Ipertrofan Revisited-The Proposal of the Complete Stereochemistry of Mepartricin A and B.

Being a methyl ester of partricin, the mepartricin complex is the active substance of a drug called Ipertrofan (Tricandil), which was proven to be useful in treatment of benign prostatic hyperplasia and chronic nonbacterial prostatitis/chronic pelvic pain syndrome. Nevertheless, no direct structural evidence on the stereochemistry of its components has been presented to date. In this contribution, we have conducted detailed, NMR-driven stereochemical studies on mepartricins A and B, aided by molecular dynamics simulations. The absolute configuration of all the stereogenic centers of mepartricin A and B was defined as 3R, 7R, 9R, 11S, 13S, 15R, 17S, 18R, 19S, 21R, 36S, 37R, and 38S, and proposed as 41R. The geometry of the heptaenic chromophore of both compounds has been established as 22E, 24E, 26E, 28Z, 30Z, 32E, and 34E. Our studies on mepartricin ultimately proved that partricins A and B are structurally identical to the previously described main components of the aureofacin complex: gedamycin and vacidin, respectively. The knowledge of the stereochemistry of this drug is a fundamental matter not only in terms of studies on its molecular mode of action, but also for potential derivatization, aiming at improvement of its pharmacological properties.

Falsified vardenafil tablets available online.

It is often reported that falsified medicines have harmful effects on patients both Japan and abroad. In this study, we purchased vardenafil tablets on the internet and investigated their quality and authenticity using visual observations, authenticity investigations, non-destructive tests (handheld NIR and Raman spectroscopy), and quality analyses (active ingredient content and tablet dissolution rate). We used genuine 20-mg Levitra tablets that were sold in Japan and tablets from Bayer AG (Germany) as controls. In April 2015, we obtained 28 samples from 15 websites on the internet. Our authenticity investigations revealed that 11 (40%) were genuine products and 17 (60%) were falsified products. Handheld NIR and Raman results revealed that the falsified products had different spectra to the genuine products. Principal component analysis of the NIR and Raman spectra showed variation among the falsified products. The 11 genuine products were of good quality, and the 17 falsified products were of poor quality. The falsified products contained sildenafil (the active ingredient of Viagra) or tadalafil (the active ingredient of Cialis) instead of vardenafil. Our results show that falsified Vardenafil tablets are sold on the internet and that it is important to prevent illegal internet sales and increase consumer awareness of the presence of falsified medicines.

Morphological Assessment of Prostatotropic Activity of (3,5-Dimethyl-4-Hydroxy)Benzyl Thiododecane on a Model of Benign Prostatic Hyperplasia in Rats.

Prostatotropic activity of (3,5-dimethyl-4-hydroxy)benzyl thiododecane (T-DD) was evaluated on a model of benign prostatic hyperplasia induced in Wistar rats by chronic (2 months) intraperitoneal administration of sulpiride (40 mg/kg). Morphometric analysis of the dorsolateral lobe of the prostate showed that after the 2-month course of intragastric T-DD (100 mg/kg) administered in parallel with sulpiride, the volume density of glandular epithelium decreased by 1.7 times, while the volume density of prostate stroma increased by 2 times. After administration of the reference drug Permixon at a dose of 50 mg/kg, the volume densities of epithelium decreased by 1.3 times and stromal volume density increased by 1.5 times. The observed effects are presumably related to suppression of 5α-reductase activity and modulation of estrogen receptors in the prostate.

LC-MS/MS Software for Screening Unknown Erectile Dysfunction Drugs and Analogues: Artificial Neural Network Classification, Peak-Count Scoring, Simple Similarity Search, and Hybrid Similarity Search Algorithms.

