Systematic model identification and optimization-based active polymorphic control of crystallization processes

Polymorphism is an important issue in industrial crystallization, since polymorphs of the same compound can present very different properties, such as solubility, melting point or density, influencing considerably the manufacturability and bioavailability of the final product. This work proposes a model-based active polymorphic control strategy that allows obtaining large crystals of the stable polymorph at the end of a batch crystallization process, even in the case of erroneous seeding or in situ nucleation of a mixture of both the stable and metastable forms. A novel systematic experimental design was applied to estimate the kinetic parameters of dissolution, growth and secondary nucleation of the stable and metastable polymorphs of the model compound (ortho-aminobenzoic acid, OABA). Such experimental approach allows the determination of the studied kinetics without any correlation between parameters during the estimation, and without the need of off-line measurements of the crystal size distribution during the experiments. The estimated kinetic parameters were used to build a population balance model for the calculation of the optimal temperature profile needed, during a batch cooling crystallization process, for the (i) elimination of the metastable form crystals nucleated in situ or erroneously seeded and the (ii) maximisation of the size of the crystals of the stable polymorph obtained at the end of the batch process

Vibrational-rotational structure of the silane molecule in the band of v2+v4 (F2)

In recent years, extensive theoretical studies have been carried out on the silane molecule, namely their vibrational-rotational structure. In this work, we continue our research series and focus on the 28SiD4 isotopologue. The IR-spectrum of the silane molecule was recorded in the range 1250-1450 cm-1 (pentad region) on Bruker IFS 120HR Fourier interferometer. The P, Q, and R branches with Jmax up to 17 were assigned, and spectroscopic constants of the v2+v4 (F2) band were derived for 28SiD4. As a result, a set of spectroscopic parameters was obtained which describe the vibrational-rotational structure of the silane molecule close to the experimental uncertainties

Human cathelicidin production by the cervix

hCAP18/LL-37 is the sole human cathelicidin; a family of host defence peptides with key roles in innate host defence. hCAP18/LL-37 is expressed primarily by neutrophils and epithelial cells, but its production and function in the lower genital tract is largely uncharacterised. Despite the significant roles for cathelicidin in multiple organs and inflammatory processes, its impact on infections that could compromise fertility and pregnancy is unknown. The aim of this study was to investigate cathelicidin production, regulation and function in the cervix. hCAP18/LL-37 was found to be present in cervicovaginal secretions collected from women in the first trimester of pregnancy and to be expressed at significantly higher levels in samples from women with alterations in vaginal bacterial flora characteristic of bacterial vaginosis. In endocervical epithelial cell lines, expression of the gene encoding hCAP18/LL-37 (CAMP) was not affected by TLR agonists, but was found to be up-regulated by both 1, 25 hydroxyvitamin D3 and 25 hydroxyvitamin D3. However, no association was found between serum levels of vitamin D and hCAP18/LL-37 concentrations in cervicovaginal secretions (n = 116). Exposure to synthetic LL-37 had a pro-inflammatory effect on endocervical epithelial cell lines, increasing secretion of inflammatory cytokine IL-8. Together these data demonstrate inducible expression of hCAP18/LL-37 in the female lower reproductive tract in vivo and suggest the capacity for this peptide to modulate host defence to infection in this system. Further investigation will elucidate the effects of hCAP18/LL-37 on the physiology and pathophysiology of labour, and may lead to strategies for the prevention of infection-associated preterm birth

Cathelicidin and its role in defence against bacterial infections of epithelial cells

Cathelicidins are antimicrobial peptides (AMPs) that were first discovered to have microbicidal properties but more recently to be multifunctional immunomodulators and thus important in influencing host defence against infectious disease. Whilst roles in various organs have been demonstrated, their expression patterns in health and disease in other organs are less clear and their key immunomodulatory functions remain undefined, particularly with regard to the balance of immunomodulatory properties and microbicidal activity in their ability to promote defence against infection. I therefore set out to describe LL-37 expression (human cathelicidin) in the female reproductive tract (across the menstrual cycle) and in the lung (during specific lung diseases), to define the effects on the function of airway epithelial cells during bacterial infection and to evaluate the key in vivo roles of endogenous cathelicidin (using a knockout mouse model) as well as the effect of therapeutic administration of LL-37 in a pulmonary Pseudomonas aeruginosa infection model. I demonstrated that cathelicidin protein and transcription shows a cyclical pattern of expression in female reproductive tissues which is maintained at high levels in decidua. LL- 37 protein was also detected in hTERT endometrial epithelial cells but despite the suggestion that cathelicidin may be regulated by steroid hormones there was no direct effect of progesterone on transcription. LL-37 is barely detected in healthy airways however is well known to increase during infection or inflammation. I observed that sputum from patients with bronchiectasis showed a correlation between the level of LL-37, TNF, MPO and chronic colonisation of Pseudomonas aeruginosa. Patients with lung cancer expressed much less LL- 37 than the bronchiectasis patients but there was a trend towards increased production postsurgery compared to pre-surgery. LL-37 was previously shown by our lab to selectively promote BAX and caspase-dependant death of infected epithelial cells. I went on to show that this appears to be a partially caspase- 1 dependent mechanism and that human bronchial epithelial (HBE) cells and A549 cell lines both express several of the components required to form inflammasomes, a caspase-1 dependant form of inflammatory cell death. Finally, I showed using murine models that cathelicidin enhances bacterial clearance during pulmonary infection in vivo, a response which is defective in mice lacking endogenous cathelicidin and that administration of exogenous, synthetic LL-37 at the time of infection can promote an early protective neutrophil influx in the absence of endogenous cathelicidin production

