DE2911558A1 - Liq. dispensing device - contains hydrophilic, water-insol. water-swellable polymer layer between compressible container and rigid casing - Google Patents

Abstract

Liq. dispensing device comprises a rigid outer casing allowing the passage of water, a compressible container impermeable to the liq. to be dispensed with water and provided with an outlet for discharging liq. and, between casing and container, a layer allowing water to be drawn into the device, to exert a pressure on the compressible container. Novelty consists in using a layer contg. a hydrophilic, water-insoluble polymer, capable of swelling in water. The layer can be a 2-layer laminate contg. one layer of water-insoluble polymer and another layer of wate-absorbing non-swellable material. The device is used for discharging a therapeutic fluid into a human or animal body, e.g. by implanting in a body cavity. Water penetrates into the rigid outer casing and is absorbed by a layer, causes swelling of the layer and presses against the container whereby medicinal liq. is squeezed out.

Description

Title: Dispenser

for liquids B e 5 r e i n g e The Invention relates to a device for dispensing liquids such as drug solutions to a aquatic environment and includes an outer shell that is rigid and the passage allowed by water. A collapsing under pressure, impermeable to liquids, water-impermeable container inside the envelope containing the liquid and has an outlet opening for dispensing the liquid, and a layer made of a hydrophilic, water-insoluble swellable polymer between the shell and the container, which in use adsorbs water from the environment, thereby swells and exerts pressure on the container and thereby the liquid through the outlet opening pushes out of the container.

The invention is a modification of the osmotically effective delivery device, according to DE-OS 26 44 267.

The dispensing device described there as the '51ini pump' is that according to the invention most similar. The mini-pump is an osmosis-effective dispensing device, the size of which makes them particularly suitable for administering drugs Animals and people. The basic components are an internal one that collapses under pressure (flexible) bag or container containing the medicine, one in between lying layer of an osmotically active soluble or dissolved agent, such as an inorganic salt that encloses the pouch and an outer dimensionally stable Membrane or shell, which is permeable to water and which is made up of both the layer the osmotically active solute as well as the pouch and a Scoring or dispensing opening which is in communication with the interior of the bag.

During the excitation, the bag is placed over the filling resp.

Dispensing orifice is filled and placed in a watery environment, such as a body cavity or in body tissue. Water is osmotic from the environment through the active substance through the membrane into the space between the inner bag and the membrane sucked. Since the bag collapses under pressure and the membrane is rigid, The sucked in water compresses the inner bag, allowing medicament through the filling or dispensing opening is pushed out.

The dispensing device according to the invention works in contrast to that not indicated above by osmosis. Instead, the drug is due a swelling reaction given between the inner bag and the outer membrane takes place.

The present invention therefore relates to a dispenser for Liquids comprising a dimensionally stable outer shell that allows the passage of Water allowed, a compressible, liquid impermeable, for water impermeable container in the envelope of the liquid to be dispensed contains, and comprises an outlet opening for dispensing the liquid, as well as a Means between the envelope and the container which causes water to enter the dispenser is sucked, which creates a pressure on the inner container and that is characterized in that the agent is a hydrophilic, water-swellable, water-insoluble one Polymer.

The invention is explained in more detail by the accompanying drawings. 1 is an enlarged view of a dispensing device according to the invention.

FIG. 2 shows a section through the dispensing device of FIG of lines 2a and 2b and FIG. g shows a section through part of the dispensing device of Figure 1 along 3-3.

The dispenser illustrated in the drawings becomes general referred to as 10. The device 10 consists of: an outer, tubular sheath 11 which is open at one end 15 and closed at the other end 16; One cylindrical container 13, which is located within the shell 11 and a filling or dispensing opening 14, which is located at the open end 15 of the casing 11, and a layer 12 made of a hydrophilic, water-swellable but insoluble one Polymer between the inside of the shell or the jacket 11 and the outside of the Container 13.

The shell 11 allows due to its structure and / or composition the penetration of water from the environment into layer 12. For example, can they from an impermeable Material that some or has multiple openings or pores that allow the water to pass through the layer 12 or made of a water-permeable material # L. Such materials are known. The shell 11 must be sufficiently rigid, again by virtue of its structure and / or composition in order to achieve a significant expansion of the layer 12 outward to prevent during application.

The container 13 consists of a material that is essentially for the liquid to be dispensed and is impermeable to water. He must be in response collapse or be compressible under pressure exerted on it.

It is typically made of an elastomeric polymer such as cyclized Rubber, silicone rubber, synthetic isoprene rubber, butadiene rubber, copolymer styrene-butadiene-rubber, nitrile rubber, chloroprene rubber, Ethylene-propylene rubber and butyl rubber.