Screening and identifying unknown erectile dysfunction (ED) drugs and analogues, which are often illicitly added to health supplements, is a challenging analytical task. The analytical technique most commonly used for this purpose, liquid chromatography-tandem mass spectrometry (LC-MS/MS), is based on the strategy of searching the LC-MS/MS spectra of target compounds against database spectra. However, such a strategy cannot be applied to unknown ED drugs and analogues. To overcome this dilemma, we have constructed a standalone software named AI-SIDA (artificial intelligence screener of illicit drugs and analogues). AI-SIDA consists of three layers: LC-MS/MS viewer, AI classifier, and Identifier. In the second AI classifier layer, an artificial neural network (ANN) classification model, which was constructed by training 149 LC-MS/MS spectra (including 27 sildenafil-type, 6 vardenafil-type, 11 tadalafil-type ED drugs/analogues and other 105 compounds), is included to classify the LC-MS/MS spectra of the query compound into four categories: i.e., sildenafil, vardenafil, and tadalafil families and non-ED compounds. This ANN model was found to show 100% classification accuracy for the 187 LC-MS/MS modeling and test data sets. In the third Identifier layer, three search algorithms (pick-count scoring, simple similarity search, and hybrid similarity search) are implemented. In particular, the hybrid similarity search was found to be very powerful in identifying unknown ED drugs/analogues with a single modification from the library ED drugs/analogues. Altogether, the AI-SIDA software provides a very useful and powerful platform for screening unknown ED drugs and analogues.

Quantitation of trace amorphous solifenacin succinate in pharmaceutical formulations by transmission Raman spectroscopy.

It is important to quantify amorphous solid in active pharmaceutical ingredients (API) of formulations to guarantee high-quality pharmaceutical products. In this study, we aimed to quantify amorphous solid in API by transmission Raman spectroscopy (TRS) and transmission near-infra-red spectroscopy (NIRS). To quantify the amount of trace amorphous solids contained in the API of a formulation, calibration curves of tablets containing 40% or 3% solifenacin succinate (SLFS) in the pharmaceutical formulations were prepared. The tablets varied in the ratio of amorphous solids in the API. TRS and NIRS were carried out with the calibration tablets and partial least square regression (PLSR) analysis was performed. Good results were obtained by both TRS and NIRS with the calibration model containing 40% SLFS. On the contrary, with the calibration model containing 3% SLFS, the PLSR analysis results using the TRS data were better than those using the NIRS data. The low content calibration model based on TRS showed good results with R2 of 0.999, RMSECV of 1.236, and LOD of 0.12. TRS can be used to specifically detect trace amorphous solids contained in the API of a formulation.

New metabolites of hongdenafil, homosildenafil and hydroxyhomosildenafil.

Recently, illegal sildenafil analogues have emerged, causing serious social issues. In spite of the importance of sildenafil analogues, their metabolic profiles or clinical effects have not been reported yet. In this study, new metabolites of illegal sildenafil analogues such as hongdenafil, homosildenafil, and hydroxyhomosildenafil were determined using liquid chromatography quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) and tandem mass spectrometry (LC-Q-TOF-MS/MS). To prepare metabolic samples, in vitro and in vivo studies were performed. For in vivo metabolites analysis, urine and feces samples of rats treated with sildenafil analogues were analyzed. For in vitro metabolites analysis, human liver microsomes incubated with sildenafil analogues were extracted and analyzed. All metabolites were characterized by LC-Q-TOF-MS and LC-Q-TOF-MS/MS. As a result, five, six, and seven metabolites were determined in hongdenafil, homosildenafil, and hydroxyhomosildenafil treated samples, respectively. These results could be applied to forensic science and other analytical fields. Moreover, these newly identified metabolites could be used as fundamental data to determine the side effect and toxicity of illegal sildenafil analogues.

Erection-stimulating, anti-diabetic and antioxidant properties of Hunteria umbellata and Cylicodiscus gabunensis water extractable phytochemicals.

