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Polygenetics, Inc. |
CavilinkTM Polymers
Highly porous polymers
“CavilinkTM “is Polygenetics’ trade name for its highly porous polymers. These polymers differ substantially from “macroporous” polymers which are characterized by the presence of irregular pores of Angstrom dimensions that terminate within the polymer matrix. In contrast, CavilinkTM polymers are characterized by very large cavities of micrometer dimensions that are interconnected. Furthermore, Cavilink polymers can be made to have porosity in excess of 90%. This enables combination products, polymers having actives incorporated into the matrix, to be 90% pure in the active. These features are illustrated in Figure 1.
A full description of this technology is contained in a monograph published
in American Laboratory (May, 2003) and written by
Dr. Benson. It is available as a PDF file for download:
Highly
Porous Polymers.
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| Fig. 1A. Conventional “macroporous” polymers. These are characterized by irregular pores that terminate inside matrix. Pores are of Angstrom dimensions and are generally not interconnected. Maximum pore volume is usually about 50%. | Fig. 1B. “Cavilink” polymers. These are characterized by relatively uniform cavities of micrometer dimensions that are interconnected by a series of smaller pores. Pore volume can be made to exceed 90%; thus large amounts of actives can be contained within the matrix. |
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| Figure 2. Conventional macroporous polymer. | Figure 3. Cavilink porous polymer. Structure is clearly differentiated from polymer in Fig. 2. |
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| Figure 4. Pore structure of conventional porous polymer. "Macroporous" polymers (Fig. 2) contain small, irregular pores that terminate inside structure. | Figure 5. Pore structure of Cavilink porous polymer. Polygenetics polymers
exhibit very large cavities of micrometer dimensions, each of which is interconnected to those adjacent.
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Physical Properties
Some physical properties of Cavilink polymers are summarized in Table 1. It is important to recognize that Polygenetics’ patents cover morphology of the microspheres independent of polymer composition. Thus, Cavilink polymers can be made into a variety of materials including polystyrene, polyvinyl alcohol, polymethylmethacrylate, polyvinylpyrrolidone and others. For drug delivery applications, only polymers already certified by the FDA as safe for human administration are employed. ("GRAS")
| Property of CavilinkTM polymers | Measurement - Description |
| Maximum internal void volume | > 90% |
| Density (typical) | < 0.1 g/cm3 |
| Cavity diameter | Up to 30 µm |
| Interconnect pore diameter | Can be varied |
| Composition | Many polymer formulations possible |
Table 1. Some properties of Cavilink polymers.