The layer 12 must be able to absorb and swell water, to increase their volume, typically 5 to 50 times. she must therefore have a swellable structure and be essentially insoluble in water be. Desirably, layer 12 is able to swell to a volume that is equal to or greater than the filling volume of the container 13, creating a complete Emptying of the liquid from the container 13 is ensured. examples for Hydrophilic polymers which are swellable in water and which are used to produce the layer 12 are, inter alia, poly (hydroxyalkyl methacrylates); Poly (acrylamide); Poly (methacrylamide) and derivatives; Poly (N-yynyl-2-pyrrolidone); anionic and cationic Hydrogels; Poly (electrolyte) - Complexes; crosslinked protein polymers; Poly (vinyl alcohol) with a small amount of acetate and cross-linked / ## ytoxal, Formaldehzrd or glutaraldehyde; Poly (oxyethylene) crosslinked by radiation; Poly (saccharide); Methyl cellulose cross-linked with dialdehyde; a mixture of agar and sodium carboxymethyl cellulose and swellable starch.

In order to increase the ability of layer 12 to soak up or absorb water, To increase, it can be formed as a laminate of 2 layers, one of which consists of the above-described hydrophilic polymer which is swellable in water and the other made of a water-absorbing, non-swellable material such as fibrous or porous materials of animal or vegetable origin such as wool, cotton, Straw, EShs, paper and sponge. Synthetic materials similar in their effect can also be used to produce the water-absorbing, non-swellable layer can be applied.

The device 10 can be used as follows: the container 13 is filled through the opening 14 with the liquid to be dispensed and into the desired water-containing environment introduced. For example, the container 13, if the device is intended to deliver drugs to humans or animals, filled with the pure drug if this is liquid or a flowable one Solution or suspension of the drug and then to the desired site on the body brought, e.g. by implantation or placement in a body cavity. If the device is in such an environment, water penetrates through the envelope 11 and is absorbed by the layer 12.

The absorbed water causes the layer 12 to swell and since the shell 11 is essentially rigid, a pressure is exerted on by the swelling exerted the exterior of the container 13, whereby it is compressed. Through this will the liquid is discharged from the container 13 via the opening 14. The rate of release of the liquid from the device 10 is thus determined by the speed and the extent to which layer 12 swells.

The invention is illustrated by the following non-limiting examples explained in more detail. Unless otherwise stated, parts and percentages are respectively Parts by weight and S 'by weight are to be understood.

Example 1 The first step was made from an elastomeric styrene-butadiene copolymer a cylindrical container was produced by injection molding at 1800C and 75.5 to 82.3 bar with a length of 2.33 cm, an inner diameter of 3.81 mm and an outer diameter 4.67 mm. Then a core was put into the container and this arrangement given into a hollow mold consisting of two parts. Then became a mixture from 30 parts of ethylene glycol monomethacrylate containing 0.12 parts of ethylene glycol dimethacrylate and 10 parts of a 0.13 show aqueous solution of sodium disulfate added to the mold in aqueous ethanol. The mixture was polymerized at 30 ° C and after 30 minutes after reaching room temperature, the mold is removed.

Then a 15 goat solution of cellulose acetate in acetone (Acetyl content 39.8 O / o) and those held on the core with hydrogel the coated container is immersed in the solution twenty times for one minute each time, drying took place for 15 minutes in between. After this dip, the dispensers became Dried at 600c for 15 days. This method gives a thickness of 0.65 mm Layer of cellulose acetate on the hydrogel layer.

Example 2 The procedure of Example 1 was repeated with the Exception that the form initially with an agent that is a cross-linked swellable hydrophilic polymer forms, consisting of 30 parts of hydroxyethyl methacrylate, 0.1 Part of ethylene dimethacrylate as a crosslinking agent and 8 parts of a 1 to 2 ensure Solution of sodium pyrosulfate was filled. The shape was about 15 to 25 minute sound heated to about 30 to 350C and then to 1000C for 5 to 10 minutes. Then became. a 0.65 mm thick cellulose acetate layer with an acetyl content of 32% with the aid sprayed onto the assembly using a Wurster sprayer.

Claims (2)

P a t e n t a n 5 p r ii c h e 1. Dispensing device for a liquid, comprising an outer shell that is rigid and allows the passage of water, a compressible, impermeable to liquid, impermeable to water Container, in the envelope, in which the liquid is located and the one outlet opening has for dispensing the liquid, as well as an Iiittel between the shell and the Container that causes water to be drawn into the device and a pressure exerts on the container, thereby g e k e n n -z e i c h n c t that the means a is hydrophilic, water-swellable, water-insoluble polymer. 2. Apparatus according to claim 1, characterized in that the means i c 11 n e is in the form of a laminate of two layers, one layer consisting of the hydrophilic water-swellable, water-insoluble polymer and the other layer a water-absorbing, non-swellable material. Apparatus according to claim 1 or 2, characterized in that it is -k e n n z e i c h n e t that the hydrophilic, water-swellable and water-insoluble polymer Poly (hydroxyalkyl methacrylate), poly (acrylamide), poly (methacrylamide, a poly (electrolyte) complex, a cross-linked protein polymer, foly (vinylallrohol) with a low acetate content or with glyoxal, formaldehyde or glutaraldehyde crosslinked, a poly (oxy #thylene) crosslinked by irradiation, poly (saccharide), with Dialdehyde cross-linked methyl cellulose, a mixture of agar and sodium carboxymethyl cellulose, swellable starch or poly (ethylene glycol methacrylate).