DETERMINATION OF DICLOFENAC SODIUM IN RABBIT PLASMA BY HPLC/UV: EVALUATION AND CHARACTERIZATION OF ITS CRYSTALLINE FORMS, ANHYDROUS AND HYDRATE, ON THE ANTIPYRETIC EFFECT

Diclofenac sodium (DS) is a non-steroidal anti-inflammatory drug that is widely prescribed for the treatment of rheumatoid arthritis and post-surgery analgesia. The active pharmaceutical ingredient is the anhydrous form; however, it can also exist in hydrate form. In this context, knowing the properties of the solid state is important and relevant in the pharmaceutical area because they have a significant impact on the solubility, bioavailability, and chemical stability of the drugs. In the present study, data from XRPD, FTIR spectroscopy, and thermal analysis were used for the identification and characterization of DS forms (anhydrous and hydrate). An HPLC method was optimized to evaluate the plasma concentration of DS in rabbits. The optimized method exhibited good linearity over the range 0.1-60 mu g/mL with correlation coefficients of >0.9991. The mean recovery was 100%. Precision and accuracy were determined within acceptable limits. Finally, to compare the pharmacological properties of anhydrous and hydrate DS forms, we investigated their effects in the febrile response induced by lipopolysaccharide from E. coli in rabbits. The results show that the antipyretic effect of anhydrous and hydrate DS forms are similar.

Solid Dispersion of Ursolic Acid in Gelucire 50/13: a Strategy to Enhance Drug Release and Trypanocidal Activity

Solid dispersions (SDs) are an approach to increasing the water solubility and bioavailability of lipophilic drugs such as ursolic acid (UA), a triterpenoid with trypanocidal activity. In this work, Gelucire 50/13, a surfactant compound with permeability-enhancing properties, and silicon dioxide, a drying adjuvant, were employed to produce SDs with UA. SDs and physical mixtures (PMs) in different drug/carrier ratios were characterized and compared using differential scanning calorimetry, hot stage microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size, water solubility values, and dissolution profiles. Moreover, LLC-MK2 fibroblast cytotoxicity and trypanocidal activity evaluation were performed to determine the potential of SD as a strategy to improve UA efficacy against Chagas disease. The results demonstrated the conversion of UA from the crystalline to the amorphous state through XRD. FTIR experiments provided evidence of intermolecular interactions among the drug and carriers through carbonyl peak broadening in the SDs. These findings helped explain the enhancement of water solubility from 75.98 mu g/mL in PMs to 293.43 mu g/mL in SDs and the faster drug release into aqueous media compared with pure UA or PMs, which was maintained after 6 months at room temperature. Importantly, improved SD dissolution was accompanied by higher UA activity against trypomastigote forms of Trypanosoma cruzi, but not against mammalian fibroblasts, enhancing the potential of UA for Chagas disease treatment.

Preparation of new crystal forms via photochemical, mechanochemical and sol-gel methods

This work of thesis involves various aspects of crystal engineering. Chapter 1 focuses on crystals containing crown ether complexes. Aspects such as the possibility of preparing these materials by non-solution methods, i.e. by direct reaction of the solid components, thermal behavior and also isomorphism and interconversion between hydrates are taken into account. In chapter 2 a study is presented aimed to understanding the relationship between hydrogen bonding capability and shape of the building blocks chosen to construct crystals. The focus is on the control exerted by shape on the organization of sandwich cations such as cobalticinium, decamethylcobalticinium and bisbenzenchromium(I) and on the aggregation of monoanions all containing carboxylic and carboxylate groups, into 0-D, 1-D, 2-D and 3-D networks. Reactions conducted in multi-component molecular assemblies or co-crystals have been recognized as a way to control reactivity in the solid state. The [2+2] photodimerization of olefins is a successful demonstration of how templated solid state synthesis can efficiently synthesize unique materials with remarkable stereoselectivity and under environment-friendly conditions. A demonstration of this synthetic strategy is given in chapter 3. The combination of various types of intermolecular linkages, leading to formation of high order aggregation and crystalline materials or to a random aggregation resulting in an amorphous precipitate, may not go to completeness. In such rare cases an aggregation process intermediate between crystalline and amorphous materials is observed, resulting in the formation of a gel, i.e. a viscoelastic solid-like or liquid-like material. In chapter 4 design of new Low Molecular Weight Gelators is presented. Aspects such as the relationships between molecular structure, crystal packing and gelation properties and the application of this kind of gels as a medium for crystal growth of organic molecules, such as APIs, are also discussed.

