Physicochemical properties of tadalafil solid dispersions – Impact of polymer on the apparent solubility and dissolution rate of tadalafil

To improve solubility of tadalafil (Td), a poorly soluble drug substance (3 μg/ml) belonging to the II class of the Biopharmaceutical Classification System, its six different solid dispersions (1:1, w/w) in the following polymers: HPMC, MC, PVP, PVP-VA, Kollicoat IR and Soluplus were successfully produced by freeze-drying. Scanning electron microscopy showed a morphological structure of solid dispersions typical of lyophilisates. Apparent solubility and intrinsic dissolution rate studies revealed the greatest, a 16-fold, increase in drug solubility (50 μg/ml) and a significant, 20-fold, dissolution rate enhancement for the Td/PVP-VA solid dispersion in comparison with crystalline Td. However, the longest duration of the supersaturation state in water (27 μg/ml) over 24 h was observed for the Td solid dispersion in HPMC. The improved dissolution of Td from Td/PVP-VA was confirmed in the standard dissolution test of capsules filled with solid dispersions. Powder X-ray diffraction and thermal analysis showed the amorphous nature of these binary systems and indicated the existence of dispersion at the molecular level and its supersaturated character, respectively. Nevertheless, as evidenced by film casting, the greatest ability to dissolve Td in polymer was determined for PVP-VA. The crystallization tendency of Td dispersed in Kollicoat IR could be explained by the low T_g (113 °C) of the solid dispersion and the highest difference in Hansen solubility parameters (6.8 MPa^0.5) between Td and the polymer, although this relationship was not satisfied for the partially crystalline dispersion in PVP. Similarly, no correlation was found between the strength of hydrogen bonds investigated using infrared spectroscopy and the physical stability of solid dispersions or the level of supersaturation in aqueous solution.     

Tadalafil for the treatment of benign prostatic hyperplasia

Introduction: In men, lower urinary tract symptoms (LUTS) are primarily attributed to benign prostatic hyperplasia (BPH). Therapeutic options are targeted to relax prostate smooth muscle and/or reduce prostate enlargement.

Areas covered: This article reviews the major preclinical and clinical data on PDE5 inhibitors with a specific focus on tadalafil. It includes details of the role of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) – PDE5 pathway in the LUT organs (bladder and prostate) in addition to the available data on tadalafil in patients with LUTS secondary to BPH with or without erectile dysfunction (ED).

Expert opinion: Preclinical and clinical data have clearly demonstrated that PDE5 inhibitors induce bladder and prostate relaxation, which contributes to the improvement seen in storage symptoms in both animal models of bladder and prostate hypercontractility. Tadalafil is effective both as a monotherapy and add-on therapy in patients with LUTS secondary to BPH. Furthermore, as LUTS-BPH and ED are urological disorders that commonly coexist in aging men, tadalafil is more advantageous than α1-adrenoceptors and should be used as the first option. Tadalafil is a safe and tolerable therapy and unlike α1- adrenoceptors and 5-alpha reductase inhibitors, which can cause sexual dysfunctions, tadalafil improves sexual function.     

Psychosocial impact and effectiveness of tadalafil among treatment-naïve and previously-treated men with erectile dysfunction in Saudi Arabia and other Gulf-region countries

ABSTRACT

Objective: This observational, comparative study, conducted in Saudi Arabia, Kuwait, and the United Arab Emirates, assessed psychosocial and efficacy outcomes of tadalafil 20 mg on demand, over a period of 20 weeks, in men with erectile dysfunction (ED) who were treatment-naïve versus pretreated with an ED treatment other than tadalafil.

Methods: The short form of the Psychological and Interpersonal Relationship Scales (SF-PAIRS) was used to assess psychosocial outcomes (Time Concerns, Spontaneity, and Sexual Self-Confidence). Change from baseline in the International Index of Erectile Function (IIEF) erectile function (EF) domain score was used to assess effectiveness, and Global Assessment Question (GAQ) was asked to determine improvement in erections.

Results: Of 1080 patients analyzed, 557 (51.6%) were treatment-naïve and 523 (48.4%) were pretreated. In all, 500 (89.8%) treatment-naïve men and 473 (90.4%) pretreated men completed the study. Some statistically significant differences were observed in baseline characteristics between treatment-naïve and pretreated groups, including ED etiology, ED severity, duration of ED, and the presence of cormorbid cardiovascular disease, other vascular disease, and neurological disease. Adjusted mean SF-PAIRS Time Concerns domain score was significantly more improved, while the Sexual Self-Confidence domain score was significantly less improved, for the pretreated group compared with the treatment-naive group (both p < 0.0001). No significant difference was observed for the Spontaneity domain. The mean change in IIEF-ED domain score for the treatment-naïve group was 13.26 compared with 9.28 for the pretreated group (p < 0.0001). Positive responses to GAQ at the last assessment were observed in 97.3% of treatment-naïve men and 94.4% of pretreated men (p < 0.0263).

