Polymer therapeutic agents

Because the ketene acetal-terminated prepolymer is a viscous Liquid at room temperature, therapeutic agents and the triol can be mixed into the prepolymer at room temperature and the mixture crosslink id at temperatures as low as 40°C. This allows incorporation of heat-sensitive therapeutic agents into a solid polymer under very mild conditions of thermal stress. However, because the prepolymer con-tedns reactive ketene acetal groups, any hydroxyl groups present in the therapeutic agent will result in the covalent attachment of the therapeutic agent to the matrix via ortho ester bonds (16). 

The use of computational methods for the calculation of molecular properties has been a perennial goal of chemists. In recent years, the field of computational chemistry has become a firmly established discipline. Computational chemists have made impressive contributions to almost every aspect of chemistry, ranging from structural organic and inorganic chemistry to the prediction of polymer properties and the design of medicinally important therapeutic agents. While many computer-based methods are robust and widely utilized, the continued development and refinement of software and the underlying theory remains an active area of research.1,2... 

Cationic and hydrophobe modified polysaccharides are preferred excipients for personal care products since they are substantive (adherent) to anionic or hydrophobic substrates (skin, hair, mucosa), hydrophilic, film forming, compatible with many therapeutic agents, nonpenetrating, and nonirritating. Polymer JR and Quatrisoft (Figure 1), are two such materials... 

Several mechanisms may be responsible for the overall release of a therapeutic agent dispersed in a degradable polymer matrix [24,60,68] ... 

The principle upon which this approach is based is an enzyme-substrate reaction that produces a change in pH and a hydrolytically labile, pH-sensitive polymer containing dispersed therapeutic agent that can vary the erosion rate and concomitant drug release in response to that pH change. Figure 1 shows two types of drug... 

An alternative device is shown in Figure 1(b). In this device the therapeutic agent and the enzyme are both dispersed in the polymer, and the enzyme-substrate reaction occurs in the outer layers of the device. The altered pH in the outer layers then modifies erosion rate of the polymer. 

---