Development and evaluation of nanosized niosomal dispersion for oral delivery of Ganciclovir

A Comprehensive Review on Niosomes as a Tool for Advanced Drug Delivery

Over the past few decades, advancements in nanocarrier-based therapeutic delivery have been significant, and niosomes research has recently received much interest. The self-assembled nonionic surfactant vesicles lead to the production of niosomes. The most recent nanocarriers, niosomes, are self-assembled vesicles made of nonionic surfactants with or without the proper quantities of cholesterol or other amphiphilic molecules. Because of their durability, low cost of components, largescale production, simple maintenance, and high entrapment efficiency, niosomes are being used more frequently. Additionally, they enhance pharmacokinetics, reduce toxicity, enhance the solubility of poorly water-soluble compounds, & increase bioavailability. One of the most crucial features of niosomes is their controlled release and targeted diffusion, which is utilized for treating cancer, infectious diseases, and other problems. In this review article, we have covered all the fundamental information about niosomes, including preparation techniques, niosomes types, factors influencing their formation, niosomes evaluation, applications, and administration routes, along with recent developments.

Targeting posterior eye infections with colloidal carriers: The case of Ganciclovir

The ocular system, unlike any other human body organ, is a system in which foreign bodies appear quite defenceless in front of the eye. Several infections of the ocular system occur due to various opportunistic conditions. Cytomegalovirus (CMV) is one of the opportunivores that causes several posterior eye infections. Ganciclovir (GCV),9-(2-hydroxy-1-(hydroxymethyl) ethoxymethyl), is aguanine-antiviral agent primarily used to treat CMV diseases. However, the major challenge is of lower bioavailability. Hence, GCV must be dosed repeatedly to enhance drug absorption. but this causes side effects like neutropenia and bone marrow suppression. So, formulators have used alternative formulation strategies such as prodrug formulation and colloidal drug delivery systems. In the prodrug strategy, they attempted to bind various compounds into the parent drug to increase the permeability and bioavailability of GCV. In colloidal drug delivery systems, mucoadhesive microspheres, nanoparticles, Niosome and liposome were employed to extend the drug residence time at the application site. This paper discusses several colloidal carriers combined with GCV to treat opportunistic CMV infection in the posterior ocular system. It reviews the limitations of conventional ocular therapy and explores various novel formulation approaches to improve the ocular bioavailability of GCV in the posterior chamber of the eye.

Transethosome: An ultra-deformable ethanolic vesicle for enhanced transdermal drug delivery

Drug delivery through the skin improves solubility, bioavailability, and unwanted systemic side effects of the drug. The selection of a suitable carrier is a challenging process. The conventional lipid vesicles have some limitations. They deliver the drug in the stratum corneum and have poor colloidal stability. Here comes the need for ultra-deformable lipid vesicles to provide the drug beyond the stratum corneum. Transethosomes are novel ultra-deformable vesicles that can deliver drugs into deeper tissues. The composition of transethosomes includes phospholipid, ethanol and surfactants. Each ingredient has a pivotal role in the properties of the carrier. This review covers the design, preparation method, characterisation, and characteristics of the novel vesicle. Also, we cover the impact of surfactants on vesicular properties and the skin permeation behaviour of novel vesicles.

Surfactant vesicles for enhanced antitoxoplasmic effect of norfloxacin: in vitro and in vivo evaluations