Conclusion: This large, observational study in the Gulf region demonstrates that ED patients treated with tadalafil in a naturalistic setting, report improvements in both psychosocial outcomes and erectile function, with some differences between the treatment-naïve and pretreated groups. The results of this study may assist physicians in tailoring tadalafil therapy and setting realistic treatment expectations.     

Co-possession of phosphodiesterase type-5 inhibitors (PDE5-I) with nitrates

Abstract

Objective:

Estimate the proportion of phosphodiesterase type-5 inhibitor (PDE5-I) patients who co-possess nitrates and compare the proportion of tadalafil patients dispensed nitrates to a matched control group. Secondarily, examine the percentage of co-possession of PDE5-Is and nitrates where the products were dispensed on the same day or written by the same prescriber.     

A 6-month,prospective, observational study of PDE5 inhibitor treatment persistence and adherence in Middle Eastern and North African men with erectile dysfunction

Abstract

Background:

Erectile dysfunction (ED) negatively impacts quality of life. Phosphodiesterase type 5 inhibitors (PDE5Is) are effective in treating ED; however, rates of discontinuation remain high.     

反相高效液相色谱法测定保健食品中他达那非

目的:建立一种保健食品中他达那非的反相液相色谱测定方法。方法:采用ODS色谱柱,0.02 mol/L三乙胺:甲醇:乙腈(45:33:22)为流动相,流速1.0 m l/m in,二极管阵列检测器,检测波长217.4 nm,标准曲线计算他达那非含量。结果:该方法他达那非在0.4~40μg/m l浓度范围内线性良好,相关系数0.9998,相对标准偏差为0.55%~0.71%,回收率为97.6%~105%,最低检出限为5 ng。结论:该方法简便快速,准确可靠,可用于保健食品中他达那非含量的测定。     

性行为与心理疗法配合他达拉非+氟西汀治疗非器质性早泄临床观察(附352例报告)

目的:观察性行为与心理疗法(停-动-停训练及默算性交抽动的次数)配合他达拉非+氟西汀治疗非器质性早泄的临床疗效.方法:352例确诊为非器质性早泄患者中,年龄22～41岁,平均28.30岁;病程6个月～8年,平均2.6年.随机分为治疗组102例(性交前2～4h口服他达拉非20mg+氟西汀20mg配合性行为与心理疗法)和对...     

Neuroprotective effects of tadalafil on gerbil dopaminergic neurons following cerebral ischemia

Impairment of dopamine function, which is known to have major effects on behaviors and cognition, is one of the main problems associated with cerebral ischemia. Tadalafil, a long-acting phosphodiesterase type-5 inhibitor, is known to ameliorate neurologic impairment induced by brain injury, but not in dopaminergic regions. We investigated the neuroprotective effects of treatment with tadalafil on cyclic guanosine monophosphate level and dopamine function following cerebral ischemia. Forty adult Mongolian gerbils were randomly and evenly divided into five groups (n = 8 in each group): Sham-operation group, cerebral ischemia-induced and 0, 0.1, 1, and 10 mg/kg tadalafil-treated groups, respectively. Tadalafil dissolved in distilled water was administered orally for 7 consecutive days, starting 1 day after surgery. Cyclic guanosine monophosphate assay and immunohistochemistry were performed for thyrosine hydroxylase expression and western blot analysis for dopamine D₂ receptor expression. A decrease in cyclic guanosine monophosphate level following cerebral ischemia was found with an increase in thyrosine hydroxylase activity and a decrease in dopamine D₂ receptor expression in the striatum and substantia nigra region. However, treatment with tadalafil increased cyclic guanosine monophosphate expression, suppressed thyrosine hydroxylase expression and increased dopamine D₂ receptor expression in the striatum and substantia nigra region in a dose-dependent manner. Tadalafil might ameliorate cerebral ischemia-induced dopaminergic neuron injury. Therefore, tadalafil has the potential as a new neuroprotective treatment strategy for cerebral ischemic injury.     

Analysis of illegally manufactured formulations of tadalafil (Cialis) by 1H NMR, 2D DOSY 1H NMR and Raman spectroscopy

Counterfeit and/or imitation medicines are becoming a major health problem not only in developing countries but also in wealthier countries. The need of new and easy analytical methods for quality control of drugs is essential. We describe the use of Raman spectroscopy, 1H nuclear magnetic resonance (NMR) and 2D diffusion-ordered spectroscopy (DOSY) NMR to analyse genuine Cialis and seven illegally manufactured formulations of this drug purchased via the internet. Seven out of the eight commercial formulations of tadalafil contain the active ingredient, measured by high performance liquid chromatography (HPLC), within 100+/-5% of stated concentration. Vardenafil and homosildenafil instead of tadalafil were found in the Chinese imitation. 2D DOSY NMR spectra clearly showed similarities and differences in the composition of the pharmaceutical formulations of tadalafil, thus giving a precise and global "signature" of the manufacturer. Our data show that the quality of the Cialis imitations manufactured in India and Syria is correct, whereas the Chinese formulation is adulterated with active pharmaceutical ingredients.