Transcript of protein kinase A knock-down modulates feeding behavior and neuropeptide Y gene expression in phenylpropanolamine-treated rats.
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Neuropeptide Y (NPY) is an appetite-controlling neuromodulator that contributes to the appetite-suppressing effect of phenylpropanolamine (PPA). Aims of this study were to investigate whether protein kinase A (PKA) signaling is involved in regulating NPY gene expression and PPA-induced anorexia. Rats were given daily with PPA for 5 days. Changes in daily food intake and hypothalamic NPY, PKA, cAMP response element binding protein (CREB), and pro-opiomelanocortin (POMC) gene expression were measured and compared. To further determine if PKA was involved, intracerebroventricular infusions of antisense oligodeoxynucleotide were performed at 60 min before daily PPA treatment in freely moving rats. Results showed that daily PKA, CREB, and POMC expression were increased following PPA treatment, which showed a closely reverse relationship with alterations of decreased feeding behaviors and NPY mRNA levels. Results also showed that PKA knock-down could block PPA-induced anorexia as well as restore NPY mRNA level, indicating the involvement of PKA signaling in the regulation of NPY gene expression. It is suggested that hypothalamic PKA signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of hypothalamic NPY gene expression. The present findings reveal that manipulations at the molecular level of PKA or cAMP may allow the development of therapeutic agents to improve the undesirable properties of PPA or other amphetamine-like anorectic drugs. (+info)
Effects of ICV administration of the alpha1A-adrenoceptor antagonist 5-methylurapidil on concurrent measures of eating and locomotion after cocaine in the rat.
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Psychostimulants including amphetamine and cocaine induce locomotion and stereotypy and suppress eating. Although the capacity of cocaine to alter locomotion is usually viewed as related to dopamine neurotransmission, recent studies suggest that norepinephrine, acting through alpha1-adrenergic receptors (alpha1-ARs) can facilitate cocaine-stimulated locomotion. Of the three alpha1-AR subtypes (alpha(1A), alpha(1B), and alpha(1D)) identified to date, inactivation of the alpha(1B)-AR subtype diminishes cocaine-stimulated locomotion, whereas the impact of inactivation of the alpha(1A)-AR subtype on either eating or locomotion is unknown. In the present study, we assessed the relative impact of ICV administration of the alpha(1B)-AR antagonist 5-methylurapidil (5-MU) on cocaine-stimulated hyperlocomotion and hypophagia, using a concurrent method [Wellman, P.J., Ho, D.H., Davis, K.W., 2005. Concurrent measures of feeding and locomotion in rats. Physiology of Behavior 84 (5), 769-774.]. Rats were infused ICV with one of 3 doses of 5-MU (0, 3, or 30 nmol) and then injected (i.p.) with 0, 2.5, 5.0, 10.0, or 20.0 mg/kg cocaine HCl on each of five tests. Rats always received the same 5-MU dose, but a different cocaine dose on each trial. Feeding and locomotion were assessed concurrently during a 45-min postinjection period. Significant suppression of eating was noted at 2.5 mg/kg cocaine, a dose that does not alter forward locomotion in the rat. Administration of 5-MU did not alter locomotion in rats treated with saline, but did significantly increase baseline food intake. Neither cocaine-induced hypophagia nor hyperlocomotion was altered by ICV administration of 5-MU. These results suggest that the capacity of alpha1-AR agonists (e.g. phenylpropanolamine) to suppress eating may be related to activation of the alpha(1A)-AR subtype, whereas cocaine does not act through the alpha(1A)-AR subtype to suppress eating nor does this subtype modulate cocaine-induced hyperlocomotion. (+info)
Analysis of the release process of phenylpropanolamine hydrochloride from ethylcellulose matrix granules IV.(1)) Evaluation of the controlled release properties for in vivo and in vitro release systems.
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In the pharmaceutical preparation of a controlled release drug, it is very important and necessary to understand the release properties. The dissolution test is a very important and useful method for understanding and predicting drug-release properties. It was readily confirmed in the previous paper that the release process could be assessed quantitatively by a combination of the square-root time law and cube-root law equations for ethylcellulose (EC) matrix granules of phenylpropanolamine hydrochloride (PPA). In this paper EC layered granules were used in addition to EC matrix. The relationship between release property and the concentration of PPA in plasma after administration using beagle dogs were examined. Then it was confirmed that the correlativity for EC layered granules and EC matrix were similar each other. Therefore, it was considered that the dissolution test is useful for prediction of changes in concentration of PPA in the blood with time. And it was suggested that EC layered granules were suitable as a controlled release system as well as EC matrix. (+info)
Transdermal oxybutynin in the treatment of overactive bladder.
