Process for microencapsulating cells

• US 5,648,099 A
• Filed: 02/03/1994
• Issued: 07/15/1997
• Est. Priority Date: 05/11/1992
• Status: Expired due to Fees

• Current Assignee: University of Florida (State University System of Florida)
• Original Assignee: University of Florida (State University System of Florida)
• Inventors: Vaghefi, Farid, Batich, Chris
• Primary Examiner(s): Lovering, Richard D.
• Application Number:
  US08/192,212
• Time in Patent Office: 1,258 Days
• Field of Search: 264/4.32, 264/4.33, 264/4.6, 424/439, 424/488, 424/494, 424/497, 514/866, 514/963, 514/965, 435/179
• US Class Current: 424/497
• CPC Class Codes: A61K 35/74 Bacteria therapeutic use of a bacterial protein A61K38/00
• CPC Class Codes: A61K 9/1652 Polysaccharides, e.g. alginate, cellulose derivatives; Cyclodextrin homeopathic globules A61K9/1623
• CPC Class Codes: A61K 9/5026 obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• CPC Class Codes: A61K 9/5031 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poly(lactide-co-glycolide)
• CPC Class Codes: A61K 9/5073 having two or more different coatings optionally including drug-containing subcoatings
• CPC Class Codes: C12N 11/04 entrapped within the carrier, e.g. gel or hollow fibres

Abstract

Oxalate-degrading enzymes and bacteria were encapsulated for both enteric and intraperitoneal administration. We have shown that via alginate microencapsulation of Oxalobacter formigenes, enzymatic activity was retained for several months. A new process was developed which strengthened the alginate microcapsules and their tolerance to citrate treatment. Much smaller (30-50 μm) alginate microcapsules were made for injection as means of implantation. For oral administration, multi-encapsulated microspheres of cellulose acetate phthalate in poly-2-vinylpyridine (pKa=3.5) were prepared to protect the enzymes from gastric juices.

Claims

1. A method for making a microcapsule for administering an active ingredient orally as part of a composition with a high moisture content such that the pH of said composition is about 6.0 to about 8.0;

said method comprising a first step of encapsulating said active ingredient in cellulose acetate phthalate and a second step of coating said cellulose acetate phthalate with a layer of polyvinylpyridine to produce a doubly coated polyvinylpyridine-cellulose acetate phthalate-encapsulated active ingredient.

2. The method, according to claim 1, wherein said second step comprises treating said cellulose acetate phthalate-encapsulated active ingredient with polyvinylpyridine dissolved in methylene chloride and evaporating the methylene chloride.

3. The method, according to claim 2, wherein Airvol 205 is used as a surfactant.

4. A method for administering to a human or animal an active ingredient for adsorption in the intestine of said human or animal, said method comprising administering said active ingredient in a food substance having a pH of about 6.0 to about 8.0 wherein said active ingredient is encapsulated in a first layer which is insoluble at pHs less than 3.0 but soluble in pHs from about 6.0 to about 8.0;

said active ingredient being encapsulated in a second layer which surrounds said first layer, wherein said second layer is insoluble in pHs from about 6.0 to about 8.0, wherein said first layer comprises cellulose acetate phthalate and said second layer comprises polyvinylpyridine.