Dual Hypoxia-Targeting RNAi Nanomedicine for Precision Cancer Therapy.

As a hallmark of solid tumors, hypoxia promotes tumor growth, metastasis, and therapeutic resistance by regulating the expression of hypoxia-related genes. Hypoxia also represents a tumor-specific stimulus that has been exploited for the development of bioreductive prodrugs and advanced drug delivery systems. Cell division cycle 20 (CDC20) functions as an oncogene in tumorigenesis, and we demonstrated the significant upregulation of CDC20 mRNA in the tumor vs paratumor tissues of breast cancer patients and its positive correlation with tumor hypoxia. Herein, a hypoxia-responsive nanoparticle (HRNP) was developed by self-assembly of the 2-nitroimidazole-modified polypeptide and cationic lipid-like compound for delivery of siRNA to specifically target CDC20, a hypoxia-related protumorigenic gene, in breast cancer therapy. The delivery of siCDC20 by HRNPs sufficiently silenced the expression of CDC20 and exhibited potent antitumor efficacy. We expect that this strategy of targeting hypoxia-correlated protumorigenic genes by hypoxia-responsive RNAi nanoparticles may provide a promising approach in cancer therapy.

Gellan Gum-Based Hydrogel for the Transdermal Delivery of Nebivolol: Optimization and Evaluation.

Poor solubility and appreciable first-pass metabolism have limited the oral bioavailability of nebivolol. The objective of the current investigation was to design, formulate, and optimize a hydrogel-based transdermal system for nebivolol using factorial design and compare its pharmacokinetics with oral suspension. Hydrogel formulations (F1-F8) were prepared by varying the amounts of gellan gum, carbopol, and polyethylene glycol. A 23 full factorial design was used to assess the effect of independent variables such as gellan gum, carbopol, and polyethylene glycol 400 on dependent variables like viscosity, in vitro release, and ex vivo permeation after 2 h at two levels. Optimized gel (F7), containing nebivolol hydrochloride (75 mg), gellan gum (300 mg), carbopol (150 mg), polyethylene glycol 400 (20 µl), tween 80 (1 ml), ethanol (10 ml), and water (up to 30 ml) was selected and evaluated in albino rats. The physicochemical properties of F7 (pH: 7.1 ± 0.15, viscosity: 8943 ± 116 centipoise, drug content: 98.81% ± 2.16%) seem ideal for transdermal application. It was noticed that the concentration of carbopol has a more significant role than gellan gum in gel viscosity. A biphasic release pattern was exhibited by gels, and the release rate was mainly influenced by the concentration of gellan gum. Greater transdermal flux (30.86 ± 4.08 µg/cm2/h) was observed in F7 as compared with other prepared gels. Noticeable enhancement in AUC0-α value (986.52 ± 382.63 ng.h/ml; p < 0.01) of transdermal therapy (~2-fold higher compared with oral administration) established the potential of F7 to improve the rate and extent of nebivolol delivery. The overall results demonstrated here signify that F7 could be a feasible alternative to oral therapy of nebivolol.

Superiority of TPGS-loaded micelles in the brain delivery of vinpocetine via administration of thermosensitive intranasal gel.

Background: Vinpocetine (VPN) is a synthetic derivative of the Vinca minor alkaloids. The drug is characterized by a short half-life, limited water solubility and high hepatic first-pass effect. The objective was to develop different lipid-based nanocarriers (NCs) loaded into a thermosensitive in situ gelling (ISG) system to improve VPN bioavailability and brain targeting via intranasal (IN) delivery. Methods:  Different lipid-based NCs were developed and characterized for vesicle size, zeta potential, VPN entrapment efficiency (EE) and morphological characterization using transmission electron microscope (TEM). The prepared NCs were loaded into ISG formulations and characterized for their mucoadhesive properties. Ex-vivo permeation and histological study of the nasal mucosa were conducted. Pharmacokinetic and brain tissue distribution were investigated and compared to a marketed VPN product following administration of a single dose to rats. Results: VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets. VPN-D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) micelles nano-formulation showed the smallest particle size, highest EE among the studied NCs. TEM images revealed an almost spherical shape for all the prepared NCs. Among the NCs studied, VPN-loaded TPGS micelles demonstrated the highest percent cumulative VPN ex vivo permeation. All the prepared ISG formulations revealed the presence of mucoadhesive properties and showed no signs of inflammation or necrosis upon histological examination. Rats administered IN VPN-loaded TPGS-micelles ISG showed superior VPN concentration in the brain tissue and significant high relative bioavailability when compared to that received raw VPN-loaded ISG and marketed drug oral tablets. Conclusion: VPN-loaded TPGS-micelles ISG formulation is a successful brain drug delivery system with enhanced bioavailability for drugs with poor bioavailability and those that are frequently administered.

