Avanafil Research Articles

Simultaneous measurement of duloxetine hydrochloride and avanafil at dual-wavelength using novel ecologically friendly TLC-densitometric method: application to synthetic mixture and spiked human plasma with evaluation of greenness and blueness

The simultaneous assay of duloxetine hydrochloride (DLX) and avanafil (AVN) in their pure forms, synthetic mixtures, and spiked human plasma was achieved using a novel, eco-friendly, sensitive, and specific HPTLC methodology that have been established and validated. Measuring the levels of co-administered antidepressants and sexual stimulants in biological fluids is an important step for individuals with depression and sexual problems. Separation was performed successfully using pre-coated silica gel 60-F254 as a stationary phase and a mobile phase composed of methanol, acetone, and 33% ammonia (8:2:0.05, v/v/v). Compact bands were produced by the optimized mobile phase that was chosen for development (Rf values were 0.23 and 0.75 for DLX and AVN, individually) after dual-wavelength detection for DLX and AVN at 232 and 253 nm, respectively. The results of polynomial regression analysis were exceptional (r = 0.9999 for both medicines) over concentration ranges of 5-800 and 10-800ng/spot for DLX and AVN, respectively. The quantitation limits were 4.69 and 9.53 ng/spot (0.31 and 0.94 µg/mL), whereas the detection limits were 1.55 and 3.15 ng/spot (0.63 and 1.91 µg/mL), for DLX and AVN, respectively. The International Council for Harmonization (ICH) criteria served as the basis for validating the established approach. Moreover, the proposed technique was evaluated in terms of greenness using four contemporary ecological metrics: The Analytical Greenness software (AGREE), the Green Analytical Procedure Index (GAPI), Eco-Scale, and the National Environmental Method Index (NEMI). Additionally, the Blue Applicability Grade Index (BAGI), a newly developed tool for evaluating the practicality (blueness) of procedures, was taken into consideration when evaluating the sustainability levels of the established approach.

Fast and simple voltammetric sensing of avanafil in the pharmaceutical formulation by using unmodified boron-doped diamond electrode.

Erectile dysfunction is a common issue among adult males involving difficulty in maintaining an erection, and it is often treated with fast-acting, low-side-effect drugs like avanafil (AVN), among other phosphodiesterase-5 inhibitors. Hence, developing fast, simple, and sensitive methods to detect AVN is crucial. This study conducts an electroanalytical inquiry and provides a new voltammetric method for accurately analyzing AVN utilizing a boron-doped diamond (BDD) electrode without any modifications. In the Britton-Robinson buffer (BR, 0.04 mol L-1, pH 4.0), cyclic voltammetry showed a clearly defined and irreversible anodic peak at around +1.44 V relative to Ag/AgCl. The pH of the solution was shown to have an impact on the voltammetric signals of the oxidation peaks. A good linear response for AVN quantification was achieved using square-wave voltammetry. This was done in a 0.04 mol L-1 BR (pH 4.0) solution at a potential of +1.33 V (vs. Ag/AgCl). The method exhibited a wide dynamic range of 0.5 to 30.0 μg mL-1 (1.0 to 62 μmol L-1) and a low limit of detection of 0.14 μg mL-1 (0.29 μmol L-1). The method proposed demonstrated suitability for determining AVN content in pharmaceutical formulations. The accuracy of the approach was demonstrated by comparing the results obtained using the developed method with those achieved using the UV-Vis spectrometry method. Our method simplifies the analytical process by eliminating the need for electrode modification, reducing both time and resource requirements while enhancing overall feasibility.

