Preclinical assessment of nanostructured liquid crystalline particles for the management of bacterial keratitis: in vivo and pharmacokinetics study

Preclinical Assessment of Nanostructured Liquid Crystalline Particles for the Management of Bacterial Keratitis: in-vivo and Pharmacokinetics Study

10.21203/rs.3.rs-481365/v1 ◽

2021 ◽

Author(s):

Shreya Kaul ◽

Upendra Nagaich ◽

Navneet Verma

Keyword(s):

Residence Time ◽

Liquid Crystalline ◽

Ex Vivo ◽

Research Work ◽

Poloxamer 407 ◽

Pharmacokinetic Studies ◽

Eye Drops ◽

Statistical Experimental Design ◽

Bacterial Keratitis

Abstract The research work was driven to develop novel nanostructured liquid crystalline particles of vancomycin for its improved pre-ocular residence time, ocular bio-availability, enhanced targeting, increased permeability, reduced dosing frequency, controlled drug release and reduced systemic side-effects. Formulation was developed by fragmenting cubic crystalline phase of glycerol monooleate, water and poloxamer 407. A four-factor, three-level Taguchi statistical experimental design was constructed to optimize the formulation. Formulations exhibited internal-cubic structure of the vesicles with particle size in the range of 51.11 ± 0.96 nm to 158.73 ± 0.46 nm and negative zeta potential. Ex-vivo transcorneal permeation studies demonstrated that the optimized cubosomes had 2.4-fold increase in apparent permeability co-efficient as compared to vancomycin solution. Whereas, in-vivo studies in rabbits demonstrated that the severity of keratitis was considerably lowered in day 3 with optimized cubosomes. Ocular pharmacokinetic studies evaluated level of drug in aqueous humor and results revealed that the time to peak concentration (Tmax) of vancomycin loaded cubosomal formulation was about 1.9-fold higher and mean residence time was 2.2-fold greater than vancomycin solution. Furthermore, histological examination revealed that the corneal layers displayed well-maintained morphology without any stromal swelling, consequently indicating safety of formulation. In conclusion, results manifested that the developed vancomycin loaded cubosomes could be a promising novel ocular carrier and an ideal substitute for conventional eye-drops for the management of bacterial-keratitis.

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Use of light microscopy in the qualitative and quantitative study of liquid crystalline order

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121727 ◽

1992 ◽

Vol 50 (1) ◽

pp. 264-265

Author(s):

Christopher Viney

Keyword(s):

Light Microscopy ◽

Liquid Crystalline ◽

Structural Characteristics ◽

Molecular Order ◽

Liquid Crystalline Phases ◽

Convenient Technique ◽

Liquid Crystalline Materials ◽

Transparent Windows

Light microscopy is a convenient technique for characterizing molecular order in fluid liquid crystalline materials. Microstructures can usually be observed under the actual conditions that promote the formation of liquid crystalline phases, whether or not a solvent is required, and at temperatures that can range from the boiling point of nitrogen to 600°C. It is relatively easy to produce specimens that are sufficiently thin and flat, simply by confining a droplet between glass cover slides. Specimens do not need to be conducting, and they do not have to be maintained in a vacuum. Drybox or other controlled environmental conditions can be maintained in a sealed chamber equipped with transparent windows; some heating/ freezing stages can be used for this purpose. It is relatively easy to construct a modified stage so that the generation and relaxation of global molecular order can be observed while specimens are being sheared, simulating flow conditions that exist during processing. Also, light only rarely affects the chemical composition or molecular weight distribution of the sample. Because little or no processing is required after collecting the sample, one can be confident that biologically derived materials will reveal many of their in vivo structural characteristics, even though microscopy is performed in vitro.

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The in vivo transformation and pharmacokinetic properties of a liquid crystalline drug delivery system

International Journal of Pharmaceutics ◽

10.1016/j.ijpharm.2017.08.098 ◽

2017 ◽

Vol 532 (1) ◽

pp. 345-351 ◽

Cited By ~ 3

Author(s):

Andrew Otte ◽

Yahira M. Báez-Santos ◽

Ellina A. Mun ◽

Bong-Kwan Soh ◽

Young-nam Lee ◽

...

Keyword(s):

Drug Delivery ◽

Drug Delivery System ◽

Delivery System ◽

Liquid Crystalline ◽

Pharmacokinetic Properties

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Hierarchical spidroin micellar nanoparticles as the fundamental precursors of spider silks

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1810203115 ◽

2018 ◽

Vol 115 (45) ◽

pp. 11507-11512 ◽

Cited By ~ 14

Author(s):

Lucas R. Parent ◽

David Onofrei ◽

Dian Xu ◽

Dillan Stengel ◽

John D. Roehling ◽

...

Keyword(s):

Liquid Crystalline ◽

Spider Silk ◽

Fiber Spinning ◽

Fiber Formation ◽

Natural Material ◽

Physical Form ◽

Spinning Process ◽

Black Widow Spiders ◽

Spider Silks

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable–properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.

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Subbasal corneal nerve damage in patients with bacterial keratitis: in vivo confocal microscopy study

Arquivos Brasileiros de Oftalmologia ◽

10.5935/0004-2749.20220010 ◽

2022 ◽

Vol 85 (1) ◽

Author(s):

Rodrigo Thiesen Müller ◽

Beatriz B. de Andrade ◽

Luciene Barbosa de Sousa

Keyword(s):

Confocal Microscopy ◽

Microscopy Study ◽

Nerve Damage ◽

Bacterial Keratitis ◽

In Vivo Confocal Microscopy ◽

Corneal Nerve

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Corneal Infection Models: Tools to Investigate the Role of Biofilms in Bacterial Keratitis

Cells ◽

10.3390/cells9112450 ◽

2020 ◽

Vol 9 (11) ◽

pp. 2450

Author(s):

Lucy Urwin ◽

Katarzyna Okurowska ◽

Grace Crowther ◽

Sanhita Roy ◽

Prashant Garg ◽

...

Keyword(s):

Ex Vivo ◽

Bacterial Species ◽

Resistance Mechanisms ◽

Bacterial Keratitis ◽

Corneal Surface ◽

Corneal Infection ◽

Infection Models

Bacterial keratitis is a corneal infection which may cause visual impairment or even loss of the infected eye. It remains a major cause of blindness in the developing world. Staphylococcus aureus and Pseudomonas aeruginosa are common causative agents and these bacterial species are known to colonise the corneal surface as biofilm populations. Biofilms are complex bacterial communities encased in an extracellular polymeric matrix and are notoriously difficult to eradicate once established. Biofilm bacteria exhibit different phenotypic characteristics from their planktonic counterparts, including an increased resistance to antibiotics and the host immune response. Therefore, understanding the role of biofilms will be essential in the development of new ophthalmic antimicrobials. A brief overview of biofilm-specific resistance mechanisms is provided, but this is a highly multifactorial and rapidly expanding field that warrants further research. Progression in this field is dependent on the development of suitable biofilm models that acknowledge the complexity of the ocular environment. Abiotic models of biofilm formation (where biofilms are studied on non-living surfaces) currently dominate the literature, but co-culture infection models are beginning to emerge. In vitro, ex vivo and in vivo corneal infection models have now been reported which use a variety of different experimental techniques and animal models. In this review, we will discuss existing corneal infection models and their application in the study of biofilms and host-pathogen interactions at the corneal surface.

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