Chitosan-TPP nanoparticles stabilized by poloxamer for controlling the release and enhancing the bioavailability of doxazosin mesylate: in vitro, and in vivo evaluation.

Objective: Control the release and enhance the bioavailability of chitosan-doxazosin mesylate nanoparticles (DM-NPs). Significance: Improve DM bioavailability for the treatment of benign prostatic hyperplasia and hypertension. Methods: Plackett-Burman design was utilized to screen the variables affecting the quality of DM-NPs prepared by ionic gelation method. The investigated variables were initial drug load (X1), chitosan percentage (X2), tripolyphosphate sodium (TPP) percentage (X3), poloxamer percentage (X4), homogenization speed (X5), homogenization time (X6) and TPP addition rate (X7). The prepared DM-loaded NPs have been fully evaluated for particle size (Y1), Zeta potential (Y2), production yield (Y3), entrapment efficiency (Y4), loading capacity (Y5), initial burst (Y6), and cumulative drug release (Y7). Finally, DM pharmacokinetic has been investigated on healthy albino male rabbits by means of non-compartmental analysis. Results: The combination of variables showed variability of Y1, Y2, and Y3 equal to 122-710 nm, 3.49-23.63 mV, and 47.31-92.96%, respectively. While Y4 and Y5, reached 99.87%, and 8.53%, respectively. The prepared NPs revealed that X2, X3, and X4 are the variables that play the important role in controlling the release behavior of DM from the NPs. The in vivo pharmacokinetic results indicated the enhancement in bioavailability of DM by 7 folds compared to drug suspension and the mean residence time prolonged to 23.72 h compared to 4.7 h of drug suspension. Conclusion: The study proved that controlling the release of DM from NPs enhance its bioavailability and improve the compliance of patients with hypertension or benign prostatic hyperplasia.

Glutathione-Responsive Prodrug Nanoparticles for Effective Drug Delivery and Cancer Therapy.

Spurred by recent progress in medicinal chemistry, numerous lead compounds have sprung up in the past few years, although the majority are hindered by hydrophobicity, which greatly challenges druggability. In an effort to assess the potential of platinum (Pt) candidates, the nanosizing approach to alter the pharmacology of hydrophobic Pt(IV) prodrugs in discovery and development settings is described. The construction of a self-assembled nanoparticle (NP) platform, composed of amphiphilic lipid-polyethylene glycol (PEG) for effective delivery of Pt(IV) prodrugs capable of resisting thiol-mediated detoxification through a glutathione (GSH)-exhausting effect, offers a promising route to synergistically improving safety and efficacy. After a systematic screening, the optimized NPs (referred to as P6 NPs) exhibited small particle size (99.3 nm), high Pt loading (11.24%), reliable dynamic stability (∼7 days), and rapid redox-triggered release (∼80% in 3 days). Subsequent experiments on cells support the emergence of P6 NPs as a highly effective means of transporting a lethal dose of cargo across cytomembranes through macropinocytosis. Upon reduction by cytoplasmic reductants, particularly GSH, P6 NPs under disintegration released sufficient active Pt(II) metabolites, which covalently bound to target DNA and induced significant apoptosis. The PEGylation endowed P6 NPs with in vivo longevity and tumor specificity, which were essential to successfully inhibiting the growth of cisplatin-sensitive and -resistant xenograft tumors, while effectively alleviating toxic side-effects associated with cisplatin. P6 NPs are, therefore, promising for overcoming the bottleneck in the development of Pt drugs for oncotherapy.

Optimized vinpocetine-loaded vitamin E D-α-tocopherol polyethylene glycol 1000 succinate-alpha lipoic acid micelles as a potential transdermal drug delivery system: in vitro and ex vivo studies.