Anatase titanium oxide nanoparticles and multi-walled carbon nanotubes-modified carbon paste electrode for simultaneous determination of avanafil and doxorubicin in plasma samples

Patients who receive anticancer drugs, might experience loss of sexual desire together with erectile dysfunction as one of cancer medications’ adverse effects. This might have a negative effect on their psychological functioning and quality of life and accordingly phosphodiesterase type 5 (PDE5) inhibitors as sex stimulants are used. One of the recently FDA-approved members of this class of drugs is avanafil (AVN) that is administered to assist in improving penile erection. Because of the seriousness of the cancer patient's health condition, it is mandatory to recognize the possible pharmacokinetic interactions in case of administering other drugs at the same time. Therefore, a sensitive sensor derived from carbon paste electrode (CPE) modified with anatase titanium dioxide nanoparticles (TiO2-NPs) and multi-walled carbon nanotubes (MWCNTs) was designed for the simultaneous determination of AVN and the anticancer drug doxorubicin (DOX) in spiked and real rabbit plasma samples. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM) were employed to fully characterize the fabricated electrode. The modified electrode offers a considerable improvement in voltammetric sensitivity toward oxidation of AVN and DOX, compared to the bare electrode. A good separation was achieved between the oxidation peak potentials of AVN (1.4 V) and DOX (0.8 V). The effect of different voltammetric parameters on the peak separation and sensitivity for both drugs was studied to select the optimum experimental conditions. It was found that the optimum pH for the simultaneous determination of both drugs was obtained utilizing a Britton-Robinson buffer (BR) of pH 3.0. Furthermore, the electrochemical oxidation of AVN and DOX was evaluated with different modified carbon paste electrodes using cyclic voltammetry (CV) and square-wave adsorptive anodic stripping voltammetry (SWAdASV). The analytical curves for the quantitative simultaneous determination of AVN and DOX exhibited acceptable linearity within the concentration range from (0.10–6.0 μmol L−1 for AVN) and (5.0–35.0 μmol L−1 for DOX) in spiked rabbit plasma. Detection and quantitation limits were determined to be 0.035 and 0.10 μmol L−1 in the case of AVN and 1.3 and 4.0 μmol L−1 in the case of DOX, respectively. The method was effectively applied for the analysis of AVN in real rabbit plasma samples after the coadministration of DOX. Moreover, the proposed voltammetric method was useful as a therapeutic drug monitoring method to investigate the possible pharmacokinetic interactions between AVN and DOX in real rabbit plasma. An increase in the level of AVN in rabbit plasma was observed after administering DOX, and accordingly, the dose of AVN should be adjusted and monitored.

Renoprotective Effect of Vardenafil and Avanafil in Contrast-Induced Nephropathy: Emerging Evidence from an Animal Model.

The potential renoprotective effects of vardenafil (VAR) have been evaluated in a very limited number of studies using acute kidney injury animal models other than contrast-induced nephropathy (CIN) with promising results, while avanafil (AVA) has not been evaluated in this respect before. The purpose of this study was to evaluate for the first time the potential renoprotective effect of VAR and AVA in a rat model of CIN. Twenty-five male Wistar rats were equally assigned into five groups: control, CIN, CIN+N-acetyl cysteine (NAC) (100 mg/kg/day) as a positive control, CIN+VAR (10 mg/kg/day) and CIN+AVA (50 mg/kg/day). CIN was induced by dehydration, inhibition of prostaglandin and nitric oxide synthesis as well as exposure to the contrast medium (CM). Serum Cr (sCr) levels were measured at 24 and 48 h after CIN induction. At 48 h of CM exposure, animals were sacrificed. Matrix metalloproteinase (MMP) 2 (MMP-2) and MMP-9, kidney injury molecule 1 (KIM-1) and cystatin-C (Cys-C) were measured on renal tissue. Histopathological findings were evaluated on kidney tissue. All treatment groups had close to normal kidney appearance. sCr levels subsided in all treatment groups compared to CIN group at 48 h following CIN induction. A significant decline in the levels of MMP-2, MMP-9, KIM-1 and Cys-C compared to CIN group was observed. These results provide emerging evidence that VAR and AVA may have the potential to prevent CIN.

Characteristics and Analytical Methods of Novel PDE5 Inhibitor Avanafil: An Update

Erectile dysfunction (ED) affects middle and older age and occurrence increasing with age of men. PDE5 inhibitors are commonly used for the treatment of ED. The incidences of adulteration of PDE5 inhibitors with herbal aphrodisiacs is evident in almost every part of world. Avanafil (AVA) is novel PDE5 inhibitor with advantage of fast action. The literatures and various analytical methods presented in this review was obtained by searching various databases like pubmed, medline, eurekaselect, sciencedirect, wiley and taylor and francis journals. The services of google scholar were also utilized for searching some literature. The literature search was performed to summarize characteristics, synthesis and analytical methods for determination of AVA. Different spectrophotometry methods, chromatography and ion mobility spectrometry methods are available in the method. The possibility for the development of green analytical method is also discussed. The various analytical methods and characteristics of AVA is described. The methods for determination as adulterants and in pharmaceutical formulations including stability indicating methods.

