Biodegradable microneedle patch for delivery of meloxicam for managing pain in cattle.

Microneedle patches are a promising source for transdermal diffusion of macromolecules and are designed to painlessly penetrate the skin. In this study, a biodegradable chitosan microneedle patch to deliver meloxicam for managing pain in cattle was tested. The potential of reuse of the polymeric solution to fabricate the patches, optimization of fabrication, morphological analysis of the microneedle patch and analysis of preservation of the chemical composition after sterilization were evaluated. In-vitro analysis consisted of studying in-vitro penetration mechanical properties, compression testing analysis of microneedle patch, and in-vitro drug release analysis. In-vivo studies were performed to analyze the dissolution capability of the microneedle patch. Results regarding the physical characteristics, chemical composition, and mechanical properties confirmed that rheological properties of the chitosan solution, present significant differences over time, demonstrating that reusing the solution on the fourth day results in failure patches. Morphological characteristics and chemical composition studies revealed that the process of sterilization (ethylene oxide gas) needed for implanting the patches into the skin did not affect the properties of microneedle patches. In-vitro studies showed that approximately 33.02 ± 3.88% of the meloxicam was released over 7 days. A full penetration of the microneedles into the skin can be obtained by applying approximately 3.2 N. In-vivo studies demonstrated that microneedle patches were capable of swelling and dissolving, exhibiting a dissolution percentage of more than 50% of the original height of microneedle after 7 days. No abnormal tissue, swelling, or inflammation was observed in the implanted area. The results of this work show that chitosan biodegradable microneedle patches may be useful to deliver meloxicam to improve pain management of cattle with positive effects for commercial manufacturing.

Immunomodulatory functions of human mesenchymal stromal cells are enhanced when cultured on HEP/COL multilayers supplemented with interferon-gamma.

Human mesenchymal stromal cells (hMSCs) are multipotent cells that have been proposed for cell therapies due to their immunosuppressive capacity that can be enhanced in the presence of interferon-gamma (IFN-γ). In this study, multilayers of heparin (HEP) and collagen (COL) (HEP/COL) were used as a bioactive surface to enhance the immunomodulatory activity of hMSCs using soluble IFN-γ. Multilayers were formed, via layer-by-layer assembly, varying the final layer between COL and HEP and supplemented with IFN-γ in the culture medium. We evaluated the viability, adhesion, real-time growth, differentiation, and immunomodulatory activity of hMSCs on (HEP/COL) multilayers. HMSCs viability, adhesion, and growth were superior when cultured on (HEP/COL) multilayers compared to tissue culture plastic. We also confirmed that hMSCs osteogenic and adipogenic differentiation remained unaffected when cultured in (HEP/COL) multilayers in the presence of IFN-γ. We measured the immunomodulatory activity of hMSCs by measuring the level of indoleamine 2,3-dioxygenase (IDO) expression. IDO expression was higher on (HEP/COL) multilayers treated with IFN-γ. Lastly, we evaluated the suppression of peripheral blood mononuclear cell (PBMC) proliferation when co-cultured with hMSCs on (HEP/COL) multilayers with IFN-γ. hMSCs cultured in (HEP/COL) multilayers in the presence of soluble IFN-γ have a greater capacity to suppress PBMC proliferation. Altogether, (HEP/COL) multilayers with IFN-γ in culture medium provides a potent means of enhancing and sustaining immunomodulatory activity to control hMSCs immunomodulation.

Design, characterization, and modeling of a chitosan microneedle patch for transdermal delivery of meloxicam as a pain management strategy for use in cattle.

This work describes the formulation and evaluation of a chitosan microneedle patch for the transdermal delivery of meloxicam to manage pain in cattle. Microneedle patches composed of chitosan and chitosan/meloxicam were evaluated regarding their chemical composition, uniformity of physical characteristics, capacity to penetrate the skin, and response to thermal and thermo-mechanical changes. Microneedle patches were prepared by varying the percentage of acetic acid used during solution preparation, including 90% (v/v), 50% (v/v), and 10% (v/v). In addition, drug release was assessed by modeling different percentages of penetration into the skin and the number of microneedles on the microneedle patch. Scanning electron microscopy confirmed the presence of microneedles uniformly organized on the patch surface for each percentage of acetic acid used. Fourier transform infrared spectroscopy revealed that 10% (v/v) of acetic acid in the solution was a suitable condition to preserve the characteristic bands of chitosan (amide I and amide II) and meloxicam (amine NH stretch and CO stretch) as compared to 90% (v/v) and 50% (v/v) of acetic acid used during the solution preparation. The resultant microneedle patches were successful in penetrating the skin in a cow's cadaver ear. Results demonstrated that the average depth penetration measured after complete dehydration of the penetrated skin was approximately 78 ± 1 µm. Chitosan and chitosan/meloxicam microneedle patches with higher acetic acid percentages reflected greater resistance to compressive force as temperature increased. Time-dependent simulation of the transport of diluted species by COMSOL revealed that the transdermal drug delivery increases in function to the increment of the number of microneedles on the surface patch and percentage of penetration per microneedle. One patch released a drug concentration of 3.57 × 10-5 mol/m3 in the skin per week, which represents the 26.2% of what is needed for pain management in cattle, established as 1.43 × 10-4 mol/m3. These results demonstrate that chitosan/meloxicam microneedles patches may be suitable to manage pain in cattle after routine procedures.