BACKGROUND: Vinpocetine (VNP), a semisynthetic natural product, is used as a vasodilator for cerebrovascular and age-related memory disorders. VNP suffers from low oral bioavailability owing to its low water solubility and extensive first-pass metabolism. This work aimed at utilizing D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and alpha lipoic acid (ALA) to develop efficient micellar system for transdermal delivery of VNP. MATERIALS AND METHODS: VNP-TPGS-ALA micelles were prepared, characterized for particle size using particle size analyzer, and investigated for structure using transmission electron microscope. Optimization of VNP-TPGS-ALA micelles-loaded transdermal films was performed using Box-Behnken experimental design. The investigated factors were percentage of ALA in TPGS (X1), citral concentration (X2), and propylene glycol concentration (X3). Elongation percent (Y1), initial permeation after 2 hours (Y2), and cumulative permeation after 24 hours (Y3) were studied as responses. RESULTS: Statistical analysis revealed optimum levels of 16.62%, 3%, and 2.18% for X1, X2, and X3, respectively. Fluorescent laser microscopic visualization of skin penetration of the optimized transdermal film revealed marked widespread fluorescence intensity in skin tissue after 0.5, 2, and 4 hours compared with raw VNP transdermal film formulation, which indicated enhancement of VNP skin penetration. CONCLUSION: The obtained results highlighted the potentiality of VNP nanostructure-based films for controlling the transdermal permeation of the drug and improving its effectiveness.

Development of optimized self-nanoemulsifying lyophilized tablets (SNELTs) to improve finasteride clinical pharmacokinetic behavior.

OBJECTIVE: Preparation of an optimized finasteride (FSD) lyophilized tablets loaded with self-nanoemulsifying drug delivery system (SNEDDS). SIGNIFICANCE: Enhance FSD bioavailability in male pattern baldness and benign prostatic hyperplasia. METHODS: Two-step optimization was implemented to achieve the study goals. First; the mixture design was used to develop an optimized SNEDDS through which the effect of cosurfactant number of carbon atoms on SNEDDS particle size and thermodynamic stability has been tested. Second; the different tablet excipients have been used to develop an optimized self-nanoemulsifying lyophilized tablets (SNELTs). The prepared tablets have been fully characterized. Interaction among tablet components has been studied. Finally, FSD clinical pharmacokinetic has been investigated on human volunteers. RESULTS: Anise oil and tween 80 were selected as oily phase and surfactant, respectively while different aliphatic alcohols were studied as cosurfactants. Percentages of oil, surfactant, and cosurfactants were significantly affecting SNEDDS particle size. Increasing cosurfactant number of carbon atoms achieved smaller particle size and higher stability. The optimized SNEDDS was found to contain 10.3455, 45.8972, and 43.7573% of anise oil, tween 80, and butanol, respectively. Variations in FSD cumulative release and disintegration time, from the prepared tablets, were attributed to change in the percent of plasdone XL, Avicel and silica. No interaction among components was noticed. Clinical pharmacokinetics illustrated significant enhancement in the studied parameters from the optimized lyophilized tablets loaded with drug SNEDDS when compared to marketed FSD product. CONCLUSION: Lyophilized tablets could be considered as a good alternative for conventional solid dosage forms especially when loaded with drug nanosystems.

A potential in situ gel formulation loaded with novel fabricated poly(lactide-co-glycolide) nanoparticles for enhancing and sustaining the ophthalmic delivery of ketoconazole.

Oral ketoconazole therapy is commonly associated with serious hepatotoxicity. Improving ocular drug delivery could be sufficient to treat eye fungal infections. The purpose of this study was to develop optimized ketoconazole poly(lactide-co-glycolide) nanoparticles (NPs) with subsequent loading into in situ gel (ISG) formulation for ophthalmic drug delivery. Three formulation factors were optimized for their effect on particle size (Y1) and entrapment efficiency (Y2) utilizing central composite experimental design. Interaction among components was studied using differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. Ketoconazole crystalline state was studied using X-ray powder diffraction. Six different polymeric ISG formulations were prepared and loaded with either optimized NPs or a pure drug. The prepared ISG formulations were characterized for in vitro gelation, drug release and antifungal activity. The permeation through human epithelial cell line was also investigated. The results revealed that all the studied formulation parameters significantly affected Y1 and Y2 of the developed NPs. DSC and FTIR studies illustrated compatibility among NP components, while there was a change from the crystalline state to the amorphous state of the NPs. The in vitro release from the ISG formulations loaded with drug NPs showed sustained and enhanced drug release compared to pure drug formulations. In addition, ISG loaded with NPs showed enhanced anti-fungal activity compared to pure drug formulations. Alginate-chitosan ISG formulation loaded with optimized ketoconazole NPs illustrated higher drug permeation through epithelial cell lines and is considered as an effective ophthalmic drug delivery in the treatment of fungal eye infections.

