Phosphodiesterase Type 5 Inhibitors for the Treatment of Erectile Dysfunction: Pharmacology and Clinical Impact of the Sildenafil Citrate Orodispersible Tablet Formulation

An overview of conventional and investigational phosphodiesterase 5 inhibitors for treating erectile dysfunction and other conditions

INTRODUCTION

There is a rising concern about developing innovative, efficacious PDE5I molecules that provide better safety, efficacy, and tolerability with less adverse effects. Innovative PDE5I with dual targets have also been defined in the literature. Additionally, some of PDE5I are able to selectively inhibit other enzymes such as histone deacetylase, acetylcholine esterase, and cyclooxygenase or act as nitric oxide donors. This review presents knowledge concerning the advanced trends and perspectives in using PDE5I in treatment of ED and other conditions.

AREAS COVERED

Pre-clinical and early clinical trials that investigated the safety, efficacy, and tolerability of novel PDE5I such as Udenafil, Mirodenafil, Lodenafil, Youkenafil, Celecoxib, and TPN729 in treatment of ED and other conditions.

EXPERT OPINION

Preclinical and limited early clinical studies of the new molecules of PDE5I have demonstrated encouraging results; however, safety, efficacy, and tolerability are still issues that necessitate further long-term multicenter clinical studies to ensure justification of their uses in treatment of ED and other conditions. Progress in molecular delivery techniques and tailored patient-specific management and additional therapeutic technology will dramatically improve care for ED and other conditions. The dream of ED and many other conditions becoming more effectively managed may be feasible in the near future.

Association between air pollution and male sexual function: A nationwide observational study in China

This study aimed to explore the associations between air pollution and male sexual function. A total of 5047 male subjects in China were included in this study. The average air pollution exposure (PM2.5, PM10, SO2, CO, NO2, and O3) for the preceding 1, 3, 6, and 12 months before the participants' response was assessed. Male sexual function was evaluated using the International Index of Erectile Function-5 (IIEF-5) and the Premature Ejaculation Diagnostic Tool (PEDT). Generalized linear models were utilized to explore the associations between air pollution and male sexual function. K-prototype algorithm was conducted to identify the association among specific populations. Significant adverse effects on the IIEF-5 score were observed with NO2 exposure during the preceding 1, 3, and 6 months (1 m: β = -5.26E-05; 3 m: β = -4.83E-05; 6 m: β = -4.23E-05, P < 0.05). PM2.5 exposure during the preceding 12 months was found to significantly negatively affect the PEDT after adjusting for confounding variables. Our research indicated negative correlations between air pollutant exposures and male sexual function for the first time. Furthermore, these associations were more pronounced among specific participants who maintain a normal BMI, exhibit extroverted traits, and currently engage in smoking and alcohol consumption.

Riociguat in patients with sickle cell disease and hypertension or proteinuria (STERIO-SCD): a randomised, double-blind, placebo controlled, phase 1-2 trial

BACKGROUND

Although nitric oxide based therapeutics have been shown in preclinical models to reduce vaso-occlusive events and improve cardiovascular function, a clinical trial of a phosphodiesterase 5 inhibitor increased rates of admission to hospital for pain. We aimed to examine if riociguat, a direct stimulator of the nitric oxide receptor soluble guanylate cyclase, causes similar increases in vaso-occlusive events.

METHODS

This was a phase 1-2, randomised, double blind, placebo-controlled trial. Eligible patients were 18 years or older, had confirmed sickle cell disease documented by haemoglobin electrophoresis or HPLC fractionation (haemoglobin SS, SC, Sβ-thalassemia, SD, or SO-Arab), and stage 1 hypertension or proteinuria. Participants were randomly assigned 1:1 to receive either riociguat or matching placebo via a web-based system to maintain allocation concealment. Both treatments were administered orally starting at 1·0 mg three times a day up to 2·5 mg three times a day (highest tolerated dose) for 12 weeks. Dose escalation by 0·5 mg was considered every 2 weeks if systolic blood pressure was greater than 95 mm Hg and the participant had no signs of hypotension; otherwise, the last dose was maintained. The primary outcome was the proportion of participants who had at least one adjudicated treatment-emergent serious adverse event. The analysis was performed by the intention-to-treat. This trial is registered with ClinicalTrials.gov (NCT02633397) and was completed.

FINDINGS

Between April 11, 2017, and Dec 31, 2021, 165 participants were screened and consented to be enrolled into the study. Of these, 130 participants were randomly assigned to either riociguat (n=66) or placebo (n=64). The proportion of participants with at least one treatment-emergent serious adverse event was 22·7% (n=15) in the riociguat group and 31·3% (n=20) in the placebo group (difference -8·5% [90% CI -21·4 to 4·5]; p=0·19). A similar pattern emerged in other key safety outcomes, sickle cell related vaso-occlusive events (16·7 [n=11] vs 21·9% [n=14]; difference -5·2% [-17·2 to 6·5]; p=0·42), mean pain severity (3·18 vs 3·32; adjusted mean difference -0·14 [-0·70 to 0·42]; p=0·69), and pain interference (3·15 vs 3·12; 0·04 [-0·62 to 0·69]; p=0·93) at 12 weeks were similar between groups. Regarding the key clinical efficacy endpoints, participants taking riociguat had a blood pressure of -8·20 mm Hg (-10·48 to -5·91) compared with -1·24 (-3·58 to 1·10) in those taking placebo (-6·96 mm Hg (90% CI -10·22 to -3·69; p<0·001).

INTERPRETATION

Riociguat was safe and had a significant haemodynamic effect on systemic blood pressure. The results of this study provide measures of effect and variability that will inform power calculations for future trials.

FUNDING

Bayer Pharmaceuticals.

