Published clinical data of Prazosin were reevaluated pharmacokinetically using explicit solutions to drug concentration as a function of total time for IV bolus injection, intermittent intravenous infusion and oral ro...Published clinical data of Prazosin were reevaluated pharmacokinetically using explicit solutions to drug concentration as a function of total time for IV bolus injection, intermittent intravenous infusion and oral routes of administration in an open two-compartment model. In a novel way, the apparent volume of distribution was estimated from a two-compartment model and found to be close to the total body water suggesting that Prazosin is distributed in all tissues both extracellularly and intracellularly. In addition, extracting the value of the apparent volume of distribution from a two-compartment model allowed comparative simulations in the one-compartment model. It is shown that dosage calculations of Prazosin intermittent infusion can be safely performed using the simpler one-compartment model equations. Lastly, several additional time-dependent pharmacokinetic parameters e.g., the peak time in the central and peripheral compartment and non-steady state and steady state peak concentration and AUC were determined using series equations for all three routes of administration, as a function of dose number and total time upon multiple drug administrations in the two-compartment model. It is also the first time that steady-state plasma drug concentration equations were derived in a two-compartment mammillary model.展开更多
Spinal cord injury （SCI） is a devastating condition that not only results in a loss of motor functions but also severe autonomic dysfunctions （Krassioukov and Claydon, 2006）. Autonomic dysreflexia （AD） is a life...Spinal cord injury （SCI） is a devastating condition that not only results in a loss of motor functions but also severe autonomic dysfunctions （Krassioukov and Claydon, 2006）. Autonomic dysreflexia （AD） is a life threatening episode of tran- sient hypertension that occurs up to 30x/day （1 Ix/day on average） in those with cervical or high thoracic SCI （Hubli et al., 2015）. Most common triggers of AD are from stimuli such as a full bowel and/or bladder, or sexual arousal （Teasell et al., 2000）. Penile vibrostimulation （PVS） is a clinical pro- cedure for sperm retrieval used for the purpose of family planning or fertility assessment that unfortunately iatrogenically induces episodes of AD （Elliott, 2006）. Recently, we published a clinical trial highlighting that prazosin may be a viable option for treating AD secondary to PVS （Phillips et al., 2014）.展开更多
In this study, a new naphthalene-prazosin derivative (compound 5) was synthetized with the objective of evaluating its activity on ischemia/reperfusion injury. The Langendorff technique was used to evaluate the effect...In this study, a new naphthalene-prazosin derivative (compound 5) was synthetized with the objective of evaluating its activity on ischemia/reperfusion injury. The Langendorff technique was used to evaluate the effect of the compound 5 on ischemia/reperfusion injury. Additionally, the mechanism of action involved in the activity exerted by the compound 5 on perfusion pressure and coronary resistance was evaluated by measuring left ventricular pressure in absence or presence of following compounds;prazosin, metoprolol, indomethacin and nifedipine. The results showed that the compound 5 reduced infarct size compared with the control conditions. Other results showed that the compound 5 significantly increases (p = 0.05) the perfusion pressure and coronary resistance in isolated rat heart. In addition, other data indicate that the compound 5 increases left ventricular pressure in a dose-dependent manner (0.001 to 100 nM);however, this phenomenon was significantly inhibited by nifedipine at a dose of 1 nM (p = 0.05) and this effect was independent of cAMP levels. In conclusion, these data suggest that the naphthalene-prazosin derivative exerts a cardio protective effect via the calcium channels activation and consequently induces changes in the left ventricular pressure levels. This phenomenon results in a decrease of myocardial necrosis after ischemia and reperfusion.展开更多
Purpose: To investigate the effects of topical prazosin and pilocarpine on uveoscleral outflow(Fu) in rabbits.Methods: Sixteen rabbits were randomly divided into the control group (5 rabbits, only topical application ...Purpose: To investigate the effects of topical prazosin and pilocarpine on uveoscleral outflow(Fu) in rabbits.Methods: Sixteen rabbits were randomly divided into the control group (5 rabbits, only topical application of normal saline in the right eye of each rabbit), Prazosin (PZ) treated group (6 rabbits, only 0.1% Prazosin eyedrop 0.1% in the right eye of each one) and Pilocarpine (PC) treated group (5 rabbits, 1% Pilocarpine eye drop in each right eye).Intraocular pressure (IOP)of bilateral eyes of each rabbit was measured before and 1 h after topical application of the eye drop.And the bilateral eyes were perfused with Fluorescein-isothiocyanate bovine serum albumin (FITC-BSA) as the tracer into the anterior chamber of each rabbit for 30 min at 90 min after topical