https://yunus.hacettepe.edu.tr/~damlacetin/kmu407/index_dosyalar/4.%20makale.pdf

Biodegradable polymers as biomaterials

Biodegradable and bioactive porous polymer/inorganic composite scaffolds for bone tissue engineering

The return of a forgotten polymer—Polycaprolactone in the 21st century

Poly(ethylene glycol) (PEG) is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery. The properties that account for the overwhelming use of PEG in biomedical applications are outlined in this Review. The first approved PEGylated products have already been on the market for 20 years. A vast amount of clinical experience has since been gained with this polymer--not only benefits, but possible side effects and complications have also been found. The areas that might need consideration and more intensive and careful examination can be divided into the following categories: hypersensitivity, unexpected changes in pharmacokinetic behavior, toxic side products, and an antagonism arising from the easy degradation of the polymer under mechanical stress as a result of its ether structure and its non-biodegradability, as well as the resulting possible accumulation in the body. These possible side effects will be discussed in this Review and alternative polymers will be evaluated.

Poly(ethylene glycol) in Drug Delivery: Pros and Cons as Well as Potential Alternatives

23 Stereocontrol of Lactide ROP 6164 231 Isotactic Polylactides 6164 232 Syndiotactic Polylactides 6166 233 Heterotactic Polylactides 6166 3 Anionic Polymerization 6166 4 Nucleophilic Polymerization 6168 41 Mechanistic Considerations 6168 42 Catalysts 6169 421 Enzymes 6169 422 Organocatalysts 6169 43 Stereocontrol of Lactide ROP 6170 44 Depolymerization 6170 5 Cationic Polymerization 6170 6 Conclusion and Perspectives 6171 7 Acknowledgments 6173 8 References and Notes 6173

Controlled ring-opening polymerization of lactide and glycolide.

http://www.afinitica.com/arnews/sites/default/files/techdocs/Synthetic%20biodegradables.pdf

Synthetic biodegradable polymers as orthopedic devices.

The present invention relates to novel nonpolymeric compounds and compositions that form liquid, high viscosity materials suitable for the delivery of biologically active substances in a controlled fashion, and for use as medical or surgical devices. The materials can optionally be diluted with a solvent to form a material of lower viscosity, rendering the material easy to administer. This solvent may be water insoluble or water soluble, where the water soluble solvent rapidly diffuses or migrates away from the material in vivo, leaving a higher viscosity liquid material.

High viscosity liquid controlled delivery system and medical or surgical device

Processes for making microparticles, preferably containing an active agent, are provided. In a preferred embodiment, the process involves preparing (1) a dispersed phase containing an agent in a solution of polymer and a first solvent; (2) a continuous phase containing a surfactant, a second solvent that is totally or partially immiscible with the first solvent, and sufficient first solvent to saturate the continuous phase; and (3) an extraction phase that is a nonsolvent for the polymer, a solvent for the continuous phase components, and a solvent for the first solvent, wherein the first solvent has solubility in the extraction phase of between about 0,1 % and 25 % by weight. Then, the dispersed phase and the continuous phase are mixed to form an emulsion, and the emulsion is then briefly mixed with a suitable quantity of extraction phase to induce skin formation at the interface of the dispersed and continuous phases. Remaining solvent is removed by an evaporation process step. The emulsification and solvent removal steps are preferably conducted in a continuous process. The brief extraction step prior to evaporation minimizes the loss of active agent from the microparticles, and reduces the required volume of extraction phase as compared to other extraction-based processes. Alternate emulsification methods and solvent removal methods, such as incremental extraction, cryogenic extraction, or membrane separation, also are provided, and can be used in various combinations to make microparticles.

Emulsion-based processes for making microparticles

Dosage forms and drug delivery devices suitable for administration of pharmaceutical compounds and compositions, including the oral drug administration of compounds.

Oral drug delivery system

A coaxial implant has been developed using entirely biodegradable polymeric materials. As referred to herein, a coaxial implant is a device having a core containing drug, surrounded by a semi-permeable membrane that controls the rate of release from the core. The device is formed by extrusion, using a pre-milling and extruding step to maximize uniformity of drug dispersion within the polymeric material. In one embodiment, the polymer is processed to yield a semi-crystalline polymer, rather than an amorphous polymer. The core containing the drug and the polymer membrane(s) can be the same or different polymer. The polymer can be the same or different composition (i.e., both polycaprolactone, or both poly(lactide-co-glycolide) of different monomer ratios, or polycaprolactone outside of a core of poly(lactide)), of the same or different molecular weights, and of the same or different chemical structure (i.e., crystalline, semi-crystalline or amorphous). The core acts as a reservoir of drug, which partitions from the core polymer to form a saturated solution of at least 10% drug at the polymer membrane.

Arthur J. Tipton

Papers

Synthetic biodegradable polymers as orthopedic devices.

High viscosity liquid controlled delivery system and medical or surgical device

Emulsion-based processes for making microparticles

Oral drug delivery system

Zero-order prolonged release coaxial implants