Drug compartmentalization as strategy to improve the physico-chemical properties of diclofenac sodium loaded niosomes for topical applications

Niosome as a promising tool for increasing the effectiveness of anti-inflammatory compounds

Niosomes are drug delivery systems with widespread applications in pharmaceutical research and the cosmetic industry. Niosomes are vesicles of one or more bilayers made of non-ionic surfactants, cholesterol, and charge inducers. Because of their bilayer characteristics, similar to liposomes, niosomes can be loaded with lipophilic and hydrophilic cargos. Therefore, they are more stable and cheaper in preparation than liposomes. They can be classified into four categories according to their sizes and structures, namely small unilamellar vesicles (SUVs), large unilamellar vesicles (LUVs,), multilamellar vesicles (MLVs), and multivesicular vesicles (MVVs). There are many methods for niosome preparation, such as thin-film hydration, solvent injection, and heating method. The current study focuses on the preparation methods and pharmacological effects of niosomes loaded with natural and chemical anti-inflammatory compounds in kinds of literature during the past decade. We found that most research was carried out to load anti-inflammatory agents like non-steroidal anti-inflammatory drugs (NSAIDs) into niosome vesicles. The studies revealed that niosomes could improve anti-inflammatory agents' physicochemical properties, including solubility, cellular uptake, stability, encapsulation, drug release and liberation, efficiency, and oral bioavailability or topical absorption. See also the graphical abstract(Fig. 1).

Advancing synthetic biology through cell-free protein synthesis

The rapid development of synthetic biology has enabled the production of compounds with revolutionary improvements in biotechnology. DNA manipulation tools have expedited the engineering of cellular systems for this purpose. Nonetheless, the inherent constraints of cellular systems persist, imposing an upper limit on mass and energy conversion efficiencies. Cell-free protein synthesis (CFPS) has demonstrated its potential to overcome these inherent constraints and has been instrumental in the further advancement of synthetic biology. Via the removal of the cell membranes and redundant parts of cells, CFPS has provided flexibility in directly dissecting and manipulating the Central Dogma with rapid feedback. This mini-review summarizes recent achievements of the CFPS technique and its application to a wide range of synthetic biology projects, such as minimal cell assembly, metabolic engineering, and recombinant protein production for therapeutics, as well as biosensor development for in vitro diagnostics. In addition, current challenges and future perspectives in developing a generalized cell-free synthetic biology are outlined.

Preparation and in vitro investigation of prostate-specific membrane antigen targeted Lycopene loaded niosomes on prostate cancer cells

In this study, it's aimed to develop prostate-specific membrane antigen (PSMA) targeted niosomes with a multifunctional theranostic approach. With this aim, PSMA-targeted niosomes were synthesized by a thin-film hydration method followed by bath sonication. Drug-loaded niosomes (Lyc-ICG-Nio) were coated with DSPE-PEG-COOH (Lyc-ICG-Nio-PEG) and subsequently anti-PSMA antibody conjugated to niosomes (Lyc-ICG-Nio-PSMA) with amide bond formation. Dynamic light scattering (DLS) analysis showed that the hydrodynamic diameter of Lyc-ICG-Nio-PSMA was approximately 285 nm and it was found with transmission electron microscopy (TEM) that the niosome formulation was spherical. Encapsulation efficiency was 45% and %65 upon dual encapsulation of ICG and lycopene. The results of fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated that PEG coating and antibody coupling were successfully done. In vitro studies showed that cell viability decreased when lycopene was entrapped into niosomes applied while the total apoptotic cell population rose slightly. When Lyc-ICG-Nio-PSMA was applied to cells, decreased cell viability and enhanced apoptotic effect were seen compared to those for Lyc-ICG-Nio. In conclusion, it was demonstrated that targeted niosomes displayed improved cellular association and decreased cell viability on PSMA+ cells.

Photodegradation of Anti-Inflammatory Drugs: Stability Tests and Lipid Nanocarriers for Their Photoprotection

The present paper provides an updated overview of the methodologies applied in photodegradation studies of non-steroidal anti-inflammatory drugs. Photostability tests, performed according to international standards, have clearly demonstrated the photolability of many drugs belonging to this class, observed during the preparation of commercial forms, administration or when dispersed in the environment. The photodegradation profile of these drugs is usually monitored by spectrophotometric or chromatographic techniques and in many studies the analytical data are processed by chemometric procedures. The application of multivariate analysis in the resolution of often-complex data sets makes it possible to estimate the pure spectra of the species involved in the degradation process and their concentration profiles. Given the wide use of these drugs, several pharmaceutical formulations have been investigated to improve their photostability in solution or gel, as well as the pharmacokinetic profile. The use of lipid nanocarriers as liposomes, niosomes or solid lipid nanoparticles has demonstrated to both minimize photodegradation and improve the controlled release of the entrapped drugs.

