Other

Biopharm Solutions Inc.

Weien Yuan

Tuo Jin

Fei Wu

Zhenhua Hu

A new microsphere formulation (composition) for controlled- or sustained-release delivery of therapeutic ingredient(s), mainly peptides and proteins not over 10K in molecular weight, comprises at least a therapeutic ingredient, a helping agent (such as PH sensitive agent whose solubility is a function of pH) and a biodegradable polymer. The therapeutic ingredient(s) and the helping agent are in the form of fine particles, less than 1O um in diameter, encapsulated in the polymer which forms the microsphere matrix. A method for preparing the composition comprises a step of in-situ precipitating the therapeutic ingredient(s) and the helping agent to the fine particles and successive steps for forming the microspheres. Such a microsphere formulation offers a well-controlled release profile for prolonged period and encapsulation efficiency over 95%.

Microspheres for controlled- or sustained-release delivery of therapeutics

A method of preparing polysaccharide glassy microparticles which are less than 10 &#x3bc;um in diameter and contain structurally delicate agents, such as proteins, peptides, gene materials, vaccines, antibodies, viruses and liposomes using low-temperature aqueous-aqueous emulsification (free of polyelectrolytes) and freezing-induced phase separation. When delicate agents are added to a polysaccharide-PEG two phase system followed by homogenization (or other shear adding process), the agents partition into the polysaccharide dispersed phase preferentially. These processes help to avoid aggregation of proteins caused by interaction with charged polyelectrolytes used for stabilizing the polysaccharide dispersed phase in our previously reported aqueous-aqueous emulsion. When this system is frozen and lyophilized, glassy particles less than 10 &#x3bc;m in diameter containing delicate agents can be formed. These fine polysaccharide particles protect proteins within their hydrophilic glassy matrix, and can therefore be easily suspended in hydrophobic polymer solutions and formulated to various forms of sustained release devices such microsphere, sheets, fibers, coating layers, and scaffolds. The particles can also be dispersed in hydrophilic gels to improve releasing kinetics and to deliver vaccines and antibodies for immune therapy.

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Shanghai, China

Weien Yuan