Adrenergic receptors blockade alleviates dexamethasone-induced neurotoxicity in adult male Wistar rats: Distinct effects on β-arrestin2 expression and molecular markers of neural injury

BACKGROUND

Dexamethasone-induced neurotoxicity has been previously reported. However, the molecular mechanisms are still not completely understood.

OBJECTIVES

The current work aimed to investigate the modulatory effects of α- and β-adrenergic receptors on dexamethasone-induced neurotoxicity in rats focused on changes in β-arrestin2 and molecular markers of neural injury in cerebral cortex.

METHODS

Male Wistar rats were subcutaneously injected with dexamethasone (10 mg/kg/day) for 7 days to induce neural injury in the cerebral cortex. The experiment involved 5 groups: control, dexamethasone, carvedilol, propranolol, and doxazosin. In the last 3 groups, drugs were given 2 hours before dexamethasone injection. At the end of experiment, brain samples were collected for measurement of brain derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), kinase activity of protein kinase B (Akt), diacylglycerol (DAG), α-smooth muscle actin (α-SMA), Smad3, β-amyloid and phospho-tau protein levels in addition to histopathological examination of brain tissue using hematoxylin-eosin, Nissl, and Sirius red stains. Moreover, β-arrestin2 levels in the cerebral cortex were measured using immunohistochemical examination.

RESULTS

Dexamethasone slightly reduced brain weight and significantly decreased BDNF, Akt kinase activity and β-arrestin2 but markedly induced degeneration of cortical neurons and significantly increased GFAP, DAG, α-SMA, Smad3, β-amyloid and phospho-tau protein levels compared to controls. Carvedilol, propranolol, and doxazosin reversed all dexamethasone-induced molecular changes and slightly ameliorated the histopathological changes. Carvedilol significantly increased brain weight and β-arrestin2 levels compared to dexamethasone, propranolol, and doxazosin groups.

CONCLUSION

blocking α- and/or β-adrenergic receptors alleviate dexamethasone-induced neurotoxicity despite their distinct effects on β-arrestin2 levels in the cerebral cortex.

The combination of doxazosin and metyrosine as a preoperative treatment for pheochromocytomas and paragangliomas

PURPOSE

Preoperative medical management is critical to prevent intraoperative cardiovascular complications in patients with pheochromocytomas and paragangliomas (PPGLs). Initial treatment involves α-adrenergic receptor blockers. However, while the routine use of metyrosine alongside these blockers is not strongly recommended due to a lack of evidence supporting its efficacy and associated safety concerns, there are previous studies on combination therapy with phenoxybenzamine and metyrosine. There are few reports on combination therapy with the selective α1-adrenergic receptor blocker doxazosin. Therefore, we investigated this combination treatment, which theoretically can affect perioperative outcomes in patients with PPGLs. To our knowledge, this is the first such study.

METHODS

This retrospective single-center observational study involved 51 patients who underwent surgical resection of PPGLs at Kobe University Hospital between 2014 and 2022. All patients received doxazosin at maximum doses. Fourteen patients received concomitant metyrosine, while 37 received doxazosin alone. Their perioperative outcomes were compared.

RESULTS

No severe event, such as acute coronary syndrome, was observed in either group. Intraoperatively, the doxazosin + metyrosine group exhibited a lower median minimum systolic blood pressure (56 [54-60] vs. 68 [59-74] mmHg, P = 0.03) and required lower median remifentanil (P = 0.04) and diltiazem (P = 0.02) doses than the doxazosin-alone group.

CONCLUSION

The combination of metyrosine and doxazosin as a preoperative treatment for PPGLs affects intraoperative circulatory hemodynamics, such as a reduced occurrence of blood pressure elevation during surgery. Further research is necessary to identify patients who will benefit most from this combination treatment.

Effect of different alpha-receptor antagonists on metabolic parameters: a head-to-head comparison

PURPOSE

Although it is known that alpha-adrenergic receptor antagonists have positive effects on metabolic parameters such as glucose metabolism, lipid profile, and insulin sensitivity, it is unclear whether this is a class effect. Tamsulosin is reported to have adverse effects on glucose metabolism and insulin resistance, and this may be because of its lack of glycolysis-enhancing effect compared with other alpha-adrenergic receptor antagonists with glycolysis-enhancing effects such as doxazosin, terazosin, and alfuzosin. The aim of this study was to compare the effect of tamsulosin on metabolic parameters with another alpha-1 adrenergic receptor antagonist, doxazosin.

METHODS

In this prospective, observational, controlled, 12-week clinical study, a total of 60 male patients aged ≥ 40 years who were first started on tamsulosin (n = 30; 0.4 mg/day, oral; mean age, 59.20 ± 8.97 years) or doxazosin (n = 30; 4 or 8 mg/day, oral; mean age, 58.50 ± 8.93 years) for benign prostatic hyperplasia (BPH) or lower urinary tract symptoms (LUTS) were enrolled. The groups were compared according to the changes in anthropometric and biochemical parameters (glycemia, lipid profile, and insulin sensitivity) at the end of treatment.

RESULTS

In intragroup analyses, systolic blood pressure, diastolic blood pressure, total cholesterol, and HbA1c levels decreased significantly in the doxazosin group compared with baseline (p < 0.05 for all), while no significant change was observed in the tamsulosin group. In comparisons between groups, systolic blood pressure, total cholesterol, and low-density lipoprotein cholesterol levels showed a significant decrease in the doxazosin group compared with the tamsulosin group (percent change: - 6.68 ± 13.08 vs. 0.53 ± 11.02, p = 0.025; - 3.63 ± 9.56 vs. 4.02 ± 10.86, p = 0.005; and - 5.62 ± 18.18 vs. 5.24 ± 15.42, p = 0.015, respectively).

CONCLUSION

Although these results do not support previous findings that tamsulosin has adverse effects on metabolic parameters, they suggest that doxazosin treatment may be a reason for preference in patients with BPH or LUTS accompanied by metabolic disorder.

Suppression of TNBC metastasis by doxazosin, a novel dual inhibitor of c-MET/EGFR

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by aggressive growth and a high propensity for recurrence and metastasis. Simultaneous overexpression of c-MET and EGFR in TNBC is associated with worse clinicopathological features and unfavorable outcomes. Although the development of new c-MET inhibitors and the emergence of 3rd-generation EGFR inhibitors represent promising treatment options, the high costs involved limit the accessibility of these drugs. In the present study, we sought to investigate the therapeutic potential of doxazosin (DOXA), a generic drug for benign prostate hyperplasia, in targeting TNBC.

METHODS

The effect of DOXA on TNBC cell lines in vitro was evaluated in terms of cell viability, apoptosis, c-MET/EGFR signaling pathway, molecular docking studies and impact on cancer stem cell (CSC)-like properties. An in vivo metastatic model with CSCs was used to evaluate the efficacy of DOXA.