Background Herbs have been used as an aphrodisiac since ages. This study was designed to investigate the effects of Hunteria umbellata (HU) seeds and Cylicodiscus gabunensis (CG) stem barks aqueous extracts on key enzymes relevant to erectile dysfunction (phosphodiesterase-5 and arginase) and type-2 diabetes (α-amylase and α-glucosidase). Methods In ascertaining the erectogenic and antidiabetic properties of the extracts, the effects of the extracts on activities of some enzymes relevant to erectile dysfunction (arginase and phosphodiesterase-5) and type-2 diabetes (α-amylase and α-glucosidase) were determined. Antioxidant properties of the extracts were assessed through several antioxidant assays (DPPH˙, OH˙). Furthermore, their phenolic constituents were estimated and quantified using HPLC. Results The results revealed that both extracts inhibited α-amylase and α-glucosidase in a concentration-dependent manner. HU showed higher α-amylase (IC50=221.30 µg/mL) and α-glucosidase (IC50=184.35 µg/mL) inhibition than CG. Also, both extracts inhibited phosphodiesterase-5 and arginase in a dose-dependent manner in vitro; nevertheless, HU showed higher inhibition [phosphodiesterase-5 (IC50=539.72 µg/mL); arginase (41.53 µg/mL)] than CG [phosphodiesterase-5 (IC50=611.35 µg/mL); arginase (47.95 µg/mL)]. In addition, the extracts possess antioxidant properties through radical (DPPH and OH) scavenging and metal (Fe2+) chelating abilities. HPLC analysis of phenolic constituents revealed the abundance of gallic acid, chlorogenic acid, caffeic acid, ellagic acid and quercetin. Conclusions The ability of samples' extract to inhibit some of key enzymes relevant to erectile dysfunction and type-2 diabetes could render them cheap, natural and alternative therapy with erectogenic and antidiabetic potentials.

Effect of urolithins on oxidative stress of colorectal adenocarcinomacells-Caco-2.

Urolithins (UROs) are metabolites derived from ellagic acid (EA) and ellagitannins (ETs) by gut microbiota after consumption of different ETs. The health effects attributed to UROs are numerous and diverse, ranging from antimalarial properties to anticancer activities and regulation of gene expression. The aim of this work was at assessing the effect of URO-A; -B; -C; -D on the oxidative status of colon epithelium using as a model colorectal adenocarcinoma cell line (Caco-2). No significant cytotoxic effects of UROs was noted, with the applied treatments. Supplementation of cell growth medium with a mixture of UROs decreased the level of intracellular reactive oxygen species both after short- and long-term exposure. UROs also affected the activity of antioxidative enzymes within the cell, especially catalase. CONCLUSIONS: At concentrations reached in the lumen of the gut, UROs can exert beneficial effects on the cells by decreasing oxidative stress thus preventing the damage caused by reactive oxygen species.

Selective Spectrofluorimetric Method with Enhanced Sensitivity for Determination of Silodosine in Dosage Form and Human Plasma. Application to Stability Studies and Content Uniformity Testing.

A novel, sensitive and selective spectrofluorimetric method has been developed and validated for determination of silodosine (SLD) in its dosage form and human plasma. The method is based on nucleophilic substitution reaction of SLD with 5-(dimethylamino) naphthalene-1-sulfonyl chloride (dansyl chloride) in presence of 5.0 × 10-4 M sodium carbonate (pH 10.50) to yield a highly fluorescent derivative that was measured at 435 nm after excitation at 347 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The fluorescence-concentration plot was rectilinear over the range 30.0-200.0 ng ml-1, with a correlation coefficient of 0.9979. The limits of detection (LOD) and quantification (LOQ) were found to be 5.44 and 16.47 ng ml-1, respectively. The proposed method was validated according to ICH guidelines, and successfully applied to the assay of commercial capsules as well as content uniformity testing. The high sensitivity of the proposed method allowed its successful application to the analysis of SLD in spiked human plasma with % recovery of 92.88 ± 1.05-100.73 ± 0.75%, (n = 6). The application of the proposed method was further extended to stability studies of SLD after exposure to different forced degradation conditions, such as acidic, alkaline and oxidative conditions, according to ICH guidelines, where this work describe the first attempt for selective spectrofluorimetric determination of silodosine in plasma and in the presence of its oxidative degradation.

Review: Antiurolithiatic plants: Formulations used in different countries and cultures.

About 12% of world population is affected by different forms of urolithiasis in which the recurrence rate in female is 47-60% and in male is 70-80%. According to WHO 75% people rely on traditional medicines for the prevention and cure of different ailments. Similarly, the majority of the world population use a number of plants to treat problems related to the urinary tract system in which urolithiasis is the major cause. The aim of the review is to collect the data of the plants used in different parts and cultures of the world against urolithiasis with their parts, mode of preparation, dosage and administration. A literature review was conducted for traditionally used antiurolithiatic plants. The articles mentioning plant, parts, mode of preparation, dose and route of administration were selected. This information was extracted to compose Mono and Poly herbal antiurolithiatic formulations used in Appalachia (region in Eastern United States), Canada, India, Iran, Israel, Italy, Jordan, Latin America, Pakistan, Turkey and Yemen. The review provides an important data about plants used as antiurolithiatic in different parts of the world. The information not only useful for common people, but also for the scientific community to carry out further phytochemical, pharmacological and toxicological studies for the discovery of new, effective and safer molecules against urolithiasis.