Optimization of molecular and crystalline forms of drugs, agrochemicals, pesticides in relation to activity, bioavailability, patentability and to the fabrication of polymorphs, solvates, co-crystals with green chemistry methods

This doctorate was funded by the Regione Emilia Romagna, within a Spinner PhD project coordinated by the University of Parma, and involving the universities of Bologna, Ferrara and Modena. The aim of the project was: - Production of polymorphs, solvates, hydrates and co-crystals of active pharmaceutical ingredients (APIs) and agrochemicals with green chemistry methods; - Optimization of molecular and crystalline forms of APIs and pesticides in relation to activity, bioavailability and patentability. In the last decades, a growing interest in the solid-state properties of drugs in addition to their solution chemistry has blossomed. The achievement of the desired and/or the more stable polymorph during the production process can be a challenge for the industry. The study of crystalline forms could be a valuable step to produce new polymorphs and/or co-crystals with better physical-chemical properties such as solubility, permeability, thermal stability, habit, bulk density, compressibility, friability, hygroscopicity and dissolution rate in order to have potential industrial applications. Selected APIs (active pharmaceutical ingredients) were studied and their relationship between crystal structure and properties investigated, both in the solid state and in solution. Polymorph screening and synthesis of solvates and molecular/ionic co-crystals were performed according to green chemistry principles. Part of this project was developed in collaboration with chemical/pharmaceutical companies such as BASF (Germany) and UCB (Belgium). We focused on on the optimization of conditions and parameters of crystallization processes (additives, concentration, temperature), and on the synthesis and characterization of ionic co-crystals. Moreover, during a four-months research period in the laboratories of Professor Nair Rodriguez-Hormedo (University of Michigan), the stability in aqueous solution at the equilibrium of ionic co-crystals (ICCs) of the API piracetam was investigated, to understand the relationship between their solid-state and solution properties, in view of future design of new crystalline drugs with predefined solid and solution properties.

Hydrodynamics and solid dosage form disintegration/dissolution : immediate release tablets and novel in situ polyelectrolyte gastroretentive drug delivery systems

Solid oral dosage form disintegration in the human stomach is a highly complex process dependent on physicochemical properties of the stomach contents as well as on physical variables such as hydrodynamics and mechanical stress. Understanding the role of hydrodynamics and forces in disintegration of oral solid dosage forms can help to improve in vitro disintegration testing and the predictive power of the in vitro test. The aim of this work was to obtain a deep understanding of the influence of changing hydrodynamic conditions on solid oral dosage form performance. Therefore, the hydrodynamic conditions and forces present in the compendial PhEur/USP disintegration test device were characterized using a computational fluid dynamics (CFD) approach. Furthermore, a modified device was developed and the hydrodynamic conditions present were simulated using CFD. This modified device was applied in two case studies comprising immediate release (IR) tablets and gastroretentive drug delivery systems (GRDDS). Due to the description of movement provided in the PhEur, the movement velocity of the basket-rack assembly follows a sinusoidal profile. Therefore, hydrodynamic conditions are changing continually throughout the movement cycle. CFD simulations revealed that the dosage form is exposed to a wide range of fluid velocities and shear forces during the test. The hydrodynamic conditions in the compendial device are highly variable and cannot be controlled. A new, modified disintegration test device based on computerized numerical control (CNC) technique was developed. The modified device can be moved in all three dimensions and radial movement is also possible. Simple and complex moving profiles can be developed and the influence of the hydrodynamic conditions on oral solid dosage form performance can be evaluated. Furthermore, a modified basket was designed that allows two-sided fluid flow. CFD simulations of the hydrodynamics and forces in the modified device revealed significant differences in the fluid flow field and forces when compared to the compendial device. Due to the CNC technique moving velocity and direction are arbitrary and hydrodynamics become controllable. The modified disintegration test device was utilized to examine the influence of moving velocity on disintegration times of IR tablets. Insights into the influence of moving speed, medium viscosity and basket design on disintegration times were obtained. An exponential relationship between moving velocity of the modified basket and disintegration times was established in simulated gastric fluid. The same relationship was found between the disintegration times and the CFD predicted average shear stress on the tablet surface. Furthermore, a GRDDS was developed based on the approach of an in situ polyelectrolyte complex (PEC). Different complexes composed of different grades of chitosan and carrageenan and different ratios of those were investigated for their swelling behavior, mechanical stability, and in vitro drug release. With an optimized formulation the influence of changing hydrodynamic conditions on the swelling behavior and the drug release profile was demonstrated using the modified disintegration test device. Both, swelling behavior and drug release, were largely dependent on the hydrodynamic conditions. Concluding, it has been shown within this thesis that the application of the modified disintegration test device allows for detailed insights into the influence of hydrodynamic conditions on solid oral dosage form disintegration and dissolution. By the application of appropriate test conditions, the predictive power of in vitro disintegration testing can be improved using the modified disintegration test device. Furthermore, CFD has proven a powerful tool to examine the hydrodynamics and forces in the compendial as well as in the modified disintegration test device. rn