LC-MS/MS methods for simultaneous determination of youkenafil and its metabolite M1 in human seminal plasma and plasma: Application to evaluate the acute effect of youkenafil on semen quality and its pharmacokinetics in human

Youkenafil is a novel Phosphodiesterase type 5 inhibitor used for treating erectile dysfunction. N-desethyl compound of youkenafil (M1) is its main active metabolite. In this study, two methods were developed and validated for the simultaneous determination of youkenafil and M1 by HPLC-MS/MS in human matrices including seminal plasma and plasma, in which the multiple reaction monitoring and electrospray ionization in positive mode were adopted, and the deuterated youkenafil (youkenafil-d5) was selected as the internal standard. The collected semen sample was kept at room temperature for approximately 30 min until fully liquefied. The volume of the liquefied semen was measured and then divided into two parts. One part was centrifuged to obtain the seminal plasma for the content detection of youkenafil and M1, while the other part was used for routine semen analysis. The chromatographic separation was accomplished with the column of Poroshell 120 EC-C18 (5 × 2.1 mm, 2.7 μm, Agilent). Protein precipitation with methanol was used for the pretreatment of seminal plasma and plasma. The intra-run and inter-run precisions were less than 6.4 % (relative standard deviation) and accuracies were all within -4.7 %-6.8 % (relative error) in both matrices. All other validated bioanalytical parameters were within the acceptance criteria set by the FDA. The methods were successfully applied to different clinical studies of youkenafil. In the clinical study of the acute effect of youkenafil on semen quality in healthy males, the content of youkenafil in seminal plasma was extremely low. Concentrations of youkenafil and M1 in seminal plasma were lower than those in plasma, at 20.7 % and 4.49 % of the plasma concentration, respectively. There was no significant acute effect of youkenafil on semen quality. In the pharmacokinetic study of youkenafil after single dose-escalation administration, the exposure to youkenafil and M1 was non-linear with the dose in the range of 100-400 mg.

Ultrasound-targeted microbubble destruction mediates PDE5i/NO integration for cavernosum remodeling and penile rehabilitation

Erectile dysfunction (ED) caused by cavernous nerve injury (CNI) is refractory to heal mainly ascribed to the adverse remodeling of the penis induced by ineffectual microvascular perfusion, fibrosis, and neurotrophins scarcity in cavernosum. Phosphodiesterase type V inhibitors (PDE5i) have been regarded as an alternative candidate drug for avoiding penile neuropathy. However, the therapeutic efficacy is severely limited due to poor accumulation under systemic medication and endogenous nitric oxide (NO) deficiency in cavernosum. Herein, an innovative liposomal microbubble (MB) loaded with both Sildenafil (one of PDE5i) and NO was designed. Ultrasound-targeted MB destruction (UTMD)-mediated efficient release and integration erectogenic agents into corpus cavernosum with high biosafety. On a bilateral CNI rat model, the multifunctional MB-cooperated UTMD improved microvascular perfusion in penis, simultaneously, alleviated hypoxia and oxidative stress, indicating successful activation of NO-cyclic guanosine monophosphate pathway. Also, evaluation of the endothelial/muscular composition, intracavernosal pressure, and neural integrity in the penis proved that coordinated intervention reversed the abnormal structural remodeling and promoted the recovery of functional erection. Our work demonstrates that MB loading Sildenafil and NO combined with UTMD hold great promise to "awaken" the efficacy of PDE5i in neurogenic ED, which provided a superior option for ensuring penile rehabilitation.

Bioequivalence Studies of Sildenafil Citrate Orodispersible Film Administered with and without Water vs ViagraⓇ Film-Coated Tablets in Healthy Male Volunteers

Background

Orodispersible film (ODF) formulation offers ease of use, convenience of administration, and other advantages, especially for patients who have difficulty in swallowing or are on liquid restriction compared with conventional oral formulations for the treatment of erectile dysfunction.

Objectives

These studies compared the bioequivalence of 50 mg sildenafil citrate ODF formulation (test drug) with the marketed 50 mg sildenafil citrate film-coated tablet (FCT) (Viagra^Ⓡ; Pfizer, New York, NY) (reference drug), with and without water in 2 randomized cross-over studies.

Methods

Two randomized cross-over studies were conducted. The first study explored the bioequivalence of test drug administered with and without water compared with the reference drug with water. The second study investigated the bioequivalence of test drug, without water, compared with the reference drug with water. Forty-two and 80 healthy male volunteers were recruited in the first and second study, respectively. All volunteers fasted for 10 hours pre-dose. A 1-day washout period between doses was observed. Blood samples were collected at both before (up to 120 minutes before dosing) and after dosing (at different intervals up to 14 hours) stages. Statistical analyses on pharmacokinetic parameters were performed. Safety and tolerability for both the formulations were evaluated.

Results

In the first study, bioequivalence was demonstrated for sildenafil citrate ODF administered with water when compared with the Viagra^Ⓡ FCT. The ratios of adjusted geometric means (90% confidence interval (CI)) were maximum plasma concentration: 1.02 (94.91-108.78) and area under the plasma concentration-time curve: 1.09 (104.49-113.21) for sildenafil citrate ODF administered with water vs Viagra^Ⓡ FCT. These ratios were within the bioequivalence acceptance range of 80% to 125%, indicating that the bioequivalence criteria were met. The pharmacokinetic parameters for the second study also showed bioequivalence for sildenafil citrate ODF (without water) compared with Viagra^Ⓡ FCT. The ratios of adjusted geometric means (90% CI) were maximum plasma concentration: 1.02 (95.47-109.36) and area under the plasma concentration-time curve: 1.06 (103.42-108.40) for sildenafil citrate ODF administered without water vs Viagra^Ⓡ FCT. Adverse events in both the studies occurred at similar rates for the 2 formulations and were mild in intensity.

Conclusions

These results suggest that the new ODF formulation can be used interchangeably with the marketed FCT formulation. Sildenafil citrate ODF administered with and without water met bioequivalence criteria compared with Viagra^Ⓡ FCT administered with water under fasted conditions in healthy adult male volunteers. The new ODF formulation can be used as a suitable alternative to the conventional oral solid dosage form.

The Italian Society of Andrology and Sexual Medicine (SIAMS), along with ten other Italian Scientific Societies, guidelines on the diagnosis and management of erectile dysfunction

PURPOSE

Erectile dysfunction (ED) is one of the most prevalent male sexual dysfunctions. ED has been in the past mistakenly considered a purely psycho-sexological symptom by patients and doctors. However, an ever-growing body of evidence supporting the role of several organic factors in the pathophysiological mechanisms underlying ED has been recognized.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) commissioned an expert task force involving several other National Societies to provide an updated guideline on the diagnosis and management of ED. Derived recommendations were based on the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Several evidence-based statements were released providing the necessary up-to-date guidance in the context of ED with organic and psychosexual comorbidities. Many of them were related to incorrect lifestyle habits suggesting how to associate pharmacotherapies and counseling, in a couple-centered approach. Having the oral therapy with phosphodiesterase type 5 inhibitors as the gold standard along with several other medical and surgical therapies, new therapeutic or controversial options were also discussed.

CONCLUSIONS

These are the first guidelines based on a multidisciplinary approach that involves the most important Societies related to the field of sexual medicine. This fruitful discussion allowed for a general agreement on several recommendations and suggestions to be reached, which can support all stakeholders in improving couple sexual satisfaction and overall general health.

