Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-11-10
2002-10-15
Ruhl, Dennis (Department: 3761)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C424S430000, C424S433000
Reexamination Certificate
active
06464670
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method of delivering therapeutic agents to the urethra, bladder and related structures and an urethral suppository for use in delivering therapeutic agents thereto.
In the treatment of various ailments affecting the urethra, bladder and related structures, it is generally not desirable to deliver therapeutic agents systemically. When delivery of such agents is accomplished in a systemic fashion such as, for example, orally or by way of a remote intravenous, intramuscular, subcutaneous or transdermal route, relatively high dosages are required in order to deliver an amount to the affected areas sufficient to have the desired therapeutic effect. The requirement for such relatively high dosages results from the dilution and dissipation effects attendant to such delivery methods as well as the loss of efficacy that can result from biochemical interactions between the therapeutic agent and unrelated systems. Further, due to the relatively high dosages required by systemic delivery methods, the risks of triggering both adverse reactions and unwanted side effects are increased. Accordingly, it is known to employ delivery methods which provide for the- local application of therapeutic agents in the treatment of urethral, bladder and related ailments in order to administer relatively small dosages to achieve delivery of relatively high concentrations of such agents to the affected areas.
While the local application of therapeutic agents permits the use of smaller dosages, and can avoid certain of the drawbacks associated with systemic delivery methods as mentioned herein above, a different set of problems arise with respect thereto. In the context of treating conditions affecting the urethra, bladder and related structures, for example, it is of primary importance that the local application of therapeutic agents be accomplished in a manner compatible with the anatomical structures involved. Accordingly, it is known to employ suppositories as delivery devices for therapeutic agents. Such suppositories are designed to be inserted into the urethra and to release therapeutic agents contained therein or applied thereon to the mucosal lining of the urethra. The release of therapeutic agents occurs upon liquefaction of the suppository which results from the transfer to the suppository of the body heat of the patient into whose urethra the suppository has been placed (Amemiya, T.; et. al. Development of emulsion type new vehicle for soft gelatin capsule. I. Selection of surfactants for development of new vehicle and its physical chemical properties. Chemical and Pharmaceutical Bulletin, 1998, Feb, 46(2): 309-13).
Various prior art suppositories, however, have been designed in such a manner that they are difficult to retain in position within the urethra where the precise delivery of therapeutic agents is desired. Experience has shown that such suppositories tend either to advance inwardly into the bladder or to be expelled out of the urethra prior to the complete decomposition within the urethra. In either case, the desired result of a precise placement of the specific dosage of the selected therapeutic agents within the urethra is not realized.
In order to address these shortcomings, it is known to configure urethral suppositories in the form disclosed in U.S. Pat. No. 5,085,650 to Giglio (the '650 patent). The '650 patent discloses an urethral suppository comprising a bulbous head and a conical tail joined by a narrow cylindrical shaft. As taught by the '650 patent, upon insertion of the suppository into the urethra of a human female patient, the bulbous head thereof is advanced through the entire length of the urethra and penetrates into the bladder to anchor the suppository at the bladder neck. The conical tail of the suppository prevents the further advance of the suppository into the bladder. More specifically, once the suppository is positioned within the urethra, the portion of the bulbous head of the suppository which curves inwardly toward the shaft is designed to prevent the suppository from expulsion by its contact with the bladder walls at the bladder neck where the bladder narrows to the meet the proximal end of the urethra. At the same time, the flared portion of the conical tail, having an increasingly larger diameter than the shaft of the suppository as well as the urethra itself, is designed to prevent the suppository from over insertion by contact with the edges of the urethral orifice at the distal end thereof. It is through this combination of contact surfaces that the suppository disclosed in the '650 patent is intended to be held in position during the liquefaction thereof
While suppositories configured with bulbous heads, conical tails and narrow cylindrical shafts, as disclosed in the '650 patent aid in the placement and retention of suppositories within the urethra as compared with purely cylindrical suppositories that lack such features, such configurations permit, nonetheless, some slippage and, moreover. present certain other disadvantages. Because retention of the suppository is effected, in part, by the contact between the inwardly curved portion of the bulbous head with the bladder neck, it is required that the bulbous head of the suppository advance beyond the urethra and invade into the bladder itself. As a result, where therapeutic agents are infused throughout the material comprising the suppository, the portion of the dosage contained within the material comprising the bulbous head thereof is not positioned so that it is in direct physical contact with the mucosal lining of the urethra and thus is not absorbed readily therein. As a result, the precise delivery of a specific dosage through absorption by the urethra cannot be realized effectively. Further, insofar as the conical tail section of the suppository disclosed in the '650 patent has a flat base, it is difficult to manipulate after insertion as it provides no projections which can be grasped readily. Moreover, the roundness of the conical tail renders the distal end of the suppository less than fully compatible with the anatomical structure of the labia. As a result, the comfort of the patient is compromised.
Any foreign body inserted into the urethra or bladder causes a degree of urgency, frequency, pain, and general discomfort to the patient. Medical devices, such as tubes, catheters, or instruments, commonly inserted in the bladder or urethra during urological procedures cause discomfort to patients (Duckett, J W; et. al. Intravesical morphine analgesia after bladder surgery. Journal of Urology, 1997, Apr 157(4): 1407-9;Campbell's Urology. Edited by Walsh, P C; et. al. W. B. Saunders and Company, Six Edition, 1992). This discomfort can become extreme when the device contacts the sensitive tissue of the bladder neck. As an example, Foley catheters are used to provide bladder drainage after surgery when normal voiding is compromised. Foley catheters are tubes inserted through the urethra into the bladder. Inflation of a balloon at the catheter tip aids in the retention of the catheter in the bladder, but causes extreme discomfort to the patient as a result of contact between the balloon and the bladder neck. The patient feels urgency and a burning sensation that persists for a period of up to 24 hours. Typically, these patients are given local anesthetics such xylocaine to reduce the discomfort during this initial period.
The bladder neck is a highly vascularized and innervated tissue containing specialized cells that play an important role in the voiding cycle. The bladder is very sensitive to pressure. Any foreign body within the bladder neck will cause major discomfort to the patient. Various prior art suppositories have been designed which do not take into consideration the effect of contacting the bladder neck with a portion of the suppository. In addition, when portions of the suppository reside in different tissues such as the bladder neck and urethra, the dose of drug delivered by the suppository to an aff
BioMed Innovations, LLC
Drinker Biddle & Reath LLP
Ruhl Dennis
LandOfFree
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