2010 update of EORTC guidelines for the use of granulocyte-colony stimulating factor to reduce the incidence of chemotherapy-induced febrile neutropenia in adult patients with lymphoproliferative disorders and solid tumours

Chemotherapy-induced neutropenia is a major risk factor for infection-related morbidity and mortality and also a significant dose-limiting toxicity in cancer treatment. Patients developing severe (grade 3/4) or febrile neutropenia (FN) during chemotherapy frequently receive dose reductions and/or delays to their chemotherapy. This may impact the success of treatment, particularly when treatment intent is either curative or to prolong survival. In Europe, prophylactic treatment with granulocyte-colony stimulating factors (G-CSFs), such as filgrastim (including approved biosimilars), lenograstim or pegfilgrastim is available to reduce the risk of chemotherapy-induced neutropenia. However, the use of G-CSF prophylactic treatment varies widely in clinical practice, both in the timing of therapy and in the patients to whom it is offered. The need for generally applicable, European-focused guidelines led to the formation of a European Guidelines Working Party by the European Organisation for Research and Treatment of Cancer (EORTC) and the publication in 2006 of guidelines for the use of G-CSF in adult cancer patients at risk of chemotherapy-induced FN. A new systematic literature review has been undertaken to ensure that recommendations are current and provide guidance on clinical practice in Europe. We recommend that patient-related adverse risk factors, such as elderly age (≥65 years) and neutrophil count be evaluated in the overall assessment of FN risk before administering each cycle of chemotherapy. It is important that after a previous episode of FN, patients receive prophylactic administration of G-CSF in subsequent cycles. We provide an expanded list of common chemotherapy regimens considered to have a high (≥20%) or intermediate (10-20%) risk of FN. Prophylactic G-CSF continues to be recommended in patients receiving a chemotherapy regimen with high risk of FN. When using a chemotherapy regimen associated with FN in 10-20% of patients, particular attention should be given to patient-related risk factors that may increase the overall risk of FN. In situations where dose-dense or dose-intense chemotherapy strategies have survival benefits, prophylactic G-CSF support is recommended. Similarly, if reductions in chemotherapy dose intensity or density are known to be associated with a poor prognosis, primary G-CSF prophylaxis may be used to maintain chemotherapy. Clinical evidence shows that filgrastim, lenograstim and pegfilgrastim have clinical efficacy and we recommend the use of any of these agents to prevent FN and FN-related complications where indicated. Filgrastim biosimilars are also approved for use in Europe. While other forms of G-CSF, including biosimilars, are administered by a course of daily injections, pegfilgrastim allows once-per-cycle administration. Choice of formulation remains a matter for individual clinical judgement. Evidence from multiple low level studies derived from audit data and clinical practice suggests that some patients receive suboptimal daily G-CSFs; the use of pegfilgrastim may avoid this problem.

Twelve factors influencing sustainable recycling of municipal solid waste in developing countries