Neutrophil derived cathelicidin in arterial inflammation

Neutrophils are the first immune cells recruited into tissues during inflammatory processes. They orchestrate the progression of inflammation through the release of preformed granule proteins such as cathelicidin, azurocidin and alpha-defensin. These proteins are well known for their antimicrobial activities. Cathelicidins have been intensively studied for their cytotoxic, chemotactic, regenerative and angiogenic properties. However, their contribution to atherosclerosis and neointima formation is not yet completely understood. Therefore, the aim of this thesis was to identify molecular mechanisms of cathelicidin-mediated vascular inflammation and a possible therapeutic strategy. Using a mouse model of arterial injury, we were able to show that cathelicidins, which are released from neutrophils, exert a healing effect. Mechanistically, cathelicidins promote adhesion of endothelial early outgrowth cells (EOCs) thus improve re-endothelialization of the injured vascular wall. In addition, cathelicidins can activate EOCs, leading to the release of growth factors, enhancing the regeneration process of vascular endothelium. In a therapeutic-oriented approach, cathelicidins were biofunctionalized by covalently binding to a nitinol stent surface. This cathelicidin-constructed stent reveals protective properties against in-stent stenosis after implantation into the carotid artery of mice. In the later studies we could show that adhesion of classical monocyte depends on the presence of neutrophils. Neutrophils mediate classical monocyte adhesion through the release of cathelicidins into tissues which are subsequently transported across endothelium and luminally presented. Endothelial-bound cathelicidins are presented to classical monocytes via formyl peptide receptor 2 (FPR2). Cathelicidin-FPR2 interaction generates intracellular signaling cascades leading to activation of integrins, thus promoting adhesion of monocytes onto endothelium. This mechanism is preferential to classical monocytes. In addition, we further corroborate the significance of neutrophil-mediated monocyte adhesion through the studies of atherosclerosis in a mouse model. Cathelicidin-deficient mice exhibited reduced atherosclerotic lesions, characterized by lower lesional macrophage content and decreased arterial adhesion of classical monocytes. In summary, we show here for the first time, the role of cathelicidins in neointima formation and atherosclerosis which could be targeted for clinical therapeutic approach

Antisolvent Crystallization of Papain

Protein crystallization plays a crucial role in the food and pharmaceutical industries, enhancing product quality and efficiency by improving purity and controlled particle characteristics. This study focused on the crystallization of the versatile protein papain, extracted from papaya. Antisolvent crystallization was performed. This method is cost-effective and is a simple and energy-efficient approach. Beyond protein crystal production, the antisolvent crystallization process serves as a method for encapsulating active pharmaceutical ingredients (APIs). The study investigated organic solvents like ethanol, acetone, and acetonitrile as potential antisolvents. Additionally, the impact of variables such as the solvent-to-antisolvent (S:AS) volume ratio and papain concentration on particle size, particle size distribution, zeta potential, crystallization yield, and residual activity of papain crystals were examined. Ethanol emerged as the optimal antisolvent, reducing the solubility of papain and preserving papain’s crystalline structure with minimal activity loss. Optimal conditions were identified at a 1:4 S:AS volume ratio and a papain concentration of 30 mg/mL, resulting in nanosized spherical crystals with a high yield and preserved activity. This research underscored the crucial role of thoughtful parameter selection in antisolvent crystallization to achieve specific particle characteristics while maintaining the functionality of the crystallized substance

รายงานการวิจัยการปรับปรุงเครื่องตกผลึกในระดับอุตสาหกรรมโดยใช้การจำลอง CFD

ได้รับทุนอุดหนุนการวิจัยจากมหาวิทยาลัยเทคโนโลยีสุรนารี ปีงบประมาณ 254