Formulation and evaluation of gastroretentive controlled release tablets of alfuzosin hydrochloride.

Alfuzosin hydrochloride is a novel drug used in the treatment of urinary incontinency. The purpose of this research was to develop controlled release floating matrix formulations of Alfuzosin HCl. Floating matrix tablets of Alfuzosin HCl were prepared using hydroxypropyl methylcellulose (HPMC), Polyethylene oxide (PEO), Carbopol 971P NF polymer (Direct compressible) and Blend of Polyvinyl Acetate and Povidone 30 (80:19:1(0.8% sodium laury sulfate and 0.2% silica)). Combination of citric acid and sodium bicarbonate were also used as gas forming agent. Matrix formulations were prepared by direct compression method and evaluated for floating, in vitro drug release profile and swelling characteristics. The mechanism of drug release was found to follow non-Fickian or anomalous type. The data obtained from the invitro release studies demonstrated that the floating matrix tablets containing HPMC 100K CR (controlled-release) and carbopol along with sodium CMC were found to sustain the release of drug over a period of 12 hours. Formulations containing 25% PEO 303WSR was also capable of sustaining delivery the release of Alfuzosin HCl.

Temperature influencing permeation pattern of alfuzosin: an investigation using DoE.

BACKGROUND AND OBJECTIVE: There has been relatively little investigation of the effect of temperature on skin permeation compared to other methods of penetration enhancement. A principal physicochemical factor which controls the passive diffusion of a solute from a vehicle into the skin arises from the skin temperature. The aim of this ex vivo study was to probe into the effect of heat on transdermal absorption of alfuzosin hydrochloride from ethyl cellulose-polyvinyl pyrrolidone (EC-PVP) based transdermal systems. MATERIALS AND METHODS: Principles of design of experiment (DoE) were used to systematically study the influence of temperature on transdermal permeation of alfuzosin. Ex vivo transdermal permeation studies were carried out at varied donor compartment temperatures. Permeation data analysis was carried out and activation energy for transdermal permeation was estimated. RESULTS: Temperature found to enhance ex vivo permeation parameters of alfuzosin hydrochloride from its transdermal systems. It was also noted that chemical permeation enhancers potentiate permeation enhancing effect of temperature. The permeation flux values approximately doubled after exposure to 45°C. The activation energy for transdermal permeation was found lower for the runs with chemical permeation enhancers indicating existence of a lower energy barrier in the presence of chemical permeation enhancers. CONCLUSION: The method reported here is a simple and useful tool for studying the effect of heat on percutaneous absorption. Such temperature dependent enhancement of flux can be more pronounced at skin surface temperatures >45°C.

Application of Orbitrap-mass spectrometry to differentiate isomeric sildenafil- and thiosildenafil-like analogues used for the adulteration of dietary supplements.

Two groups of isomeric phosphodiestrase-type 5 inhibitors (PDE-5), consisting of four sildenafil- and three thiosildenafil-like analogues, have been successfully differentiated using high-resolution MS/MS. The optimised MS/MS data obtained from each compound were used to build a database with the aid of mass processing software. Isomeric compounds with very close chromatographic separation like dimethylsildenafil and homosildenafil could be distinguished by their unique fingerprint fragment ions in the MS/MS database. All fragment ions were within the mass tolerance of 5 ppm. One case study using an adulterated dietary supplement is included to provide more insights into this application.

Improvement of trospium-specific absorption models for fasted and fed states in humans.

