Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Patent
1994-12-28
1997-11-18
Kight, John
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
536 21, 536112, 536115, 536119, 5361231, 53612312, 530300, 530322, C08B 3702, C08B 3708, C07H 1302, C07K 500
Patent
active
056889313
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drug carrier comprising a novel polysaccharide and a drug complex. More particularly, the present invention relates to a drug carrier comprising a polysaccharide combined with a peptide, and a drug complex comprising the drug carrier and a drug introduced into the drug carrier.
2. Related Art
An attempt to use a water-soluble polymer as a carrier for a drug has hitherto been made especially in the field of a pharmaceutical preparation, and many related techniques for this purpose have been proposed in the art. In many of these proposals, use is made of cellulose derivatives such as carboxymethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methylcellulose, and the dispersion and sustained release of the drug are intended by virtue of physical and chemical properties of these substances per se. While in these attempts the drug is mixed homogeneously with the cellulose derivatives as a carrier, the drug is not chemically bonded to the carrier.
In the so-called "drug delivery technique" wherein a drug is delivered by a necessary amount at a desired time to a target organ, when a water-soluble polymer is utilized as a carrier for a drug, the drug and the carrier should be chemically bonded to each other rather than being combined by mere mixing. There have been reported such attempts for polysaccharides in the following references 1), 2) and 3). Reference 1) discloses the technique to bond a carboxylated dextran with mitomycin C. Reference 2) discloses the technique to bond mannan with mitomycin C. Moreover, reference 3) discloses the technique to bond mannan with bleomycin. 2155, 2154.
It is, however, the present situation that the drug delivery technique by means of chemical bond between a drug and a carrier has not sufficiently been developed for use yet.
SUMMARY OF THE INVENTION
The present inventors have examined the possibility for use of polysaccharides as a drug carrier. As a result, it has been found that a polysaccharide derivative in which a peptide chain is introduced into a polysaccharide exhibits an excellent property as a drug carrier.
Therefore, an object of the present invention is to provide a novel drug carrier on which a drug is conjugated through chemical bond and which is capable of drug delivery, and a drug complex of the drug carrier and a drug.
Thus, the present invention provides a polysaccharide derivative comprising a polysaccharide having a carboxyl group into which a peptide chain is introduced at a part or all of the carboxyl groups of the polysaccharide, the peptide chain comprising 1-8 amino acids where the amino acids may be the same or different, wherein a part or all of the amino groups in the peptide chain which are not involved in the linkage with the carboxyl groups of the polysaccharide or a part or all of the carboxyl groups in the peptide chain may form an acid amide linkage or an ester linkage with a carboxyl group, an amino group or a hydroxyl group of a third compound having the carboxyl group, the amino group or the hydroxyl group, and a salt thereof.
The polysaccharide derivative according to the present invention has a property of highly accumulating at a tumor. Therefore, the compound can efficiently deliver to a tumor a drug having a side effect or limited sustainment of its efficacy against tumor.
In addition, the polysaccharide derivative according to the present invention has a property of gradually distributing a drug in a body, so that the drug concentration can be highly retained in blood for a long period.
Accordingly, the present invention provides a drug carrier and a drug complex comprising the polysaccharide derivative.
In the present invention, the term "polysaccharide containing a carboxyl group" means, a polysaccharide which naturally contains a carboxyl group in its structure such as hyaluronic acid, pectic acid, alginic acid, chondroitin or heparin. In addition, the term also means a polysaccharide naturally containing no carboxyl groups such as
REFERENCES:
patent: 5463022 (1995-10-01), Inoue et al.
Tokura et al., "Carboxymethyl-Chitin as a Drug Carrier of Substained Release", Carbohydrate Polymers 13 (1990), 273-281.
Carbohydrate Rearch, vol. 245, issued 1993, Dean et al, "Synthesis of Multivalent .beta.-Lactosyl Clusters as Potential Tumor Metastasis Inhibitors", pp. 175-192.
Hamana Hiroshi
Inoue Kazuhiro
Kajiki Masahiro
Kashima Nobukazu
Nogusa Hideo
Drug Delivery System Institute, Ltd.
Kight John
White Everett
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