The goal was to scrutinize niosomes as potential carriers for enhanced efficacy of norfloxacin against Toxoplasma gondii RH strain. This was assessed in vitro and in vivo. Standard niosomes of Span 60 and cholesterol were prepared. Gelucire 48/16 or Tween 80 was incorporated as hydrophilic fluidizer. The prepared vesicles were characterized for shape, size, viscosity and norfloxacin release. The in vitro anti-Toxoplasma was assessed by monitoring tachyzoites viability after incubation with niosomes. In vivo efficacy of niosomes encapsulated norfloxacin was evaluated on infected mice. Transmission electron micrographs showed nano-sized spherical vesicles. Norfloxacin release varied with niosomal composition to show faster liberation in presence of fluidizing agent. The half maximum effective concentration of norfloxacin against tachyzoites (EC50) was significantly reduced after niosomal encapsulation compared with simple drug solution with no significant difference between vesicular formulations. Tachyzoite count in the peritoneal fluid of infected mice was reduced by 45.2, 90.8, 88.3 and 84% after treatment with simple drug dispersion, standard niosomes, Gelucire containing and Tween containing vesicles, respectively compared to infected untreated mice. These results correlate with the in vitro data and reflects the efficacy of niosomes. The study introduced surfactant vesicles as a tool for enhanced efficacy of norfloxacin against toxoplasma.

Niosomes: a novel targeted drug delivery system for cancer

Recently, nanotechnology is involved in various fields of science, of which medicine is one of the most obvious. The use of nanoparticles in the process of treating and diagnosing diseases has created a novel way of therapeutic strategies with effective mechanisms of action. Also, due to the remarkable progress of personalized medicine, the effort is to reduce the side effects of treatment paths as much as possible and to provide targeted treatments. Therefore, the targeted delivery of drugs is important in different diseases, especially in patients who receive combined drugs, because the delivery of different drug structures requires different systems so that there is no change in the drug and its effectiveness. Niosomes are polymeric nanoparticles that show favorable characteristics in drug delivery. In addition to biocompatibility and high absorption, these nanoparticles also provide the possibility of reducing the drug dosage and targeting the release of drugs, as well as the delivery of both hydrophilic and lipophilic drugs by Niosome vesicles. Since various factors such as components, preparation, and optimization methods are effective in the size and formation of niosomal structures, in this review, the characteristics related to niosome vesicles were first examined and then the in silico tools for designing, prediction, and optimization were explained. Finally, anticancer drugs delivered by niosomes were compared and discussed to be a suitable model for designing therapeutic strategies. In this research, it has been tried to examine all the aspects required for drug delivery engineering using niosomes and finally, by presenting clinical examples of the use of these nanocarriers in cancer, its clinical characteristics were also expressed.

Nanomedicine based approaches for combating viral infections

Millions of people die each year from viral infections across the globe. There is an urgent need to overcome the existing gap and pitfalls of the current antiviral therapy which include increased dose and dosing frequency, bioavailability challenges, non-specificity, incidences of resistance and so on. These stumbling blocks could be effectively managed by the advent of nanomedicine. Current review emphasizes over an enhanced understanding of how different lipid, polymer and elemental based nanoformulations could be potentially and precisely used to bridle the said drawbacks in antiviral therapy. The dawn of nanotechnology meeting vaccine delivery, role of RNAi therapeutics in antiviral treatment regimen, various regulatory concerns towards clinical translation of nanomedicine along with current trends and implications including unexplored research avenues for advancing the current drug delivery have been discussed in detail.

Functional supramolecular systems: design and applications

The interest in functional supramolecular systems for the design of innovative materials and technologies, able to fundamentally change the world, is growing at a high pace. The huge array of publications that appeared in recent years in the global literature calls for systematization of the structural trends inherent in the formation of these systems revealed at different molecular platforms and practically useful properties they exhibit. The attention is concentrated on the topics related to functional supramolecular systems that are actively explored in institutes and universities of Russia in the last 10–15 years, such as the chemistry of host–guest complexes, crystal engineering, self-assembly and self-organization in solutions and at interfaces, biomimetics and molecular machines and devices.

The bibliography includes 1714 references.