Mixed Avanafil and Dapoxetin Hydrochloride cyclodextrin nano-sponges: Preparation, in-vitro characterization, and bioavailability determination

Avanafil (AVA) and Dapoxetine hydrochloride are BCS Class II drugs, which means that the bioavailability depends on its solubility extent.Nano-sponges are hyper-crosslinked cyclodextrin nano-polymers that have been developed recently to make solid particles with nonporous structure; they're prepared by reacting different types of cyclodextrins with an appropriate cross-linking agent like diphenyl carbonate. Nano-sponges can improve the solubility of poorly soluble active molecules and increase stability by protecting labile groups.Hence, the purpose of this work was to study the effects of different types of cyclodextrins and crosslinker ratios on the solubility and oral bioavailability of Avanafil (AVA) and Dapoxetine hydrochloride (DA) by loading them to Nano-sponges prepared by crosslinking of β-CD, SBE-β-CD with diphenyl carbonate (DPC) as a crosslinker at various molar ratios.AVA and DA-loaded nano-sponges were fabricated using the freeze-drying method and characterized for particle size, zeta potential, loading capacities, and in-vitro drug release. Scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy were used to characterize the NS and AVA/DA incorporation within the NS.In-vitro drug release was significantly higher with AVA and DA-loaded nano-sponges. Furthermore, the results revealed that AVA and DA-loaded nano-sponges fabricated with β-CD had a higher release in dissolution with both drugs than those fabricated using SBE-β-CD.AVA and DA-loaded nano-sponges increased the oral bioavailability of both drugs by 2.5 and 7.5 folds, respectively, when compared to Spedra® and Priligy®. While there is no significant difference in Tmax between F10 and Spedra®, E12 has a faster onset than Priligy®. A one-way ANOVA revealed a substantial increase in Cmax and T1/2 for AVA and DA. Therefore, AVA and DA-loaded nano-sponges are considered a better alternate to the regular dosage forms for efficient AVA and DA oral delivery.

Transdermal Film Loaded with Avanafil Ultra-deformable Nanovesicles to Enhance its Percutaneous Absorption and Bioavailability.

The in vitro dissolution of Avanafil (AVA) is the rate-limiting step for its bioavailability. Also, it undergoes the first-pass metabolism, and its absorption is altered significantly in the presence of food. So, our study aimed to overcome the previous hurdles and improve the AVA bioavailability by its incorporation in the ultra-deformable nanovesicles, transfersomes (TRF), then loading these nanovesicles in transdermal films. The AVA-loaded TRF formulation was optimized using Draper-Lin small composite design (D-LSCD). The optimized AVA-loaded TRF was evaluated for quality attributes and assessed for skin permeation using a fluorescence laser microscope and for pharmacokinetic parameters after topical application on the rats. The optimized AVA-loaded TRF showed a vesicle size of 97.75 nm, a zeta potential of -28.83 mV, and entrapment efficiency of 95.14% with good deformability and release profile. The intense discoloration in the deep skin layers of the rats indicated the permeation efficiency of AVA-loaded TRF films. The pharmacokinetic parameters specified the augmented absorption extent with Cmax of 254.66 ± 8.02 ng/mlversus 70.33 ± 3.05 ng/ml which reflected on the AUC0-inf that has a value of 2050.45 ± 159.14 ng/ml h versus 497.34 ± 102.61 ng/ml h for the optimized AVA-loaded TRF film and raw AVA-loaded film, respectively. These promising results wide open the field for broader clinical application of this alternative delivery pathway for superior bioavailability, efficacy, and patient compliance and satisfaction.