Sustainable management of solid waste is a global concern, as exemplified by the United Nations Millennium Development Goals (MDG) that 191 member states support. The seventh MDG indirectly advocates for municipal solid waste management (MSWM) by aiming to ensure environmental sustainability into countries’ policies and programs and reverse negative environmental impact. Proper MSWM will likely result in relieving poverty, reducing child mortality, improving maternal health, and preventing disease, which are MDG goals one, four, five, and six, respectively (UNMDG, 2005). Solid waste production is increasing worldwide as the global society strives to obtain a decent quality of life. Several means exist in which the amount of solid waste going to a landfill can be reduced, such as incineration with energy production, composting of organic wastes, and material recovery through recycling, which are all considered sustainable methods by which to manage MSW. In the developing world, composting is already a widely-accepted method to reduce waste fated for the landfill, and incineration for energy recovery can be a costly capital investment for most communities. Therefore, this research focuses on recycling as a solution to the municipal solid waste production problem while considering the three dimensions of sustainability environment, society, and economy. First, twenty-three developing country case studies were quantitatively and qualitatively examined for aspects of municipal solid waste management. The municipal solid waste (MSW) generation and recovery rates, as well as the composition were compiled and assessed. The average MSW generation rate was 0.77 kg/person/day, with recovery rates varying from 5 – 40%. The waste streams of nineteen of these case studies consisted of 0 – 70% recyclable material and 17 – 80% organic material. All twenty-three case studies were analyzed qualitatively by identifying any barriers or incentives to recycling, which justified the creation of twelve factors influencing sustainable municipal solid waste management (MSWM) in developing countries. The presence of regulations, enforcement of laws, and use of incentive schemes constitutes the first factor, Government Policy. Cost of MSWM operations, the budget allocated to MSWM by local to national governments, as well as the stability and reliability of funds comprise the Government Finances factor influencing recycling in the third world. Many case studies indicated that understanding features of a waste stream such as the generation and recovery rates and composition is the first measure in determining proper management solutions, which forms the third factor Waste Characterization. The presence and efficiency of waste collection and segregation by scavengers, municipalities, or private contractors was commonly addressed by the case studies, which justified Waste Collection and Segregation as the fourth factor. Having knowledge of MSWM and an understanding of the linkages between human behavior, waste handling, and health/sanitation/environment comprise the Household Education factor. Individuals’ income influencing waste handling behavior (e.g., reuse, recycling, and illegal dumping), presence of waste collection/disposal fees, and willingness to pay by residents were seen as one of the biggest incentives to recycling, which justified them being combined into the Household Economics factor. The MSWM Administration factor was formed following several references to the presence and effectiveness of private and/or public management of waste through collection, recovery, and disposal influencing recycling activity. Although the MSWM Personnel Education factor was only recognized by six of the twenty-two case studies, the lack of trained laborers and skilled professionals in MSWM positions was a barrier to sustainable MSWM in every case but one. The presence and effectiveness of a comprehensive, integrative, long-term MSWM strategy was highly encouraged by every case study that addressed the tenth factor, MSWM Plan. Although seemingly a subset of private MSWM administration, the existence and profitability of market systems relying on recycled-material throughput, involvement of small businesses, middlemen, and large industries/exporters is deserving of the factor Local Recycled-Material Market. Availability and effective use of technology and/or human workforce and the safety considerations of each were recurrent barriers and incentives to recycling to warrant the Technological and Human Resources factor. The Land Availability factor takes into consideration land attributes such as terrain, ownership, and development which can often times dictate MSWM. Understanding the relationships among the twelve factors influencing recycling in developing countries, made apparent the collaborative nature required of sustainable MSWM. Factors requiring the greatest collaborative inputs include waste collection and segregation, MSWM plan, and local recycled-material market. Aligning each factor to the societal, environmental, and economic dimensions of sustainability revealed the motives behind the institutions contributing to each factor. A correlation between stakeholder involvement and sustainability existed, as supported by the fact that the only three factors driven by all three dimensions of sustainability were the same three that required the greatest collaboration with other factors. With increasing urbanization, advocating for improved health for all through the MDG, and changing consumption patterns resulting in increasing and more complex waste streams, the utilization of the collaboration web offered by this research is ever needed in the developing world. Through its use, the institutions associated with each of the twelve factors can achieve a better understanding of the collaboration necessary and beneficial for more sustainable MSWM.

Pore water (SO4, CH4, alkalinity, HS-, Ca, Sr, Mg, Ba) and solid phase (Ca, Sr, Mg, Ba) data measured in pockmark sediments of the Northern Congo Fan

