CONTINUOUS INFUSION APPARATUS

Abstract: An apparatus for the continued infusion of an emulsified medicament, comprising a reservoir (6), connected via a delivery tube (10) and a giving set to a needle (7), in which the reservoir (6) and the delivery tube (10) are each made from, or substantially internally coaed with, a non-halogenated polymeric plastics material (for example polyethylene or polypropylene).

Description: CONTINUOUS INFUSION APPARATUS This invention relates to continuous infusion apparatus, in particular for the infusion of medicaments and especially the continuous intravenous infusion of medicaments to control agitation and fits. The control of chronic anxiety, agitation and fits is a sizeable medical problem that crosses a number of traditional medical fields. Significant agitation, frequently developing into fits, occurs in patients who are terminally ill, who are suffering from withdrawal symptoms following drug or alcohol abuse or who have a chronic condition such as status epilepticus. These patients are currently treated in practice with repeated bolus injections of a suitable medicament, such as Diazemuls® . Diazemuls®, an oil-in-water emulsion containing diazepam, is particularly suitable for treating these conditions as it and its principal metabolite are potent anxiolytic agents with antiepileptoigenic properties as well as possessing a sedative effect. The hitherto recommended manner of accomplishing continuous infusion of Diazemuls® and similar medicaments is to mix the medicament with an aqueous 5% or 10% dextrose solution and then to infuse over a period of 6 hours. The present invention provides an apparatus for the continued infusion of a medicament, said apparatus comprising a reservoir for the medicament, operatively connected with a delivery tube and a needle, in which the reservoir and the delivery tube are each made from or substantially fully internally coated with a non-halogenated polymeric plastics material. This invention recognises that adequate continuous control of the dosage of a medicament cannot effectively be accomplished using repeated bolus injections of that medicament. Such a method is time-consuming and can be inaccurate. This invention further recognises that the recommended manner of accomplishing continual infusion is ineffective with many medicaments due to the strong adherence of the medicament to the polyvinyl chloride used to make currently-available bags and associated delivery equipment. This invention provides a simple and safe delivery system for the continuous infusion of such medicaments, enabling the dosage of the medicament to be controlled. Preferably, the material used to make or coat the reservoir and delivery tube is a low-sorbent material. Suitable materials include polyolefins such as polyethylene and polypropylene. The reservoir may be contained in a syringe, if the medicament is to be used undiluted or in a bag, if the medicament is to be used diluted. The apparatus may further comprise one or more valves to control the flow of the medicament through the apparatus. Such valves may be manually or automatically operated. The medicament may be infused under the action of gravity. Alternatively, a pump may be used to control and/or meter the flow of the medicament through the apparatus. This pump may be a roller-type or peristaltic pump. In a preferred embodiment, when the reservoir is contained in a syringe, the pump comprises a syringe pump which operates by controlling the movement of the piston within the syringe. When a syringe pump is used to control the rate of infusion, it must be capable of delivering at a rate of 0.2 ml per hour. Preferably the medicament is a benzodiazepine-based substance such as diazepam. For injection purposes, this material is customarily supplied as an emulsion, known as Diazemuls®. This formulation reduces the risk of localised pain and thrombophlebitis. Diazemuls® is licensed for control of acute muscle spasm due to tetanus or poisoning and for the control of convulsions, status epilepticus, and for the management of severe acute anxiety or agitation including delirium tremens. This invention allows an extension of the uses of Diazemuls®. The medication can now be used for general sedation, including alcohol and drug withdrawal. Following the invention it has been used to control violence in patients. This invention recognises that Diazemuls® is particularly difficult to infuse using the hitherto-recommended method for continuous infusion. It cannot be easily mixed with dextrose or saline solutions and tends to precipitate out of its emulsion. It has been found that the stability of the medicament is enhanced by use of an apparatus according to the present invention. For example, a diazepam emulsion has been found to remain stable for up to 28 days when stored in apparatus according to the present invention. The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying drawing. The single drawing figure is a schematic view of an apparatus according to the present invention. Undiluted Diazemuls®, or alternatively Diazemuls® diluted with 10% or 20% Intralipid solution, is drawn up into a 50 ml polyethylene syringe 2. This syringe comprises a main body 3 and a piston 4. The syringe is mounted in a syringe pump 5 which controls the volume of a reservoir 6 of Diazemuls® by depressing the piston 4. The syringe 2 is in fluid communication with a hollow needle 7 via a giving set shown generally at 8. The needle 7 is designed for insertion into a patient, and is preferably inserted into a peripheral vein. The giving set 8 includes a delivery tube 10, a connector 11 to connect one end of the delivery tube 10 to the syringe 2 and a connector 12 to connect the opposite end of the delivery tube 10 to the needle 7. A valve 9, incorporated into connector 12, may be manually operable to prevent or allow flow of the Diazemuls® through the apparatus. All components of the giving set are manufactured from polyethylene. The pump 5 must be capable of steady infusion at rates as low as 0.2 ml per hour, for example in order to cater for the needs of a patient particularly sensitive to Diazemuls®. Alternatively, infusion may be started at a low rate, for example, 0.5 ml / hr, and increased in stepwise intervals of, for example, 0.5 ml / hr until control of symptoms is achieved. It is possible to use the pump 5 to deliver an initial bolus injection if rapid relief of symptoms is required. It is also possible to program the pump 5 to vary the amount of Diazemuls® delivered. Although Diazemuls® is an optically opaque liquid, the pump must be capable of operating to effectively dispense such a liquid at the low rates required. This means that common methods such as optical feedback to sense the position of the syringe cannot be used. This apparatus enables safe and effective continuous infusion of Diazemuls® and similar medicaments. The increased stability of the solution means that administration by means of this apparatus can take place on an outpatient basis if appropriate, or even at home.