Comparative Evaluation of Sildenafil Citrate and Estrogen as an Adjuvant Therapy for Treatment of Unexplained Infertility in Women

BACKGROUND

Uterine blood flow determines endometrial thickness. This study examined how vaginal sildenafil citrate and estradiol valerate altered endometrial thickness, blood flow, and fertility in infertile women.

METHODS

This study observed 148 infertile women whose infertility was unexplained. Group 1 comprised 48 patients who received oral estradiol valerate (Cyclo-Progynova 2 mg/12 h white tablets) from day 6 till ovulation was initiated with clomiphene citrate. A number of 50 participants in group 2 received oral sildenafil (Respatio 20 mg/12 h film-coated tablets) for 5 days starting the day after their previous menstrual period and finishing on the day they ovulated with clomiphene citrate. Group 3 was the control group, with 50 patients receiving clomiphene citrate (Technovula 50 mg/12 h tablets) ovulation induction from the 2nd to 7th day of cycle. All patients had transvaginal ultrasounds to determine ovulation, follicle count, and fertility. Miscarriage, ectopic pregnancy, and multiple pregnancies were monitored for three months.

RESULTS

The three groups' mean ETs differed statistically at p = 0.0004. A statistically significant difference was found between the three groups in terms of the number of follicles, with 69% of patients in group 1 having one and 31% having two or more, 76% of patients in group 2 having one and 24% having two or more, and 90% of patients in the control group having one and 10% having two or more (p = 0.038). The clinical pregnancy rates of the three groups were 58%, 46%, and 27%, respectively (p = 0.005). The distribution of all side effects was not statistically different between the three groups.

CONCLUSION

It is possible to claim that adding oral estrogen to clomiphene citrate therapy as an adjuvant therapy can improve endometrial thickness and, as a result, increase the pregnancy rates in unexplained infertility compared to sildenafil, especially in cases where the infertility has lasted less than two years. Most people who take sildenafil end up with a mild headache.

The Role of the "Anti-Inflammatory" Couple for the Management of Hyperuricemia With Deposition

INTRODUCTION

Gout is the most prevalent inflammatory crystal arthropathy worldwide and is a chronic disease requiring strict, lifelong adherence to drug therapy and healthy lifestyles. Gout has a heavy burden on the patient's sexual health, owing to the associated inflammatory status, long-term complications, and chronic pain; however, the effects of gout also extend to the partner's sexual health.

AIMS

We aimed to investigate how the presence of a partner could influence the complex interaction between risk factors for sexual dysfunctions in gout in order to define novel strategies to improve sexual health and disease management.

METHODS

Clinical and experimental data on the role of the couple in chronic diseases, as well as on the association between gout and sexual health, were searched through Pubmed.

MAIN OUTCOME MEASURES

Evidence from studies describing how the presence of a couple and leveraging sexual health can improve management and clinical outcomes for chronic diseases.

RESULTS

Treatment adherence can improve the sexual health of gout patients and their partners; likewise, by leveraging sexual health, it would be possible to promote better health-seeking behaviors, ultimately improving gout management.

CLINICAL IMPLICATIONS

Promoting awareness of the sexual health relevance of gout can potentially be a pivotal strategy to improve disease management and prevent the progression of sexual dysfunctions from subclinical to overt forms.

STRENGTHS AND LIMITATIONS

Identifying a bidirectional association between sexual health and disease management paves the way for improved disease control and can potentially prevent the development of sexual dysfunctions in couples affected by gout. However, the relevance of the couple has not been adequately addressed in gout management, and most evidence comes from other chronic diseases.

CONCLUSION

Improving gout management results in better sexual health, and vice-versa promoting better sexual health can improve disease control for gout. The presence of a partner improves the behavioral well-being of gout patients, with beneficial effects on both sexual health and gout management. Sansone A, Reisman Y, Meto S, et al. The Role of the "Anti-Inflammatory" Couple for the Management of Hyperuricemia With Deposition. Sex Med 2022;10:100562.

Orodispersible Film (ODF) Platform Based on Maltodextrin for Therapeutical Applications

Orodispersible film (ODF) is a new dosage form that disperses rapidly in the mouth without water or swallowing. The main ingredient of an ODF is a polymer that can be both of natural or synthetic origin. Maltodextrin is a natural polymer, mainly used in pharmaceutical and nutraceutical fields. This review aims to examine the literature regarding ODFs based on maltodextrin as the platform for developing new products for therapeutical application. ODFs based on maltodextrin contain plasticizers that enhance their flexibility and reduce their brittleness. Surfactants; fillers, such as homopolymer and copolymer of vinylacetate; flavour and sweetener were introduced to improve ODF characteristics. Both water-soluble and insoluble APIs were introduced up to 100 mg per dosage unit. The solvent casting method and hot-melt extrusion are the most useful techniques for preparing ODFs. In particular, the solvent casting method allows manufacturing processes to be developed from a lab scale to an industrial scale. ODFs based on maltodextrin are characterized in terms of mechanical properties, dissolution rate, taste and stability. ODFs made of maltodextrin, developed by IBSA, were tested in vivo to evaluate their bioequivalence and efficacy and were demonstrated to be a valid alternative to the marketed oral dosage forms.

Assessment of a New Formulation of Sildenafil on Common Practice: An Observational Study

Erectile dysfunction (ED) has a significant impact on the quality of life of patients. Xybilun® (IBSA Pharma SAS, France) is a new formulation of sildenafil in an orodispersible film (ODF). This study aims to assess the response rate (RR), satisfaction with, and safety of sildenafil-ODF in daily practice in France. Patients aged ≥18 years with ED were included in four groups: Group 1 mild, Group 2 moderate, Group 3 severe ED, according to the International Index for Erectile Function (IIEF)-6 subscore, never treated with phosphodiesterase inhibitors (PDE)5-I; Group 4, patients previously treated with another PDE5-I. Patients were evaluated at baseline (V1), one (V2), and three (V3) months. The RR and satisfaction were assessed using the IIEF-6 subscore questionnaire, a 5-point Likert scale, and a Global Assessment Question (GAQ). The primary endpoint for Groups 1 to 3 was the RR according to Rosen criteria at V3 compared to V1. For Group 4, the primary endpoint was the RR, defined as the satisfaction compared with previous treatment. Secondary endpoints were the RR at V2 compared to V1, the evolution of IIEF-6 and IIEF-15 scores, dose adjustment, satisfaction, convenience, and safety. One hundred and five patients were enrolled, 83 analysed. The RR at V3 was 100% (Group 1); 75% (Group 2); 65.2% (Group 3); and 84.2% (Group 4). The overall RR was 78.3%. Secondary parameters confirmed the satisfaction with sildenafil-ODF, with 81.6% of patients very satisfied at V3. No Serious Adverse Events (SAEs) were observed. In conclusion, sildenafil-ODF seems beneficial for patients irrespective of the severity of the ED. This study confirms in the context of daily clinical practice the satisfaction of patients with sildenafil-ODF. Data suggest that the availability of the intermediate dose of 75 mg could add greater flexibility to the therapy.

