CLAIMS 1. A cartridge (1) for a delivery device, comprising: a tubular reservoir member formed substantially from glass and having an inner and an outer surface, the reservoir member comprising a proximal opening adapted to receive a piston in sliding engagement with the inner surface of the reservoir, and a distal opening adapted to have a closure member mounted, and a sleeve arranged on at least a portion of the outer surface, wherein the sleeve exerts a compression force on the reservoir. 2. A cartridge as in claim 1, comprising a piston received in the proximal opening and a closure member closing the distal opening. 3. A cartridge as in claim 2, containing a fluid drug. 4. A cartridge as in any of claims 1-3, wherein the sleeve is formed from a polymeric material. 5. An assembly comprising a cartridge as in claims 3 or 4, a jet expelling device (201) and an outlet nozzle (36, 270) in fluid communication with an interior of the drug filled cartridge, wherein the jet expelling device comprises an impulse generating assembly (150) for displacing the piston, thereby reducing the volume of the reservoir and thereby expelling an amount of drug through the outlet nozzle. 6. A cartridge (1) for a drug delivery device, comprising: a tubular reservoir member having an outer surface, and a sleeve arranged on at least a portion of the outer surface, wherein the sleeve exerts a compression force on the reservoir. 7. A method of forming a cartridge, comprising the steps of: providing a tubular reservoir member having an inner and an outer surface, arranging the reservoir member in a mould leaving a circumferential space between the mould and at least a portion of the outer surface of the reservoir member, injecting a polymeric material in the circumferential space, allowing the polymeric material to cool thereby creating residual compressive stress in the polymeric material exerting a compressive force on at least a portion of the reservoir member. 8. A method as in claim 7, wherein the reservoir member comprises a proximal opening adapted to receive a proximal closure member, and a distal opening adapted to have a distal closure member mounted, the method comprising the further steps of: arranging a closure member closing either the proximal or distal opening filling the reservoir member with a fluid drug, and arranging a closure member in the other of the proximal or distal opening. 9. A method as in claim 8, wherein the proximal closure member is a piston in sliding engagement with the inner surface of the reservoir member and the distal closure member is a needle penetratable elastomeric member. 10. A method as in claim 8, wherein the proximal closure member is a piston in sliding engagement with the inner surface of the reservoir and the distal closure member comprises a nozzle. 11. A method as in any of claims 7-10, wherein the reservoir member is formed substantially from glass.CLAIMS 1. A cartridge (1) for a delivery device comprising: a tubular reservoir member formed substantially from glass and having an inner and an outer surface, the reservoir member comprising a proximal opening adapted to receive a piston in sliding engagement with the inner surface of the reservoir, and a distal opening adapted to have a closure member mounted, and a sleeve arranged on at least a portion of the outer surface, the sleeve exerts a compression force on the reservoir. 2. A cartridge as claimed in claim 1, comprising a piston received in the proximal opening and a closure member closing the distal opening. 3. A cartridge as claimed in claim 2, containing a fluid drug. 4. A cartridge as in any of claims 1-3, wherein the sleeve is formed of a polymeric material. 5. An assembly comprising a cartridge as in claims 3 or 4, a jet expelling device (201) and an outlet nozzle (36, 270) in fluid communication with an interior of the drug filled cartridge, wherein the jet expelling device comprises an impulse generating assembly (150) for displacing the piston, thereby reducing the volume of the reservoir and thereby expelling an amount of drug through the outlet nozzle. 6. A cartridge (1) for a drug delivery device, comprising: a tubular reservoir member having an outer surface, and a sleeve arranged on at least a portion of the outer surface, the sleeve exerts a compression force on the reservoir. A method of forming a cartridge comprising the steps of: providing a tubular reservoir member having an inner and an outer surface, arranging the reservoir member in a mold leaving a circumferential space between the mold and at least a portion of the outer surface of the reservoir member, injecting a polymeric material into the circumferential space, allowing the polymeric material to cool thereby creating residual compressive stress in the polymeric material exerting a compressive force on at least a portion of the reservoir member. 8. A method as claimed in claim 7, wherein the reservoir member comprises a proximal opening member receiving a proximal closure member, and a distal opening member having a distal closure member mounted, the method comprising the further steps of: arranging a closure member closing either the proximal or distal opening filling the reservoir member with a fluid drug, and arranging a closure member in the other of the proximal or distal opening. 9. A method as claimed in claim 8, wherein the proximal closure member is a piston in sliding engagement with the inner surface of the reservoir member and the distal closure member is a needle penetratable elastomeric member. A method as in claim 8, wherein the proximal closure member is a piston in sliding engagement with the inner surface of the reservoir and the distal closure member comprises a nozzle. 11. A method as claimed in any of claims 7-10, wherein the reservoir member is formed substantially from glass.