Recent advances in non-ionic surfactant vesicles (niosomes): Fabrication, characterization, pharmaceutical and cosmetic applications

Development of nanocarriers for drug delivery has received considerable attention due to their potential in achieving targeted delivery to the diseased site while sparing the surrounding healthy tissue. Safe and efficient drug delivery has always been a challenge in medicine. During the last decade, a large amount of interest has been drawn on the fabrication of surfactant-based vesicles to improve drug delivery. Niosomes are self-assembled vesicular nano-carriers formed by hydration of non-ionic surfactant, cholesterol or other amphiphilic molecules that serve as a versatile drug delivery system with a variety of applications ranging from dermal delivery to brain-targeted delivery. A large number of research articles have been published reporting their fabrication methods and applications in pharmaceutical and cosmetic fields. Niosomes have the same advantages as liposomes, such as the ability to incorporate both hydrophilic and lipophilic compounds. Besides, niosomes can be fabricated with simple methods, require less production cost and are stable over an extended period, thus overcoming the major drawbacks of liposomes. This review provides a comprehensive summary of niosomal research to date, it provides a detailed overview of the formulation components, types of niosomes, effects of components on the formation of niosomes, fabrication and purification methods, physical characterization techniques of niosomes, recent applications in pharmaceutical field such as in oral, ocular, topical, pulmonary, parental and transmucosal drug delivery, and cosmetic applications. Finally, limitations and the future outlook for this delivery system have also been discussed.

Use of transethosomes for enhancing the transdermal delivery of olmesartan medoxomil: in vitro, ex vivo, and in vivo evaluation

Introduction and aim

Olmesartan medoxomil (OLM) is an antihypertensive drug with low oral bioavailability due to extensive first-pass metabolism. This study aimed to prepare transetho somes (TEs) for enhancing the transdermal delivery of OLM to avoid its oral problems.

Methods

TE formulae were prepared utilizing 51.31 full factorial design using various surfactants (SAAs) and different phospholipid-to-SAA ratios. The formulae were characterized regarding their entrapment efficiency percentage (EE%), particle size (PS), polydispersity index (PDI), zeta potential (ZP), and the amount of drug released after 6 hours (Q6h). Design Expert^® software was employed to select the optimum formula.

Results

The optimum formula (TE14) had an EE% of 58.50%±1.30%, PS of 222.60±2.50 nm, PDI of 0.11±0.06, ZP of -20.80±0.30 mV, and Q6h of 67.40%±0.20%. In addition, TE14 was compared to transferosomes (TFs) in terms of elasticity and was found to show higher deformability index. Further, evaluation of ex vivo permeation using both rat and shed snake skin showed higher permeability of TE14 compared to TFs and OLM suspension. Confocal laser scanning microscopy confirmed the capability of the fluorolabeled TE14 to penetrate deep within the skin, while the histopathological study confirmed its safety. TE14 successfully maintained normal blood pressure values of rats up to 24 hours. Moreover, TE14 showed superiority in dermatokinetic study when compared with drug suspension.

Conclusion

Taken together, the obtained results confirmed the potential of employing TEs as a successful carrier for the transdermal delivery of OLM.

Brief Effect of a Small Hydrophobic Drug (Cinnarizine) on the Physicochemical Characterisation of Niosomes Produced by Thin-Film Hydration and Microfluidic Methods

Novel niosomal formulations containing cinnarizine were developed to enhance its drug characteristics. In this work, niosomes (non-ionic surfactant vesicles) were prepared by conventional thin-film hydration (TFH) and microfluidic (MF) methods with sorbitan monostearate (Span^® 60), cholesterol, and co-surfactants (Cremophor^® ELP, Cremophor^® RH40 and Solutol^® HS15) as key excipients. The aim was to study the effect of cinnarizine on the characteristics of different niosomal formulations manufactured by using different methods. For effective targeted oral drug delivery, the efficacy of niosomes for therapeutic applications is correlated to their physiochemical properties. Niosome vesicles prepared were characterised using dynamic light scattering technique and the morphology of niosomes dispersion was characterised using optical microscopy. Dialysis was carried out to purify niosome suspensions to determine drug loading and drug release studies was performed to study the potential use of niosomal systems for cinnarizine.

