United States Patent:  6,087,396

Assignee:  Situs Corporation (Solana Beach, CA)

Filed:  January 15, 1999

Oxybutynin chloride formulations having increased stability at body temperature, even at high concentrations. These formulations comprise oxybutynin chloride at a pH of between 3.0 and 5.0, and may include a buffer capable of providing adequate buffering capacity in this range. The OC solutions can be placed in an infuser device for treatment of bladder dysfunction.

SUMMARY OF THE INVENTION

One embodiment of the present invention is a pharmaceutical composition comprising oxybutynin chloride, wherein the composition is stable at 37^oC. for at least 12 hours when placed within the bladder. Preferably, the oxybutynin chloride has a concentration of between about 1 mg/ml and 30 mg/ml. More preferably, the concentration of oxybutynin chloride is between about 10 mg/ml and 25 mg/ml. Most preferably, the concentration of oxybutynin chloride is about 20 mg/ml. In another aspect of this preferred embodiment, the composition has a pH of between about 3.0 and 5.0; preferably between about 3.5 and 4.5; more preferably about 4.0. The composition may further comprise a buffering agent having a concentration of between about 0.005 M and 0.1 M. Preferably, the buffering agent has a concentration of between about 0.01 and 0.05 M. In one aspect of this preferred embodiment, the buffering agent is acetate or citrate. The composition may further comprise a cosolvent. Preferably, the cosolvent is a viscosity-enhancing agent. In another aspect of this preferred embodiment, the viscosity-enhancing agent is a carbohydrate or cellulosic viscosity enhancing agent, such as carboxymethylcellulose or hydroxypropylmethylcellulose. The composition may be provided in combination with an infuser capable of releasing the composition at a particular flow rate. Preferably, the infuser is an intravesical infuser. Advantageously, the flow rate is less than about 400 .mu.l/hour.

The present invention also provides a method for treating a bladder disorder, comprising the steps of: placing the intravesical infuser in the bladder; and placing the pharmaceutical composition described above in the intravesical infuser. Preferably, the bladder disorder is secondary urge incontinence, hyperreflexive voiding dysfunction, neurologic bladder or decreased bladder capacity.

Claim 1 of 16 Claims

1. A pharmaceutical composition comprising an aqueous oxybutynin chloride solution, wherein said composition has an oxybutynin concentration of about 1.0 to 30 mg/ml and a pH of 3 to 5 is stable at about 37 degrees C for at least 12 hours, when placed within the bladder.

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