Validated Capillary Zone Electrophoretic Determination of Avanafil and Dapoxetine Hydrochloride in their Pure form and Pharmaceutical Preparation

Aims: In this study, a simple, green, and rapid capillary zone electrophoresis (CZE) method coupled with a diode array detector (DAD) was applied for the analysis of avanafil (AVA) and dapoxetine hydrochloride (DAP) as a binary mixture using vardenafil (VAR) as an internal standard (IS) in pure form and pharmaceutical formulation.
 Methodology: The separation was done using fused silica capillary (58.5 cm total length, 50 cm effective length, and 50 μm internal diameter) and the running background electrolyte (BGE) was 100 mM acetate buffer at pH 3.6. During the separation process, the applied voltage was 30 KV, while the temperature was 25 °C. The sample injection was applied at a pressure of 50 mbar for 10 s, and detection was carried out at 210 nm for DAP and 248 nm for AVA and VAR.
 Results: Analysis of the tested drugs and the internal standard was carried out in less than 6.5 min, where the migration times were 4.29, 4.90, and 6.02 min for IS, DAP and AVA respectively. The proposed method showed linearity in the concentration range 5-80 and 5-70 μg/mL with correlation coefficients 0.9996 and 0.9999 for AVA and DAP respectively. The limit of detection (LOD) was 0.523 and 0.531 for AVA and DAP respectively, while the limit of quantification (LOQ) was 1.585 and 1.608 in respective order. The Peak purity and identity in the proposed method were validated by DAD.
 Conclusion: The proposed CZE method was validated according to ICH guidelines and applied successfully for the estimation of AVA and DAP in their combined pharmaceutical preparation.

Hybrid NiO nanostructured/sulfanilamide polymeric film for studying possible pharmacokinetic interaction between avanafil and nimodipine in real human serum by their simultaneous determination using square-wave voltammetry

Avanafil (AVN) is a new selective phosphodiesterase-5 (PDE-5) inhibitor, which is used as an oral treatment of erectile dysfunction. Coadministration of avanafil (AVN) with some antihypertensive drugs especially in elderly patients is a very common case. Nimodipine (NIM) is one of these hypotensive drugs that are commonly coadministered. Synergistic hypotension effect as a result of AVN and NIM coadministration is expected; therefore, it is mandatory to study the possible pharmacokinetic interaction between them. The main aim of the current work is to develop a simple, sensitive, and selective electrochemical method for simultaneous determination of AVN and NIM in human serum samples. Nickel oxide nanoparticles/poly(sulfanilamide) film was used as a new electrochemical modifier, which is electrodeposited on the surface of pencil graphite electrode (PGE) to improve its electrochemical properties. The best resolution between the two studied drugs was achieved by using Britton-Robinson buffer (BRB) at pH 3.0 producing two peaks at 1.45 V and 0.80 V for AVN and NIM, respectively. Furthermore, cyclic voltammetry was utilized for the first time to study the oxidation behavior of AVN and NIM and a plausible oxidation mechanism was suggested for both of them. The proposed square wave voltammetric method was successfully applied for trace quantification of AVN and NIM in real human serum samples with detection and quantitation limits of 0.037 and 0.10 μmol L−1 for AVN and 0.32 and 0.98 μmol L−1 for NIM, respectively. Moreover, the suggested approach was effectively implemented to investigate the possible pharmacokinetic interaction between AVN and NIM in serum samples of heathy human male volunteers. It was found from the pharmacokinetic parameters calculated for AVN when administered alone or in presence of NIM that there is a significant increase of serum concentration of AVN, when it is coadminstered with NIM, which stresses the importance of dose adjustment of AVN when coadministered with NIM.

An Eco-Friendly Solid-State Electrode Modified With ZnO Nanoparticles Decorated With MWCNT as an Electrochemical Sensor for the Determination of Avanafil in Pure Form, Dosage Form and Human Plasma

A sensitive voltammetric technique for the determination of avanafil (AVA) has been investigated at a carbon paste electrode modified with Zinc oxide nanoparticles and multi-walled carbon nanotubes (ZnO-NPs/MWCNT/CP). The study investigated the electrochemical behavior of AVA, and the morphology of the modified electrode was evaluated by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction patterns. The influence of different electrodes and the content of ZnO-NPs on the voltammetric behavior of AVA were evaluated. Square wave voltammetry was studied and a linear correlation resulted within the range of (1.3–16 μg ml−1) with correlation coefficient 0.999, LOD 0.342 μg ml−1 and LOQ 1.141 μg ml−1. The proposed procedure was applied successfully for the determination of AVA with good recovery in commercial dosage form and human plasma. The technique was validated and found to be accurate and reproducible according to the ICH guidelines.

