on split-thickness human skin in a Franz diffusion cell (FDC) system. Fundamental permeation characteristics of spilanthol in a solvent-independent way (100% aqueous dose solution) were also obtained using an extrapolation approach with different organic solvent/H(2)O ratios. RESULTS AND CONCLUSIONS We demonstrated for the first time that spilanthol permeates the skin. The following aqueous-extrapolated primary transdermal parameters were obtained (mean+/-SEM): K(p,aq)=3.31 (+/-0.29)x10(-3)cm/h, D(m,aq)=1.86 (+/-0.09)x10(-4)cm(2)/h and K(m,aq)=7.28 (+/-1.59)x10(-1). Partitioning (K(m)) was strongly dependent on the donor solution composition, while diffusion (D(m)) was mainly influenced by the receptor fluid composition.

Evaluation of dissolution profiles using principal component analysis

The performance of principal component analysis (PCA) for the evaluation of dissolution profiles is examined and compared with other methods such as the similarity factor and the calculation of the area under the curve. Both simulated and real data from the pharmaceutical industry are used. The PCA scores plots of the dissolution curves provide information about the between- and within-batch variations. Differences in level or shape can be observed in the first two principal components (PCs). Irrelevant irregularities, which have a strong influence on the similarity factor, are neglected in PC1/PC2. To detect outliers in a set of dissolution curves, PCA was preferred above Hotellings T2 test. In general, PCA is found to be a useful technique to examine dissolution data visually, but however, it does not contain criteria to decide if batches are similar or not. This can be done by combining PCA with the resampling with replacement or bootstrap method to construct confidence limits.

A strategy for two-dimensional, high-performance thin-layer chromatography, applied to local anesthetics

SummaryA straightforward and simple strategy for the selection of the two systems in two-dimensional, high-performance thin-layer chromatography (HPTLC) is presented. The choice is based on the absolute values of the correlation matrix elements. The response function, expressed as a percentage, is also based on the correlation coefficient. The applicability and usefulness of this approach is demonstrated by the separation of fourteen local anesthetics. After identification, one-dimensional HPTLC can be used for quantisation by reflectance scanning by UV at the optimum wavelength.

Differential gene expression of the toll-like receptor-4 cascade and neutrophil function in early- and mid-lactating dairy cows

During early lactation, neutrophils display several reduced immune functions. Particularly, a delayed recruitment of neutrophils into the infected udder seems to be one of the underlying events involved in the severity of postpartum Escherichia coli intramammary infections. The purpose of this study was to analyze the effect of in vitro chemotaxis and diapedesis on the expression of toll-like receptor-4 (TLR4)-related genes in bovine blood neutrophils isolated from 10 early-lactating (EL) and 10 mid-lactating (ML) cows. Functional characterization of the neutrophil population was performed by measuring phagocytosis and production of reactive oxygen species (chemiluminescence). Messenger RNA was extracted from neutrophils, and the expression of TLR4 and associated genes in EL and ML cows was analyzed by reverse-transcription quantitative PCR. To study the effect of chemotaxis and diapedesis on the expression of genes of the TLR4 cascade, neutrophils were stimulated to (trans)migrate in response to C5a using in vitro models. Our salient findings were that both neutrophil migration in vitro and lactation stage induced significant changes in the expression of several genes of the TLR4 signaling cascade. Before migration, expression of TRAF6, ATF3, RELA, IL8, and C5aR were lower in EL than in ML cows. Diapedesis and chemotaxis induced an increase in expression of TLR4, ATF3, and IL8 in both EL and ML cows. Diapedesis resulted in a downregulation of Syk, a TLR4-associated gene, in ML cows. This study shows that the perturbations in neutrophil functions during EL are accompanied by modulation of TLR4 pathway genes. These data can contribute to the understanding of the mechanisms explaining the relationship between stage of lactation and risk of severe E. coli mastitis.

Quality analytics of internet pharmaceuticals

Trading pharmaceutical products through the Internet poses several challenges related to legal responsibilities, good distribution practices, information content and patient use, financial implications, but also regarding product quality. One of the major concerns is the well-known phenomenon of counterfeited and/or substandard drugs commercialized through rogue Internet sites. Therefore, controlling and assuring the quality of those products has become an important and challenging task for the authorities. This review gives an overview of the different quality attributes that can be evaluated to have a complete understanding of the quality of the finished pharmaceutical product traded through the Internet, as well as the current analytical techniques that serve this objective. Aspects considered are labelling and packaging, physicochemical quality attributes, identification and assay of active substances and/or excipients, impurity profiling, biopharmaceutical testing and data interpretation.