New Nanomaterials with Intrinsic Antioxidant Activity by Surface Functionalization of Niosomes with Natural Phenolic Acids

Nanoantioxidants have emerged as smart devices able to provide improved stability and biocompatibility and sustained and targeted release of conventional antioxidants. In the current research, a new family of nanoantioxidants has been developed by covalently grafting gallic (GA), caffeic (CF) and ferulic (FR) acid on the surfaces of Tween 80 niosomes. First, empty and curcumin (CUR)-loaded vesicles were prepared using a thin-layer evaporation technique and then functionalized with phenolic acids using carbodiimide chemistry. Nanoantioxidants obtained were characterized in terms of size, polydispersity index, zeta potential, and loading efficiency. Their antioxidant activity was studied by ABTS and DPPH assays. Surface functionalization of empty and CUR-loaded vesicles provided stable vesicles with intrinsic antioxidant properties. In vitro antioxidant assays highlighted that vesicles functionalized with FR or GA exhibited better antioxidant activity compared to CF-grafted niosomes. Furthermore, vesicles loaded with CUR and functionalized with GA and CF showed an enhanced scavenging ability of ABTS and DPPH radicals, compared to the single antioxidant-loaded formulations, highlighting an important synergic effect of CUR when used in combination with GA ad CF.

Ex vivo transdermal absorption of a liposome formulation of diclofenac

Topical formulations of non-steroidal anti-inflammatory drugs are often used to provide effective local drug concentration while limiting systemic exposure and associated adverse events. Formulation composition has great influence on the rate of transdermal drug transport through human skin. This study was performed to compare the ex vivo transdermal transport of diclofenac from three topical formulations, a 1% liposomal gel formulation of diclofenac sodium and two emulsion gel formulations, 1.16% and 2.32% diclofenac diethylamine (equivalent to 1% and 2% diclofenac sodium). Human skin was obtained during unrelated surgical procedures and frozen at -20 °C until use. Three skin specimens were thawed, prepared for testing, and placed in a Franz cell with the stratum corneum facing the donor compartment. About 200 μl of each formulation was placed on the skin, and the receptor compartment fluid (phosphate buffered saline, pH 7.4, 32 °C) was sampled over the next 48 h. Diclofenac concentration was measured with a validated HPLC method. The transdermal permeability coefficient for the liposome 1% gel was 69.3 ± 14.4 10^-8 cm•s^-1, compared with 34.9 ± 9.1 10^-8 cm•s^-1 (P = 0.001) and 47.1±9.5 10^-8 cm•s^-1 (P = 0.005) for the emulsion gel 1.16% and emulsion gel 2.32%, respectively. A statistically significant difference between transdermal transport of diclofenac from the liposome gel 1% and the emulsion gel 1.16% was evident after 9 h, a clinically relevant result because these products are typically applied 2 to 4 times daily. Based on these observations, liposome gel 1% formulation of diclofenac may have a clinical advantage compared with the emulsion gel 1.16% formulation.

Innovative topical formulations from diclofenac sodium used as surfadrug: The birth of Diclosomes

HYPOTHESIS

Due to the well-know surfactant-like properties of diclofenac sodium (DS), vesicular systems consisting exclusively of DS, named diclosomes, were designed with the aim to minimize or avoid the use of other excipients and to improve the formulation biocompatibility.

EXPERIMENTS

Diclosomes were designed and characterized in terms of dimensions, polydispersity index, ξ-potential, drug retained, stability as a function of storage time and ex-vivo percutaneous permeation profiles. Additionally, diclosomes were incorporated into gel dosage forms and their performance in terms of permeation enhancement were evaluated.

FINDINGS

DS was found to form nanosized vesicular systems, both alone and in presence of cholesterol. Increasing hydrophobicity (due to the presence of cholesterol) resulted in smaller vesicles, always spherical and homogeneous in shape. Permeation of DS from free solution was found to be lower respect to ones obtained for all diclosomal formulations, allowing these aggregates to be considered as percutaneous permeation enhancers. DS permeated from diclosomal gels was higher than that obtained with traditional niosomal gel, DS plain gel and commercial specialty Voltaren Emulgel^® 1%, while containing a considerably lower drug amount.