Absorption, distribution, metabolism, and excretion of [14C]TPN729 after oral administration to rats

TPN729, a novel phosphodiesterase type 5 (PDE5) inhibitor for the treatment of erectile dysfunction (ED), is in phase II clinical trials in China. Previous studies suggested that TPN729 possesses promising therapeutic value. In previous non-radiolabeled rat excretion studies, the recovery of TPN729 and its major metabolites accounted for approximately 8.58% of the administration dose in urine and feces by 48 h post-dose.To solve this problem and further study the metabolism of TPN729 in rats, we used the radio-isotopic tracing technique for the first time. In this study, the mass balance, tissue distribution, and metabolism of TPN729 were evaluated in rats after a single oral dose of 25 mg/kg [¹⁴C]TPN729 (150 μCi/kg).At 168 h post-dose, the mean total radioactivity recovery of the dose was 92.13%. Feces was the major excretion route, accounting for 74.63% of the dose, and urine excretion accounted for 17.50%. After oral administration of [¹⁴C]TPN729, radioactivity was widely distributed in all examined tissues, and a higher radioactivity concentration was observed in the stomach, large intestine, lung, liver, small intestine, and eyes. The concentration of drug-related materials were similar in plasma and blood cells. A total of 51 metabolites were identified in rat plasma, urine, feces, and bile, and the predominant metabolically susceptible position of TPN729 was the pyrrolidine moiety. The main metabolic pathways were N-dealkylation, oxidation, dehydrogenation, and glucuronidation.In summary, we solved the previous problem of low drug recovery, elucidated the major excretion pathway, determined the tissue distribution patterns, and investigated the metabolism of TPN729 in rats by using a radioisotopic tracing technique.

Application of laser speckle blood perfusion imaging in the evaluation of erectile function in rats

Intracavernosal pressure measurement is the gold standard for evaluating erectile function in experimental animals, but it has the shortcoming of being invasive. This study aimed to explore the application of laser speckle perfusion imaging in evaluating erectile function in rats. Sixty Sprague Dawley rats were randomly divided into the sham operation and model groups (n = 30 each). A rat model of neuroinjury erectile dysfunction was established by surgically damaging the bilateral cavernous nerves in the model group. Simulated surgery was performed in the sham operation group; the nerves were not damaged. Erectile function was evaluated by comparing the changes in intracavernosal pressure and blood flow fluctuations when the cavernous nerve was stimulated using the same voltage parameters. Intracavernosal pressure in the model group was significantly lower than that in the other group when using 2.5 V. No significant difference was found in cavernous blood flow fluctuation between the two groups when using 0.5 V. Cavernous blood flow fluctuation in the model group after 2.5 V, 5 V and 7.5 V stimulations was significantly lower than that in the sham operation group. Evaluating erectile function in rats is feasible by measuring the cavernous blood flow using laser speckle perfusion imaging.

Facing Counterfeit Medications in Sexual Medicine. A Systematic Scoping Review on Social Strategies and Technological Solutions

Introduction

The counterfeit phenomenon is a largely under-reported issue, with potentially large burden for healthcare. The market for counterfeit drugs used in sexual medicine, most notably type 5 phosphodiesterase inhibitors (PDE5i), is rapidly growing.

Aims

To report the health risks associated with the use of counterfeit medications, the reasons driving their use, and the strategies enacted to contain this phenomenon.

Methods

A systematic scoping review of the literature regarding counterfeit PDE5i was carried between January and June 2021, then updated in August 2021.

Main Outcome Measure

We primarily aimed to clarify the main drivers for counterfeit PDE5i use, the health risks associated, and the currently available strategies to fight counterfeiters.

Results

One hundred thirty-one records were considered for the present scoping review. Production of fake PDE5i is highly lucrative and the lacking awareness of the potential health risks makes it a largely exploitable market by counterfeiters. Adulteration with other drugs, microbial contamination and unreliable dosages make counterfeit medications a cause of worry also outside of the sexual medicine scope. Several laboratory techniques have been devised to identify and quantify the presence of other compounds in counterfeit medications. Strategies aimed at improving awareness, providing antitampering packaging and producing non-falsifiable products, such as the orodispersible formulations, are also described.

Clinical implications

Improving our understanding of the PDE5i counterfeit phenomenon can be helpful to promote awareness of this issue and to improve patient care.

Strengths & Limitations

Despite the systematic approach, few clinical studies were retrieved, and data concerning the prevalence of counterfeit PDE5i use is not available on a global scale.

Conclusion

The counterfeit phenomenon is a steadily growing issue, with PDE5i being the most counterfeited medication with potentially large harmful effects on unaware consumers.

Sansone A, Cuzin B, and Jannini EA. Facing Counterfeit Medications in Sexual Medicine. A Systematic Scoping Review on Social Strategies and Technological Solutions. Sex Med 2021;9:100437.

Sildenafil Supplementation for Women Undergoing Infertility Treatments: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of this systematic review and meta-analysis is to summarize data on the effectiveness of Sildenafil supplementation for women undergoing assisted reproduction techniques. This meta-analysis of randomized controlled trials (RCTs) evaluates the effects of Sildenafil administration during infertility treatments compared with a control group in infertile women. Outcomes evaluated were endometrial thickness (ETh) and the clinical pregnancy rate (CPR). The chemical pregnancy rate (ChPR) was also evaluated. Pooled results were expressed as the risk ratio (RR) or mean differences (MD) with a 95% confidence interval (95% CI). Women undergoing ovulation induction who received Sildenafil showed higher ETh and a higher CPR in comparison to controls. In this group, both the ETh and ChPR resulted in significantly higher values only with delayed start administration. Women undergoing fresh or frozen embryo transfer who received Sildenafil showed no significant advantages regarding ETh and CPR in comparison to controls. In this group, we found a significantly higher ChPR in women receiving Sildenafil. A subgroup analysis revealed significant advantages regarding ETh with oral administration for women undergoing fresh or frozen embryo transfer. Sildenafil therapy appears to improve endometrial thickness and pregnancy rate in women undergoing timed intercourses but it resulted not effective in IUI and IVF treatments. Further RCTs with rigorous methodology are still mandatory.

