Drug delivery applications materials

Another class of environmentally sensitive materials that are being targeted for use in drug delivery applications is thermally sensitive polymers. This type of hydrogel exhibits temperature-sensitive swelling behavior... 

Many polyanionic materials, such as poly(aciylic acid), are pH sensitive and the degree of swelling of such polymers can be modulated by changing the pH. An application of such technology has been in the development of biomimetic secretory granules for drug delivery applications. 

Obviously, the regulatory status of polyesters means that these materials dominate the field as far as commercial development is concerned. However, there is a myriad assortment of polymers that continue to be developed for drug delivery applications. These efforts are aimed at developing new polymeric materials designed specifically to overcome obstacles in drug... 

RESS is useful for materials that are soluble in CO2. Unfortunately, CO2, with no dipole moment and very low polarizability, is a very weak solvent and dissolves very few polymers. Cosolvents such as methanol or acetone can be mixed with SCFs to increase the solvating power of SCFs during RESS. In drug delivery applications, RESS has been used to prepare polymeric films, microparticles, nanospheres, liposomes, and porous foams (Figure 1). A... 

Diffusion of materials out of a PSi sensor was monitored by Koh and coworkers in a proof-of-concept device for monitored drug delivery applications [29], Poly-methyl methacrylate (PMMA) containing 0.25 mg/ml caffeine was first cast onto a freestanding PSi thin film. Exposure of this composite material to a pH 7 buffer caused a time-dependent decrease in the intensity of reflection at a fixed wavelength, or alternatively a time-dependent blue shift of the peak, corresponding to diffusion of the small molecule out of the PMMA-PSi composite. These data correlated well with appearance of caffeine in the buffer solution, as measured by UV-Vis spectrophotometry. 

Polyanhydrides are useful bioabsorbable materials for controlled drug delivery. They are hydrolytically unstable and hydrolyze to diacid monomers in contact with body fluids. Since their introduction to the field of controlled drug delivery, about 10 years ago, extensive research has been conducted to study their chemistry as well as their toxicity and medical applications. Several review articles have been published on polyanhydrides and the focus has been on controlled drug delivery applications [1, 2]. 

West, J.L. and J.A. Hubbell, Photopolymerized hydrogel materials for drug delivery applications. Reactive Polymers, 1995, 25, 139-147. 

---