Current progress and challenges of nanoparticle-based therapeutics in pain management

Pain is a widespread and growing health problem worldwide that exerts a considerable social and economic impact on both patients and healthcare systems and, therefore, on society in general. Although current treatment modalities include a wide variety of pharmacological and non-pharmacological approaches, due to the complexity of pain and individual differences in clinical response these options are not always effective in mitigating and relieving pain. In addition, some pain drugs such as non-steroidal anti-inflammatory drugs (NSAIDs), local anesthetics and opioids show several unfavorable side effects. Therefore, current research advances in this medical field are based on the development of potential treatments to address many of the unmet needs and to overcome the existing limitations in pain management. Nanoparticle drug delivery systems present an exciting opportunity as alternative platforms to improve efficacy and safety of medications currently in use. Herein, we review a broad range of nanoparticle formulations (organic nanostructures and inorganic nanoparticles), which have been developed to encapsulate an array of painkillers, paying special attention to the key advantages that these systems offer, (compared to the use of the free drug), as well as to the more relevant results of preclinical studies in animal models. Additionally, we will briefly discuss the impact of some of these nanoformulations in clinical trials.

Ultrasonic Processing Technique as a Green Preparation Approach for Diacerein-Loaded Niosomes

In this study, the feasibility of ultrasonic processing (UP) technique as green preparation method for production of poorly soluble model drug substance, diacerein, loaded niosomes was demonstrated. Also, the effects of different surfactant systems on niosomes' characteristics were analyzed. Niosomes were prepared using both the green UP technique and traditional thin-film hydration (TFH) technique, which requires the use of environmentally hazardous organic solvents. The studied surfactant systems were Span 20, Pluronic L64, and their mixture (Span 20 and Pluronic L64). Both the production techniques produced well-defined spherical vesicles, but the UP technique produced smaller and more monodisperse niosomes than TFH. The entrapment efficiencies with the UP method were lower than with TFH, but still at a feasible level. All the niosomal formulations released diacerein faster than pure drug, and the drug release rates from the niosomes produced by the UP method were higher than those from the TFH-produced niosomes. With UP technique, the optimum process conditions for small niosomal products with low PDI values and high entrapment efficiencies were obtained when 70% amplitude and 45-min sonication time were used. The overall results demonstrated the potency of UP technique as an alternative fast, cost-effective, and green preparation approach for production of niosomes, which can be utilized as drug carrier systems for poorly soluble drug materials.

Pharmaceutical versatility of cationic niosomes derived from amino acid-based surfactants: Skin penetration behavior and controlled drug release

The natural capability shown by cationic vesicles in interacting with negatively charged surfaces or biomolecules has recently attracted increased interest. Important pharmacological advantages include the selective targeting of the tumour vasculature, the promotion of permeation across cell membranes, as well as the influence of cationic vesicles on drug delivery. Accordingly, cationic amphiphiles derived from amino acids may represent an alternative to traditional synthetic cationic surfactants due to their lower cytotoxicity. The importance of a synthesized lysine-based gemini surfactant (labelledC₆(LL)₂) was evaluated in drug delivery by designing cationic niosomes as usable pharmaceutical tools of chemotherapeutics and antibiotics, respectively like methotrexate and tetracycline. The influence of formulation factors on the vesicles' physical-chemical properties, drug entrapment efficiency, in vitro release and ex-vivo skin permeation were investigated. A niosomal gel containing the gemini surfactant was also tested as a viable multi-component topical formulation. Results indicate that in the presence of cholesterol, C₆(LL)₂ was able to form stable and nanosized niosomes, loading hydrophilic or hydrophobic molecules. Furthermore, in vitro release studies and ex-vivo permeation profiles showed that C₆(LL)₂-based vesicles behave as sustained and controlled delivery systems in the case of parenteral administration, and as drug percutaneous permeation enhancers after topical application. Finally, cationic C₆(LL)₂ acts as a carrier constituent, conferring peculiar and interesting functionality to the final formulation.

Photostability and ex-vivo permeation studies on diclofenac in topical niosomal formulations

Photostability studies were performed on topical formulations containing diclofenac (DC). Niosomal gels were designed as photostabilization systems and ascorbic acid was also added to the new topical formulations because of its antioxidant property. Photodegradation tests were applied on commercial formulations containing DC and novel prepared gels, according to the ICH rules. The experiments were monitored by spectrophotometry and the data processed by multivariate curve resolution analysis to estimate the spectra and concentration profiles of evolved components. Characterization of niosomes was evaluated by size and distribution measurement, morphological analysis and encapsulation efficiency. Permeation experiments were performed across rabbit ear skin up to 24 h. Photodegradation rate of DC was found very fast in commercial formulation, with a residual content of 90% after only 4.38 min under a radiant exposure of 450 W/m(2). Photostability resulted increased significantly when the drug was entrapped in niosomal systems. The best results were obtained by reaching a 10% degradation after 50.00 min of light exposure after incorporation of DC in niosomes in presence of 5% ascorbic acid. Moreover, niosomal gel also influenced the permeation capability of DC by enhancing the transdermal delivery of the drug. The cumulative dose permeated of DC from niosomal gel was about three times that obtained with the commercial gel.