This study focuses on the vertical distribution of authigenic carbonates (aragonite and high Mg-calcite) in the form of finely disseminated precipitates as well as massive carbonate concretions present in and above gas hydrate bearing sediments of the Northern Congo Fan. Analyses of Ca, Mg, Sr and Ba in pore water, bulk sediments and authigenic carbonates were carried out on gravity cores taken from three pockmark structures (Hydrate Hole, Black Hole and Worm Hole). In addition, a background core was retrieved from an area not influenced by fluid seepage. Pore water Sr/Ca and Mg/Ca ratios are used to reveal the current depths of carbonate formation as well as the mineralogy of the authigenic precipitates. The Sr/Ca and Mg/Ca ratios of bulk sediments and massive carbonate concretions were applied to infer the presence and depth distribution of authigenic aragonite and high Mg-calcite, based on the approach presented by Bayon et al. [Bayon et al. (2007). Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments. Marine Geology 241(1-4), 93-109, doi:10.1016/j.margeo.2007.03.007]. We show that the approach developed by Bayon et al. (2007) for sediments of cold seeps of the Niger Delta is also suitable to identify the mineralogy of authigenic carbonates in pockmark sediments of the Congo Deep-Sea Fan. We expand this approach by combining interstitial with solid phase Sr/Ca and Mg/Ca ratios, which demonstrate that high Mg-calcite is the predominant authigenic carbonate that currently forms at the sulfate/methane reaction zone (SMRZ). This is the first study which investigates both solid phase and pore water signatures typical for either aragonite or high Mg-calcite precipitation for the same sediment cores and thus is able to identify active and fossil carbonate precipitation events. At all investigated pockmark sites fossil horizons of the SMRZ were deduced from high Mg-calcite located above and below the current depths of the SMRZ. Additionally, aragonite enrichments typical for high seepage rates were detected close to the sediment surface at these sites. However, active precipitation of aragonite as indicated by pore water characteristics only occurs at the Black Hole site. Dissolved and solid phase Ba concentrations were used to estimate the time the SMRZ was fixed at the current depths of the diagenetic barite fronts. The combined pore water and solid phase elemental ratios (Mg/Ca, Sr/Ca) and Ba concentrations allow the reconstruction of past changes in methane seepage at the investigated pockmark sites. At the Hydrate Hole and Worm Hole sites the time of high methane seepage was estimated to have ceased at least 600 yr BP. In contrast, a more recent change from a high flux to a more dormant stage must have occurred at the Black Hole site as evidenced by active aragonite precipitation at the sediment surface and a lack of diagenetic Ba enrichments.

Fluid-solid interaction in arteries incorporating the autoregulation concept in boundary conditions

In pre-surgery decisions in hospital emergency cases, fast and reliable results of the solid and fluid mechanics problems are of great interest to clinicians. In the current investigation, an iterative process based on a pressure-type boundary condition is proposed in order to reduce the computational costs of blood flow simulations in arteries, without losing control of the important clinical parameters. The incorporation of cardiovascular autoregulation, together with the well-known impedance boundary condition, forms the basis of the proposed methodology. With autoregulation, the instabilities associated with conventional pressure-type or impedance boundary conditions are avoided without an excessive increase in computational costs. The general behaviour of pulsatile blood flow in arteries, which is important from the clinical point of view, is well reproduced through this new methodology. In addition, the interaction between the blood and the arterial walls occurs via a modified weak coupling, which makes the simulation more stable and computationally efficient. Based on in vitro experiments, the hyperelastic behaviour of the wall is characterised and modelled. The applications and benefits of the proposed pressure-type boundary condition are shown in a model of an idealised aortic arch with and without an ascending aorta dissection, which is a common cardiovascular disorder.

Structural changes in hemoglobin during adsorption to solid surfaces: Effects of pH, ionic strength, and ligand binding

We have studied the adsorption of two structurally similar forms of hemoglobin (met-Hb and HbCO) to a hydrophobic self-assembled methyl-terminated thiol monolayer on a gold surface, by using a Quartz Crystal Microbalance (QCM) technique. This technique allows time-resolved simultaneous measurements of changes in frequency (f) (c.f. mass) and energy dissipation (D) (c.f. rigidity/viscoelastic properties) of the QCM during the adsorption process, which makes it possible to investigate the viscoelastic properties of the different protein layers during the adsorption process. Below the isoelectric points of both met-Hb and HbCO, the ΔD vs. Δf graphs displayed two phases with significantly different slopes, which indicates two states of the adsorbed proteins with different visco-elastic properties. The slope of the first phase was smaller than that of the second phase, which indicates that the first phase was associated with binding of a more rigidly attached, presumably denatured protein layer, whereas the second phase was associated with formation of a second layer of more loosely bound proteins. This second layer desorbed, e.g., upon reduction of Fe3+ of adsorbed met-Hb and subsequent binding of carbon monoxide (CO) forming HbCO. Thus, the results suggest that the adsorbed proteins in the second layer were in a native-like state. This information could only be obtained from simultaneous, time-resolved measurements of changes in both D and f, demonstrating that the QCM technique provides unique information about the mechanisms of protein adsorption to solid surfaces.