Preparation, Optimization and Evaluation of Chitosan-Based Avanafil Nanocomplex Utilizing Antioxidants for Enhanced Neuroprotective Effect on PC12 Cells.

(1) Introduction: in recent decades, interdisciplinary research on the utilization of natural products as “active moiety carriers” was focused on due to their superior safety profile, biodegradability, biocompatibility and the ability for sustained or controlled release activity. The nano-based neuroprotective strategy is explored as an imperative treatment for diabetic neuropathy (DN). Avanafil (AV), that selectively inhibits the degradation of cGMP-specific phosphodiesterase, thereby increasing the levels of cGMP, makes a decisive mediator for cytoprotection. (2) Methods: AVnanocomplex formulations were prepared by a modified anti-solvent precipitation method and the method was optimized by Box–Behnken design. An optimized formulation was characterized and evaluated for various in vitro parameters; (3) results:based on the desirability approach, the formulation containing 2.176 g of chitosan, 7.984 g of zein and 90% v/v ethanol concentration can fulfill the prerequisites of optimum formulation (OB-AV-NC).OB-AV-NC was characterized and evaluated for various parameters. The neuroprotective mechanism of AV was evaluated by pretreatment of PC12 cells with plain AV, avanafil nanocomplex (NC) without antioxidants (AV-NC) and with antioxidants (α-Lipoic acid LP; Ellagic Acid EA), AV-LP-EA-Nanocomplex has also shown considerable attenuation in intracellular reactive oxygen species (ROS) and lipid peroxidation with a significant increase in the PC 12 viability under HG conditions in comparison to pure AV; (4) conclusion: the nanocomplex of AV prepared to utilize natural polymers and antioxidants aided for high solubility of AV and exhibited desired neuroprotective activity.This can be one of the promisingstrategy to translate the AV nanocomplex with safety and efficacy in treating DN.

Investigating the Potential of Transdermal Delivery of Avanafil Using Vitamin E-TPGS Based Mixed Micelles Loaded Films.

To avoid the first-pass metabolism of avanafil (AVA) and its altered absorption in the presence of food after oral administration, this study aimed to investigate the potential of TPGS-based mixed micelle (MM)-loaded film for transdermal delivery and the enhancement of bioavailability. A Box–Behnken design was employed to optimize the permeation behavior of AVA from the transdermal film across the skin. The variables were the hydrophile-lipophile balance (HLB) of the surfactant (X1), the concentration of mixed micelles (MMs) in the film (X2), and the concentration of the permeation enhancer (X3). The initial permeation of AVA after 1 h (Y1), and the cumulative permeation of AVA after 24 h (Y2) were the dependent variables. Ex vivo studies were carried out on freshly isolated rat skin to investigate the drug’s permeation potential and results were visualized using a fluorescence laser microscope. Moreover, the pharmacokinetic behavior after a single application on male Wistar rats, in comparison with films loaded with raw AVA, was evaluated. The results showed that the optimum factor levels were 9.4% for the HLB of the surfactant used, and 5.12% MMs and 2.99% penetration enhancer in the film. Imaging with a fluorescence laser microscope indicated the ability of the optimized film to deliver the payload to deeper skin layers. Furthermore, optimized AVA-loaded TPGS-micelles film showed a significant increase (p < 0.05) in the Cmax of AVA and the area under the AVA plasma curve (approximately three-fold). The optimized AVA-loaded TPGS-MM film thus represents a successful delivery system for enhancing the bioavailability of AVA.

Formulation and Optimization of Avanafil Biodegradable Polymeric Nanoparticles: A Single-Dose Clinical Pharmacokinetic Evaluation.