Ganciclovir

Ganciclovir is synthetic nucleoside analog of guanine closely related to acyclovir but has greater activity against cytomegalovirus. This comprehensive profile on ganciclovir starts with a description of the drug: nomenclature, formulae, chemical structure, elemental composition, and appearance. The uses and application of the drug are explained. The methods that were used for the preparation of ganciclovir are described and their respective schemes are outlined. The methods which were used for the physical characterization of the dug are: ionization constant, solubility, X-ray powder diffraction pattern, crystal structure, melting point, and differential scanning calorimetry. The chapter contains the spectra of the drug: ultraviolet spectrum, vibrational spectrum, nuclear magnetic resonance spectra, and the mass spectrum. The compendial methods of analysis of ganciclovir include the United States Pharmacopeia methods. Other methods of analysis that were reported in the literature include: high-performance liquid chromatography alone or with mass spectrometry, electrophoresis, spectrophotometry, voltammetry, chemiluminescence, and radioimmunoassay. Biological investigation on the drug includes: pharmacokinetics, metabolism, bioavailability, and biological analysis. Reviews on the methods used for preparation or for analysis of the drug are provided. The stability of the drug in various media and storage conditions is reported. More than 240 references are listed at the end of the chapter.

Non-Ionic Surfactant Vesicles (Niosomes) as New Drug Delivery Systems

Lipid vesicular systems composed of hydrated amphihiles with or without bilayer inducing agents such as cholesterol. On the basis of used amphiphilic molecule different nomenclature are used as liposomes, ufasomes and niosomes. Nonionic surfactants with mono-, di- or trialkyl chains form niosomes which are lipid vesicles with more chemical stability in comparison with phospholipids of liposomes. Both hydrophobic and hydrophilic chemicals can be encapsulated in niosomes as a new drug delivery system. This drug carrier system could have administered via injection, oral, pulmonary, vaginal, rectal, ophthalmic, nasal or transdermal routes with penetration enhancing potential. This chapter presents a detailed explain about niosome forming components, methods of preparation and routes of administration. Many examples for drug delivery potential of niosomes are also available in this review. Vaccine adjuvant and genetic substances vector capabilities are not given here.

Non-Ionic Surfactant Vesicles (Niosomes) as New Drug Delivery Systems

Lipid vesicular systems composed of hydrated amphihiles with or without bilayer inducing agents such as cholesterol. On the basis of used amphiphilic molecule different nomenclature are used as liposomes, ufasomes and niosomes. Nonionic surfactants with mono-, di- or trialkyl chains form niosomes which are lipid vesicles with more chemical stability in comparison with phospholipids of liposomes. Both hydrophobic and hydrophilic chemicals can be encapsulated in niosomes as a new drug delivery system. This drug carrier system could have administered via injection, oral, pulmonary, vaginal, rectal, ophthalmic, nasal or transdermal routes with penetration enhancing potential. This chapter presents a detailed explain about niosome forming components, methods of preparation and routes of administration. Many examples for drug delivery potential of niosomes are also available in this review. Vaccine adjuvant and genetic substances vector capabilities are not given here.

Recent trends in the development of nanophytobioactive compounds and delivery systems for their possible role in reducing oxidative stress in Parkinson's disease models

Oxidative stress plays a very critical role in neurodegenerative diseases, such as Parkinson's disease (PD), which is the second most common neurodegenerative disease among elderly people worldwide. Increasing evidence has suggested that phytobioactive compounds show enhanced benefits in cell and animal models of PD. Curcumin, resveratrol, ginsenosides, quercetin, and catechin are phyto-derived bioactive compounds with important roles in the prevention and treatment of PD. However, in vivo studies suggest that their concentrations are very low to cross blood-brain barrier thereby it limits bioavailability, stability, and dissolution at target sites in the brain. To overcome these problems, nanophytomedicine with the controlled size of 1-100 nm is used to maximize efficiency in the treatment of PD. Nanosizing of phytobioactive compounds enhances the permeability into the brain with maximized efficiency and stability. Several nanodelivery techniques, including solid lipid nanoparticles, nanostructured lipid carriers, nanoliposomes, and nanoniosomes can be used for controlled delivery of nanobioactive compounds to brain. Nanocompounds, such as ginsenosides (19.9 nm) synthesized using a nanoemulsion technique, showed enhanced bioavailability in the rat brain. Here, we discuss the most recent trends and applications in PD, including 1) the role of phytobioactive compounds in reducing oxidative stress and their bioavailability; 2) the role of nanotechnology in reducing oxidative stress during PD; 3) nanodelivery systems; and 4) various nanophytobioactive compounds and their role in PD.