Matrix-type transdermal films to enhance simvastatin ex vivo skin permeability.

This study aimed at employing Plackett-Burman design in screening formulation variables that affect quality of matrix-type simvastatin (SMV) transdermal film. To achieve this goal, 12 formulations were prepared by casting method. The investigated variables were Eudragit RL percentage, polymer mixture percentage, plasticizer type, plasticizer percentage, enhancer type, enhancer percentage and dichloromethane fraction in organic phase. The films were evaluated for physicochemical properties and ex vivo SMV permeation. SMV initial, delayed flux, diffusivity and permeability coefficient were calculated on the delayed flux phase with constraint to minimize the initial flux and approaching steady-state flux. The obtained results revealed flat films with homogeneous distribution of SMV within the films. Thickness values changed from 65 to 180 µm by changing the factors' combinations. Most of the permeation profiles showed sustained release feature with fast permeation phase followed by slow phase. Analysis of variance (ANOVA) showed significant effects (p < 0.05) of the investigated variables on the responses with Prob > F values of 0.0147, 0.0814, 0.0063 and 0.0142 for the initial and delayed fluxes, permeability coefficients and diffusivities, respectively. The findings of screening study showed the importance of the significant variables to be scaled up for full optimization study as a promising alternative drug delivery system.

Combined strategy for suppressing breast carcinoma MCF-7 cell lines by loading simvastatin on alpha lipoic acid nanoparticles.

BACKGROUND: Augmentation of simvastatin (SMV) cytotoxicity in breast carcinoma cell lines MCF-7, by: improvement of cellular uptake and loading on alpha lipoic acid (ALA). METHODS: In this study, SMV was loaded on ALA nanoparticles and characterized for surface morphology, SMV entrapment efficiency percent (%EE), zeta potential and release profile. Cellular viability, morphology and uptake and DNA fragmentations were analyzed as a hallmark of cellular apoptosis. RESULTS: TEM images demonstrated spherical nanoparticles with particle size 104.7 ± 5.5 nm, SMV %EE was 95.8 ± 2.1% with a zeta potential - 23.6 ± 5.4 mV, and release properties were significantly enhanced. IC50 was decreased to 22.2 ± 2.4 µM while raw SMV was 49.3 ± 6.6 µM. Cellular uptake of SMV-ALA nanoparticles was increased by about 3- and 2-folds after 2 and 4 h, respectively. DNA fragments confirmed the apoptosis property of ALA, which is associated with SMV cytotoxicity. CONCLUSION: This study suggests evidence that SMV loaded on ALA nanoparticles increases the MCF-7 cellular uptake and cytotoxic effects induced by SMV as revealed by significantly enhanced cell death rates in MCF-7 cells. These findings demonstrate that ALA induces cell death, which makes the combination a candidate for tumor therapy.

Nicotinamide polymeric nanoemulsified systems: a quality-by-design case study for a sustained antimicrobial activity.