RESULTS

DOXA exhibits notable anti-proliferative effects on TNBC cells by inducing apoptosis via caspase activation. Molecular docking studies revealed the direct interaction of DOXA with the tyrosine kinase domains of c-MET and EGFR. Consequently, DOXA disrupts important survival pathways including AKT, MEK/ERK, and JAK/STAT3, while suppressing CSC-like characteristics including CD44high/CD24low subpopulations, aldehyde dehydrogenase 1 (ALDH1) activity and formation of mammospheres. DOXA administration was found to suppress tumor growth, intra- and peri-tumoral angiogenesis and distant metastasis in an orthotopic allograft model with CSC-enriched populations. Furthermore, no toxic effects of DOXA were observed in hepatic or renal function.

CONCLUSIONS

Our findings highlight the potential of DOXA as a therapeutic option for metastatic TNBC, warranting further investigation.

Anti-cell Proliferative Mechanism of Doxazosin on Human Oral Cancer Cells Through the Modulation of Antioxidant and Apoptotic Pathway

Oral squamous cell carcinoma (OSCC), a global threatening disease, is reported mostly in the middle and elderly male population. Even though the exact cause of OSCC was not known, consumption of tobacco in any form has been reported in most of OSCC patients. OSCC is a massive invasive type of cancer which easily spreads to the distant organs. Hence treating it at appropriate time is necessary and the rate of OSCC incidence is also constantly increasing. At present, chemoradiation is the only therapy prescribed for OSCC patients which renders various side effects. Hence, the treatment with lesser side effect was of current research interest. Doxazosin (α1 adrenorecptor antagonist) had been proven to render anticancer effect in prostate, renal, hepatic, and ovarian cancers but its role in oral cancer cells was not been elucidated. Therefore, we have assessed the anticancer effect of doxazosin on oral squamous cancer cells via through the induction of apoptosis, and antioxidant property. The cytoprotective effect of doxazosin on normal Vero cells and anticancer effect on oral cancer KB cells were analyzed with MTT assay. Doxazosin antioxidant activity were analyzed by their reactivity with free radicals and metal ions by the method of FRAP, DPPH, chemilumiscence, and ORAC assay. The antioxidant levels were also assessed by TBARS, SOD, and glutathione levels, and later on apoptosis staining techniques like DCFH-DA, Rhodamine 123, and AO/EtBr stain were conducted. Apoptosis was confirmed by estimating the levels of apoptotic proteins in doxazosin-treated KB human oral cancer cells by ELISA method. The results from our study show that doxazosin is a potent antioxidant and it significantly induces apoptosis in human oral cancer by altering various cellular molecules at downstream signaling which has been depict in the results. Our study proves doxazosin as a potent anticancer drug which may be used in the treatment of oral carcinoma, if it is subjected to further research using human clinical trials.

Drug repositioning: doxazosin attenuates the virulence factors and biofilm formation in Gram-negative bacteria

The resistance development is an increasing global health risk that needs innovative solutions. Repurposing drugs to serve as anti-virulence agents is suggested as an advantageous strategy to diminish bacterial resistance development. Bacterial virulence is controlled by quorum sensing (QS) system that orchestrates the expression of biofilm formation, motility, and virulence factors production as enzymes and virulent pigments. Interfering with QS could lead to bacterial virulence mitigation without affecting bacterial growth that does not result in bacterial resistance development. This study investigated the probable anti-virulence and anti-QS activities of α-adrenoreceptor blocker doxazosin against Proteus mirabilis and Pseudomonas aeruginosa. Besides in silico study, in vitro and in vivo investigations were conducted to assess the doxazosin anti-virulence actions. Doxazosin significantly diminished the biofilm formation and release of QS-controlled Chromobacterium violaceum pigment and virulence factors in P. aeruginosa and P. mirabilis, and downregulated the QS encoding genes in P. aeruginosa. Virtually, doxazosin interfered with QS proteins, and in vivo protected mice against P. mirabilis and P. aeruginosa. The role of the membranal sensors as QseC and PmrA was recognized in enhancing the Gram-negative virulence. Doxazosin downregulated the membranal sensors PmR and QseC encoding genes and could in silico interfere with them. In conclusion, this study preliminary documents the probable anti-QS and anti-virulence activities of doxazosin, which indicate its possible application as an alternative or in addition to antibiotics. However, extended toxicological and pharmacological investigations are essential to approve the feasible clinical application of doxazosin as novel efficient anti-virulence agent. KEY POINTS: • Anti-hypertensive doxazosin acquires anti-quorum sensing activities • Doxazosin diminishes the virulence of Proteus mirabilis and Pseudomonas aeruginosa • Doxazosin could dimmish the bacterial espionage.

The Effects of Verapamil, Hydralazine, and Doxazosin on Renin, Aldosterone, and the Ratio Thereof

PURPOSE

Hydralazine, doxazosin, and verapamil are currently recommended by the Endocrine Society as acceptable bridging treatment in those in whom full cessation of antihypertensive medication is infeasible during screening for primary aldosteronism (PA). This is under the assumption that they cause minimal to no effect on the aldosterone-to-renin ratio, the most widely used screening test for PA. However, limited evidence is available regarding the effects of these particular drugs on said ratio.

METHODS

In the present study, we retrospectively assessed the changes in aldosterone, renin, and aldosterone-to-renin values in essential hypertensive participants before and after treatment with either hydralazine (n = 26) or doxazosin (n = 20) or verapamil (n = 15). All samples were taken under highly standardized conditions.

RESULTS

Hydralazine resulted in a borderline significant rise in active plasma renin concentration (19 vs 25 mIU/L, p = 0.067) and a significant fall in the aldosterone-to-renin ratio (38 vs 24, p = 0.017). Doxazosin caused declines in both plasma aldosterone concentration (470 vs 330 pmol/L, p = 0.028) and the aldosterone-to-renin ratio (30 vs 20, p = 0.020). With respect to verapamil, we found no statistically significant effect on any of these outcome variables.

CONCLUSION

We conclude that the assumption that these drugs can be used with little consequence to the aldosterone-to-renin cannot be substantiated. While it is possible that they are indeed the best option when full antihypertensive drug cessation is infeasible, the potential effects of these drugs must still be taken into account when interpreting the aldosterone-to-renin ratio.

