Formulation and characterisation of an effective particulate delivery vehicle for the novel sub-unit vaccine antigen, Ag85B-ESAT-6

This research focused on the formation of particulate delivery systems for the sub-unit fusion protein, Ag85B-ESAT-6, a promising tuberculosis (TB) vaccine candidate. Initial work concentrated on formulating and characterising, both physico-chemically and immunologically, cationic liposomes based on the potent adjuvant dimethyl dioctadecyl ammonium (DDA). These studies demonstrated that addition of the immunomodulatory trehalose dibehenate (TDB) enhanced the physical stability of the system whilst also adding further adjuvanticity. Indeed, this formulation was effective in stimulating both a cell mediated and humoural immune response. In order to investigate an alternative to the DDA-TDB system, microspheres based on poly(DL-lactide-co-glycolide) (PLGA) incorporating the adjuvants DDA and TDB, either alone or in combination, were first optimised in terms of physico-chemical characteristics, followed by immunological analysis. The formulation incorporating PLGA and DDA emerged as the lead candidate, with promising protection data against TB. Subsequent optimisation of the lead microsphere formulation investigated the effect of several variables involved in the formulation process on physico-chemical and immunological characteristics of the particles produced. Further, freeze-drying studies were carried out with both sugar-based and amino acid-based cryoprotectants, in order to formulate a stable freexe-dried product. Finally, environmental scanning electron microscopy (ESEM) was investigated as a potential alternative to conventional SEM for the morphological investigation of microsphere formulations. Results revealed that the DDA-TDB liposome system proved to be the most immunologically efficient delivery vehicle studied, with high levels of antibody and cytokine production, particularly gamma-interferon (IFN-ϒ), considered the key cytokine marker for anti-mycobacterial immunity. Of the microsphere systems investigated, PLGA in combination with DDA showed the most promise, with an ability to initiate a broad spectrum of cytokine production, as well as antigen specific spleen cell proliferation comparable to that of the DDA-TDB formulation

Current formulation approaches in design and development of solid oral dosage forms through three-dimensional printing

Three-dimensional (3D) printing technologies are continuously applied to novel fields, laying the foundations for a new industrial revolution. With regard to pharmaceutical sciences, 3D printed drug products are emerging as attractive and innovative tools in personalised medicine. For example, solid oral dosage forms (e.g. tablets) can be printed in a wide range of dosages, release profiles, geometries and sizes by simply modifying a digital model, thus providing patients with tailored therapies. Various 3D printing technologies have been applied to pharmaceutical manufacture in recent years, and different materials have been investigated to fabricate solid oral dosage forms in a broad range of properties. Therefore, the aim of this review is to describe the state of the art of 3D printing oral pharmaceuticals, with the view to provide formulation scientists with essential information to approach the development of 3D printed drug products, from digital design to final product quality control. Short- to long-term potential areas of application of 3D printed drug products and their relative regulatory pathway challenges are also presented

Knot concordance and Heegaard Floer homology invariants in branched covers

By studying the Heegaard Floer homology of the preimage of a knot K in S^3 inside its double branched cover, we develop simple obstructions to K having finite order in the classical smooth concordance group. As an application, we prove that all 2-bridge knots of crossing number at most 12 for which the smooth concordance order was previously unknown have infinite smooth concordance order.Comment: Expanded references; 25 pages, 5 figure

Activated carbon as a carrier for amorphous drug delivery:effect of drug characteristics and carrier wettability

Recent research on porous silica materials as drug carriers for amorphous and controlled drug delivery has shown promising results. However, due to contradictory literature reports on toxicity and high costs of production, it is important to explore alternative safe and inexpensive porous carriers. In this study, the potential of activated carbon (AC) as an amorphous drug carrier was investigated using paracetamol (PA) and ibuprofen (IBU) as model drugs. The solution impregnation method was used for drug loading, with loading efficiency determined by UV spectroscopy and drug release kinetics studied using USP II dissolution apparatus. The physical state of the drug in the complex was characterised using differential scanning calorimetry and X-ray diffractions techniques, whilst sites of drug adsorption were studied using Fourier transform infrared spectroscopy and N2 adsorption techniques. In addition, the cytotoxicity of AC on human colon carcinoma (Caco-2) cells was assessed using the MTT assay. Results presented here reveal that, for PA/AC and IBU/AC complexes, the saturation solubility of the drug in the loading solvent appears to have an effect on the drug loading efficiency and the physical state of the drug loaded, whilst drug release kinetics were affected by the wettability of the activated carbon particles. Furthermore, activated carbon microparticles exhibited very low cytotoxicity on Caco-2 cells at the concentrations tested (10–800 μg/mL). This study, therefore, supports the potential of activated carbon as a carrier for amorphous drug delivery

Isolation of white blood cells using paper-triggered dissolvable-film valves on a centrifugal platform

The inherent centrifugation capability of the so-called ‘Lab-on-a-Disc’ (LoaD) platforms is widely used for blood processing during sample preparation. Here we introduce a valving technique which ena-bles rotational control of paper wetting to actuate dissolvable film (DF) valves. This mechanism is applied to the separation of whole blood into its chief constituents; plasma, leukocytes and erythrocytes

