Small particle formation and encapsulation

Patent 4606940 Issued on August 19, 1986. Estimated Expiration Date:

December 21, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3037849

3043782

3242051

3533958

3574132

3725014

Process for preparing microcapsules in a liquid vehicle Patent #: 4460563
Issued on: 07/17/1984
Inventor: Calanchi

Inventors

Assignee

The Ohio State University Research Foundation

Application

No. 06/684457 filed on 12/21/1984

US Classes:

427/213.32, Hardening424/492, Gelatin424/494, Cellulose derivatives424/495, Ethyl cellulose427/213.3, Solid encapsulation process utilizing an emulsion or dispersion to form a solid-walled microcapsule (includes liposome)427/213.33, Using crosslinking agent427/213.35, Solid-walled microcapsule formed from gelatin or derivative thereof427/213.36, Solid-walled microcapsule formed from preformed synthetic polymer514/962CAPSULE (E.G., GELATIN, ETC.)

Examiners

Primary: Lovering, Richard D.

International Classes

A61K 9/16 (20060101)
A61K 9/50 (20060101)
B01J 13/06 (20060101)
B01J 13/10 (20060101)

Abstract

Process for the formation and the simultaneous encapsulation of small particles of a compound from solution which comprises:(a) dissolving said compound in a first solvent;(b) preparing a solution of encapsulating material and an electrolyte in a second solvent which is miscible with the first solvent and in which the compound to be encapsulated is more or less insoluble, in an amount which is effective, but present in an amount just insufficient to cause coacervation of the encapsulating material without interacting with it;(c) mixing the solutions from step (a) and (b) while stirring to cause the concurrent precipitation of the compound as small particles and formation of a coacervate of the encapsulating material; and(d) gelling the encapsulating material.

Other References

The Merck Index, Tenth Edition, Published by Merck & Co., Inc., Rahway, N.J., 1983, pp. 202 and 569
O. Siddiqui et al., "Physical Factors Affecting Microencapsulation by Simple Coacervation of Gelatin", J. Pharm. Pharmacol., 35, 70-73 (1983)
Chih-Ming James Chen, "Production of Drugs in Small Particle Form", Dissertation, The Ohio State University, 1981
G. I. Mukhayer et al., "Interactions between Large Organic Ions of Opposite Charge: VI. Coacervation in Mixtures of Sodium Dodecyl Sulfate and Benzyltriphenylphosphonium Chloride", J. Coll. and Int. Sci., 66, 110-117 (1978)
J. R. Nixon et al., "The In Vitro Evaluation of Gelatin Coacervate Microcapsules", J. Pharm. Pharmac., 23, 147S-155S (1971)
P. L. Madan, "Clofibrate Microcapsules: III. Mechanism of Release", Drug Development and Industrial Pharmacy, 6, 629-644 (1980)
H. P. Merckle and P. Speiser, "Preparation and In Vitro Evaluation of Cellulose Acetate Phthalate Coacervate Microcapsules", J. Pharm. Sci., 62, 1444-1448 (1973)
A. S. Michaels et al., "The Effect of Surface Active Agents on Crystal Growth Rate and Crystal Habit", J. Phys. Chem., 64, 13-19 (1960)
V. K. LaMer, et al., "Theory Production and Mechanism of Formation of Monodispersed Hydrosols", J. Amer. Chem. Soc., 72, 4847-4854 (1950)
P. L. Madan, "Microencapsulation: I. Phase Separation or Coacervation", Drug Development and Industrial Pharmacy, 4, 95-116 (1978)
P. L. Madan, "Microencapsulation: II. Interfacial Reactions", Drug Development and Industrial Pharmacy, 4, 289-304 (1978)
McCutcheon's Detergents & Emulsifiers, 1973 No. American Edition, Publ. by McCutcheon's Division, Allured Publishing Corp., Ridgewood, NJ, 1973, p. 173
Poorly Water-Soluble Drugs by Crystallization in Aqueous Surfactant Solutions I: Sulfathiazole, Prednisone, and Chloramphenicol", J. Pharm. Sci., 65, 1702-1704 (1976)
K. Ikeda, et al., "Micellar Interaction of Tetracycline Antibiotics", Chem. Pharm. Bull., 25, 1067-1072 (1977)