α1-Adrenergic receptor mediates adipose-derived stem cell sheet-induced protection against chronic heart failure after myocardial infarction in rats

Cell-based therapy using adipose-derived stem cells (ADSCs) has emerged as a novel therapeutic approach to treat heart failure after myocardial infarction (MI). The purpose of this study was to determine whether inhibition of α1-adrenergic receptors (α1-ARs) in ADSCs attenuates ADSC sheet-induced improvements in cardiac functions and inhibition of remodeling after MI. ADSCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ADSCs, we determined the mRNA levels of vascular endothelial growth factor (VEGF)-A and α1-AR under normoxia or hypoxia and the effects of norepinephrine and an α1-blocker, doxazosin, on the mRNA levels of angiogenic factors. Hypoxia increased α1-AR and VEGF mRNA levels in ADSCs. Norepinephrine further increased VEGF mRNA expression under hypoxia; this effect was abolished by doxazosin. Tube formation of human umbilical vein endothelial cells was promoted by conditioned media of ADSCs treated with the α1 stimulant phenylephrine under hypoxia but not by those of ADSCs pretreated with phenylephrine plus doxazosin. In in vivo studies using rats with MI, transplanted ADSC sheets improved cardiac functions, facilitated neovascularization, and suppressed fibrosis after MI. These effects were abolished by doxazosin treatment. Pathway analysis from RNA sequencing data predicted significant upregulation of α1-AR mRNA expression in transplanted ADSC sheets and the involvement of α1-ARs in angiogenesis through VEGF. In conclusion, doxazosin abolished the beneficial effects of ADSC sheets on rat MI hearts as well as the enhancing effect of norepinephrine on VEGF expression in ADSCs, indicating that ADSC sheets promote angiogenesis and prevent cardiac dysfunction and remodeling after MI via their α1-ARs.

Analysis of Voiding Impairment after Prostate Biopsy and the Effect of Doxazosin Treatment: Outcomes from a Regional Cancer Center

INTRODUCTION

The aim of this study was to investigate the association of transrectal ultrasound (TRUS)-guided prostate biopsy with voiding impairment and the efficacy of doxazosin treatment.

METHODS

A prospective observational study including 200 male patients undergoing TRUS-guided prostate biopsy was performed between May 2020 and December 2020. One hundred patients underwent biopsy with doxazosin (doxazosin group). The remaining 100 patients underwent biopsy without doxazosin (control group). All patients were questioned regarding post-biopsy voiding difficulty and acute urinary retention. The International Prostate Symptom Score (IPSS), maximal urinary flow rate (Qmax), and residual urine volume were recorded before biopsy and at 7 and 30 days after biopsy.

RESULTS

There were no significant differences in baseline parameters between the two groups. The rate of post-biopsy voiding difficulty in the doxazosin group was significantly lower than that in the control group. Compared with baseline values, doxazosin treatment significantly improved IPSS, quality of life scores, and Qmax after biopsy (p < 0.05). The baseline values of IPSS and prostate size may be risk factors for post-biopsy voiding difficulty.

CONCLUSION

TRUS-guided prostate biopsy causes transient voiding impairments, which may be improved by doxazosin treatment.

Hypertension in Pheochromocytoma and Paraganglioma: Evaluation and Management in Pediatric Patients

PURPOSE OF REVIEW

The rare catecholamine-secreting tumors, pheochromocytomas and paragangliomas (PPGL), account for a minority of cases of secondary hypertension in pediatrics. As such, perioperative blood pressure (BP) management in pediatric patients presents a distinct challenge. This review will expand the practitioner's knowledge of antihypertensive treatment options for the pediatric patient with PPGL with a focus on literature in the past several years.

RECENT FINDINGS

There continue to be only small case series and single-center experiences to provide guidelines regarding BP management. While phenoxybenzamine has been more routinely used, selective α₁-blockers, such as doxazosin, as well as calcium channel blockers, have also been utilized with success in pediatric patients. While the concept of obligatory α-adrenergic blockade for adult patients has been recently challenged, international guidelines and current practice patterns among pediatric clinicians continue to support preoperative α-adrenergic blockade to ensure the best possible patient outcomes. Selective α₁-blockers and calcium channel blockers are becoming more commonly used given the high cost, limited availability, and undesirable side effect profile of phenoxybenzamine.

Evaluation of the effect of doxasozin and zonisamide on voluntary ethanol intake in mice that experienced chronic intermittent ethanol exposure and stress

The comorbidity between alcohol use disorder and post-traumatic stress disorder represents a serious health care burden with few effective treatment options. The current study was designed to evaluate the effect of an alpha 1 receptor antagonist (doxazosin) and a novel anticonvulsant (zonisamide) in a model of alcohol (ethanol) dependence and stress exposure. The main dependent variable was voluntary ethanol intake in mice that experienced chronic intermittent ethanol (CIE) exposure and forced swim stress (FSS) alone, and in combination. Adult male and female C57BL/6J mice had access to a single bottle of 15% (v/v) ethanol for 1-hr in the home cage, 3-hr into the dark phase of the light/dark cycle. Once stable ethanol intake was established (~4 weeks), mice were separated into four groups (CTL, CIE, FSS, CIE + FSS). Mice in the FSS condition received 10-min FSS exposure 4-hr prior to drinking sessions (remaining mice were not disturbed). During baseline and the first two test cycles, all mice received vehicle (saline) injections (IP) 30-min before ethanol access. As previously observed, FSS increased ethanol drinking in dependent (CIE-exposed) mice but not in nondependent control (CTL) mice. In the following test cycles mice were evaluated for ethanol intake after administration of doxazosin, zonisamide or their combination. Results indicated that the three doses of doxazosin evaluated significantly reduced voluntary ethanol intake in all mice. Zonisamide had a more modest effect and may require a more prolonged treatment regime. The combined administration of both compounds was not more effective than each drug alone. This study suggests that doxazosin is reliable at reducing voluntary ethanol intake in mice independently of their history of ethanol dependence and stress exposure.

Photolytic and photocatalytic degradation of doxazosin in aqueous solution

Doxazosin (DOX), a selective alpha blocker, is widely used in medical therapy as an effective antihypertensive agent. It is a frequently prescribed drug and for this reason, environmental and ecotoxicological research is of great importance in terms of exposure and risk for both aquatic species and humans. In this study we focused on photolytic and TiO₂ photocatalytic degradation processes of doxazosin under different simulated conditions, with the emphasis on identification of degradation products. Photolytic (without TiO₂) experiments were performed in the presence and absence of oxygen, while photocatalytic degradation of doxazosin aqueous solution has been carried out under constant oxygen flow. DOX degradation was more efficient in the TiO₂/UVA photocatalytic experiment than during photolytic processes (UVA and UVC, UVC-N₂). LC-HRMS analyses with electrospray ionization allowed observing the formation of several major degradation products depending on the reaction conditions (presence or absence of oxygen, photocatalysis). The transformation products were identified based on exact mass measurements, isotopic distribution, and fragmentation pattern. Among them, dominated C₁₇H₂₁N₅O₃ and C₁₇H₂₃N₅O₄ (cleavage of the dioxane cycle), and C₂₃H₂₅N₅O₇ (hydroxylation). The detailed degradation pathway has been proposed. Toxicity testing with V. fischeri luminescent bacteria revealed higher toxicity of samples in photolytic rather than photocatalytic experiments which might be attributed to the formation of different products.