Male Sexual Health and Sexual Behaviors during the First National COVID-19 Lockdown in a Western Country: A Real-Life, Web-Based Study

Restriction measures enacted during the COVID-19 pandemic had severe effects on male sexual and reproductive health. We aimed to investigate the real-life impact and perception of sexual function in 2020 in Italy, as the first Western country experiencing a national lockdown by measuring relative search volume for keywords pertaining to sexual health and behaviors provided by Google Trends and sales data for pro-erectile treatments. No significant change was observed for erectile dysfunction and premature ejaculation. Interest towards most phosphodiesterase type 5 inhibitors decreased significantly during lockdown (e.g., sildenafil, p = 0.0002; tadalafil p = 0.0016), then reverted to pre-lockdown levels (e.g., sildenafil, p < 0.0001; tadalafil p < 0.0001), mirroring a concomitant sales decrement (p = 0.0292). A subsequent recovery to previous levels at the end of the social confinement was also found (e.g., after vs. before lockdown, sildenafil, p = 0.8459; tadalafil p = 0.1166). During lockdown, interest towards pornography significantly increased during restrictions (p = 0.0053) and remained high (after vs. before lockdown, p = 0.0004), whereas interest towards paid and casual sex declined (p = 0.0015 and p = 0.049, respectively), then reverted to previous levels (after vs. before lockdown, p = 0.3969 and 0.8373, respectively). During the first Italian lockdown, we observed a transient but measurable decrease of sexual health-seeking behaviors and changes in sexual behaviors, with unknown impact for sexual medicine and public health.

Cavernous artery intima-media thickness predicts the response to sildenafil in erectile dysfunction patients as a morphological parameter

While the intima-media thickness (IMT) of the cavernous artery was used for diagnosis for vascular erectile dysfunction (ED) with more accuracy than the peak systolic velocity, the role of the IMT in predicting treatment responses remained unexamined. A total of 136 patients with ED were enrolled. The baseline clinical and laboratory characteristics were collected. Penile Doppler ultrasonography (PDU) was performed on all patients by a blinded sonographer. Sildenafil was administrated to all patients with an adjusted dose of 50 or 100 mg on demand over a period of 3 months. A follow-up was conducted on all patients using the Erectile Hardness Score (EHS) questionnaire along with the visual and tactile version of the standardised EHS tool. The peak systolic velocity (PSV) and IMT were compared between sildenafil responders and sildenafil nonresponders, while receiver operator characteristic (ROC) curves were used to calculate the cut-off values and compare the test power respectively. There was no statistical difference from the baseline characteristics. The IMT of cavernous artery was more accurate than PSV to predict the sildenafil response (AUC = 0.809, 0.626 respectively). IMT could predict sildenafil responders more accurately than PSV, and the cut-off value of the IMT of the cavernous artery was less than 0.22 mm.

Exploitation of Design-of-Experiment Approach for Design and Optimization of Fast-Disintegrating Tablets for Sublingual Delivery of Sildenafil Citrate with Enhanced Bioavailability Using Fluid-Bed Granulation Technique

Sildenafil citrate undergoes first-pass metabolism, resulting in poor oral bioavailability at 25-41% of the administered dose. This study aimed to design and optimize fast-disintegrating tablets for the sublingual delivery of sildenafil citrate to improve bioavailability and facilitate rapid onset of action. The design-of-experiment (DoE) approach using 32 full factorial design was conducted to develop a new formulation of sildenafil fast-disintegrating sublingual tablets (FDSTs) using the fluid-bed granulation technique. The levels of partially pre-gelatinized starch (5-15%) and microcrystalline cellulose (10-60%) were selected as independent formulation variables. The prepared FDSTs were investigated for physical properties. Further, the optimum formulation was chosen for in vivo study in rabbits. Regression analysis showed that independent variables have a significant (p < 0.05) influence on critical attributes of FDSTs. The optimized formulation showed acceptable mechanical strength (friability < 1.0%) with very fast disintegration (14.561 ± 0.84 s) and dissolution (94.734 ± 2.76% after 15 min). Further, the optimized formulation demonstrated a significant increase (p < 0.01) in Cmax and AUC0-∞ with short tmax compared to the market product (Viagra®). Based on these results, using the DoE approach, a high level of assurance was achieved for FDSTs' product quality and performance.

Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis

Introduction

The association between folic acid (FA) and erectile dysfunction (ED) was contradictory in the published original articles, and no meta-analysis was conducted to pool these data.

Aim

To verify the role of FA in the pathology of ED and explore the treatment efficacy of FA for ED patients.

Methods

An extensive search was performed on PubMed, Cochrane Library, and Web of Science to obtain all relevant studies published up to October 31, 2020. Studies comparing the serum FA level between ED patients and healthy controls, or comparing the score of the IIEF-5, or IIEF before and after folic acid therapy alone or combination in ED patient were eligible for our meta-analysis. The Newcastle-Ottawa Scales (NOS) was used to qualify included studies.

Main Outcome Measures

The standardized mean differences (SMD) and their corresponding 95% confidence intervals (95% CIs) were calculated to pool our data.

Results

Nine studies were eligible for our meta-analysis to verify the association between FA and ED, and to explore the treatment efficacy of FA for ED patients. The pooled SMD of the FA level difference between ED patients and healthy subjects was -0.94 (95% CI: -1.59, -0.30, P = .004). Moreover, the level of folic acid in healthy subjects, Mild ED patients, Moderate ED patients and Severe ED patients was 11.847 (95%CI = 9.671, 14.022), 9.496 (95%CI = 8.425, 10.567), 6.597 (95%CI = 5.187, 8.007) and 5.623 (95%CI = 3.535, 7.711) respectively. The SMD of changes in score of IIEF-5 was 1.89 with 95%CI (1.60, 2.17) after FA administration in ED patients. Our analysis also showed that combination therapy of FA plus tadalafil changed the score of IIEF with 0.90 (95%CI = 0.44, 1.36) comparing to combination of placebo plus tadalafil.

Conclusion

This novel meta-analysis demonstrated that FA was an independent risk factor for ED and FA supplement may have potentially positive effects in the treatment of ED patients.