Deteksi Mutasi Pada Quinolone Resistant Determining Regions (QRDRs ) Gen GyrA Pada Salmonella Typhi Isolat Klinik Dan Galur Khas Indonesia

A number of researchers in endemic regions in Asia have proved that mutations in Quinolone Resistant Determining Regions (QRDRs), parts of gyrA gene of Salmonella typhi, can reduce the susceptibility of ciprofloxacin therapeutic in enteric fever. The sites of amino acid mutations in QRDRs in relation with decreased fluoroquinolone susceptibility are different in each endemic region. The present study attempted to investigate the association of the decrease of fluoroquinolone susceptibility and the mutations in QRDRs of clinical and typical Indonesian Salmonella typhi isolates. All isolates were subjected to the antimicrobial susceptibility test applying the Kirby-Bauer method of disk diffusion with ciprofloxacin and were examined by PCR and direct nucleotide sequencing for genetic alteration in QRDRs. One ciprofloxacin sensitive isolate was observed and it showed no mutation; ciprofloxacin resistant galurs were observed in 2 isolates and they also showed no mutation. The data imply that QRDRs mutations in this research are not associated with fluoroquinolone resistance in clinical and typical Indonesian Salmonella typhi isolates. It is suggested that nucleotide re-sequencing should be used to verify this result. &nbsp

Submersed Aquatic Vegetation Trends in Impounded and Backwater Habitat Types of Pool 13, Upper Mississippi River System: 1994-2000

Submersed aquatic vegetation (SAV) was sampled from 1994-2000 at fixed sires along established transects in Pool 13 of the Upper Mississippi River System (UMRS), as part of the Long Term Resource Monitoring Program (LTRMP). These data were used to quantify the annual percent frequency of occurrence and mean relative density of SAV within three backwaters (Brown\u27s Lake, Savanna Bay, and Spring Lake) and the impounded area of Pool 13. This investigation used Spearman rank correlation to assess the strength of bivariate relationships between measurements of SAV abundance and biological, physical, and hydrological variables at fixed water quality monitoring sites within vegetation monitoring areas. In backwater habitats, the percent frequency of occurrence and mean relative density of SAV exhibited significant negative correlations (P\u3c 0.05) with May-August median turbidity and mean velocity. Mean velocity and median turbidity were strongly correlated, which suggested that water inputs from channel habitats caused observed differences in water clarity, as well as subsequent differences in the percent frequency of occurrence and mean relative density of SAV. In the impounded area of Pool 13, the percent frequency of occurrence and mean relative density of SAV increased during the period of study and was strongly correlated with tooted floating leaved vegetation (RFV). None of the other physical or hydrological variables analyzed for the impounded area demonstrated significant correlations. The cause for the lack of significant relationships between independent variables and measurements of SAV abundance in the impounded area of Pool 13 are uncertain, bur the differences may be due to previously established SAV beds creating favorable near-shore habitat with increased water clarity and reduced velocities when compared to main channel habitat

The role of lipid geometry in designing liposomes for the solubilisation of poorly water soluble drugs

Liposomes are well recognised for their ability to improve the delivery of a range of drugs. More commonly they are applied for the delivery of water-soluble drugs, but given their structural attributes, they can also be employed as solubilising agents for low solubility drugs as well as drug targeting agents. To further explore the potential of liposomes as solubilising agents, we have investigated the role of bilayer packaging in promoting drug solubilisation in liposome bilayers. The effect of alkyl chain length and symmetry was investigated to consider if using 'mis-matched' phospholipids could create 'voids' within the bilayers, and enhance bilayer loading capacity. Lipid packing was investigated using Langmuir studies, which demonstrated that increasing the alkyl chain length enhanced lipid packing, with condensed monolayers forming, whilst asymmetric lipids formed less condensed monolayers. However, this more open packing did not translate into improved drug loading, with the longer chain, condensed bilayers formed from long-chain, saturated lipids offering higher drug loading capacity. These studies demonstrate that liposomes formulated from longer chain, saturated lipids offer enhanced solubilisation capacity. However the molecular size, rather than lipophilicity, of the drug to be incorporated was also a key factor dominating bilayer incorporation efficiency. © 2012 Elsevier B.V. All rights reserved

Developing solid particulate vaccine adjuvants:surface bound antigen favouring a humoural response, whereas entrapped antigen shows a tendency for cell mediated immunity

This present study compares the efficacy of microsphere formulations, and their method of antigen presentation, for the delivery of the TB sub-unit vaccine antigen, Ag85B-ESAT-6. Microspheres based on poly(lactide-co-glycolide) (PLGA) and chitosan incorporating dimethyldioctadecylammonium bromide (DDA) were prepared by either the w/o/w double emulsion method (entrapped antigen) or the o/w single emulsion method (surface bound antigen), and characterised for their physico-chemical properties and their ability to promote an immune response to Ag85B-ESAT-6. The method of preparation, and hence method of antigen association, had a pronounced effect on the type of immune response achieved from the microsphere formulations, with surface bound antigen favouring a humoural response, whereas entrapped antigen favoured a cellular response