Question

1. A company wants to deliver proteins such as pro-apoptosis protein (e.g. apoptin, tumor necrosis factor related apoptosis, etc) to tumor to treat cancer. You are asked to design a polymer-based drug delivery system which can be suitable for the company purpose. List all fabrication techniques involved and advantages of your system?

2. List the diffusion mechanisms by which rate-controlled release maybe achieved.

A company is trying to develop a polymeric implant for controlled release of a drug loaded hydrogel for a period of 8 weeks. Which mechanism and related techniques would you recommend to the company to increase the drug release rate?

Describe the technique can be used to improve drug release rates of a Drug-Delivery System of conventional non-degradable matrix-type polymeric device.

Answer 1

Answer 1:)

PCL (poly-ε-caprolactone) is appropriate for controlled drug delivery because of high permeability to many drugs, outstanding biocompatibility and its ability to be completely excreted from the body when resorbed. PCL is degraded by hydrolysis of its ester bonds in physiological conditions and has thus received large attention in order to be castoff as an implantable biomaterial. PCL may be entirely degraded and resorbed via an intracellular mechanism when the molecular weight was condensed to 3000 or less. The rate of hydrolysis can change by copolymerization with other glycolides/lactides or lactones. Biodegradation of PCL is gentle in assessment to other polymers, thus it is more appropriate for long-term delivery, which ranges over a period of more than one year.

Answer 2:)

To increase the drug release rate by an implant, we recommend the use of vascular grafts. Dacron(R), expanded polytetrafluoroethylene, and polyurethane is some biomaterials are used for vascular grafts. The best is expanded polytetrafluoroethylene (ePTFE ) material for the vascular graft.

Characteristics:

1. This is a porous polymer having an electronegative luminal surface.
2. The material does not cause immunogenic, high flexibility of tailoring and high patency rate.
3. This material is nondegradable due to the presence of the electronegative luminal surface. The fibril length of ePTFE is 30 μm. This graft shows graft healing due to fibronectin bonding with the ePTFE fibers.
4. The main advantages of the material are its non-degradable nature and high patency rate.