Mending the fluorescence of two α-blockers through a semiquinoid formation: Hyphenated with experimental design optimization

Herein, a selective and rapid spectrofluorimetric method coupled with experimental design approach for reliable and efficient determination of two α-blockers, namely: terazosin hydrochloride (TER) and doxazosin mesylate (DOX) in their marketed tablets was developed. The presented method adopts formation of a semi-quinoid form of the studied drugs in borate buffer. The effects of parameters influencing fluorescence intensity including pH, the volume of buffer and diluting solvent were optimized using an experimental design methodology. The optimum conditions were found to be pH: 9.8, the volume of buffer: 2.0 mL and diluting solvent: water. Under the optimum experimental conditions, a large enhancement of the studied drugs fluorescence was obtained, measured at 387 after excitation at 246 nm for either TER or DOX with limits of detection 0.05 and 0.14 ng mL^-1 and limits of quantification 0.14 and 0.43 ng mL^-1 in the concentration ranges of 0.2-30.0 ng mL^-1 and 0.5-30.0 ng mL^-1 for TER and DOX, respectively. The presented method was validated according to the ICH guidelines. Furthermore, it extended to perform the content uniformity testing and analysis of the studied drugs in spiked human plasma with % recovery (96.00 ± 0.45-101.42 ± 1.20%, n = 3).

Dimeric small molecule agonists of EphA2 receptor inhibit glioblastoma cell growth

EphA2 receptor kinase could become a novel target for anti-glioblastoma treatment. Doxazosin previously identified acts like the endogenous ligand of EphA2 and induces cell apoptosis. Through lead structure modification a derivative of Doxazosin possessing unique dimeric structure showed an improvement in the activity. In the current study, we expanded the dimeric scaffold by lead optimization to explore the chemical space of the conjoining moieties and a slight variation to the core structure. 27 new derivatives were synthesized and examined with EphA2 overexpressed and wild type glioblastoma cell lines for cell proliferation and EphA2 activation. Three new compounds 3d, 3e, and 7bg showed potent and selective activities against the growth of EphA2 overexpressed glioblastoma cells. Dimer 3d modification replaces the long alkyl chain with a short polyethylene glycol chain. Dimer 7bg has a relatively longer polyethylene glycol chain in comparison to compound 3d and the length is more similar to the lead compound. Whereas dimer 3e has a rigid aromatic linker exploring the chemical space. The diversity of the linkers in the active suggest additional hydrogen binding sites has a positive correlation to the activity. All three dimers showed selective activity in EphA2 overexpressed cells, indicating the activity is correlated to the EphA2 targeting effect.

Potential role of EphrinA2 receptors in postconditioning induced cardioprotection in rats

EphA2 receptor has emerged as a novel cardioprotective target against myocardial infarction by preserving cardiac function, limiting infarct size and inflammation and enhancing cell survival via elevating phosphorylated Akt protein levels. However, the role of Eph receptors in postconditioning remains to be elucidated. Thus, the present study was designed to explore the role of EphA2 receptors in cardioprotective mechanism of postconditioning by employing Doxazosin as EphA2 receptor agonist, Lithocholic acid as antagonist and Wortmannin as specific phosphoinositide 3-kinase (PI3K) inhibitor. In Langendorff perfused isolated rat hearts, exposure of ischemia for 30 min succeeded by reperfusion for 2 h produced cardiac damage as determined by increase in size of infarct, LVDP, liberation of LDH and CK in effluent from coronary arteries. The reperfused hearts were homogenized and tissue concentrations of TBARs, reduced GSH and Catalase were determined. A marked rise in infarct size, liberation of LDH and CK in effluent and TBARs in myocardial tissue was observed in ischemic and reperfused hearts. Ischemic postconditioning comprising of 6 alternate episodes of 10 s ischemia and 10 s reperfusion and pharmacological post-conditioning by Doxazosin infusion for 5 min Before reperfusion confers significant protection against myocardial injury as manifested by remarkably decreased infarct size, levels of LDH, CK and tissue TBARs along with increase in GSH and Catalase activity. Pre-treatment of EphA2 antagonist, Lithocholic acid and PI3K inhibitor, Wortmannin attenuated the cardioprotective effect of postconditioning. Our results suggest that EphA2 receptors may be involved in postconditioning mediated cardioprotection probably through PI3K/Akt pathway.

Kaolinite/cashew gum bionanocomposite for doxazosin incorporation and its release

Incorporation of drugs in clay minerals has been widely proposed for the controlled-release or increased solubility of drugs. In this context, a bionanocomposite based on kaolinite and cashew gum (Kln/Gum) was synthesized and characterized by X-ray diffraction (XRD), thermal analysis (TG/DTA), and Fourier transform infrared spectroscopy (FTIR). The bionanocomposite was applied to the incorporation and further release of doxazosin mesylate (DB). The influence of solution pH (1-3), adsorbent dose (20-50 mg), initial drug concentration (20.0-70.0 mg L^-1), contact time (15-300 min), and temperature (25, 35, and 45 °C) were systematically evaluated. Equilibrium was reached around 60 min, with a maximum adsorption capacity of 31.5 ± 2.0 mg g^-1 at a pH of 3.0 and 25 °C. Hydrogen bonding contributed to DB incorporation on the Kln/Gum. In addition, DB maximum amounts of 16.80 ± 0.58 and 77.00 ± 2.46% were released at pH values of 1.2 and 7.4, respectively. These results indicated that the Kln/Gum bionanocomposite is an effective and promising material for the incorporation/release of drugs with similar structures to DB.

Primary aldosteronism in Klinefelter's syndrome: two cases

SUMMARY

Primary aldosteronism (PA) is more common than expected. Aberrant adrenal expression of luteinizing hormone (LH) receptor in patients with PA has been reported; however, its physiological role on the development of PA is still unknown. Herein, we report two unique cases of PA in patients with untreated Klinefelter's syndrome, characterized as increased serum LH, suggesting a possible contribution of the syndrome to PA development. Case 1 was a 39-year-old man with obesity and hypertension since his 20s. His plasma aldosterone concentration (PAC) and renin activity (PRA) were 220 pg/mL and 0.4 ng/mL/h, respectively. He was diagnosed as having bilateral PA by confirmatory tests and adrenal venous sampling (AVS). Klinefelter's syndrome was suspected as he showed gynecomastia and small testes, and it was confirmed on the basis of a low serum total testosterone level (57.3 ng/dL), high serum LH level (50.9 mIU/mL), and chromosome analysis. Case 2 was a 28-year-old man who had untreated Klinefelter's syndrome diagnosed in his childhood and a 2-year history of hypertension and hypokalemia. PAC and PRA were 247 pg/mL and 0.3 ng/mL/h, respectively. He was diagnosed as having a 10 mm-sized aldosterone-producing adenoma (APA) by AVS. In the APA, immunohistochemical analysis showed co-expression of LH receptor and CYP11B2. Our cases of untreated Klinefelter's syndrome complicated with PA suggest that increased serum LH levels and adipose tissues, caused by primary hypogonadism, could contribute to PA development. The possible complication of PA in hypertensive patients with Klinefelter's syndrome should be carefully considered.