Avanafil (AVA) is a second-generation phosphodiesterase-5 (PDE5) inhibitor. AVA shows high selectivity to penile tissues and fast absorption, but has a bioavailability of about 36%. The aim was to formulate and optimize AVA-biodegradable nanoparticles (NPs) to enhance AVA bioavailability. To assess the impact of variables, the Box–Behnken design was utilized to investigate and optimize the formulation process variables: the AVA:poly (lactic-co-glycolic acid) (PLGA) ratio (w/w, X1); sonication time (min, X2); and polyvinyl alcohol (PVA) concentration (%, X3). Particle size (nm, Y1) and EE% (%, Y2) were the responses. The optimized NPs were characterized for surface morphology and permeation. Furthermore, a single-oral dose (50 mg AVA) pharmacokinetic investigation on healthy volunteers was carried out. Statistical analysis revealed that all the investigated factors exhibited a significant effect on the particle size. Furthermore, the entrapment efficiency (Y2) was significantly affected by both the AVA:PLGA ratio (X1) and PVA concentration (X3). Pharmacokinetic data showed a significant increase in the area under the curve (1.68 folds) and plasma maximum concentration (1.3-fold) for the AVA NPs when compared with raw AVA. The optimization and formulation of AVA as biodegradable NPs prepared using solvent evaporation (SE) proves a successful way to enhance AVA bioavailability.

An innovative impurity profiling of Avanafil using LC and LC-MS/MS with in-silico toxicity prediction

Degradation of the drug can lead to the formation of toxic substance hence drug quality and stability is a major concern by pharma regulators. A Selected phosphodiesterase type 5 inhibitor drug Avanafil (AV) structure has amide, arylchloro and hydroxide as functional groups which can easily eliminated during hydrolysis. Henceforth, thoroughly chemical stability of AV was carried out according to ICH guideline Q1A (R2). The drug and marketed tablet formulation undergoes degradation in hydrolytic (acid, base, neutral), thermal, photolytic, oxidative conditions and forms a total new sixteen degradation products (D.P.s) which were identified by LC, characterized by LC-MS/MS and probable degradation mechanism for each stress conditions are proposed. All sixteen D.P.s were identified by optimized LC conditions; C18 column using 10 mM ammonium acetate: ACN (60:40, v/v), pH 4.5 as mobile phase at 0.9 mL min−1 of flow rate, 239 nm wavelength at 20 °C column temperature and the method being LC-MS compatible characterized by LC-MS/MS confirmed by relative retention time (RRT). The structure of D.P.s was confirmed from the fragmentation pattern obtained by LC-MS/MS and further probable degradation mechanism for each stress condition is proposed. The drug and its marketed tablet formulation showed similar degradation peaks which were confirmed using RRT, photodiode array (PDA) and LC-MS. Drug degradation happens due to nucleophilic substitution reaction, amide hydrolysis, electron withdrawing properties of amide, dechlorination and bond cleavage due to energy. The amide group in AV structure can undergo hydrolysis, while due to aryl chloride and hydroxide group in structure it undergoes photodecomposition. A comprehensive stress study reveals that AV is more prone to degrade in light, temperature and moisture; hence AV requires proper storage condition temperature below 25 °C with protection to light and moisture. In silico toxicity prediction of physicochemical properties revealed that all the physicochemical parameters of impurities were within the acceptable limit which indicates that no impurity is at any risk of toxicity. In detail, the LC-MS/MS compatible AV degradation study is fully validated as per ICH Q2 (R1) guideline.

Native and synchronous fluorescence spectroscopy for determination of avanafil in presence of its co-formulated drug (dapoxetine hydrochloride): Application to pharmaceutical product, biological fluid and content uniformity.

The native and synchronous fluorescence spectroscopy procedures have been established and validated for the simultaneous determination of a binary mixture of dapoxetine hydrochloride (DAP) and avanafil (AVA). The first procedure is based on measurement of native fluorescence intensity of both drugs at λEm 337nm and 370nm using λEx 290nm and 314nm for DAP and AVA in methanol respectively. The second procedure describes a measurement of synchronous fluorescence intensity of these drugs at 232nm for DAP, and 267nm for AVA, using Δλ of 90nm. In the first procedure the fluorescence concentration were 0.1-4.0μg/mL for DAP and 0.5-16μg/mL for AVA. For the second procedure fluorescence concentrations were 0.025-1.0μg/mL and 0.5-16μg/mL for DAP and AVA respectively, with lower detection limit and quantification limits. The processes were successfully used for the limitation of DAP and AVA in their drug product without pre-separation. Then, the techniques were utilized for the determination of DAP and AVA in biological fluids. There is a good agreement between these results and the results obtained using a reference method.