treatment. Then the rabbits were killed for Fu measurement.Results: IOP of PZ-treated eyes decreased [ (0.71 +0.07)kPa ] in 1 hour after PZ application.IOP of PC-treated eyes decreased [(0.70+0.08)kPa] in 1 hour after PC application. The average value of Fu was (0.176+0.048)μl/min in control eyes. The average value of Fu in PZ-treated eyes was (0.339+0.018)μl/min. The average value of Fu in PC-treated eye was(0.123+0.022) μl/min.Conclusion: Both of PZ and PC can decrease IOP in rabbits following topical application.Topical PZ can increase Fu in rabbits and this is one of the mechanisms of PZ-induced IOP decrease.Topical PC can prevent Fu. PC decreases IOP not through uveoscleral pathway.This study demonstrates that uveoscleral pathway plays an important role in aqueous humor drainage. PZ may be a novel drug for decreasing IOP. FITC-BSA is an effective tracer for studying uveoscleral pathway.展开更多
Prazosin（PRZ） and levonorgestrel（LNG） are widely used as an anti-disease drugs due to their biological activity in the human body. The frequent detection of these compounds in water samples requires alternative te...Prazosin（PRZ） and levonorgestrel（LNG） are widely used as an anti-disease drugs due to their biological activity in the human body. The frequent detection of these compounds in water samples requires alternative technologies for the removal of both compounds. After electrochemical degradation of PRZ and LNG, the parent compounds could be completely removed after treatment, but the identification and characterization of by-products are necessary as well. In this study, the effects of NaCl concentration and applied voltage were investigated during the electrochemical degradation process. The results revealed that the increase of NaCl concentration and applied voltage could promote the generation of hypochlorite OCl-and then enhance the degradation of PRZ and LNG. After initial study, 6 V and 0.2 g NaCl were selected for further experiments（96% and 99% removal of PRZ and LNG after 40 min, respectively）. Energy consumption was also evaluated and calculated for PRZ and LNG at 3, 6 and 8 V. Solid phase extraction（SPE） method plays an important role in enhancing the detection limit of by-products. Furthermore, characterization and identification of chlorinated and non-chlorinated by-products were conducted using an accurate liquid chromatography-time of flight/mass spectrometry LC-TOF/MS instrument. The monitoring of products during the electrochemical degradation process was performed at6 V and 0.2 g NaCl in a 50 m L solution. The results indicated that two chlorinated products were formed during the electrochemical process. The toxicity of by-products toward E. coli bacteria was investigated at 37°C and 20 hr incubation time.展开更多
文摘Published clinical data of Prazosin were reevaluated pharmacokinetically using explicit solutions to drug concentration as a function of total time for IV bolus injection, intermittent intravenous infusion and oral routes of administration in an open two-compartment model. In a novel way, the apparent volume of distribution was estimated from a two-compartment model and found to be close to the total body water suggesting that Prazosin is distributed in all tissues both extracellularly and intracellularly. In addition, extracting the value of the apparent volume of distribution from a two-compartment model allowed comparative simulations in the one-compartment model. It is shown that dosage calculations of Prazosin intermittent infusion can be safely performed using the simpler one-compartment model equations. Lastly, several additional time-dependent pharmacokinetic parameters e.g., the peak time in the central and peripheral compartment and non-steady state and steady state peak concentration and AUC were determined using series equations for all three routes of administration, as a function of dose number and total time upon multiple drug administrations in the two-compartment model. It is also the first time that steady-state plasma drug concentration equations were derived in a two-compartment mammillary model.
基金AAP is supported by the Heart and Stroke Foundation of Canadathe Michael Smith Foundation for Health Research+3 种基金AVK is supported by the Paralyzed Veterans of Americathe Craig Neilson Foundationthe Canadian Institute of Health Researchthe Heart and Stroke Foundation of Canada
文摘Spinal cord injury （SCI） is a devastating condition that not only results in a loss of motor functions but also severe autonomic dysfunctions （Krassioukov and Claydon, 2006）. Autonomic dysreflexia （AD） is a life threatening episode of tran- sient hypertension that occurs up to 30x/day （1 Ix/day on average） in those with cervical or high thoracic SCI （Hubli et al., 2015）. Most common triggers of AD are from stimuli such as a full bowel and/or bladder, or sexual arousal （Teasell et al., 2000）. Penile vibrostimulation （PVS） is a clinical pro- cedure for sperm retrieval used for the purpose of family planning or fertility assessment that unfortunately iatrogenically induces episodes of AD （Elliott, 2006）. Recently, we published a clinical trial highlighting that prazosin may be a viable option for treating AD secondary to PVS （Phillips et al., 2014）.