Effect of lactose solid-state on the aerosolization performance of drug-carrier mixtures

Lactose, in particular α-lactose monohydrate, is the most used carrier for inhalation. Its surface and solid-state properties are of paramount importance in determining drug aerosolization performance. However, these properties may be altered by processing, such as micronization, thus affecting the product performance and stability. The present research project focused on the study of the effect of lactose solid-state on the aerosolization performance of drug-carrier mixtures, giving particular attention to the impact of micronization on lactose physico-chemical properties. The formation of a fraction of hygroscopic anhydrous α-lactose, rather than amorphous lactose, as a consequence of the mechanical stress stemming from micronization was evidenced by 1H NMR, XRPD and DSC analyses performed on samples of micronized lactose. The development of a new DVS method capable to identify and quantify different forms of α-lactose (hygroscopic anhydrous, stable anhydrous and amorphous), even simultaneously present in the same sample, confirmed the results obtained with the above-mentioned techniques. The influence of lactose solid-state on drug respirability was then evaluated through the preparation and in vitro aerodynamic assessment of ternary and binary mixtures containing two different drugs. In particular, the use, as carriers, of anhydrous forms of α-lactose in place of the conventional α-lactose monohydrate resulted in significantly improved respirability in the case of salbutamol sulphate and poorer performance in the case of budesonide. In an attempt to rationalize the obtained results, IGC was selected as a tool to investigate possible variations in the surface energy of the studied lactose carriers and APIs. A direct correlation between the total surface free energy of lactose carriers and drug respirability was not found. However, salbutamol sulphate and budesonide exhibited different specific surface free energy, to which the difference in the aerosolization performance may be, at least in part, ascribed.

Electromagnetic modeling of conformal wideband and multi-band patch antennas by bridging a solid-object modeler with MoM software

The advantages of antennas that can resemble the shape of the body to which they are attached are obvious. However, electromagnetic modeling of such unusually shaped antennas can be difficult. In this paper, the commercially available software SolidWorks(TM) is used for accurately drawing complex shapes in conjunction with the electromagnetic software FEKO(TM) to model the EM behavior of conformal antennas. The application of SolidWorks and custom-written software allows all the required information that forms the analyzed structure to be automatically inserted into FEKO, and gives the user complete control over the antenna being modeled. This approach is illustrated by a number of simulation examples of single, wideband, multi-band planar and curved patch antennas.

Molecular investigations into vaginal immunization with HIV gp41 antigenic construct H4A in a quick release solid dosage form

A robust vaginal immune response is considered essential for an effective prophylactic vaccine that prevents transmission of HIV and other sexually acquired diseases. Considerable attention has recently focused on the potential of vaginally administered vaccines as a means to induce such local immunity. However, the potential for vaccination at this site remains in doubt as the vaginal mucosa is generally considered to have low immune inductive potential. In the current study, we explored for the first time the use of a quick release, freeze-dried, solid dosage system for practical vaginal administration of a protein antigen. These solid dosage forms overcome the common problem associated with leakage and poor retention of vaginally administered antigen solutions. Mice were immunized vaginally with H4A, an HIV gp41 envelope based recombinant protein, using quick release, freeze-dried solid rods, and the immune responses compared to a control group immunized via subcutaneous H4A injection. Vaginally immunized mice failed to elicit robust immune responses. Our detailed investigations, involving cytokine analysis, the stability of H4A in mouse cervicovaginal lavage, and elucidation of the state of H4A protein in the immediate-release dosage form, revealed that antigen instability in vaginal fluid, the state of the antigen in the dosage form, and the cytokine profile induced are all likely to have contributed to the observed lack of immunogenicity. These are important factors affecting vaginal immunization and provide a rational basis for explaining the typically poor and variable elicitation of immunity at this site, despite the presence of immune responsive cells within the vaginal mucosae. In future mucosal vaccine studies, a more explicit focus on antigen stability in the dosage form and the immune potential of available antigen-responsive cells is recommended.

Zirconium phosphate supported tungsten oxide solid acid catalysts for the esterification of palmitic acid

A series of zirconium phosphate supported WOx solid acid catalysts with W loadings from 1–25 wt% have been prepared on high surface area zirconium phosphate by a surface grafting method. Catalysts were characterized by N2 adsorption, FTIR, Raman, UV-Vis, 31P MAS NMR, pyridine TPD and X-ray methods. Spectroscopic measurements suggest a Keggin-type structure forms on the surface of zirconium phosphate as a ([triple bond, length as m-dash]ZrOH2+)(ZrPW11O405−) species. All catalysts show high activity in palmitic acid esterification with methanol. These materials can be readily separated from the reaction system for re-use, and are resistant to leaching of the active heteropolyacid, suggesting potential industrial applications in biodiesel synthesis. © The Royal Society of Chemistry 2006.