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Overactive bladder is a dreadful syndrome that affects a considerable number of patients. Antimuscarinics are the mainstay of pharmacotherapy for this condition. Transdermal (TD) oxybutynin (OXY) bypasses the first-pass metabolism and reduces the formation of N-desethyloxybutynin, a compound believed to be associated with anticholinergic side effects. The 3.9 mg matrix TD system is applied twice weekly and transports OXY directly into the systemic circulation. The patch can be applied to abdomen, buttock, and hip, and provides continuous OXY delivery that minimizes peak and trough fluctuations in plasma levels. In clinical trials, TD and oral OXY produced a significant reduction in incontinence episodes, with no difference between oral and TD treatments. In addition, TDOXY was similar to tolterodine, and it produced a significant improvement in the number of urinary incontinence episodes, complete continence, and urodynamic and quality of life parameters compared with placebo. The incidence of anticholinergic adverse events with TDOXY was similar to placebo. Most common adverse events were mild-moderate skin reactions. Treatment satisfaction survey suggested patients' preference to use the TD system in the future. Counseling on healthy skin care and appropriate product use can enhance patients' knowledge about TDOXY for overactive bladder treatment. (+info)
Pharmacologic management of overactive bladder.
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Overactive bladder (OAB) is a prevalent and costly condition that can affect any age group. Typical symptoms include urinary urgency, frequency, incontinence and nocturia. OAB occurs as a result of abnormal contractions of the bladder detrusor muscle caused by the stimulation of certain muscarinic receptors. Therefore, antimuscarinic agents have long been considered the mainstay of pharmacologic treatment for OAB. Currently, there are five such agents approved for the management of OAB in the United States: oxybutynin, tolterodine, trospium, solifenacin and darifenacin. This article summarizes the efficacy, contraindications, precautions, dosing and common side effects of these agents. All available clinical trials on trospium, solifenacin and darifenacin were reviewed to determine its place in therapy. (+info)
Results of stability studies with doping agents in urine.
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For a correct interpretation of analytical results in doping control, knowledge on the stability of prohibited substances in the urinary matrix is a prerequisite. So far, limited data is available on the stability of prohibited substances in unaltered urine because most of the studies investigating the stability of drugs have used stabilized, sterilized, or filtered urine. In this work, the long-term stability of ephedrine, methylephedrine, cathine, 19-norandrosterone glucuronide, and a wide range of diuretics was determined over a period of 9 months at -20 degrees C, 4 degrees C, 22 degrees C, and 37 degrees C. Short-term stability, including the influence of 6 freeze-thaw cycles and 15 h storage at 60 degrees C, was also investigated. Often, a tolerance limit of 15%, similar to what is commonly used in the evaluation of precision data during method validation, is used to evaluate stability. This paper describes an alternative approach, using measurement uncertainty data to evaluate long-term stability with a probability of 95%, and proposes a simple alternative for investigating the stability for non-threshold substances. The results indicate that all the investigated substances are stable (alpha=0.05) when stored at -20 degrees C and 4 degrees C, but that at higher temperatures significant degradation effects can occur. The study also shows that degradation can be dependent on the urinary matrix and that the results from stability studies using stabilized, filtered, or sterilized urine can underestimate degradation effects. (+info)
Analysis of the release process of phenylpropanolamine hydrochloride from ethylcellulose matrix granules V. Release properties of ethylcellulose layered matrix granules.
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In the pharmaceutical preparation of a controlled release drug, it is very important and necessary to understand the release properties. In previous papers, a combination of the square-root time law and cube-root law equations was confirmed to be a useful equation for qualitative treatment. It was also confirmed that the combination equation could analyze the release properties of layered granules as well as matrix granules. The drug release property from layered granules is different from that of matrix granules. A time lag occurs before release, and the entire release property of layered granules was analyzed using the combination of the square-root time law and cube-root law equations. It is considered that the analysis method is very useful and efficient for both matrix and layered granules. Comparing the granulation methods, it is easier to control the manufacturing process by tumbling granulation (method B) than by tumbling-fluidized bed granulation (method C). Ethylcellulose (EC) layered granulation by a fluidized bed granulator might be convenient for the preparation of controlled release dosage forms as compared with a tumbling granulator, because the layered granules prepared by the fluidized bed granulator can granulate and dry at the same time. The time required for drying by the fluidized bed granulator is shorter than that by the tumbling granulator, so the fluidized bed granulator is convenient for preparation of granules in handling and shorter processing time than the tumbling granulator. It was also suggested that the EC layered granules prepared by the fluidized bed granulator were suitable for a controlled release system as well as the EC matrix granules. (+info)
Persistence, adherence, and switch rates among extended-release and immediate-release overactive bladder medications in a regional managed care plan.
