Extended-release Formulations Of Tolterodine Research Articles

DEVELOPMENT AND EVALUATION OF NOVEL DRUG DELIVERY SYSTEM OF TOLTERODINE TARTRATE

Objective: Tolterodine tartrate (tolterodine) is used for treating overactive bladder (OAB) with symptoms of urinary frequency, urgency and leakage. Tolterodine is an antimuscarinic (anticholinergic) agent. It works by blocking a chemical that causes contractions of the bladder. Present work involved development of a novel drug delivery system of tolterodine intended to be taken once daily.Methods: Extended release (ER) pellets of tolterodine were prepared and optimized for in vitro drug release. Subsequently, these pellets were filled into a suitable sized capsule. The resulting capsules were evaluated for in vitro drug release. Optimized formulation was subjected to accelerated stability studies for 3 mo and was evaluated for description, average weight, assay and drug release.Results: The optimized ER capsule exhibited similar dissolution profile as that of the reference listed drug (RLD), with approximately 45%, 75% and more than 80% release in 3 h, 5 h and 7 h respectively. Accelerated stability studies indicated good physical and chemical stability of the formulation.Conclusion: ER formulation of tolterodine was optimized and can be used as once a day dosage, reducing the frequency of administration when compared with the immediate release formulation. The developed formulation exhibited similar behavior as that of reference formulation Detrol LA marketed in the US.

Comparative efficacy and safety of extended-release and instant-release tolterodine in children with neural tube defects having cystometric abnormalities

Aim To evaluate the comparative efficacy and safety of extended-release (ER) and instant-release (IR) tolterodine preparations in a pediatric population with neural tube defects having cystometric abnormalities. Materials and methods Twenty-five patients with neural tube defects and a similar demographic profile underwent a routine hemogram, liver function tests, renal function tests, urine culture, X-ray lumbo-sacral spine, and renal and bladder ultrasound. Vesicoureteric reflux was diagnosed by micturating cystourethrogram under fluoroscopy. Dimercaptosuccinic acid renal scintigraphy was performed to study the presence or absence of renal scars. Patients were treated with tolterodine ER (Group I: 2 mg once daily for 21 days) and tolterodine IR (Group II: 2 mg twice daily for 21 day) in a cross-over study with a 10-day washout period between administrations. Evaluation was by subjective assessment, visual analog scale, urodynamic assessment and adverse drug reaction monitoring. Results There was ultrasound evidence of hydroureteronephrosis in 20% of the patients. One patient out of 25 had impaired renal function and eight patients had renal scarring on dimercaptosuccinic acid scans. Both forms of the drug increased the maximum cystometric bladder capacity, decreased detrusor leak pressures and increased compliance compared to pre-therapy levels ( P = 0.0001). Visual analog scale showed a significant clinical improvement with both ER and IR tolterodine. A significant increase in maximum bladder capacity in the group receiving IR tolterodine as compared to the ER preparation was noted ( P = 0.0001). The decrease in detrusor leak pressures and improvement in compliance were not significantly different between the groups. No adverse effects of hyperpyrexia, flushing or intolerance to outdoor temperatures, or dryness of mouth were observed in either group. No patient suffered from constipation. Conclusion ER tolterodine 2 mg once daily is as effective and well tolerated in children with neurogenic bladder as IR tolterodine 2 mg twice a day. The latter was found to be more effective in terms of urodynamic parameters. ER formulation of tolterodine is less expensive and has the advantage of single dosage.

Human Muscarinic Receptor Binding Characteristics of Antimuscarinic Agents to Treat Overactive Bladder

We characterized the binding affinities of several antimuscarinic agents in human muscarinic receptors. Competitive inhibitory effects of antimuscarinic agents on specific NMS [H] (PerkinElmer Life Sciences, Boston, Massachusetts) binding were examined in human tissue homogenates and in CHO-K1 cell membranes expressing human muscarinic receptor subtypes. Oxybutynin, propiverine, tolterodine, the respective metabolites DEOB, DPr-P-4(N-->O) and 5-HM, and darifenacin inhibited in concentration dependent fashion specific [(3)H]NMS binding in homogenates of the human bladder and parotid gland as well as in membranes of CHO-K1 cell lines expressing human muscarinic M(1) to M(5) receptor subtypes. Based on inhibition constant values the inhibitory effects of tolterodine, 5-HM and DPr-P-4(N-->O) were 1.4 to 1.7 times greater in the bladder than in the parotid gland, whereas the inhibitory effects of oxybutynin, DEOB, propiverine and darifenacin were 2 to 10 times greater in the parotid gland. Consequently tolterodine, 5-HM and DPr-P-4(N-->O) compared with oxybutynin, DEOB, propiverine and darifenacin were found to show 3 to 4 times greater affinity to muscarinic receptors in the human bladder than in the parotid gland. Tolterodine and 5-HM were 2-fold more potent for inhibiting specific [(3)H]NMS binding at cell membranes expressing the M(2) vs the M(3) subtype. Conversely oxybutynin, DEOB, propiverine, DPr-P-4(N-->O) and darifenacin showed 2 to 22 times higher affinity to the M(3) than to the M(2) subtype. Compared with oxybutynin, tolterodine, 5-HM and DPr-P-4(N-->O) may bind more selectively to muscarinic receptors in the human bladder than in the parotid gland.

Central nervous system safety of anticholinergic drugs for the treatment of overactive bladder in the elderly

Background: Overactive bladder (OAB) is characterizedby urgency and increased frequency of micturition, with or without urinary urge incontinence. Anticholinergic agents are important in the treatment of OAB. However, concerns have emerged about their central nervous system (CNS) safety and the associated risk of cognitive impairment. Objective: This article describes the CNS adverseeffects of anticholinergic drugs used for the treatment of OAB, with particular emphasis on their use in the elderly. Its objective is to help physicians make optimal choices when selecting anticholinergic treatment for OAB. Methods: Relevant data from the literature wereidentified primarily through a MEDLINE search of articles published through December 2003. The search terms included overactive bladder, central nervous system, anticholinergic, and antimuscarinic. This was not intended to be a systematic review, and articles were chosen for inclusion based on their pertinence to the focus on treatment of OAB in the elderly. Results: Several anticholinergic drugs are available for the treatment of OAB, including oxybutymn, tolterodine, trospium chloride, and propiverine (not available in the United States). Among the agents reviewed, penetration of the blood-brain barrier (as predicted by lipophilicity, polarity, and molecular size and structure) is highest for oxybutymn, lower for tolterodine, and lowest for trospium chloride; limited data are available for propiverine. The total anticholinergic drug burden may also be important in determining the potential for CNS adverse effects. The spectrum of anticholinergic CNS adverse effects ranges from drowsiness to hallucinations, severe cognitive impairment, and even coma. The immediate-release (IR) and extended-release (ER) formulations of oxybutynin have been associated with cognitive impairment. In the only published clinical trial that was identified, no significant differences in CNS adverse effects were observed between the IR and ER formulations of tolterodine. There were few clinical data on the use of propiverine in patients with OAB. Trospium chloride has shown favorable CNS tolerability in postmarketing surveillance studies. Conclusion: When considering treatment choices for patients with OAB, particularly the elderly, the potential CNS adverse effects of each anticholinergic agent must be weighed against the severity of OAB symptoms.