Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Liposomes
Reexamination Certificate
2002-11-14
2004-06-08
Guzo, David (Department: 1636)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Liposomes
C514S04400A, C536S023100
Reexamination Certificate
active
06746690
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to complex preparations which contain a complex of cationic carriers and nucleic acid polymers. This complex is sometimes called a lipoplex.
As used herein, the term “cationic carriers” refers to drug carriers having positive charges in water and effective for transferring drugs, especially transferring anionic drugs into cells. Cationic carriers have been recently studied as drug carriers for the transfer of genes and RNA such as poly I:C into cells.
“Nucleic acid polymers” refer to naturally occurring or synthesized or semi-synthesized polynucleotides (DNA, RNA), and to naturally occurring or synthesized or semi-synthesized oligonucleotides.
BACKGROUND OF THE INVENTION
Nucleic-acid-containing complex preparations that contain a complex of a cationic carrier and a polyanionic double strand nucleic acid polymer having a double helical structure can be produced by only mixing the cationic carrier and the double strand nucleic acid polymer.
However, in the nucleic-acid-containing complex preparations produced by this method, the resulting particles are generally coarse with diameters ranging from a few micrometers to several hundred micrometers, and are heterogeneous. These nucleic acid containing nucleic-acid-containing complex preparations, with their coarse and heterogeneous particles, make it difficult to obtain data for homogeneous preparations in studies on intracellular transfers and signal expressions of nucleic acid polymers. The most critical problems concerning particle coarseness are that sterilization is difficult on an industrial scale and that potential embolizations and the like may occur in capillaries and injection needles or capillaries during intravenous administrations despite the pharmaceuticals being prepared on assumption that they are safe for administration to humans. These problems are difficult problems to solve not only by methods in which the complex preparations are produced by mixing as described above, but also in production methods that apply a dispersion process using appropriate emulsifying dispersion devices.
Another problem is aggregation of the particles resulting from freeze-drying to stabilize the complex preparations.
Nucleic acid polymers in the complex preparations are preferably highly concentrated in order to decrease the dosages and reduce the burden to patients and medical workers at the time of administration as well as in order to achieve productive efficacy of the complex preparations. However, by conventional processes when the total amount of nucleic acid polymers is 0.1 mg/mL or more, especially 0.5 mg/mL or more, aggregation occurs during the production process methods which yields large precipitates of suspended solids, easily grossly confirmed with the naked eye. These precipitates are incapable of being dispersed sufficiently by any dispersion process.
Conventionally, double strand RNA having double helical structures, such as poly I:C, have been commonly employed as genes and RNA from the view of their physiological features and stability for various nucleases. For example, it has been known that sufficient pharmacological efficacy is not obtained by the separate administration of poly I and poly C instead of poly I:C, which has physiological activities such as a strong induction potency of interferon and immunopotentiating actions (Archives of Virology, 51, 199-215 (1976)). Thus, double strands having double helical strand structures, such as poly I:C, are believed to be essential for genes and RNA.
For nucleic-acid-containing complex preparations which contain a complex of cationic carriers and nucleic acid polymers, the necessity for double helical structures has not been discussed at all, and double strand DNA and double strand RNA having the double helical structure have been commonly employed in production procedures of the complex preparations.
The present applicants have applied for the patent for the nucleic-acid-containing complex preparations as nuclease activating preparations in cancer cells since nucleic-acid-containing complex preparations consisting of cationic carriers and double strand RNA such as poly I:C activate nucleases in cancer cells that are effective for the treatment of cancers, and have already applied for the patent for the nucleic-acid-containing complex preparations as therapeutic agents for hepatitis since they induce effective amounts of interferons specifically for the liver and spleen for a long time (PCT/JP98/04695, PCT/JP99/01438).
DISCLOSURE OF THE INVENTION
The objective of the present invention is, in particular, to provide a production method for homogenous nucleic acid containing complex preparations with good quality characterized in that the preparations are capable of being preformed with sterilized by so-called sterilizing filtration and do not contain coarse particles of diameter greater than or equal to 7 &mgr;m, which are considered to be unsafe for administration to humans.
The present inventors were the first to discover that the above problems can be solved without having an effect on their pharmacological activities. The invention involves preparing nucleic acid polymers with a single strand that have been separated from a double helical structure or initially formed without a double strand structure, but without using double strand DNA or and double strand RNA usually having double helical structures, in a production process of nucleic-acid-containing complex preparations which contain a cationic carrier and nucleic acid polymers.
Therefore, the present invention can include a production method of the nucleic-acid-containing complex preparations characterized in that two single strand nucleic acid polymers which can at least partly form double strands are separately added, in a single strand form, to a cationic carrier or source materials for a cationic carrier, and the two single strand nucleic acid polymers are dispersed during the production process of the said nucleic-acid-containing complex preparation that contains a cationic carrier and nucleic acid polymers (referred to as “nucleic-acid-containing complex preparations” hereinafter).
The present invention will be described in detail below.
“Cationic carriers” applicable to the present invention can include drug carriers disclosed in PCT WO94/19314 such as 2-o-(2-diethylaminoethyl) carbamoyl-1,3-o-dioleoyl glycerol (referred to as “compound A” hereinafter) represented as the following structural formula [□], drug carriers formed by phospholipids as essential components, and drug carriers such as polylysine, in addition to commercially available drug carriers such as lipofectin (brand name), lipofectoamine (brand name), lipofectoace (brand name), and DMRIE-C (brand name).
“Two single strand nucleic acid polymers” applicable to the present invention can include, for example, two single strand DNA and RNA polymers which construct natural genes or artificially modified genes (e.g. plasmid), and two single strand RNA polymers such as poly I and poly C, poly I and poly C12U, poly I with partially chemical modification (e.g. poly (7-deazainosinic acid)) and poly C, poly I and poly C with partially chemical modification (e.g. poly(bromocytidylic acid), poly(thiocytidylic acid)). The invention is not limited to these examples if the nucleic-acid polymers are two single strand nucleic acid polymers which can at least partly form double strands. The present invention can be applied to two single strand RNA such as poly I and poly C which construct poly I:C with physiological activities such as a strong induction potency of interferons. As used herein, “poly I”, “poly C”, “poly A”, “poly U”, and “poly C12U” mean polyinosinic acid, polycytidylic acid, polyadenylic acid, polyuridylic acid, and copolymer of cytidylic acid and uridylic acid where one uridylic acid is substituted for about every 12 cytidylic acids, respectively.
“Can at least partly form double strands” refers to those polynucleotides which exist as two single stranded complementary nucleic
Hirabayashi Kazuko
Seki Junzo
Sugihara Katsuhiro
Greenberg & Traurig, LLP
Guzo David
Nippon Shinyaku Co. Ltd.
Rzucidlo Eugene C.
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