Niosomal carriers enhance oral bioavailability of carvedilol: effects of bile salt-enriched vesicles and carrier surface charge

Carvedilol (CRV) is an antihypertensive drug with both alpha and beta receptor blocking activity used to preclude angina and cardiac arrhythmias. To overcome the low, variable oral bioavailability of CRV, niosomal formulations were prepared and characterized: plain niosomes (without bile salts), bile salt-enriched niosomes (bilosomes containing various percentages of sodium cholate or sodium taurocholate), and charged niosomes (negative, containing dicetyl phosphate and positive, containing hexadecyl trimethyl ammonium bromide). All formulations were characterized in terms of encapsulation efficiency, size, zeta potential, release profile, stability, and morphology. Various formulations were administered orally to ten groups of Wistar rats (n=6 per group). The plasma levels of CRV were measured by a validated high-performance liquid chromatography (HPLC) method and pharmacokinetic properties of different formulations were characterized. Contribution of lymphatic transport to the oral bioavailability of niosomes was also investigated using a chylomicron flow-blocking approach. Of the bile salt-enriched vesicles examined, bilosomes containing 20% sodium cholate (F2) and 30% sodium taurocholate (F5) appeared to give the greatest enhancement of intestinal absorption. The relative bioavailability of F2 and F5 formulations to the suspension was estimated to be 1.84 and 1.64, respectively. With regard to charged niosomes, the peak plasma concentrations (C_max) of CRV for positively (F7) and negatively charged formulations (F10) were approximately 2.3- and 1.7-fold higher than after a suspension. Bioavailability studies also revealed a significant increase in extent of drug absorption from charged vesicles. Tissue histology revealed no signs of inflammation or damage. The study proved that the type and concentration of bile salts as well as carrier surface charge had great influences on oral bioavailability of niosomes. Blocking the lymphatic absorption pathway significantly reduced oral bioavailability of CRV niosomes. Overall twofold enhancement in bioavailability in comparison with drug suspension confers the potential of niosomes as suitable carriers for improved oral delivery of CRV.

Advances in lipid-based drug delivery: enhancing efficiency for hydrophobic drugs

INTRODUCTION

Many drug candidates with high therapeutic efficacy have low water solubility, which limits the administration and transport across physiological barriers, for example, the tumor tissue barrier. Therefore, strategies are needed to permeabilize the physiological barriers safely so that hydrophobic drugs may be delivered efficiently.

AREAS COVERED

This review focuses on prospects for therapeutic application of lipid-based drug delivery carriers that increase hydrophobic drugs to improve their solubility, bioavailability, drug release, targeting and absorption. Moreover, novel techniques to prepare for lipid-based drug delivery to extend pharmaceuticals with poor bioavailability such as surface modifications of lipid-based drug delivery are presented. Industrial developments of several drug candidates employing these strategies are discussed, as well as applications and clinical trials.

EXPERT OPINION

Overall, hydrophobic drugs can be encapsulated in the lipid-based drug delivery systems, represent a relatively safe and promising strategy to extend drug retention, lengthen the lifetime in the circulation, and allow active targeting to specific tissues and controllable drug release in the desirable sites. However, there are still noticeable gaps that need to be filled before the theoretical advantage of these formulations may truly be realized such as investigation on the use of lipid-based drug delivery for administration routes. This research may provide further interest within the area of lipid-based systems, both in industry and in the clinic.