Nicotinamide, the amide form of vitamin B3, was demonstrated to combat some of the antibiotic-resistant infections that are increasingly common around the world. The objective of this study was to thoroughly understand the formulation and process variabilities affecting the preparation of nicotinamide-loaded polymeric nanoemulsified particles. The quality target product profile and critical quality attributes of the proposed product were presented. Plackett-Burman screening design was employed to screen eight variables for their influences on the formulation's critical characteristics. The formulations were prepared by an oil-in-water emulsification followed by solvent replacement. The prepared systems were characterized by entrapment capacity (EC), entrapment efficiency (EE), particle size, polydispersity index, zeta potential, transmission electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, in vitro drug release, and their antibacterial activity against bacterial scrums. EC, EE, particle size, polydispersity index, zeta potential, and percentage release in 24 hours were found to be in the range of 33.5%-68.8%, 53.1%-67.1%, 43.3-243.3 nm, 0.08-0.28, 9.5-53.3 mV, and 5.8%-22.4%, respectively. One-way analysis of variance and Pareto charts revealed that the experimental loadings of 2-hydroxypropyl-ß-cyclodextrin and Eudragit(®) S100 were the most significant for their effects on nicotinamide EC and EE. Moreover, the polymeric nanoemulsified particles demonstrated a sustained release profile for nicotinamide. The Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction demonstrated a significant interaction between the drug and 2-hydroxypropyl-ß-cyclodextrin that might modulate the sustained release behavior. Furthermore, the formulations provided a sustained antibacterial activity that depended on nicotinamide-loading concentration, release rate, and incubation time. In conclusion, the study demonstrated the potential of polymeric nanoemulsified system to sustain the release and antibacterial activity of nicotinamide.

Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery.

Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated.

Transdermal glimepiride delivery system based on optimized ethosomal nano-vesicles: Preparation, characterization, in vitro, ex vivo and clinical evaluation.

This work aimed to develop an optimized ethosomal formulation of glimepiride then loading into transdermal films to offer lower drug side effect, extended release behavior and avoid first pass effect. Four formulation factors were optimized for their effects on vesicle size (Y1), entrapment efficiency (Y2) and vesicle flexibility (Y3). Optimum desirability was identified and, an optimized formulation was prepared, characterized and loaded into transdermal films. Ex-vivo permeation study for the prepared films was conducted and, the permeation parameters and drug permeation mechanism were identified. Penetration through rat skin was studied using confocal laser microscope. In-vivo study was performed following transdermal application on human volunteers. The percent of alcohol was significantly affecting all the studied responses while the other factors and their interaction effects were varied on their effects on each response. The optimized ethosomal formulation showed observed values for Y1, Y2 and Y3 of 61 nm, 97.12% and 54.03, respectively. Ex-vivo permeation of films loaded with optimized ethosomal formulation was superior to that of the corresponding pure drug transdermal films and this finding was also confirmed after confocal laser microscope study. Permeation of glimepiride from the prepared films was in favor of Higushi-diffusion model and exhibited non-Fickian or anomalous release mechanism. In-vivo study revealed extended drug release behavior and lower maximum drug plasma level from transdermal films loaded with drug ethosomal formulation. So, the ethosomal formulation could be considered a suitable drug delivery system especially when loaded into transdermal vehicle with possible reduction in side effects and controlling the drug release.

Risperidone oral disintegrating mini-tablets: A robust-product for pediatrics.

This study was aimed at developing risperidone oral disintegrating mini-tablets (OD-mini-tablets) as age-appropriate formulations and to assess their suitability for infants and pediatric use. An experimental Box-Behnken design was applied to assure high quality of the OD-mini-tablets and reduce product variability. The design was employed to understand the influence of the critical excipient combinations on the production of OD-mini-tablets and thus guarantee the feasibility of obtaining products with dosage form uniformity. The variables selected were mannitol percent in Avicel (X1), swelling pressure of the superdisintegrant (X2), and the surface area of Aerosil as a glidant (X3). Risperidone-excipient compatibilities were investigated using FTIR and the spectra did not display any interaction. Fifteen formulations were prepared and evaluated for pre- and post-compression characteristics. The prepared OD-mini-tablet batches were also assessed for disintegration in simulated salivary fluid (SSF, pH 6.2) and in reconstituted skimmed milk. The optimized formula fulfilled the requirements for crushing strength of 5 kN with minimal friability, disintegration times of 8.4 and 53.7 s in SSF and skimmed milk, respectively. This study therefore proposes the risperidone OD-mini-tablet formula having robust mechanical properties, uniform and precise dosing of medication with short disintegration time suitable for pediatric use.

Utilization of nanotechnology to enhance percutaneous absorption of acyclovir in the treatment of herpes simplex viral infections.

