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Thesis
Studies on a new ultrasound contrast agent: strategies for increasing the population of nano bubbles and for encapsulation of Paclitaxel
Master of Science (M.S.), Drexel University
Jun 2011
DOI:
https://doi.org/10.17918/etd-3555
Abstract
Paclitaxel (Taxol) is an anti-cancer drug obtained from the bark and needles of Taxus brevifolia. It is known for its unique mode of action and used for the treatment of breast and ovarian cancer. Also, paclitaxel shows very low solubility in water and is associated with a number of toxic side effects. The currently used formulation of paclitaxel with cremophor EL results in several hypersensitivity reactions. In order to tackle this problem, there is a need to develop targeted paclitaxel therapy for cancer treatment. Since, paclitaxel is highly hydrophobic, it can be incorporated in the hydrophobic core of vesicles such as SE61, a surfactant stabilized mixture of micro and nano gas bubbles. When ultrasound is transmitted in the body and encounters a medium with different acoustic impedance, such as a gas bubble, the backscatter is greatly increased, giving contrast enhancement. Ultrasound also causes the bubble to oscillate and break releasing any entrapped drug, for example at a tumor site. This helps in controlled and target drug release, preventing the drug action on normal healthy cells. An added advantage is that ultrasound facilitates drug uptake by increasing the permeability of the cell membrane. Nanobubbles can easily pass through the capillary walls of blood vessels in the targeted tumors enabling site specific delivery of drug. The gas core of SE61 contrast agent was Paclitaxel (Taxol) is an anti-cancer drug obtained from the bark and needles of Taxus brevifolia. It is known for its unique mode of action and used for the treatment of breast and ovarian cancer. Also, paclitaxel shows very low solubility in water and is associated with a number of toxic side effects. The currently used formulation of paclitaxel with cremophor EL results in several hypersensitivity reactions. In order to tackle this problem, there is a need to develop targeted paclitaxel therapy for cancer treatment. Since, paclitaxel is highly hydrophobic, it can be incorporated in the hydrophobic core of vesicles such as SE61, a surfactant stabilized mixture of micro and nano gas bubbles. When ultrasound is transmitted in the body and encounters a medium with different acoustic impedance, such as a gas bubble, the backscatter is greatly increased, giving contrast enhancement. Ultrasound also causes the bubble to oscillate and break releasing any entrapped drug, for example at a tumor site. This helps in controlled and target drug release, preventing the drug action on normal healthy cells. An added advantage is that ultrasound facilitates drug uptake by increasing the permeability of the cell membrane. Nanobubbles can easily pass through the capillary walls of blood vessels in the targeted tumors enabling site specific delivery of drug. The gas core of SE61 contrast agent was formulation change did not affect paclitaxel encapsulation efficiency. The encapsulation efficiency of paclitaxel loaded into standard SE61 nanobubbles was 14.4% and in paclitaxel loaded newly formulated nanobubbles was 13.9%.
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Details
- Title
- Studies on a new ultrasound contrast agent
- Creators
- Shweta Naidu Chitoor - DU
- Contributors
- Margaret A. Wheatley (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 3555; 991014632699204721