Delayed drug-releasing microspheres
AssigneeShiseido Company, Ltd.
InventorsTakashi Yoshimoto, Masahiro Tajima, Kazuo Watabe
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Abstract
Microspheres prepared by emulsifying an aqueous phase containing a drug and an oil phase containing a biodegradable polymer to form a W/O emulsion, and then mixing and agitating this emulsion with another aqueous phase constituting a continuous phase to form a W/O/W emulsion. These microspheres can release a major portion of the drug after a predetermined period of time has elapsed after their administration to the patient, and are especially suitable for intracerebral implantation.
Claims11
Delayed drug-releasing microspheres derived from a W/O/W emulsion which can be prepared by a process comprising
- (A) the step of emulsifying an aqueous solution containing a drug and a water-immiscible solution containing a biodegradable .alpha.-hydroxycarboxylic acid polymer to form a W/O emulsion, and
- (B) the step of emulsifying the emulsion resulting from step (A) in an aqueous solution to form a W/O/W emulsion,
- wherein said drug is a peptide having the effect of suppressing cerebral vasospasm, and wherein
- (i) in an in vivo drug-releasing test, said microspheres release more than 75% of the drug into body fluids when from 2 to 10 days have passed after the microspheres make contact with the fluids, and
- (ii) in an in vitro drug-releasing test, said microspheres release less than 10% of the drug into simulated body fluids when 5 days have passed after the microspheres make contact with the fluids.
A method for the prophylaxis or treatment of human cerebral vasospasm by administering a pharmaceutical preparation to a patient whose cerebral aneurysm is expected to rupture or has ruptured, wherein the pharmaceutical preparation comprises delayed drug-releasing microspheres prepared by a process comprising
- (A) the step of emulsifying an aqueous solution containing a drug and a water-immiscible solution containing a biodegradable .alpha.-hydroxycarboxylic acid polymer to form a W/O emulsion, and
- (B) the step of emulsifying the emulsion resulting from step (A) in an aqueous solution to form a W/O/W emulsion,
- wherein said drug is a peptide having the effect of suppressing cerebral vasospasm, and wherein
- (i) in an in vivo drug-releasing test, said microspheres release more than 75% of the drug into body fluids when from 2 to 10 days have passed after the microspheres make contact with the fluids, and
- (ii) in an in vitro drug-releasing test, said microspheres release less than 10% of the drug into simulated body fluids when 5 days have passed after the microspheres make contact with the fluids and
- wherein said administering is conducted by the implantation of the pharmaceutical preparation in the brain.
Dependencies are inferred from the claim text.