Pharmaceutical Sciences
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21636
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Browsing Pharmaceutical Sciences by Author "Curry, Stephen"
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Item 3D-Printed Insert for Visualization of Liposomal Interactions with Collagen Fibers(2019-03-05) Mishra, Ina; Kastellorizios, Michail; Curry, StephenPurpose: Nanoparticles, such as liposome, are commonly used as vehicles for drug delivery to target tissues such as tumors. However, relatively little research has focused on liposomal interactions with the tumor extracellular matrix (ECM), a huge hurdle in the process of perfecting dosage. To our knowledge, there is no method available that allows the observation liposomes against a whole collagen fiber. In order to better study these interactions, we have designed a 3D-printed frame that helps in visualizing liposome transport around a collagen fiber. Observation of our replicated microenvironment will allow us to shed more light on the movements of liposomes within the ECM of tumor cells. Methods: Collagen fiber was removed from adult rat tail and allowed to soak in phosphate-buffered saline (PBS) overnight. Primary design of the frame was done using SketchUp software. Printing of 12mm frame design was done using a Form 2 3D printer (Formlabs). Fiber-in-frame was placed in a glass bottom microwell dish (MatTek Corp.). Research-grade liposomes that mimic the clinical product Doxil (DoxomTM, Liposomics) were used in a background of 0.07mg/ml BSA solution, and added to the channel. Visualization of the interaction was done using confocal microscope (Nikon A1R-MP+ Multiphoton System). Results: As a proof-of-concept, we mounted a collagen fiber into our frame and filled channel with BSA solution. Observation indicates that liposomes prefer to accumulate on the collagen fiber surface. Multiple trial frames were needed to account for height requirements necessary for confocal microscopy. Our built-in sample well allowed for a maximum 20 uL of formulation to be added into the channel environment from one end of the fiber. Our next steps will focus on reducing height and volume of background and sample needed as well as removing the need for a dish or slide altogether. Future studies will focus on kinetic phenomena in this microenvironment. Conclusions: Using the methods described above, we observed that Doxom liposomes accumulated near the fiber surface. This suggests that liposomes can use collagen as a route of travel in the extracellular environment. Future experiments with this frame design and others will be used to study the liposomal interactions with collagen and other ECM components. In addition to new frame designs, instruments with higher intensity and resolution will provide more accurate data.Item An Alternative Method To Quantify Surface Properties of Anti-Cancer Drugs(2019-03-05) Curry, Stephen; Kastellorizios, Michail; Mishra, InaPurpose Physicochemical properties such as size and size distribution affect liposome formulations’ physical stability and accumulation in the target tissue. The FDA’s “Liposome Drug Products, Guidance for Industry”, 2018 emphasized size and size-distribution as “critical quality attributes”, however, it does not mention the criteria for an acceptable polydispersity index (PDI), currently measured using size-scattering technique. A monodisperse, homogenous size distribution population (PDI≤0.3) is desired. In this work, we measured surface tension of two different size distributions of liposome populations, with lipid composition similar to clinically approved anticancer formulation DOXIL, as a method to quantify liposome surface properties. This work establishes a building block in our long-term goal of obtaining insight into and facilitating the translation of nanoparticles from animal to human studies by offering additional preclinical characterization techniques based on surface properties of nanoparticles. Method Liposome formulations A and B, consisting of hydrogenated (Soy) phosphatidyl choline, cholesterol, and DSPE-PEG (7.64:5.17:1 molar ratio) were formulated in-house using thin film hydration method and probe sonication. Average particle size (PS) and PDI was obtained using dynamic light scattering (Mobius122, Wyatt Technology). The two formulations were fabricated with small differences in probe sonication process, yielding slightly different PDIs but the same average PS. The formulations were tested at two different lipid concentrations: 1mg/ml and 0.1mg/ml. Surface energy measurements were obtained on all four using pendant drop method, reported as mean with standard error (n=3) against the PDI. Results Average PS for A and B was similar (92.9±1.6 nm, 90.3±0.4 nm respectively), with PDIs 0.1±0.02 and 0.04±0.02 respectively. As expected, the surface tension was significantly decreased with concentration. PDI was found to significantly affect the total surface tension at higher concentration tested (1mg/ml) while it did not play a role at the lower concentration tested (0.1mg/ml). Interestingly, this trend was reversed when the surface tension was broken into its polar and dispersive components. Conclusions This work confirmed that small PDI changes, arising from slight variations in fabrication/manufacturing process, can translate into measurable changes in surface properties that can be obtained more rapidly and with higher accuracy than conventional DLS-based sizing techniques.