LEARNING POINTS

The pathogenesis of primary aldosteronism is still unclear. Expression of luteinizing hormone receptor has been reported in aldosterone-producing adenoma. Serum luteinizing hormone, which is increased in patients with Klinefelter's syndrome, might contribute to the development of primary aldosteronism.

Validated RP-HPLC method for quantification of doxazosin in human plasma: Application in a bioequivalence study

OBJECTIVES

The aim of the present study was to validate a simple, sensitive, HPLC method of analysis of doxazosin in human plasma with fluorescence detection.

METHODS

The validated method employed one-step direct protein precipitation with acetonitrile. Chromatographic separation was attained using a reverse-phase 250mm×4.6mm 5μ Hypersil® BDS C 18 column and the mobile phase consisted of 10mm sodium dihydrogen phosphate dihydrate (pH=3.0) and acetonitrile at a ratio of (65:35 v/v). The method was evaluated in terms of linearity, precision, accuracy, selectivity and stability as per standard guidelines. The total run time was about 4.5min which make this method suitable for high throughput analyses. This method was applied to the bioequivalence study of two doxazosin tablets in healthy human volunteers.

RESULTS

Good linear response was achieved over the range of 5.0-200ng/mL. The observed within- and between-day assay precision ranged from 0.64% to 14.73%; accuracy varied between 94.11% and 105%. The 90% confidence intervals for the ratio Cmax, and AUC 0-∞ of the test product over those of reference were within the acceptable range (0.8-1.25) for bioequivalence.

CONCLUSION

The developed method was simple and could be applied to therapeutic drug monitoring of doxazosin.

Somatostatin analog challenge test in the pre-surgical management of ACTH-secreting pheochromocytoma

SUMMARY

ACTH-secreting pheochromocytoma is a very rare cause of Cushing's syndrome, with a high morbidity and mortality risk due to both cortisol and catecholamines excess. We report the case of a 45-year-old female patient with a 3 cm, high-density, left adrenal mass, diagnosed as an ACTH-secreting pheochromocytoma. The biochemical sensitivity of the tumor to somatostatin analogues was tested by a 100 μg s.c. octreotide administration, which led to an ACTH and cortisol reduction of 50 and 25% respectively. In addition to alpha and beta blockers, preoperative approach to laparoscopic adrenalectomy included octreotide, a somatostatin analogue, together with ketoconazole, in order to achieve an adequate pre-surgical control of cortisol release. Histopathological assessment confirmed an ACTH-secreting pheochromocytoma expressing type 2 and 5 somatostatin receptors (SSTR-2 and -5).

LEARNING POINTS

ACTH-secreting pheochromocytomas represent a rare and severe condition, characterized by high morbidity and mortality risk. Surgical removal of the adrenal mass is the gold standard treatment, but adequate medical therapy is required preoperatively to improve the surgical outcome and to avoid major complications. Somatostatin analogs, in addition to other medications, may represent a useful therapeutic option for the presurgical management of selected patients. In this sense, the octreotide challenge test is a useful tool to predict favorable therapeutic response to the treatment.

Myocardial Infarction with non-obstructed coronaries - atypical presentation of pheochromocytoma

SUMMARY

Although pheochromocytoma classically presents with headaches, palpitations and paroxysmal hypertension, atypical presentations such as cardiomyopathy, stroke and subarachnoid haemorrhage have been infrequently documented. We present in this case report, an uncommon presentation of pheochromocytoma with myocardial infarction with normal coronary arteries (MINOCA). A 79-year-old woman presented with central crushing chest pain radiating to left arm associated with headache, palpitations, sweating and difficulty in breathing. For 2 years, she experienced brief episodes of headache, tinnitus, dizziness, palpitations, and sweating that spontaneously resolved. Clinical examination was unremarkable except for high blood pressure (210/105 mmHg). Her electrocardiogram showed T wave inversions from V1 to V6 and elevated troponins (774 ng/L at baseline and 932 ng/L 3 h from baseline (normal <16 ng/L) in keeping with a diagnosis of non-ST elevated myocardial infarction. Coronary angiography showed normal coronary arteries. Patient was hence treated as myocardial infarction with normal coronaries (MINOCA). Despite appropriate treatment for MINOCA, she continued to experience episodic headaches, palpitations, dizziness and erratic blood pressures (particularly severe hypertension shortly after beta-blocker administration). Further investigations revealed raised urine noradrenaline of 4724 nmol/24 h (<554 nmol/24 h) and urine adrenaline of 92863 nmol/24 h (<77 nmol/24 h). Computerised tomography demonstrated a well-defined rounded mass in right adrenal gland morphological of pheochromocytoma. She underwent laparoscopic right adrenalectomy with histology confirming pheochromocytoma. This case highlights the importance of thorough investigation for the underlying cause for MINOCA. In patients with unexplained erratic blood pressure control, pheochromocytoma should be considered as a differential diagnosis.

LEARNING POINTS

Pheochromocytoma is rare tumour that often presents with non-specific symptoms. It is important to investigate underlying cause of MINOCA. Thorough history is the key to diagnosis.

Prolonged acidosis is a feature of SGLT2i-induced euglycaemic diabetic ketoacidosis

SUMMARY

We describe two cases of SGLT2i-induced euglycaemic diabetic ketoacidosis, which took longer than we anticipated to treat despite initiation of our DKA protocol. Both patients had an unequivocal diagnosis of type 2 diabetes, had poor glycaemic control with a history of metformin intolerance and presented with relatively vague symptoms post-operatively. Neither patient had stopped their SGLT2i pre-operatively, but ought to have by current treatment guidelines.

LEARNING POINTS

SGLT2i-induced EDKA is a more protracted and prolonged metabolic derangement and takes approximately twice as long to treat as hyperglycaemic ketoacidosis. Surgical patients ought to stop SGLT2i medications routinely pre-operatively and only resume them after they have made a full recovery from the operation. While the mechanistic basis for EDKA remains unclear, our observation of marked ketonuria in both patients suggests that impaired ketone excretion may not be the predominant metabolic lesion in every case. Measurement of insulin, C-Peptide, blood and urine ketones as well as glucagon and renal function at the time of initial presentation with EDKA may help to establish why this problem occurs in specific patients.

Bilateral pheochromocytoma after kidney transplantation in neurofibromatosis type 1

We present the case of a 25-year-old male with a history of neurofibromatosis type 1 and bilateral pheochromocytoma 4 years after kidney transplantation that was successfully treated with simultaneous bilateral posterior retroperitoneoscopic adrenalectomy. Learning points: Hypertensive patients with NF1 should always be screened for pheochromocytoma. Pheochromocytoma is rarely associated with transplantation, but it must be ruled out in patients with genetic susceptibility. Posterior retroperitoneoscopic adrenalectomy (PRA) allows more direct access to the adrenal glands, especially in patients with previous abdominal surgeries.