The purpose of this study was to mechanistically interpret the oral absorption pattern of trospium in fasted and fed states by means of gastrointestinal simulation technology. A drug absorption model was built on the basis of experimental data. According to the generated model, low permeability across the intestinal epithelium, delayed gastric emptying time and a prolonged residence time in the small intestine are the key factors governing trospium absorption in the fasted state. Furthermore, in silico modelling provided a plausible explanation of the pronounced reduction in the oral bioavailability of trospium when administered with food. The simulation results support the decreased dissolution in viscous medium, and the reduced drug permeability in the fed state as the predominant mechanisms for the food effect on trospium absorption.

Discovery history and clinical development of mirabegron for the treatment of overactive bladder and urinary incontinence.

INTRODUCTION: Overactive bladder (OAB) and urinary incontinence, although not life-threatening, are very bothersome chronic health conditions. The limitations of current pharmacological treatment urge the need for novel drugs with alternative mechanisms of action. Huge efforts in this area of research led to the synthesis of several selective and potent ß3-adrenoceptor agonists that gained relevance through research during the late 80s and 90s. Mirabegron was the first compound of this new class of drugs that showed preclinical efficacy in several models of storage bladder dysfunction, together with a favorable human pharmacological profile. Having passed the proof-of-concept stage, an extensive clinical development and pharmacology program was performed during the last 10 years, involving >10,000 individuals, before mirabegron was granted marketing approval. AREAS COVERED: In this case history, the authors review the milestones in mirabegron's discovery based on a systematic literature review. EXPERT OPINION: Thanks to its tolerability and safety/efficacy balance, mirabegron has potential to fill a need for new treatment options for OAB, and paves the way for further development of a completely new class of drugs aimed to treat this condition. However, the exact role of mirabegron in clinical practice has yet to be defined. Further studies are needed in order to clarify, together with post-launch information, critical safety issues and cost-effectiveness in head-to-head comparison with current standard treatments.

Enhanced oral bioavailability and controlled release of dutasteride by a novel dry elixir.

To develop a solid dosage form of dutasteride for improving its oral bioavailability, a novel dry elixir (DE) system was fabricated. DEs incorporating dextrin and/or xanthan gum were prepared using spray-drying and evaluated by morphology, ethanol content, crystallinity, dissolution and oral bioavailability. DEs were spherical with a smooth surface and had an average particle size of 20-25 µm. The ethanol content could be easily varied by controlling the spray-drying temperature. The dissolution profiles of dutasteride from each DE proved to be much faster than that of dutasteride powder due to the amorphous state and a high amount of incorporated ethanol. In particular, the pharmacokinetic profiles of dutasteride were significantly altered depending on the proportions of dextrin and xanthan gum. Blood concentrations of dutasteride from DE formulations were similar to those of market products and much greater than those of native dutasteride. Interestingly, the dissolution and pharmacokinetic profiles were easily controlled by changing the ratio of dextrin to xanthan gum. The data suggests that a DE using dextrin and/or xanthan gum could provide an applicable solid dosage form to improve the dissolution and bio-availability of dutasteride as well as to modulate its pharmacokinetics.

Preparation and evaluation of once-daily sustained-release coated tablets of tolterodine-L-tartrate.

In this study, once-daily, sustained-release matrix tablets of tolterodine l-tartrate (TOL) for treatment of overactive bladder (OAB) were prepared by direct compression using various amounts of hydrophilic polymers such as HPMC 2910 and HPMC 2208 along with other tablet excipients; the tablets were then coated. In vitro dissolution studies were carried out under different pH conditions. The dissolution data were fitted into zero-order, first-order, Higuchi and Korsemeyer-Peppas models to identify the pharmacokinetics and mechanism of drug release. Among the four formulations (F1-F4), the dissolution profiles of formulation F2 were most similar to the marketed product with similarity and difference factors of 70.25 and 1.59 respectively. Furthermore, pharmacokinetic studies were carried out in healthy human volunteers after oral administration of the prepared TOL sustained-release matrix-coated tablet and the marketed product. The results revealed that the pharmacokinetic parameters of AUC, Cmax, Tmax, t1/2, Kel, and MRT of TOL for the developed formulation (F2) were not significantly different from that for the marketed product, suggesting that they were bioequivalent. Therefore, the developed sustained-release tablet formulation of TOL could be an alternative dosage form to the SR capsule for treatment of OAB.

Evaluation of fesoterodine fumarate for the treatment of an overactive bladder.

