Shin-Etsu Chemical Co., Ltd.

Hiroshi Umezawa

Naosuke Maruyama

Mitsuo Narita

Masaki Tabata

Atsushi Yoshida

Ikuo Fukui

Yuichi Nishiyama

Fumie Kusaki

Takafumi Hoshino

Akira Yamamoto

Tohru Kubota

Shigehiro Nagura

Mikio Endo

Sakae Obara

Fumie Tanno

Atsushi Hatayama

Satoshi Uchida

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a bucket conveyor type contactor to generate a contact mixture, and draining the contact mixture; a method for preparing a cellulose ether comprising use of the alkali cellulose thus prepared; and an apparatus for preparing alkali cellulose comprising a bucket conveyor contactor comprising at least one inlet port for introducing pulp and an alkali metal hydroxide solution at one end and at least one outlet port for discharging a contact mixture wherein the pulp and the alkali metal hydroxide solution can be moved from one end to the other end while bringing them into contact with each other to generate the contact mixture; and a drainer for separating a cake from the contact mixture discharged from the outlet port.

Methods for preparing alkali cellulose and cellulose ether

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, pulp and an excess alkali metal hydroxide solution are introduced continuously in a screw conveyor type contactor and brought into contact with each other in the screw conveyor type reactor. By changing at least one factor selected from the group consisting of a rotation speed of the screw conveyor, a screw pitch and a length of immersion zone, a ratio of an alkali to cellulose in the alkali cellulose obtained by draining is controlled. The alkali cellulose thus obtained is etherified into the corresponding cellulose ether.

The invention is an efficient method for preparing alkali cellulose having the low water content and a uniform alkali distribution therein. More specifically, the invention is a method for continuously preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution to generate a contact mixture and then draining the contact mixture by a centrifugal separator. The invention also includes a method for preparing cellulose ether comprising a step of etherifying the alkali cellulose.

Provided is a low-substituted hydroxypropylcellulose powder having high compressibility, good flowability and excellent disintegration. The powder has an average particle size of 10 to 100 &#x3bc;m and a specific surface area measured by BET method of at least 1.0 m/g.

Low-substituted hydroxypropylcellulose powder

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a rotary feeder type contactor to generate a contact mixture, and draining the contact mixture; and a method for preparing cellulose ether comprising use of the alkali cellulose thus prepared; an apparatus for preparing alkali cellulose, comprising a rotary feeder comprising a cyclic housing comprising an inlet port and an outlet port, a cyclic contact drum being circularly rotatable along the housing in the housing and comprising a plurality of filter cells arranged in a circumferential direction, and a filtrate-discharging tube being disposed in a diameter direction inside of the cyclic contact drum and collecting the filtrate which has passed the filter, and a drainer for draining a cake discharged from the contactor.

The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, the invention is a method for preparing alkali cellulose comprising steps of bringing pulp into continuous contact with an alkali metal hydroxide solution in a pipe type contactor to generate a contact mixture and draining the contact mixture; a method for preparing cellulose ether comprising use of the alkali cellulose; and an apparatus for preparing alkali cellulose, comprising a pipe type contactor having at least one inlet port at one end thereof for introducing pulp and an alkali metal hydroxide solution, and an outlet port at the other end for discharging a contact mixture, wherein the pulp and the alkali metal hydroxide solution are moved from one end to the other end while bringing them into contact with each other, and a drainer for separating a cake from the contact mixture discharged from the contactor.

Provided are a low-substituted hydroxypropylcellulose powder having high compressibility, good flowability and excellent disintegration, and a method for producing the same. More specifically, provided is a method for producing a low-substituted hydroxypropylcellulose powder having a molar substitution number per anhydrous glucose unit of 0.05 to 1.0, which is insoluble in water and swollenable by absorbing water, comprising the steps of: adding an aqueous sodium hydroxide solution to powdered pulp in such a manner that weight ratio of sodium hydroxide with respect to anhydrous cellulose is 0.1 to 0.3 so as to produce alkali cellulose; etherifying the obtained alkali cellulose to obtain a crude product; neutralizing the sodium hydroxide contained in the obtained crude reaction product; washing the resultant; drying; and pulverizing using by compaction-grinding.