Hypertension due to a deoxycorticosterone-secreting adrenal tumour diagnosed during pregnancy

Mineralocorticoid hypertension is most often caused by autonomous overproduction of aldosterone, but excess of other mineralocorticoid precursors can lead to a similar presentation. 11-Deoxycorticosterone (DOC) excess, which can occur in 11-β hydroxylase or 17-α hydroxylase deficiencies, in DOC-producing adrenocortical tumours or in patients taking 11-β hydroxylase inhibitors, may cause mineralocorticoid hypertension. We report a 35-year-old woman who in the third trimester of pregnancy was found to have a large adrenal mass on routine obstetric ultrasound. On referral to our unit, persistent hypertension and long-standing hypokalaemia was noted, despite good compliance with multiple antihypertensives. Ten years earlier, she had hypertension noted in pregnancy which had persisted after delivery. A MRI scan confirmed the presence of a 12 cm adrenal mass and biochemistry revealed high levels of DOC and low/normal renin, aldosterone and dehydroepiandrosterone, with normal catecholamine levels. The patient was treated with antihypertensives until obstetric delivery, following which she underwent an adrenalectomy. Histology confirmed a large adrenal cortical neoplasm of uncertain malignant potential. Postoperatively, blood pressure and serum potassium normalised, and the antihypertensive medication was stopped. Over 10 years of follow-up, she remains asymptomatic with normal DOC measurements. This case should alert clinicians to the possibility of a diagnosis of a DOC-producing adrenal tumours in patients with adrenal nodules and apparent mineralocorticoid hypertension in the presence of low or normal levels of aldosterone. The associated diagnostic and management challenges are discussed. Learning points: Hypermineralocorticoidism is characterised by hypertension, volume expansion and hypokalaemic alkalosis and is most commonly due to overproduction of aldosterone. However, excess of other mineralocorticoid products, such as DOC, lead to the same syndrome but with normal or low aldosterone levels. The differential diagnosis of resistant hypertension with low renin and low/normal aldosterone includes congenital adrenal hyperplasia, syndrome of apparent mineralocorticoid excess, Cushing's syndrome, Liddle's syndrome and 11-deoxycorticosterone-producing tumours. DOC is one intermediate product in the mineralocorticoid synthesis with weaker activity than aldosterone. However, marked DOC excess seen in 11-β hydroxylase or 17-α hydroxylase deficiencies in DOC-producing adrenocortical tumours or in patients taking 11-β hydroxylase inhibitors, may cause mineralocorticoid hypertension. Excessive production of DOC in adrenocortical tumours has been attributed to reduced activity of the enzymes 11-β hydroxylase and 17-α hydroxylase and increased activity of 21-α hydroxylase. The diagnosis of DOC-producing adrenal tumours is challenging because of its rarity and poor availability of DOC laboratory assays.

Double trouble: two cases of dual adrenal pathologies in one adrenal mass

Context Adrenal incidentalomas (AI) represent an increasingly common problem in modern endocrine practice. The diagnostic approach to AIs can be challenging and occasionally reveals surprising features. Here we describe two rare cases of complex adrenal lesions consisting of phaeochromocytomas with synchronous metastases from extra-adrenal primaries. Case descriptions Patient 1 - a 65-year-old gentleman with a newly diagnosed malignant melanoma was found to harbour an adrenal lesion with suspicious radiographic characteristics. Percutaneous adrenal biopsy was consistent with adrenocortical adenoma. After excision of the skin melanoma and regional lymphatic metastases, he was followed up without imaging. Three years later, he presented with abdominal discomfort and enlargement of his adrenal lesion, associated with high plasma metanephrines. Adrenalectomy revealed a mixed tumour consisting of a large phaeochromocytoma with an embedded melanoma metastasis in its core. Patient 2 - a 63-year-old lady with a history of NF-1-related phaeochromocytoma 20 years ago and previous breast cancer presented with a new adrenal lesion on the contralateral side. Plasma normetanephrine was markedly elevated. Elective adrenalectomy revealed an adrenal tumour consisting of chromaffin cells intermixed with breast carcinoma cells. Conclusions Adrenal incidentalomas require careful evaluation to exclude metastatic disease, especially in the context of a history of previous malignancy. Adrenal biopsy provides limited and potentially misleading information. Phaeochromocytomas are highly vascularised tumours that may function as a sieve, extracting and retaining irregularly shaped cancer cells, thereby yielding adrenal masses with intriguing dual pathology. Learning points: Adrenal incidentalomas require careful evaluation focused on exclusion of underlying hormone excess and malignant pathology. Adrenal biopsy can be misleading and should only be considered in select cases. Phaeochromocytomas harbouring intratumoural metastases from other, extra-adrenal primary malignancies represent rare pathological entities that highlight the complexities that can be presented by adrenal tumours.

An efficient spectrofluorimetric method adopts doxazosin, terazosin and alfuzosin coupling with orthophthalaldehyde: Application in human plasma

A new, selective and sensitive spectrofluorimetric method was designed for the quantitation of doxazosin (DOX), terazosin (TER) and alfuzosin (ALF) in their dosage forms and human plasma. The method adopts efficient derivatization of the studied drugs with ortho-phthalaldehyde (OPA), in the presence of 2-mercaptoethanol in borate buffer (pH9.7) to generate a highly fluorescent isoindole derivatives, which can strongly enhance the fluorescence intensities of the studied drugs, allowing their sensitive determination at 430nm after excitation at 337nm. The fluorescence-concentration plots were rectilinear over the ranges (10.0-400.0) ng/mL. Detection and quantification limits were found to be (0.52-3.88) and (1.59-11.76) ng/mL, respectively. The proposed method was validated according to ICH guidelines, and successfully applied for the determination of pharmaceutical preparations of the studied drugs. Moreover, the high sensitivity of the proposed method permits its successful application to the analysis of the studied drugs in spiked human plasma with % recovery (96.12±1.34-100.66±0.57, n=3). A proposal for the reaction mechanism was presented.

Design and synthesis of small molecule agonists of EphA2 receptor

Ligand-independent activation of EphA2 receptor kinase promotes cancer metastasis and invasion. Activating EphA2 receptor tyrosine kinase with small molecule agonist is a novel strategy to treat EphA2 overexpressing cancer. In this study, we performed a lead optimization of a small molecule Doxazosin that was identified as an EphA2 receptor agonist. 33 new analogs were developed and evaluated; a structure-activity relationship was summarized based on the EphA2 activation of these derivatives. Two new derivative compounds 24 and 27 showed much improved activity compared to Doxazosin. Compound 24 possesses a bulky amide moiety, and compound 27 has a dimeric structure that is very different to the parental compound. Compound 27 with a twelve-carbon linker of the dimer activated the kinase and induced receptor internalization and cell death with the best potency. Another dimer with a six-carbon linker has significantly reduced potency compared to the dimer with a longer linker, suggesting that the length of the linker is critical for the activity of the dimeric agonist. To explore the receptor binding characteristics of the new molecules, we applied a docking study to examine how the small molecule binds to the EphA2 receptor. The results reveal that compounds 24 and 27 form more hydrogen bonds to EphA2 than Doxazosin, suggesting that they may have higher binding affinity to the receptor.