INTRODUCTION: Fesoterodine fumarate is an approved drug for overactive bladder. The aim of this study is to review the preclinical and most up to date clinical data on fesoterodine, with a special emphasis on its unique pharmacokinetic features and its implications on safety and tolerability in various patient populations. AREAS COVERED: In this review, the authors extensively reviewed available literature via PubMed search regarding fesoterodine, covering its mechanism of action, pharmacodynamics and pharmacokinetics, clinical efficacy, safety, and tolerability. EXPERT OPINION: Fesoterodine is an anti-muscarinic agent with a unique pharmacokinetic profile. It is a prodrug that is rapidly metabolized to its active form by nonspecific plasma esterases. Its metabolism is independent of the cytochrome P450 enzyme system. This along with its dual excretion pathways and minimal central nervous system penetration leads to less variability in drug exposure and allowance of administration in those with mild to moderate renal and hepatic insufficiency and in the geriatric population.

The molecular basis for the selectivity of tadalafil toward phosphodiesterase 5 and 6: a modeling study.

Great attention has been paid to the clinical significance of phosphodiesterase 5 (PDE5) inhibitors, such as sildenafil, tadalafil, and vardenafil widely used for erectile dysfunction. However, sildenafil causes side effects on visual functions since it shows similar potencies to inhibit PDE5 and PDE6, whereas tadalafil gives a high selectivity of 1020-fold against PDE6. Till now, their molecular mechanisms of selectivity of PDE5 versus PDE6 have remained unknown in the absence of the crystal structure of PDE6. In order to elucidate its isoform-selective inhibitory mechanism, a 3D model of PDE6 was constructed by homology modeling, and its interaction patterns with tadalafil plus sildenafil were exploited by molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations. The present work reveals that tadalafil exhibits a less negative predicted binding free energy of -35.21 kcal/mol with PDE6 compared with the value of -41.12 kcal/mol for PDE5, which suggests that tadalafil prefers PDE5 rather than PDE6 and confers a high selectivity for PDE5 versus PDE6. The binding free energy results for tadalafil were consistent with external bioassay studies (IC50 = 5100 and 5 nM toward PDE6 and PDE5, respectively). Two important residues from the Q2 pockets (Val782 and Leu804 in PDE5 and their corresponding Val738 and Met760 in PDE6) were further identified to account for the high selectivity of tadalafil for PDE5 versus PDE6. These findings have shed light on the continuous puzzle of why sildenafil (IC50 = 74 and 6 nM toward PDE6 and PDE5, respectively) causes visual disorders because of its poor selectivity but tadalafil does not. In addition, the homology model of PDE6 can be used to design more potent and selective second-generation PDE5 inhibitors with less inhibitory potency against PDE6.

Development of long-acting bioadhesive vaginal gels of oxybutynin: formulation, in vitro and in vivo evaluations.

Overactive bladder (OAB) and vaginal dryness are common problems after menopause. Oxybutynin (OXY) is an antimuscarinic agent that has been available for more than 30 years in the treatment of OAB patients. The aim of the work reported in this paper was to develop long acting mucoadhesive gel formulations of OXY and to investigate their effects on blood levels compared to those of oral OXY immediate release tablets, in rabbits. Mucoadhesive gels were prepared with chitosan, hydroxypropyl methylcellulose (HPMC K100M) and Poloxamer 407 (Pluronic F 127). The physicopharmaceutical properties of gels were evaluated. The gel formulation which was prepared with HPMC K100M, exhibited the highest viscosity, the greatest adhesiveness, cohesiveness and mucoadhesion values. The formulation which was prepared from HPMC K100M showed suitable permeation characteristics across the vaginal mucosa. Comparative bioavailability studies were carried out on rabbits with vaginal HPMC gel, vaginal chitosan gel, vaginal OXY solution and commercially available oral Üropan tablets. It was concluded that the highest AUC and relative bioavailability values were obtained for the bioadhesive vaginal gel formulation prepared with HPMC K100M. Therefore, the mucoadhesive vaginal gels of OXY can be a promising and innovative alternative therapeutic system for the treatment of OAB. It can be safely used in cases of overactive bladder and as well as vaginal dryness after menopause.