Methods for producing a low-substituted hydroxypropylcellulose powder

Provided are a solid dosage form comprising a solid dispersion that allows a drug in the preparation to be rapidly dissolved without compromising the solubility of the solid dispersion, and a method for producing the same. More specifically, provided is a solid dosage form comprising a solid dispersion, the dispersion comprising: a poorly soluble drug, a water-soluble polymer and a disintegrant, wherein the disintegrant is low-substituted hydroxypropylcellulose having an average particle size of 10 to 100 &#x3bc;m and a specific surface area measured by BET method of at least 1.0 m/g. Moreover, provided is a method for producing a solid dosage form comprising a solid dispersion, the method comprising steps of: spraying a water-soluble polymer solution in which a poorly soluble drug has been dispersed or dissolved, on a powder of low-substituted hydroxypropylcellulose having an average particle size of 10 to 100 &#x3bc;m and a specific surface area measured by BET method of at least 1.0 m/g and serving as a disintegrant and granulating the resultant; and drying.

Solid dosage form comprising solid dispersion

Provided are a solid dosage form comprising an enteric solid dispersion that allows a drug in the preparation to be rapidly dissolved without compromising the solubility of the solid dispersion, and a method for producing the same. More specifically, provided is a solid dosage form comprising an enteric solid dispersion comprising a poorly soluble drug, an enteric polymer and a disintegrant, wherein the disintegrant is low-substituted hydroxypropylcellulose having an average particle size of 10 to 100 &#x3bc;m and a specific surface area measured by BET method of at least 1.0 m/g. Moreover, provided is a method for producing a solid dosage form comprising an enteric solid dispersion, the method comprising steps of: spraying an enteric polymer solution in which a poorly soluble drug has been dispersed or dissolved, on a powder of low-substituted hydroxypropylcellulose having an average particle size of 10 to 100 &#x3bc;m and a specific surface area measured by BET method of at least 1.0 m/g and serving as a disintegrant; and granulating the resultant; and drying.

Provided is a method for preparing alkali cellulose having alkali distributed uniformly therein. A uniform alkali distribution in the alkali cellulose makes it possible to prepare cellulose ether which has been substituted uniformly in an etherification reaction step. The resulting cellulose ether does not contain a floating water-insoluble portion which will otherwise appear owing to insufficient substitution. More specifically, provided are a method for preparing alkali cellulose, comprising simultaneously feeding pulp powder and an aqueous alkali solution to a high speed disperser to continuously bring them into contact with each other and a method for preparing cellulose ether, comprising reacting the resulting alkali cellulose with an etherifying agent.

Provided is an agent serving as a binder and a disintegrant for dry direct compression having a high binding property and fluidity. More specifically, provided are low-substituted hydroxypropyl cellulose having coiled fibers; an agent serving both as a binder and a disintegrant for dry direct compression and a solid preparation, each comprising the low-substituted hydroxypropyl cellulose; and a process for producing the low-substituted hydroxypropyl cellulose having coiled fibers.

Low-substituted hydroxypropyl cellulose and agent serving both as binder and disintegrant for dry direct compression

An object of the present invention is to provide a process for the production of low-substituted hydroxypropyl cellulose wherein, in the formation of low-substituted hydroxypropyl cellulose particles, a granular material obtained by granulating the reaction product is neutralized with an acid to form neutralization-precipitated particles of low-substituted hydroxypropyl cellulose which can reduce the treating time as compared with conventional processes and, moreover, permit its ash content to be easily decreased in a subsequent washing step. Specifically, the reaction product of an alkali cellulose with a hydroxypropylating agent is granulated, and the resulting granular material is neutralized with an acid.

Method for the formation of low-substituted hydroxypropyl cellulose particles

The present invention provides a low-substituted hydroxypropyl cellulose having a loose bulk density of not less than 0.40 g/mL and a tap bulk density of not less than 0.60 g/mL and a process for producing the same.

Low-substituted hydroxypropyl cellulose and process for producing same

Disclosed is a novel organosilicon-containing derivative of pullulan of which an organopolysiloxane moiety having a silethylene linkage is bonded to the glucose residue of pullulan through a urethane linkage. Different from conventional organopolysiloxane-modified pullulans, the inventive derivative is stable against attack of water and exhibits unique properties as a combination of the properties inherent in pullulan and in silicones. The organosilicon-containing pullulan of the invention can be easily prepared under mild reaction conditions by reacting an isocyanato group-containing organopolysiloxane with the glucosic hydroxy groups of pullulan.

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Joetsu, Japan

Hiroshi Umezawa