Zhang Y, Zhang W, Dai Y, et al. Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis. Sex Med 2021;9:100356.

Environmental Factors-Induced Oxidative Stress: Hormonal and Molecular Pathway Disruptions in Hypogonadism and Erectile Dysfunction

Hypogonadism is an endocrine disorder characterized by inadequate serum testosterone production by the Leydig cells of the testis. It is triggered by alterations in the hypothalamic–pituitary–gonadal axis. Erectile dysfunction (ED) is another common disorder in men that involves an alteration in erectile response–organic, relational, or psychological. The incidence of hypogonadism and ED is common in men aged over 40 years. Hypogonadism (including late-onset hypogonadism) and ED may be linked to several environmental factors-induced oxidative stresses. The factors mainly include exposure to pesticides, radiation, air pollution, heavy metals and other endocrine-disrupting chemicals. These environmental risk factors may induce oxidative stress and lead to hormonal dysfunctions. To better understand the subject, the study used many keywords, including “hypogonadism”, “late-onset hypogonadism”, “testosterone”, “erectile dysfunction”, “reactive oxygen species”, “oxidative stress”, and “environmental pollution” in major online databases, such as SCOPUS and PUBMED to extract relevant scientific information. Based on these parameters, this review summarizes a comprehensive insight into the important environmental issues that may have a direct or indirect association with hypogonadism and ED in men. The study concludes that environmental factors-induced oxidative stress may cause infertility in men. The hypothesis and outcomes were reviewed critically, and the mechanistic approaches are applied through oxidant-sensitive pathways. This study also provides reccomendations on future therapeutic interventions and protective measures against such adverse environmental factors-induced hypogonadism and ED.

Effects of the dutasteride and sildenafil association in the penis of a benign prostatic hyperplasia animal model

OBJECTIVE

The aim of this study was to investigate whether concomitant treatment of dutasteride and sildenafil could prevent structural changes in the penis of a BPH rodent model.

METHODS

Thirty-two adult male rats were divided into the following groups: Ctrl, untreated control rats; BPH, untreated spontaneously hypertensive rats (SHRs); BPH + D, SHRs treated with dutasteride; and BPH + DS, SHRs treated with dutasteride and sildenafil. All treatments were performed during 40 days, following which the penises were collected for histomorphometrical analysis. The results were compared via one-way ANOVA with Bonferroni's post-test, considering p values <.05 as significant.

RESULTS

The smooth muscle density decreased by 28.6% and 21.4% in BPH + D and BPH + DS, respectively, when compared to the BPH group. The sinusoid space density reduced by 32.2% in BPH, when compared to the Ctrl group; this density was also reduced by 22.6% in BPH + D, when compared to the BPH group. The density of the elastic fibers increased 51.6% and 65.6% in BPH + D and BPH + DS, when compared to the BPH group.

CONCLUSION

Treatment with dutasteride promoted morphological changes in the corpus cavernous of this BPH model. Concomitant treatment with sildenafil did not prevent the morphological changes caused by dutasteride; on the contrary, it also promoted a further increase in elastic fibers.

Drug delivery options and therapeutic advances in the management of erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is estimated that 20-30% of adult men will have at least one episode of ED during their lifetime and the prevalence increases with age. ED is known to have significant negative psychological implications for men, resulting in impaired functional status and a greater prevalence of anxiety and depression.

AREAS COVERED

Medications for the treatment of erectile dysfunction largely revolve around oral, injection, and topical therapies. Though all three modalities are widely used, each delivery option has its own advantages and specific indications. Likewise, there are several new developing treatments for ED that may change the landscape of treatment. The goal of this review is to summarize contemporary drug delivery options used in the treatment of ED and highlight future promising pharmacological developments.

EXPERT OPINION

There are a myriad of new developments on the horizon including new PDE5Is and drug targets, nanotechnology enhancements, stem cell and gene therapy, shockwave therapy, and platelet-rich plasma injections. These are all promising new methods to not only treat ED but also to address the pathology and prevent or eliminate further damage.

Sildenafil-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms: Case report with review

Sildenafil is one of the commonest over the counter drugs which is orally taken by the people for sexual enhancement. It is an inhibitor of phosphodiesterase type 5 (PDE5) and results in engorgement of carpora cavernosa and help in erectile dysfunction. There are fewer adverse cutaneous drug reactions reported by sildenafil perhaps due to use of the drug without medical prescription. Here we are reporting a case of sildenafil induced hypersensitivity syndrome that is possibly the first one and reviewing the medical literature on type of adverse cutaneous drug eruption due to sildenafil and other PDE5 inhibitors.

Pharmacology and perspectives in erectile dysfunction in man

Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.

Phosphodiesterase inhibitors say NO to Alzheimer's disease

Phosphodiesterases (PDEs) consisted of 11 subtypes (PDE1 to PDE11) and over 40 isoforms that regulate levels of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP), the second messengers in cell functions. PDE inhibitors (PDEIs) have been attractive therapeutic targets due to their involvement in diverse medical conditions, e.g. cardiovascular diseases, autoimmune diseases, Alzheimer's disease (AD), etc. Among them; AD with a complex pathology is a progressive neurodegenerative disorder which affect mostly senile people in the world and only symptomatic treatment particularly using cholinesterase inhibitors in clinic is available at the moment for AD. Consequently, novel treatment strategies towards AD are still searched extensively. Since PDEs are broadly expressed in the brain, PDEIs are considered to modulate neurodegenerative conditions through regulating cAMP and cGMP in the brain. In this sense, several synthetic or natural molecules inhibiting various PDE subtypes such as rolipram and roflumilast (PDE4 inhibitors), vinpocetine (PDE1 inhibitor), cilostazol and milrinone (PDE3 inhibitors), sildenafil and tadalafil (PDE5 inhibitors), etc have been reported showing encouraging results for the treatment of AD. In this review, PDE superfamily will be scrutinized from the view point of structural features, isoforms, functions and pharmacology particularly attributed to PDEs as target for AD therapy.

The first-generation phosphodiesterase 5 inhibitors and their pharmacokinetic issue

Background

Erectile dysfunction (ED) is a relatively frequent disease that negatively impacts the overall quality of life, well‐being, and relationships. Although the use of phosphodiesterase 5 inhibitors (PDE5is) has revolutionized the treatment of ED, a high percentage of ED patients discontinue PDE5i treatment.