Ring-opening polymerization of ε-caprolactone initiated by ganciclovir (GCV) for the preparation of GCV-tagged polymeric micelles

Ganciclovir (GCV) is a nucleoside analogue with antiviral activity against herpes viral infections, and the most widely used antiviral to treat cytomegalovirus infections. However, the low bioavailability and short half-life of GCV necessitate the development of a carrier for sustained delivery. In this study, guanosine-based GCV was used as the initiator directly in ring-opening polymerization of ε-caprolactone (ε-CL) to form hydrophobic GCV-poly(caprolactone) (GCV-PCL) which was then grafted with hydrophilic chitosan to form amphiphilic copolymers for the preparation of stable micellar nanoparticles. Successful synthesis of GCV-PCL and GCV-PCL-chitosan were verified by ¹H-NMR analysis. Self-assembled micellar nanoparticles were characterized by dynamic light scattering and zetasizer with an average size of 117 nm and a positive charge of 24.2 mV. The drug release kinetics of GCV was investigated and cytotoxicity assay demonstrated that GCV-tagged polymeric micelles were non-toxic. Our results showed that GCV could be used directly in the initiation of ring-opening polymerization of ε-CL and non-toxic polymeric micelles for GCV delivery can be formed.

Niosomes from 80s to present: the state of the art

Efficient and safe drug delivery has always been a challenge in medicine. The use of nanotechnology, such as the development of nanocarriers for drug delivery, has received great attention owing to the potential that nanocarriers can theoretically act as "magic bullets" and selectively target affected organs and cells while sparing normal tissues. During the last decades the formulation of surfactant vesicles, as a tool to improve drug delivery, brought an ever increasing interest among the scientists working in the area of drug delivery systems. Niosomes are self assembled vesicular nanocarriers obtained by hydration of synthetic surfactants and appropriate amounts of cholesterol or other amphiphilic molecules. Just like liposomes, niosomes can be unilamellar or multilamellar, are suitable as carriers of both hydrophilic and lipophilic drugs and are able to deliver drugs to the target site. Furthermore, niosomal vesicles, that are usually non-toxic, require less production costs and are stable over a longer period of time in different conditions, so overcoming some drawbacks of liposomes. The niosome properties are specifically dictated by size, shape, and surface chemistry which are able to modify the drug's intrinsic pharmacokinetics and eventual drug targeting to the areas of pathology. This up-to-date review deals with composition, preparation, characterization/evaluation, advantages, disadvantages and application of niosomes.

Potentials of proniosomes for improving the oral bioavailability of poorly water-soluble drugs

Abstract Objective: The objectives of this study were, first, to develop a free-flowing and stable proniosome formulation for poorly water-soluble drugs such as vinpocetine; and second, to estimate its bioavailability as oral drug delivery system.

METHODS

The proniosomes consisting of span60, cholesterol, sorbitol and vinpocetine were prepared by a novel approach. After the proniosomes were contacted with water, the suspension of vinpocetine-loaded niosomes formed automatically. The proniosomes and reconstituted niosomes were evaluated for their physicochemical characteristics, in vitro drug dissolution and release, integrity and stability at different GI tract pH conditions, in situ single-pass intestinal perfusion and in vivo bioavailability.

RESULTS

The proniosome powder exhibited excellent flowability. The reconstituted niosomes with high drug entrapment efficiency (89.67 ± 3.28%) showed spherical morphology with smooth surface under transmission electron microscope (TEM). X-ray diffraction (XRD) indicated that the drug was in an amorphous or molecular state in proniosome powder. In vitro dissolution and release study, proniosomes did enhance the dissolution and release rate compared to vinpocetine suspension in phosphate buffer solution (pH 7.2). Proniosome-derived niosomes could keep their integrity and stability at different GI tract pH conditions. The in situ single-pass intestinal perfusion indicated that encapsulation of vinpocetine into niosomes could largely improved the absorption of vinpocetine. The AUC(0-∞) of F2 and F3 was about 4.0- and 4.9-fold higher than that of the vinpocetine suspension, respectively. The results demonstrated the proniosomes indeed remarkably enhanced the oral bioavailability of vinpocetine.

CONCLUSION

This study suggested the potential of proniosomes as stable precursors for the immediate preparation of niosome carrier systems.