Higher pretreatment blood pressure is associated with greater alcohol drinking reduction in alcohol-dependent individuals treated with doxazosin

BACKGROUND

Preclinical and clinical research suggest that the α₁ receptor antagonist prazosin reduces alcohol consumption. Furthermore, clinical studies indicate a role for prazosin in treating Post-Traumatic Stress Disorder (PTSD) symptoms and a recent trial suggested that pre-treatment blood pressure (BP) predicts therapeutic response for prazosin in PTSD patients. Whether pre-treatment BP may predict response to α₁ blockers in alcohol-dependent (AD) patients is unknown. We previously reported a randomized controlled trial (RCT) where doxazosin, an α₁ receptor antagonist with a more favorable pharmacokinetic profile than prazosin, reduced drinks per week (DPW) and heavy drinking days (HDD) in AD patients with a high family history density of alcoholism. In this study, we tested pre-treatment BP as another potentially valuable clinical moderator of doxazosin's response on alcohol consumption.

METHODS

This was a double-blind placebo-controlled RCT testing doxazosin up to 16mg/day in AD treatment-seeking patients (N=41). The hypothesized moderator effect of baseline standing systolic and diastolic BP on DPW and HDD was tested.

RESULTS

With pre-treatment standing diastolic BP as a moderator, there were significant BP x medication interactions for both DPW [**p=0.009, d=0.80] and HDD [*p=0.018, d=1.11]. Post-hoc analyses indicated significant doxazosin effects in patients with higher standing BP in reducing both DPW and HDD.

CONCLUSION

These findings suggest that higher standing diastolic BP at baseline (pre-treatment) may represent a predictor of doxazosin's response on alcohol consumption in AD patients. These results further elucidate the possible efficacy and mechanisms of action of α₁ receptor antagonism in AD individuals.

Doxazosin oral intake therapy to relieve stent - related urinary symptoms and pain: a prospective, randomized, controlled study

Objective:

To assess the impact of Doxazosin Oral Intake Therapy on urinary symptoms and pain in patients with indwelling ureteral stents

Patients and Methods:

A total of 239 patients with ureteral stone-related hydronephrosis who underwent a double-J stent insertion after ureteroscopic lithotripsy were enrolled. Patients were randomized to receive doxazosin cotrolled release 4 mg once daily for 4 weeks or matching placebo. Patients completed the brief-form Chinese version Ureteric Stent Symptom Questionnaire (USSQ) and quality of life (QoL) score 2 weeks and 4 weeks after stent placement and 4 weeks after stent withdrawal. The analgesic use was also recorded during the stenting period.

Results:

Patients in Doxazosin Oral Intake Therapy group, in the first 2 weeks and second 2 weeks with the stent in situ, expressed significant lower daytime frequency (p=0.028 and p=0.038), nocturia (p=0.021 and p=0.008) and urgency (p=0.012 and p=0.014), respectively. Similarly, flank pain score, QoL score and analgesic use were also significant less in the stenting period. There was no significant difference in scores of urinary symptoms, pain and QoL during the post-stent period between two cohorts.

Conclusions:

Doxazosin Oral Intake Therapy reduced stent-related urinary symptoms, pain and the negative impact on QoL.

Release mechanism of doxazosin from carrageenan matrix tablets: Effect of ionic strength and addition of sodium dodecyl sulphate

The polyelectrolyte matrix tablets loaded with an oppositely charged drug exhibit complex drug-release mechanisms. In this study, the release mechanism of a cationic drug doxazosin mesylate (DM) from matrix tablets based on an anionic polyelectrolyte λ-carrageenan (λ-CARR) is investigated. The drug release rates from λ-CARR matrices are correlated with binding results based on potentiometric measurements using the DM ion-sensitive membrane electrode and with molecular characteristics of the DM-λ-CARR-complex particles through hydrodynamic size measurements. Experiments are performed in solutions with different ionic strength and with the addition of an anionic surfactant sodium dodecyl sulphate (SDS). It is demonstrated that in addition to swelling and erosion of tablets, the release rates depend strongly on cooperative interactions between DM and λ-CARR. Addition of SDS at concentrations below its critical micelle concentration (CMC) slows down the DM release through hydrophobic binding of SDS to the DM-λ-CARR complex. On the contrary, at concentrations above the CMC SDS pulls DM from the complex by forming mixed micelles with it and thus accelerates the release. Results involving SDS show that the concentration of surfactants that are naturally present in gastrointestinal environment may have a great impact on the drug release process.

A comparison of efficacy of doxazosin 4 and 8 mg in medical expulsive therapy of distal ureteral stones: a prospective randomized clinical trial

We aimed to investigate the efficacy of two different doses of doxazosin, 4 and 8 mg, in medical expulsive therapy (MET). This prospective randomized study included a total of 66 patients with distal ureteral stones which were radio-opaque and ≤10 mm. All patients were randomly divided into three groups: Group 1 included 25 patients receiving 4 mg doxazosin. Group 2 included 22 patients receiving 8 mg doxazosin. Diclofenac 100 mg p.o. and daily 1500-2000 cc hydration were advised to the patients in Groups 1 and 2 to relieve pain. Group 3 consisted of 19 patients who were defined as control group and received only hydration and analgesics. The mean age of the patients was 30 ± 7.6, 37.9 ± 11.5 and 33 ± 11.3 in Group 1, Group 2 and Group 3, respectively. The mean stone size was 6.6 ± 1.4, 7.1 ± 1.5 and 6.6 ± 1.5 in Group 1, Group 2 and Group 3, respectively. The stone expulsion rate of the patient groups was 18/25 (72 %), 15/22 (68.1 %) and 5/19 (25.3 %). There were significantly fewer pain episodes and lower analgesic requirement in Groups 1 and 2 (p = 0.021). However, the difference between Group 1 and Group 2 was non-significant (p = 0.207). Given the data of the present study, doxazosin, an alpha receptor blocker, exhibited equal efficacy with 4 or 8 mg doses in MET and was used safely and efficiently in ureteral stones <10 mm. The findings of the present study showed that 4 mg dose is effective, when doxazosin is preferred for MET.

Highly sensitive spectrofluorimetric method for determination of doxazosin through derivatization with fluorescamine; Application to content uniformity testing

A highly sensitive, simple and selective spectrofluorimetric method has been developed and validated for determination of doxazosin mesylate in pure form, pharmaceutical formulations and human plasma. The method is based on the reaction between doxazosin mesylate and fluorescamine in Teorell buffer solution (pH 3) to give highly fluorescent derivative that can be measured at 489 nm using excitation wavelength of 385 nm. Different experimental parameters affecting the reaction were carefully studied and optimized. The calibration plot was constructed over the concentration range of 16-400 ng mL(-1) with quantitation limit of 14.3 ng mL(-1). The developed procedure was validated according to ICH guidelines and the results were satisfactory. The proposed method has been successfully applied to the analysis of the cited drug in its pharmaceutical preparations as well as for content uniformity testing. The results showed excellent agreement with the reported method with respect to precision and accuracy. In addition, the drug concentration was determined in the spiked human plasma by the suggested method with % recovery in the range of 96.2-98.3% (SD; 0.76-0.93, n=5).