This study aimed to formulate an optimized acyclovir (ACV) nanoemulsion hydrogel in order to provide a solution for the slow, variable, and incomplete oral drug absorption in patient suffering from herpes simplex viral infection. Solubility of ACV in different oils, surfactants, and cosurfactants was explored utilizing a cubic model mixture design to obtain a nanoemulsion with minimum globule size. Preparation of an optimized ACV nanoemulsion hydrogel using a three-factor, three-level Box-Behnken statistical design was conducted. The molecular weight of chitosan (X1), percentage of chitosan (X2), and percentage of Eugenol as a skin permeation enhancer (X3) were selected to study their effects on hydrogel spreadability (Y1) and percent ACV permeated through rat skin after 2.5 hours (Y2). A pharmacokinetic study of the optimized ACV nanoemulsion hydrogel was conducted in rats. Mixtures of clove oil and castor oil (3:1 ratio), Tween 80 and Span 80 (3:1 ratio), and propylene glycol and Myo-6V (3:1 ratio) were selected as the oil, surfactant, and cosurfactant phases, respectively. Statistical analysis indicated that the molecular weight of chitosan has a significant antagonistic effect on spreadability, but has no significant effect on the percent ACV permeated. The percentage of chitosan also has a significant antagonistic effect on the spreadability and percent ACV permeated. On the other hand, the percentage of Eugenol has a significant synergistic effect on percent ACV permeated, with no effect on spreadability. The ex vivo study demonstrated that the optimized ACV nanoemulsion hydrogel showed a twofold and 1.5-fold higher permeation percentage than the control gel and marketed cream, respectively. The relative bioavailability of the optimized ACV nanoemulsion hydrogel improved to 535.2% and 244.6% with respect to the raw ACV hydrogel and marketed cream, respectively, confirming improvement of the relative bioavailability of ACV in the formulated nanoemulsion hydrogel.

Taste-masked orodispersible tablets of cyclosporine self-nanoemulsion lyophilized with dry silica.

The aim of the current study was to investigate the effects of formulation parameters on the disintegration, water absorption and dissolution characteristics of cyclosporine A (CyA) loaded self-emulsifying drug delivery system (SEDDS) in an orodispersible compacts. Its taste masking efficiency was also attempted using an electronic tongue. ODTs were prepared by freeze-drying liquid SEDDS and synthetic amorphous silica suspension followed by direct compression. The influences of the compression forces and super-disintegrant were evaluated to optimize tablet characteristics. The liquid SEDDS was characterized by vesicular size of 48.5 nm, polydispersity index of 0.95, turbidity of 40.7 NTU and rapid CyA dissolution and emulsification rate. The results of micrometric studies demonstrated an acceptable flow, hardness and friability to indicate good mechanical strength of ODTs. The interaction and Pareto charts demonstrated a greater effect of low compression force to increase the porosity and facilitate the disintegration rather than the deformation action of the super-disintegrant. Super-disintegrant level was the most important factor affecting the dissolution parameter followed by the compression force then their interaction effect. Moreover, as indicated by Euclidean distance values and discrimination indices, the unpalatable taste and aversion taste of CyA to stimuli were masked in its optimized SEDDS incorporated ODTs.

Sildenafil citrate as oral solid lipid nanoparticles: a novel formula with higher bioavailability and sustained action for treatment of erectile dysfunction.

OBJECTIVE: The aim of this study was to prepare sildenafil citrate as solid lipid nanoparticles (SLNs), in order to find an innovative way for alleviating the disadvantages associated with commercially available sildenafil citrate tablets. These limitations include poor solubility and extensive first-pass metabolism, resulting in low (40%) bioavailability and short elimination half-life (4 h). METHODS: SLNs were prepared by hot homogenization followed by ultrasonication. Solubility of sildenafil citrate in different solid lipids was measured, effect of process variables as surfactant type and concentration, homogenization time, ultrasonication time and charge-inducing agent on the particle size, zeta potential and encapsulation efficiency were also determined. Furthermore, in vitro drug release, stability and in vivo pharmacokinetics were studied in rabbits Results: The best SLN formula consisted of 2% precirol ATO5, 0.5% phosphatidylcholine, 2.5% gelucire 44/14, 0.125% stearylamine, had an average particle size of 28.5 nm with 95.34% entrapment efficiency and demonstrated a controlled drug release over 24 h. An in vivo pharmacokinetic study revealed enhanced bioavailability by > 1.87 fold, and the mean residence time was longer than that for the commercially available tablet. CONCLUSION: SLN could be a promising carrier for sustained/prolonged sildenafil citrate release with enhanced oral bioavailability.