Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Matrices
Reexamination Certificate
2000-02-16
2003-12-30
Webman, Edward J. (Department: 1617)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Matrices
C424S487000
Reexamination Certificate
active
06669958
ABSTRACT:
TECHNICAL FIELD
The field of this invention is chemotherapeutic pharmaceutical formulations.
BACKGROUND OF THE INVENTION
In the treatment of cellular proliferative diseases characterized by the abnormal proliferation of cells, such as cancer, psoriasis and hyperplasia, a variety of diverse methods have been developed. These methods include surgery, radiation therapy and immunotherapy. Of increasing interest in the treatment of cancer and other cellular proliferative diseases is the use of chemotherapeutic agents, either alone or in combination with other known treatment methods. In chemotherapy, the chemotherapeutic agents may be administered either systemically or regionally. While systemic administration of a chemotherapeutic agent has proved effective in the treatment of some cancers, there are consequences with this mode of chemotherapeutic agent delivery. For example, in systemic administration, normal tissue quite distal to the target tissue is exposed to the chemotherapeutic agent along with the diseased tissue. Depending on the toxicity of the particular chemotherapeutic agent employed, the consequences of systemic delivery may outweigh the therapeutic benefit of the agent.
Furthermore, some chemotherapeutic agents are poorly water soluble. Thus, to be administered intravenously (one particular mode of systemic administration) steps must be taken to compensate for this poor water solubility, e.g. dilution in large volumes of an aqueous vehicle, use of surfactants, and the like. However, dilution of the drug in this manner can limit the dosage level of the drug that can be achieved in the host blood stream or in proliferative disease tissue. Other factors which can adversely affect the dosage level of drug which is achieved in the blood stream include metabolism, chemical instability and in situ precipitation of the drug. Other problems include adverse effects of the surfactants, etc.
In view of these considerations, there is increasing interest in methods of regional and local administration of chemotherapeutic agents. With these routes of administration, when choosing a suitable formulation consideration must be given to several factors. One factor to be considered is how readily the agent will diffuse from the vehicle into the region of administration or into other regions of the host, thereby causing toxic side effects. Other factors to be considered include the stability and bioavailability of the agent in the particular delivery vehicle formulation.
Thus, there is a continued interest in the identification of new delivery vehicle formulations suitable for the regional and local administration of anticellular proliferative agents to hosts suffering from cellular proliferative diseases. Such delivery vehicles should ideally provide for at least one of enhanced agent efficacy, reduced systemic toxicity, agent stability, and bioavailability at the site of administration.
Relevant Literature
U.S. Patents describing the intratumoral delivery of antineoplastic agents include U.S. Pat. Nos. 5,051,257 and RE 33,375. RE 33,375 describes the use of an aqueous proteinaceous matrix, e.g. collagen matrix, as a chemotherapeutic delivery vehicle. U.S. Pat. No. 4,938,763 reports the preparation of biodegradable implants prepared from thermoplastic systems of non-reactive polymers dissolved in biocompatible solvents.
Intratumoral injections of cisplatin in a sesame oil-water emulsion delivery vehicle is described in Théon et al., J.A.V.M.A. (1993) 202: 261-267. Regional chemotherapy of Wilms' tumors in rats is described in Cancer Chemother. Pharmacol. (1989) 23:31-36.
Non-aqueous, intraperitoneal drug delivery vehicles are described in Ansel, Introduction to Pharmaceutical Dosage Forms (Lea & Freiberger, Philadelphia) (1976) p. 246; Hoover, Dispensing of Medication (Mack Publishing Co.) (1976); and Targo & King, Sterile Dosage Forms, Their Preparation and Clinical Application (Lea & Freiberger, Philadelphia) (1987) pp. 17-24.
A review of pharmaceutical dosage formulations and methods of their preparation is provided in Ansel et al., Pharmaceutical Dosage Forms and Drug Delivery Systems (1995).
SUMMARY OF THE INVENTION
Methods and compositions are provided for the treatment of a host with a cellular proliferative disease, wherein at least one antiproliferative agent is administered to the host in a substantially non-aqueous, gel delivery vehicle capable of enhancing the efficiency of the agent. The vehicles employed in the subject invention are pharmaceutically acceptable and comprise at least one polar organic solvent in combination with at least one thickening agent. The subject methods and compositions find use in the treatment of a variety of cellular proliferative diseases, where the subject methods result in at least enhanced efficacy of the administered agent.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
Methods and compositions are provided for the treatment of a host suffering from a cellular proliferative disease. In the subject methods, substantially non-aqueous gel delivery vehicles are employed for the regional or local administration of one or more antiproliferative agents. The substantially non-aqueous gel delivery vehicles are pharmaceutically acceptable and comprise at least one polar organic solvent in combination with at least one thickening agent. The subject methods and compositions find use in the treatment of a variety of cellular proliferative diseases, and provide for at least enhanced efficacy of the delivered agent.
Critical to the subject methods is the use of a substantially non-aqueous gel vehicle for delivery of the antiproliferative agent. The vehicle formulations are pharmaceutically acceptable when used in accordance with the subject methods. By “substantially non-aqueous” is meant that these vehicles contain no more than about 30% water. More preferably, they will comprise less than about 15% (v/v) water, usually less than about 10% (v/v) water, more usually between 5% and 10% (v/v) water.
The substantially non-aqueous delivery vehicles employed in the subject methods are capable of acting as a depot for one or more cellular antiproliferative agents. As the subject delivery vehicles act as a depot for the agent(s), the dispersion of the agent(s) from the vehicle and site of administration will be retarded or slowed as compared to the dispersion of the agent when delivered in a saline solution.
The delivery vehicles have gel-like consistencies but are sufficiently flowable so as to be capable of local or regional administration through a catheter, needle, or other comparable means of local or regional administration. Generally, the subject vehicles will have a viscosity ranging f 50,000 mPa·sec, usually from about 1,000 to 40,000 mPa·sec, and more usually from about 2,000 to 30,000 mPa·sec, all at a shear rate of 10 sec
−1
.
The gel vehicles of the subject invention will comprise at least one polar organic solvent, where two or more different polar organic solvents may be present in the formulation, usually not more than four polar organic solvents, more usually not more than three polar organic solvents. The organic solvent component will make up the majority of the vehicle formulation and provide for a continuous fluid phase, with the organic solvent component ranging from about 65 to 98% (v/v) of the formulation, usually from about 80 to 98% (v/v) of the formulation, more usually from about 90 to 99.5% (v/v) of the vehicle formulation, most preferably from about 75 or 80% to 99.5% (v/v).
Polar organic solvents that find use in the subject invention are not excessively toxic at the dosage levels at which, as well as the manner in which, they are administered, where “not excessively toxic” intends that the solvents in the subject vehicles do not result in unacceptable systemic toxicity when administered in accordance with the subject invention. Polar organic solvents of interest will be at least somewhat water soluble, having a Hildebrand Solubility Parameter of at least about 7.5 or 8 (cal/cc)
½
, usually at least about 9, more usual
Jones Richard E.
Trager George
BioMedicines, Inc.
Dorsey & Whitney LLP
Webman Edward J.
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