Development of an optimized avanafil-loaded invasomal transdermal film: Ex vivo skin permeation and in vivo evaluation.

Avanafil (AVA) is a recent FDA approved selective phosphodiesterase type 5 inhibitor used for oral treatment of erectile dysfunction. The oral bioavailability of the drug is challenged by its reduced water solubility, considerable presystemic metabolism, and altered absorption in the presence of food. Accordingly, this work aimed to surmount the aforementioned challenges through the development of optimized nanosized AVA invasomes with enhanced transdermal delivery. AVA invasomes were prepared according to a Box-Behnken experimental design to explore the impact of the following formulation factors: phospholipid % (X1), ethanol % (X2), terpene % (X3), and terpene type (X4) on vesicle size (Y1) and entrapment efficiency (Y2). The three numerical variables were used at three levels, while the categorical variable was used at two levels. The optimized formulation with vesicular size of 109.92 nm and entrapment efficiency of 96.98% was incorporated into a hydroxypropyl methyl cellulose-based transdermal film and characterized for its ex vivo permeation behavior and in vivo performance in rats. The optimized AVA invasomal film showed enhanced ex vivo permeation with an enhancement factor of 2.514 and a more than four-fold increase in relative bioavailability compared to the raw AVA film. These results provide insight into the capability of the optimized invasomal film to enhance the transdermal permeation and bioavailability of AVA.

Development of Validated and Stability-Indicating LC-DAD and LC-MS/MS Methods for Determination of Avanafil in Pharmaceutical Preparations and Identification of a Novel Degradation Product by LCMS-IT-TOF.

Avanafil (AVA), one of the most effective drugs prescribed for erectile dysfunction, is a pyrimidine-derivative PDE5 inhibitor. In the current work, new LC methods were developed and validated for quantitative determination of avanafil and qualitative determination of its degradation products. The quantitative determination of avanafil was carried out using liquid chromatography with photodiode array detection (LC-DAD) and liquid chromatography-tandem mass spectrometry LC-MS/MS methods, and fully validated according to the ICH Q2 (R1) guideline, while qualitative determination was performed using a liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) instrument. The separation of avanafil and its degradation products was carried out using the same reversed-phase chromatographic conditions, in which a second-generation C18-bonded monolithic silica column (Chromolith® High Resolution RP-18e, 100 × 4.6 mm, Merck KGaA) was used as stationary phase. Briefly, the methods enable quantitation of avanafil with high accuracy (recovery > 95%) and precision (RSD% < 2.0), within the ranges of 0.5–20 μg/mL for LC-DAD and 150–6000 ng/mL for LC-MS/MS. In the forced degradation studies, over and above currently existing data, a new oxidation-based degradation product, whose predicted m/z is 367.1168, was identified and its structure was confirmed by high-resolution mass spectrometric analysis. As the main advantage, either an LC-DAD or LC-MS/MS instrument can be chosen for interference-free quantitation of AVA, according to the facilities in quality-control laboratories.

Multivariate Approaches for Simultaneous Determination of Avanafil and Dapoxetine by UV Chemometrics and HPLC-QbD in Binary Mixtures and Pharmaceutical Product.

Multivariate UV-spectrophotometric methods and Quality by Design (QbD) HPLC are described for concurrent estimation of avanafil (AV) and dapoxetine (DP) in the binary mixture and in the dosage form. Chemometric methods have been developed, including classical least-squares, principal component regression, partial least-squares, and multiway partial least-squares. Analytical figures of merit, such as sensitivity, selectivity, analytical sensitivity, LOD, and LOQ were determined. QbD consists of three steps, starting with the screening approach to determine the critical process parameter and response variables. This is followed by understanding of factors and levels, and lastly the application of a Box-Behnken design containing four critical factors that affect the method. From an Ishikawa diagram and a risk assessment tool, four main factors were selected for optimization. Design optimization, statistical calculation, and final-condition optimization of all the reactions were Carried out. Twenty-five experiments were done, and a quadratic model was used for all response variables. Desirability plot, surface plot, design space, and three-dimensional plots were calculated. In the optimized condition, HPLC separation was achieved on Phenomenex Gemini C18 column (250 × 4.6 mm, 5 μm) using acetonitrile-buffer (ammonium acetate buffer at pH 3.7 with acetic acid) as a mobile phase at flow rate of 0.7 mL/min. Quantification was done at 239 nm, and temperature was set at 20°C. The developed methods were validated and successfully applied for simultaneous determination of AV and DP in the dosage form.