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BACKGROUND: Pharmacotherapy constitutes an important adjunct to behavioral therapy for the treatment of overactive bladder (OAB). Tolterodine and oxybutynin are commonly prescribed drugs for OAB treatment that exert their beneficial effect by suppressing bladder muscle contractions. However, high discontinuation rates have been observed for these drugs in clinical trials, as well as in real-world settings, in part due to adverse effects. Extended-release (ER) formulations were introduced with an improved tolerability profile over immediate-release (IR) versions of the 2 drugs. No study has compared persistence and adherence to therapy for both the ER and IR versions of tolterodine and oxybutynin. OBJECTIVE: To compare persistence, adherence, and switch rates for the IR and ER formulations of oxybutynin and tolterodine for patients enrolled in a regional managed care plan. METHODS: Study patients were adults (aged e 18 years), with at least 1 pharmacy claim for either tolterodine extended-release (tol-ER), oxybutynin extended-release (oxy-ER), tolterodine immediate-release (tol-IR), or oxybutynin immediate-release (oxy-IR) during the period from July 1, 1999, to December 31, 2003, and were continuously eligible for benefits from 6 months before through 12 months after the initial OAB pharmacy claim (index) date. A retrospective cohort study design was used following patients from the index date to the occurrence of non-persistence with the index medication (i.e., a gap of > 45 days between successive prescription fills or a switch to any other OAB medication), or the end of a 1-year follow-up period, through December 31, 2004. Switching was defined as any change from the index medication, including a change in dose form (e.g., tol-IR to tol-ER), to one of the other 3 study drugs, or to a different OAB treatment (e.g., trospium chloride, oxybutynin patch, flavoxate, hyoscyamine sulfate, or propantheline bromide) during the follow-up period. Adherence was measured as the proportion of patients with a medication possession ratio (MPR) of at least 80%. MPR was calculated as (1) the sum of days supply for all pharmacy claims except the last pharmacy claim, divided by (2) the total number of days from the first fill date to the fill date of the last pharmacy claim. The association of drug therapy with study outcomes was assessed with bivariate and adjusted (multivariate) analyses. Multivariate analyses controlled for demographic and clinical characteristics, plan type, patient out-of-pocket cost for the index medication, and year of therapy initiation. RESULTS: 1,117 patients had at least 1 pharmacy claim for an OAB study drug (n = 454 for tol-ER [40.6%], n = 249 for oxy-ER [22.3%], n = 306 for tol-IR [27.4%], n = 108 for oxy-IR [9.7%]), of whom 81.6% were women. The mean (standard deviation [SD]) age of the study population was 55.7 (14.5) years. Only 53.7% had at least 1 OAB diagnosis recorded during the 18-month eligibility period. 44.5% of patients did not have a refill after the initial (index) pharmacy claim (39.4% for oxy-ER, 42.7% for tol-ER, 46.1% for tol-IR, and 59.3% for oxy-IR; P = 0.004). Only 13.2% persisted with treatment for at least 1 year (tol-ER = 15.0%, oxy-ER = 15.3%, tol-IR = 11.4%, oxy-IR = 6.5%; P = 0.050). The median days to discontinuation (non-persistency) were 31.0 overall, 33.0 for tol-ER, 34.0 for oxy-ER, 32.0 for tol-IR, and 0 for oxy-IR; P = 0.010. The overall switch rate as a percentage of all study patients was 13.3%, ranging from 9.9% for tol-ER, 13.7% for tol-IR, 16.5% for oxy-ER, and 19.4% for oxy-IR; P = 0.020. Of patients who refilled their initial prescription at least once, 24.0% made a medication switch. Adherence rates as measured by percentage of patients with MPR >or= 80% were 30.3% overall and higher for the ER formulations: 35.2% for tol-ER, 36.1% for oxy-ER, 23.5% for tol-IR, and 14.8% for oxy-IR; P < 0.001. CONCLUSIONS: Adherence was significantly better for ER than IR agents. The high rate of non-persistence (44.5%) following the first (index) prescription highlights the need for medication counseling by health care professionals. (+info)