A novel bending point criterion for dissolution profile interpretation.

A novel bending point criterion was developed and compared with a number of existing criteria for the interpretation of certain dissolution profiles; these comparison criteria were the percentage dissolved at a fixed time point, the fitted Weibull parameters, and the area under the dissolution curve (AUC). The statistical bending point model was applied to dissolution curves that showed linear dissolution. The bending point model is based on a general linear model, and its confidence information is obtained using the variance-covariance matrix of the parameter estimates. Practically, three time points in the linear part and two time points on the plateau level are used for a reliable bending point estimation. A comparative study with three batches and three storage conditions of slow-release mucoadhesive buccal tablets was performed. The relative standard deviation (RSD) values of the bending point were typically between 1% and 5%, which are considerably lower than the corresponding values of the other criteria (typically between 3% and 15%). The bending point criterion is considered robust and stable for the characterization of certain dissolution profiles. Moreover, the bending point has a particular physical interpretation that is helpful in the framework of the slow-release application of this buccal tablet.

An integrated view on how the management of the dry period length of lactating cows could affect mammary biology and defence

The dry period is necessary to facilitate cell turnover in the bovine mammary gland and to optimize milk production in the next lactation. An 8-week dry period has long been the golden standard of management for dairy cows. Genetic improvements and new management technologies have led to higher milk production and a need for re-evaluation of the dry period length. Over the last decade, dry period length has been proposed to be shortened or eliminated mainly from an economic point of view. However, the influence of modified dry period length on the immune defence of the bovine mammary gland and the occurrence of new intramammary infections has not yet been appreciated. The objective of this review is to discuss the bovine mammary gland biology, defence and systemic health when the dry period length is modified. Shortening or eliminating the dry period may minimize or remove the impact of milk accumulation at dry off, thereby lessening the immunodeficiency of the dam that is characteristic of this period. Composition of mammary secretions may change and the extent of tissue remodelling may be reduced when the dry period is reduced or eliminated. Additionally, impact of the dry period length on energy and nutritional status, and on hormonal and local regulatory factors, lead us to hypothesize that changing the dry period length might also affect the response to intramammary infection. It is concluded that there is a need to integrate mammary gland biology and defence mechanisms in studies dealing with modified dry period lengths.

Ion mobility spectrometry as a high-throughput technique for in vitro transdermal Franz diffusion cell experiments of ibuprofen

Rapid, low-cost and sensitive analytical methods are needed to analyse the large number of samples that are generated when investigating the absorption profile of drugs through the skin using Franz diffusion cell experiments (FDC). The goal of this study was to evaluate the potential of ion mobility spectrometry (IMS) for the quantitative analysis of active pharmaceutical ingredients (API) in transdermal research. Ibuprofen was used as a model drug and the optimal IMS parameters were determined using a Doehlert experimental design. To assess the usefulness of the IMS method, FDC experiments using human skin were conducted, covering a concentration range of 0.32-69.57μg/ml. The resulting analytical samples were analysed using IMS and subsequently compared to HPLC as a reference method. No significant differences were found between the results obtained using both analytical methods, with a mean skin permeability coefficient (K(p)) value of 0.013cm/h. The combination of fast detection times, sensitivity, low costs and easy maintenance of IMS instruments makes this technique an attractive alternative for HPLC in this type of experiments.

Recognition of anatomical predilection sites in canine elbow pathology on bone scans using micro-single photon emission tomography.

The limited resolution of planar bone scintigraphy precludes exact anatomical localisation within a joint. Micro-single photon emission tomography (μ-SPECT) has a much higher resolution, and in this study the use of μ-SPECT in the evaluation of the canine elbow joint and fusion with structural imaging data were tested. Twelve elbows of seven normal dogs were included. μ-SPECT was performed with a conventional triple head gamma camera adapted with three multi-pinhole collimators (HiSPECT). Radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) were performed on all elbows and data from CT and MRI were fused to the HiSPECT data using dedicated software. Different important anatomical regions could be recognised on the HiSPECT images. The improved resolution of the HiSPECT system allowed better differentiation of the anatomical areas in the elbow joint. Two case studies were included to demonstrate the potential of this methodology. Fusion software facilitated the use of combined structural and functional information.