Solid lipid nanoparticles for transdermal delivery of avanafil: optimization, formulation, in-vitro and ex-vivo studies

Context: Avanafil (AVA) is used in the treatment of erectile dysfunction, but is reported for its poor aqueous solubility. Solid lipid nanoparticles (SLNs) are lipid carriers that can greatly enhance drug solubility and bioavailability.Objective: This work was aimed to formulate and optimize AVA SLNs with subsequent loading into hydrogel films for AVA transdermal delivery.Materials and methods: AVA SLNs were prepared utilizing homogenization followed by ultra-sonication technique. The prepared SLNs were characterized for particle size, charge, surface morphology and drug content. The optimized SLNs formulation was incorporated into transdermal films prepared using HPMC and chitosan. Hydrogel films were evaluated for ex-vivo rat skin permeation using automated Franz diffusion cells. The permeation parameters and the release mechanism were evaluated. The transdermal permeation of the prepared AVA SLNs through the skin layers was studied using confocal laser scanning microscope.Results: Lipid concentration and % of oil in lipid had a pronounced effect on particle size while, entrapment efficiency was significantly affected by lipid concentration and % of cholesterol. The optimized AVA SLNs showed particle size and entrapment efficiency of 86 nm and 85.01%, respectively. TEM images revealed spherecity of the particles. High permeation parameters were observed from HPMC films loaded with AVA SLNs. The release data were in favor of Higuchi diffusion model. The prepared AVA SLNs were able to penetrate deeper in skin layers.Conclusion: HPMC transdermal film-loaded AVA SLNs is an effective and alternative to per-oral drug administration.

AB041. Evolution of PDE5 inhibitors in Korea

After launching of Sildenafil Citrate, the last invention of 20th century, in 1998, oral PDE5 inhibitor has been established as first line treatment of erectile dysfunction (ED) and shift new paradigm of diagnosis and treatment of ED. The big success of sildenafil in pharmaceutical R&D induced the consecutive development of the so-called ‘The second viagra’, e.g., Tadalafil and Vardenafil in 2003. Currently, these 3 kinds of PDE5 inhibitors are most famous and well-known PDE5 inhibitors worldwide. In Korea, another 3 kinds of PDE5 inhibitors, Udenafil (2005), Mirodenafil (2007) and Avanafil (2011) have been developed and 6 kinds of PDE5 inhibitors were used in the competitive market. In last 10 years, the evolution of PDE5 inhibitors competition has changed the dosage concept from on-demand to daily low-dose and applied for other indications beyond ED such as pulmonary hypertension in Sildenafil, and BPH/LUTS in Tadalafil and penile rehabilitation with daily low dose. For the preparations of PDE5 inhibitors, the termination of Korean patent of sildenafil in 2012 released 4 preparations of PDE5 inhibitors, tablet, oro-disposable film, granule and chewable of 60 generic Sildenafil from 49 companies. The oro-disposable film and chewable are favorable from patients. In Korea, patent of Cialis will be terminated in near future and the development of generic drugs like Viagra will go in the right way and as expected. The long half-life of Tadalafil enabled the approval for BPH/LUTS with daily low dose usage. In turn, the generic Cialis also will be developed as various preparations including oro-disposable film and as combination with antihypertensive for ED/HT, PDE5 inhibitor with alpha blockers for ED/LUTS and PDE5 inhibitor with antidepressant for ED/PE. The present lecture review the evolution of PDE5 inhibitors from the development of sildenafil citrate in 1998 to combination in 2015, Korea.