文摘In this study, a new naphthalene-prazosin derivative (compound 5) was synthetized with the objective of evaluating its activity on ischemia/reperfusion injury. The Langendorff technique was used to evaluate the effect of the compound 5 on ischemia/reperfusion injury. Additionally, the mechanism of action involved in the activity exerted by the compound 5 on perfusion pressure and coronary resistance was evaluated by measuring left ventricular pressure in absence or presence of following compounds;prazosin, metoprolol, indomethacin and nifedipine. The results showed that the compound 5 reduced infarct size compared with the control conditions. Other results showed that the compound 5 significantly increases (p = 0.05) the perfusion pressure and coronary resistance in isolated rat heart. In addition, other data indicate that the compound 5 increases left ventricular pressure in a dose-dependent manner (0.001 to 100 nM);however, this phenomenon was significantly inhibited by nifedipine at a dose of 1 nM (p = 0.05) and this effect was independent of cAMP levels. In conclusion, these data suggest that the naphthalene-prazosin derivative exerts a cardio protective effect via the calcium channels activation and consequently induces changes in the left ventricular pressure levels. This phenomenon results in a decrease of myocardial necrosis after ischemia and reperfusion.
基金This study is supported by Chinese Natural Science Foundation (No.39370724)
文摘Purpose: To investigate the effects of topical prazosin and pilocarpine on uveoscleral outflow(Fu) in rabbits.Methods: Sixteen rabbits were randomly divided into the control group (5 rabbits, only topical application of normal saline in the right eye of each rabbit), Prazosin (PZ) treated group (6 rabbits, only 0.1% Prazosin eyedrop 0.1% in the right eye of each one) and Pilocarpine (PC) treated group (5 rabbits, 1% Pilocarpine eye drop in each right eye).Intraocular pressure (IOP)of bilateral eyes of each rabbit was measured before and 1 h after topical application of the eye drop.And the bilateral eyes were perfused with Fluorescein-isothiocyanate bovine serum albumin (FITC-BSA) as the tracer into the anterior chamber of each rabbit for 30 min at 90 min after topical treatment. Then the rabbits were killed for Fu measurement.Results: IOP of PZ-treated eyes decreased [ (0.71 +0.07)kPa ] in 1 hour after PZ application.IOP of PC-treated eyes decreased [(0.70+0.08)kPa] in 1 hour after PC application. The average value of Fu was (0.176+0.048)μl/min in control eyes. The average value of Fu in PZ-treated eyes was (0.339+0.018)μl/min. The average value of Fu in PC-treated eye was(0.123+0.022) μl/min.Conclusion: Both of PZ and PC can decrease IOP in rabbits following topical application.Topical PZ can increase Fu in rabbits and this is one of the mechanisms of PZ-induced IOP decrease.Topical PC can prevent Fu. PC decreases IOP not through uveoscleral pathway.This study demonstrates that uveoscleral pathway plays an important role in aqueous humor drainage. PZ may be a novel drug for decreasing IOP. FITC-BSA is an effective tracer for studying uveoscleral pathway.
基金Universiti Kebangsaan Malaysia for the scholarship of Z. H. Mussa (matric No. p69014)
文摘Prazosin（PRZ） and levonorgestrel（LNG） are widely used as an anti-disease drugs due to their biological activity in the human body. The frequent detection of these compounds in water samples requires alternative technologies for the removal of both compounds. After electrochemical degradation of PRZ and LNG, the parent compounds could be completely removed after treatment, but the identification and characterization of by-products are necessary as well. In this study, the effects of NaCl concentration and applied voltage were investigated during the electrochemical degradation process. The results revealed that the increase of NaCl concentration and applied voltage could promote the generation of hypochlorite OCl-and then enhance the degradation of PRZ and LNG. After initial study, 6 V and 0.2 g NaCl were selected for further experiments（96% and 99% removal of PRZ and LNG after 40 min, respectively）. Energy consumption was also evaluated and calculated for PRZ and LNG at 3, 6 and 8 V. Solid phase extraction（SPE） method plays an important role in enhancing the detection limit of by-products. Furthermore, characterization and identification of chlorinated and non-chlorinated by-products were conducted using an accurate liquid chromatography-time of flight/mass spectrometry LC-TOF/MS instrument. The monitoring of products during the electrochemical degradation process was performed at6 V and 0.2 g NaCl in a 50 m L solution. The results indicated that two chlorinated products were formed during the electrochemical process. The toxicity of by-products toward E. coli bacteria was investigated at 37°C and 20 hr incubation time.