Cardio-ankle vascular index (CAVI) differentiates pharmacological properties of vasodilators nicardipine and nitroglycerin in anesthetized rabbits

Cardio-ankle vascular index (CAVI) has been developed for measurement of vascular stiffness from the aorta to tibial artery, which is clinically utilized for assessing the progress of arteriosclerosis. In this study, we established measuring system of the CAVI in rabbits, and assessed whether the index could reflect different pharmacological actions of nitroglycerin and nicardipine on the systemic vasculature. Rabbits were anesthetized with halothane, and the CAVI was calculated from the well-established basic equations with variables obtained from brachial and tibial blood pressure and phonocardiogram. Nicardipine (1, 3 and 10 μg/kg, i.v.) decreased the blood pressure, femoral vascular resistance, and heart-ankle pulse wave velocity (haPWV). Meanwhile, no significant change was detected in the CAVI at the low or middle dose, which reflects the defining feature of the CAVI that is independent of blood pressure. The index increased at the high dose. Nitroglycerin (2, 4 and 8 μg/kg, i.v.) decreased the blood pressure, femoral vascular resistance, and haPWV. Meanwhile, the CAVI was decreased during the nitroglycerin infusion, which may reflect its well-known pharmacological action dilating conduit arteries. These results suggest that the CAVI differentiates the properties of these vasodilators in vivo.

Insights into cardio-oncology: Polypharmacology of quinazoline-based α1-adrenoceptor antagonists

New uses of cardiovascular drugs with proven experience are emerging, including for treating cancer. Quinazoline is a compound made up of two fused six member simple aromatic rings, benzene and pyrimidine rings, with several biological effects. Cardiologists first used quinazoline-based α₁-adrenoceptor antagonists prazosin, doxazosin, and terazosin; currently available data support their use as safe, well tolerated, and effective add-on therapy in uncontrolled hypertension with additional favourable metabolic effects. Recent findings highlight the anticancer effects of quinazoline-based α₁-adrenoceptor antagonists, indicating that they may have a significant role in uncontrolled hypertensive cancer patients without signs of ischemia.

Mixed micelle cloud point-magnetic dispersive μ-solid phase extraction of doxazosin and alfuzosin

Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive μ-solid phase extraction (MD-μ-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe₃O₄ magnetic nanoparticles were used as the adsorbent in MD-μ-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5-300 ng mL(-1), and the limits of detection were 0.21 and 0.16 ng mL(-1), respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples.

Evaluation of the effect of sildenafil and/or doxazosin on Benign prostatic hyperplasia-related lower urinary tract symptoms and erectile dysfunction

PURPOSE

To verify the association between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) and evaluate the influence of sildenafil and doxazosin either as single agents or combined on both symptoms.

MATERIAL AND METHODS

A prospective randomized study including 150 patients presented with LUTS caused by BPH in association with clinically diagnosed ED, with age equal or more than 45 years from April 2010 to April 20011. They were categorized into three comparative groups each one containing 50 patients. These groups were comparable regarding pretreatment international prostate symptoms score (IPSS) and international index of erectile function (IIEF). The patients of the first group were given sildenafil 50 mg as monotherapy, those of the second group were given doxazosin 2 mg and those of the third group were given combination of both drugs for 4 months for each group. The main post-treatment parameters for assessment and comparison include assessment of patient's symptoms by repeated IPS Sand IIEF, uroflowmetry and assessment of PVR. The statistics was done by use of the Qui--square test.

RESULTS

Pre-treatment parameters were assessed and compared between the three groups. After 4 months of treatment, the comparative parameters were applied to all groups and the differences were measured post-treatment regarding IPSS, erectile function score, uroflowmetry, and post-void residual (PVR) urine. Sildenafil alone caused mild improvement in IPSS, more improvement in IIEF score, and little effect on flow rate and PVR urine. Doxazosin alone caused more improvement in IPSS, flow rate and PVR urine and less improvement in IIEF score. A combination of both sildenafil and doxazosin caused more improvement in all of the comparative parameters than when each drug was given alone.

CONCLUSIONS

There is a strong relationship between LUTS and ED. Doxazosin or sidenafil as a single drug could be used in treating mild or mild to moderate symptoms but more severe symptoms may usually need a combination of both drugs.

Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Prazosin, Terazosin, and Doxazosin in Pharmaceutical Formulations

The current study was carried out with an attempt to separate similarly structured title drugs by liquid chromatography. Spectrophotometric techniques were generally insufficient under these conditions because of the spectral overlapping of drugs with similar functional groups. The pharmaceutical drugs prazosin, terazosin, and doxazosin contain the same parent quinazoline nucleus, thus making it especially difficult to separate the former two drugs because of their very similar structures. A simple and sensitive method for the routine determination of these drugs in pharmaceutical formulations was attempted. We found that the mobile phase consisting of A: ACN-diethylamine (0.05 ml), B: methanol, and C: 10 mM Ammonium acetate separated these drugs effectively. Separations were carried out on a new Kromasil C18 column (250 × 4.6 mm, 5.0 μm) at 254 nm wavelength. The calibration curve was found to be linear in the range of 2-500 μg/ml. The stated method was then validated in terms of specificity, linearity, precision, and accuracy. Additionally, the proposed method reduced the duration of the analysis.

Determination of Doxazosin Mesylate in Tablets by RP-HPLC

A simple, precise and rapid RP-HPLC method was developed for the determination of doxazosin mesylate in pharmaceutical formulations. The method was carried out on a Chromolith RP-C₁₈ column using a mixture of potassium phosphate buffer and methanol (40:60 v/v) and detection was done at 251 nm. The linearity range was 1-5 μg/ml. The retention time of the drug was 3.8 min. The LOD and LOQ were found to be 0.1 μg/ml and 0.5 μg/ml, respectively.

Alpha blockers for the treatment of benign prostatic hyperplasia

The evolution of alpha blocker therapy for benign prostatic hyperplasia (BPH) has focused on improving convenience and tolerability. Indications for treating BPH include reversing signs and symptoms or preventing progression of the disease. The indication that most commonly drives the need for intervention is relief of lower urinary tract symptoms (LUTS) with the intent of improving quality of life. Alpha blockers are the most effective, least costly, and best tolerated of the drugs for relieving LUTS. Four long-acting alpha 1 blockers are approved by the Food and Drug Administration for treatment of symptomatic LUTS/BPH: terazosin, doxazosin, tamsulosin, and alfuzosin. All are well tolerated and have comparable dose-dependent effectiveness. Tamsulosin and alfuzosin SR do not require dose titration. Alfuzosin, terazosin, and doxazosin have all been shown to be effective in relieving LUTS/BPH independent of prostate size.