Claims: CLAIMS 1. An apparatus for the continuous infusion of a medicament, said apparatus comprising a reservoir (6) , for the medicament, operatively connected with a delivery tube (10) , and a needle (7) in which the reservoir (6) and the delivery tube (10) are each made from, or substantially fully internally coated with, a non-halogenated polymeric plastics material . 2. An apparatus according to Claim 1 in which the material used to make or coat the reservoir (6) and the delivery tube (10) comprises a low sorbent material . 3. An apparatus according to Claim 2 in which the material comprises a polyolefin. 4. An apparatus according to Claim 2 or 3 in which the material comprises polyethylene or polypropylene. 5. An apparatus according to any preceding claim in which the reservoir (6) is contained in a syringe (2) . 6. An apparatus according to any preceding claim further comprising a valve (9) to control the flow of the medicament through the apparatus. 7. An apparatus according to any preceding claim further comprising a pump (5) , to control and/or meter the flow of the medicament through the apparatus. 8. An apparatus according to Claim 7 as dependent from Claim 5 in which the pump (5) comprises a syringe pump capable of delivering the medicament at a rate of about 0.5 ml/hr or lower. 9. An apparatus according to Claim 8 in which the pump (5) is capable of delivering the medicament at a rate of about 0.2 ml/hr or lower. 10. An apparatus according to any one of Claims 7 to 9 in which the medicament is optically opaque. 11. An apparatus according to any preceding claim in which the medicament comprises an emulsion. 12. An apparatus according to Claim 10 or 11 in which the medicament comprises an emulsion containing diazepam.

Inventors: JACKSON MAURICE ANDREW, REED MICHAEL DAVID, JACKSON, MAURICE, ANDREW, REED, MICHAEL, DAVID
Applicants: DUMEX ALPHARMA, JACKSON MAURICE ANDREW, REED MICHAEL DAVID, ROYAL WOLVERHAMPTON HOSPITAL N, DUMEX-ALPHARMA, JACKSON, MAURICE, ANDREW, REED, MICHAEL, DAVID, THE ROYAL WOLVERHAMPTON HOSPITAL NHS TRUST
Application year: 2000
Main classification: A61M5
IPC codes: A61M5