Bone mineral density (BMD) and computer tomographic measurements of the equine proximal phalanx in correlation with breaking strength.

Despite the fact that bone mineral density (BMD) is an important fracture risk predictor in human medicine, studies in equine orthopedic research are still lacking. We hypothesized that BMD correlates with bone failure and fatigue fractures of this bone. Thus, the objectives of this study were to measure the structural and mechanical properties of the proximal phalanx with dual energy X-ray absorptiometry (DXA), to correlate the data obtained from DXA and computer tomography (CT) measurements to those obtained by loading pressure examination and to establish representative region of interest (ROI) for in vitro BMD measurements of the equine proximal phalanx for predicting bone failure force. DXA was used to measure the whole bone BMD and additional three ROI sites in 14 equine proximal phalanges. Following evaluation of the bone density, whole bone, cortical width and area in the mid-diaphyseal plane were measured on CT images. Bones were broken using a manually controlled universal bone crusher to measure bone failure force and reevaluated for the site of fractures on follow-up CT images. Compressive load was applied at a constant displacement rate of 2 mm/min until failure, defined as the first clear drop in the load measurement. The lowest BMD was measured at the trabecular region (mean +/- SD: 1.52 +/- 0.12 g/cm2; median: 1.48 g/cm2; range: 1.38-1.83 g/cm2). There was a significant positive linear correlation between trabelcular BMD and the breaking strength (P = 0.023, r = 0.62). The trabecular region of the proximal phalanx appears to be the only significant indicator of failure of strength in vitro. This finding should be reassessed to further reveal the prognostic value of trabecular BMD in an in vivo fracture risk model

Testing breast cancer serum biomarkers for early detection and prognosis in pre-diagnosis samples

This research was funded by the National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre. UKCTOCS was core funded by the Medical Research Council, Cancer Research UK, and the Department of Health with additional support from the Eve Appeal, Special Trustees of Bart’s and the London, and Special Trustees of UCLH. OB and JFT also received support from the Eve Appeal Gynaecological Cancer Research Trust and Cancer Research UK PRC Programme Grant A12677

Supercritical fluid impregnation of a biocompatible polymer for ophthalmic drug delivery

Supercritical fluid impregnation was tested to prepare a new ophthalmic drug delivery device. Poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate), P(MMA-EHA-EGDMA) has been proposed by Mariz [M. Mariz, Preparação de uma lente intra-ocular dotada de um sistema de libertação controlada de fármaco, Master Thesis, Universidade de Coimbra, 1999] as a promising matrix to be used for intraocular delivery of anti-inflammatory drugs used in eye surgery. This matrix was successfully impregnated with flurbiprofen, a non-steroidal anti-inflammatory agent.http://www.sciencedirect.com/science/article/B6VMF-4N02J5M-1/1/ee8d7c5effb50ccf2b99656a67b77da

Supercritical solvent impregnation of poly(ɛ-caprolactone)/poly(oxyethylene-b-oxypropylene-b-oxyethylene) and poly(ɛ-caprolactone)/poly(ethylene-vinyl acetate) blends for controlled release applications

Poly(ɛ-caprolactone) blends were successfully impregnated with timolol maleate, an anti-glaucoma drug, using a supercritical solvent impregnation (SSI) technique. Supercritical fluid impregnation efficiency results suggested that the best impregnating conditions were obtained when a cosolvent was used and when specific drug–polymer interactions occurred as a consequence of different chemical structures due to polymer blending. Pressure can be either a favourable factor, when there is enough drug affinity for the polymers, or an unfavourable factor when weaker bonding is involved. In order to determine the relative hydrophilicity/hydrophobicity of the blends, contact angle analysis was performed, while crystallinity determination was also useful to understand the obtained release profiles. Drug loading, heterogeneous/homogeneous dispersion of drug inside the matrix, hydrophilicity, crystallinity, all seem to influence the obtained drug release rates. The “in vitro” release results suggested that a sustained drug release rate can be obtained by changing the SSI operational conditions and by modulating the composition of blends, as a mean to control crystallinity, hydrophilicity and drug affinity for the polymer matrix. After a first day burst release, all samples showed a sustained release profile (1.2–4 μg/(ml day), corresponding to a mass of 3–10 μg/day) which is between the therapeutic and toxic levels of timolol maleate, during a period of 1 month. These drug-loaded polymeric matrices can be a feasible alternative treatment modality for the conventional repeated daily administration of eye drops

Supercritical solvent impregnation of ophthalmic drugs on chitosan derivatives

In this work, three chitosan derivatives (N-carboxymethyl chitosan (CMC), N-carboxybutyl chitosan (CBC) and N-succinyl chitosan (SCC)) were impregnated with flurbiprofen (an anti-inflammatory drug) and timolol maleate (an anti-glaucoma drug), using a supercritical solvent impregnation (SSI) technique (and employing high pressure CO2 and CO2 + EtOH mixtures) in order to develop hydrogel-type ophthalmic drug delivery applications. Impregnation experiments were carried out from 9.0 up to 14.0 MPa, and at 303.0, 313.0 and 323.0 K. The resulting polymeric drug delivery systems, as well as other polymeric samples processed in CO2, were characterized by FTIR spectroscopy and scanning electron microscopy (SEM). Drug release kinetics studies were performed for all prepared systems. The effects of impregnation pressure and temperature on the release kinetics results were studied and compared to the traditional soaking impregnation method. For the same operational conditions, results confirmed that the three different (chemically and physically) polymeric structures conditioned the impregnation and the drug release processes. Despite the final released drug mass is always the result of the employed operational impregnation conditions and of the very complex relative specific interactions that may occur between all species present in the system (drugs, polymers, CO2 and ethanol), results showed that, for N-carboxymethyl chitosan, the predominant effects in the impregnation process seemed to be the solubility of drugs in CO2 and in CO2 + EtOH mixtures, as well as the swelling and plasticizing effect of CO2 and ethanol on the polymer. Finally, the SSI method proved to be a more efficient and "tunable" impregnation process than the traditional impregnation of drugs by a soaking method. Therefore, and using this "tunable" SSI method, these N-chitosan derivatives-based ophthalmic drug delivery systems can be easily and efficiently prepared taking in consideration the desired drug levels according to patients needs.http://www.sciencedirect.com/science/article/B6VMF-4PXM6CP-1/1/a112be9d86677ed00ff98cac80b9c39