Objectives

(i) To analyze the reasons for patient dissatisfaction leading to PDE5i discontinuation; (ii) analyze the pharmacokinetics of new formulations focusing on the time needed to reach an effective plasma concentration of PDE5is (T_onset) following drug intake; and (iii) summarize the physicochemical properties of sildenafil to understand which excipients may increase the absorption rate.

Material and methods

An online PubMed literature search was conducted to identify English language publications from inception to January 2019.

Results

The main reasons for patient dissatisfaction when using PDE5is on demand are the relatively long T_onset after taking vardenafil and sildenafil, including formulations such as film‐coated tablets, fine granules, orally disintegrating tablets (ODTs), and oral thin films (ODFs). The relatively long T_onset, further worsened when accompanied by eating, highlights the following: (i) the need for planning intercourse, determining partner‐related issues; (ii) issues when having sex before the maximum effect of the drug; and (iii) lower drug‐related placebo effects. Some data suggest that sildenafil is a ‘difficult’ molecule, but T_onset can be improved following absorption by buccal mucosa using appropriate excipients.

Conclusions

We conclude that several ODT and ODF formulations can improve the ‘discretion’ issue because they are taken without water, but they have similar pharmacokinetics to corresponding film‐coated tablet formulations. One ODF formulation of sildenafil was characterized by a shorter T_onset and could potentially increase patient satisfaction following treatment. However, more clinical studies are needed to confirm the findings. Surfactants and ascorbic acid appear to be crucial excipients for achieving a high absorption rate, but more studies are needed.

End-to-side Somatic-to-autonomic Nerve Grafting to Restore Erectile Function and Improve Quality of Life After Radical Prostatectomy

BACKGROUND

Radical prostatectomy (RP) is recommended for the treatment of men with clinically localised prostate cancer. However, RP is associated with a high incidence of erectile dysfunction (ED), which can impact the quality of life (QoL) significantly.

OBJECTIVE

To evaluate the effectiveness of end-to-side nerve grafting surgery to restore erectile function and improve sexual QoL in men with ED after RP.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review of a single-centre experience of nerve grafting in men with ED following RP was performed. Seventeen men had surgery between March 2015 and October 2017 in Melbourne, Australia, which fulfilled study inclusion and exclusion criteria.

INTERVENTION

Microsurgical bilateral end-to-side nerve grafts from a selective fascicular neurotomy of the femoral nerve to the penile corpora cavernosa.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Results were serially measured utilising the International Index of Erectile Function (IIEF-5) and the sexual domain of Expanded Prostate Cancer Index Composite (EPIC-26). The proportion and 95% confidence interval (CI) of men recovering sexual function following nerve grafting were determined.

RESULTS AND LIMITATIONS

All patients had ED following their RP. Median age at nerve grafting was 64yr (interquartile range [IQR] 60-66yr). Median time between nerve- and non-nerve-sparing RP, and nerve grafting was 2.4 (IQR 2.1-3.1) and 2.2 (IQR 1.7-5.1)yr, respectively. Median follow-up was 18 (IQR 15-24) mo. At 12mo after nerve grafting, 71% (95% CI 44-90%) of patients had erectile function recovery sufficient for satisfactory sexual intercourse, and 94% (95% CI 71-99%) and 82% (95% CI 57-96%) had clinically significant improvements in sexual function and reduced bother, respectively. There were two minor wound infections. Limitations include the retrospective study design.

CONCLUSIONS

End-to-side nerve grafting restored erectile function in 71% of men with ED following RP, supporting previous findings. Of the men, 94% had clinically relevant improvements in sexual QoL. We recommend multicentre implementation of post-RP nerve grafting into clinical practice with appropriate data collection to confirm its efficacy and feasibility.

PATIENT SUMMARY

We provide confirmatory evidence that end-to-side nerve grafting surgery restored erectile function and improved sexual quality of life in, respectively, 71% and 94% of men with erectile dysfunction following radical prostatectomy.

Needs and Expectations of Patients with Erectile Dysfunction: An Update on Pharmacological Innovations in Phosphodiesterase Type 5 Inhibition with Focus on Sildenafil

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5-Is) have an excellent efficacy and tolerability profile and remain the first-line choice for the treatment of erectile dysfunction (ED). However, ED is still an underdiagnosed and undertreated condition, and many men prematurely discontinue therapy with conventional dosage formulations despite successful intercourse.

AIM

To review the unmet needs and expectations of patients with ED and describe the latest pharmaceutical innovations in the field of PDE5-I formulations designed to address these needs, with particular reference to a new orodispersible film (ODF) formulation of the PDE5-I, sildenafil.

METHODS

Online literature search in PubMed and the Cochrane Library.

MAIN OUTCOME MEASURE

To identify English-language publications relevant to the aims of the present review.

RESULTS

Improved recognition and management of ED would enable the early diagnosis of underlying and comorbid conditions that contribute to ED, leading to improved patient health and health-related quality of life. To ensure successful outcomes and patient and partner satisfaction, the complex and personal issues that influence the patient's needs and expectations regarding treatment for ED must be considered along with their personal experiences and preferences. Innovative drug delivery systems, including orally disintegrating formulations, have been developed as alternatives to conventional dosage forms with the aim of improving patient convenience and acceptability and enhancing compliance. These alternative formulations include the sildenafil ODF, which is designed to improve acceptance and compliance over conventional solid dosage forms and extend the treatment options for men with ED by offering a convenient and discrete dosage form of a drug with proven efficacy.

CONCLUSION

The sildenafil ODF is an example of an innovative dosage formulation for ED that can be used interchangeably with the conventional film-coated formulation to better address the needs and expectations of men with ED. Jannini EA, Droupy S. Needs and Expectations of Patients with Erectile Dysfunction: An Update on Pharmacological Innovations in Phosphodiesterase Type 5 Inhibition with Focus on Sildenafil. Sex Med 2019;7:1-10.

Evaluation of the effectiveness and safety of a daily dose of 5 mg of tadalafil, over an 8-week period, for improving quality of life among Korean men with andropause symptoms, including erectile dysfunction: A pilot study

BACKGROUND

The primary aim of this study was to evaluate the effects of a once-a-day 5 mg dose of tadalafil, prescribed for 8 weeks, on the quality of life (QoL) of South Korean men with andropause symptoms, including erectile dysfunction (ED), using a single group, open-labeled, before-and-after preliminary trial. The secondary objective was to evaluate the effectiveness and safety of tadalafil for ED.

METHODS

Forty South Korean men (>35 years of age) with andropause symptoms including ED were enrolled into our trial. Andropause syndrome was defined using the androgen deficiency in aging males (ADAM) questionnaire and other screening tests, including testosterone levels. The following outcome measures were obtained at baseline and at 4 and 8 weeks of tadalafil treatment: physical examination, adverse effects, Short Form 12 Health Survey (SF-12) score, International Index of Erectile Function (IIEF-5) score, bioelectrical impedance analysis (BIA), and free radical testing.

RESULTS

Treatment increased the SF-12 Mental component score, used as a proxy measure of quality of life, from baseline to at 4 and 8 weeks (P < .05). In addition, the mean IIEF-5 score, which assesses sexual function, increased from baseline at 4 and 8 weeks (P < .05), with this increase being significant at both time points. No adverse effects were noted.

CONCLUSION

Tadalafil (5 mg dose, once daily) is a safe and effective treatment to improve ED, and overall QoL, among Korean men with andropause symptoms, including ED.

Cilostazol, a phosphodiesterase 3 inhibitor, activates proteasome-mediated proteolysis and attenuates tauopathy and cognitive decline

Alzheimer's disease and several variants of frontotemporal degeneration including progressive supranuclear palsy and corticobasal degeneration are characterized by the accumulation of abnormal tau protein into aggregates. Most proteins, including tau, are degraded via the ubiquitin proteasome system, but when abnormal tau accumulates, the function of 26S proteasomes is downregulated. The negative effect of tau aggregates on the function of the proteasome can have deleterious consequences on protein homeostasis and disease progression. Developing therapies aimed at clearing abnormal tau are thus of considerable interest. In the present study, we investigated the effect of cilostazol, an FDA-approved selective phosphodiesterase 3 inhibitor, on a mouse model of tauopathy (line rTg4510). Administration of cilostazol for 30 days enhanced proteasome function via the cyclic adenosine 3',5'-monophosphate/protein kinase A pathway and attenuated tauopathy and cognitive decline in rTg4510 mice. These results suggest that cilostazol, or other FDA-approved drugs acting via the same pathway, has the potential to be repurposed for the treatment of patients with early-stage tauopathy.

Use of phosphodiesterase type 5 inhibitors and risk of melanoma: a meta-analysis of observational studies

Background

Phosphodiesterase type 5 inhibitor (PE5i) administration may stimulate the proliferation and survival of melanocytes. However, discrepancies remain regarding the association between PDE5i use and melanoma risk in observational studies in humans.

Aim

To evaluate the association between PDE5i use and melanoma in a meta-analysis.

Materials and methods

Studies were identified by searching the PubMed and Embase databases. A random-effects model was applied to synthesize the data. A stratified study was performed to evaluate the influence of study characteristics on outcomes.

Results

Four prospective cohort studies and three case–control studies with 1,534,615 male participants and 16,053 melanoma cases were incorporated. Patients who received a PDE5i had a significantly increased risk for melanoma (adjusted risk ratio [RR] =1.12, 95% CI =1.03–1.33, P=0.008) with moderate heterogeneity (I²=54%). Cohort studies (adjusted RR =1.22, 95% CI =1.02–1.46, P=0.03) largely contributed to this result rather than case–control studies. Subsequent stratified analyses revealed that sildenafil was associated with an increased risk of melanoma (adjusted RR =1.26, 95% CI =1.07–1.50, P=0.007), but tadalafil and vardenafil were not. Also, PDE5i use was associated with a significantly increased risk of in situ melanoma (adjusted RR =1.31, 95% CI =1.01–1.69, P=0.04), but not of localized or nonlocalized melanoma.

Conclusion

PDE5i use may be associated with a significantly increased risk for melanoma in men. However, further research is needed to determine whether the association is causative.

Fabrication and evaluation of magnetic phosphodiesterase-5 linked nanoparticles as adsorbent for magnetic dispersive solid-phase extraction of inhibitors from Chinese herbal medicine prior to ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis

In the present study, the preparation of the magnetic phosphodiesterase-5 linked Fe₃O₄@ SiO₂ nanoparticles was successfully achieved by amide reaction and the magnetic phosphodiesterase-5 linked Fe₃O₄@SiO₂ nanoparticles were evaluated as a new adsorbent for magnetic dispersive solid-phase extraction of ligands from medicinal plant samples before the analysis by UHPLC-Q-TOF/MS. The prepared phosphodiesterase-5 linked Fe₃O₄@SiO₂ nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, vibration sample magnetometer and potential laser particle size analyzer. The effects of EDC concentration, incubation time and bead-protein ratio on the amount of immobilized protein were studied. The main experimental parameters affect extraction efficiency of ligands, such as wash times, wash solvents, incubation pH, ion strength and incubation temperature, were investigated and optimized by using echinacoside as a model compound. The absolute recovery of echinacoside was ranged from 98.36%-102.16% in Cistanche tubulosa sample under the optimal extraction conditions. Good linearity was observed in the investigated concentration range of 0.006 mgmL^-1-0.97 mgmL^-1(R² = 0.9999). The limit of detection was 0.002 mgmL^-1. The RSDs of within-day and between-day precision were less than 2.3%. Due to the excellent magnetic behavior of Fe₃O₄@SiO₂ nanoparticles, the proposed method was shown to be simple and rapid. Remarkably, the magnetic phosphodiesterase-5 linked Fe₃O₄@SiO₂ nanoparticles could be recycled for ten times with loss of 10% activity.

Penile prosthesis in the management of erectile dysfunction following cancer therapy

Erectile dysfunction (ED) is a common problem in older men and occurs with even greater frequency following the treatment of pelvic malignancies. Inflatable penile prosthesis (IPP) implantation is a safe and effective form of definitive ED treatment for those men who fail more conservative measures, and it can be used with similar outcomes in men following cancer therapy. Although many of these men remain dissatisfied with other therapeutic options for ED, IPPs are underutilized in this population. This review will discuss the current practice patterns, outcomes and nuances to surgical technique regarding the use of IPPs in patients with ED following cancer therapy.

A comprehensive review on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases

Phosphodiesterases are a group of enzymes that hydrolyze cyclic nucleotides, which assume a key role in directing intracellular levels of the second messengers' cAMP and cGMP, and consequently cell function. The disclosure of 11 isoenzyme families and our expanded knowledge of their functions at the cell and molecular level stimulate the improvement of isoenzyme selective inhibitors for the treatment of various diseases, particularly cardiovascular diseases. Hence, future and new mechanistic investigations and carefully designed clinical trials could help reap additional benefits of natural/synthetic PDE inhibitors for cardiovascular disease in patients. This review has concentrated on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases.