Elastic liposomes-in-vehicle formulations destined for skin therapy: the synergy between type of liposomes and vehicle

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

Polysaccharide hydrogel platforms as suitable carriers of liposomes and extracellular vesicles for dermal applications

Lipid-based nanocarriers have been extensively investigated for their application in drug delivery. Particularly, liposomes are now clinically established for treating various diseases such as fungal infections. In contrast, extracellular vesicles (EVs) - small cell-derived nanoparticles involved in cellular communication - have just recently sparked interest as drug carriers but their development is still at the preclinical level. To drive this development further, the methods and technologies exploited in the context of liposome research should be applied in the domain of EVs to facilitate and accelerate their clinical translation. One of the crucial steps for EV-based therapeutics is designing them as proper dosage forms for specific applications. This review offers a comprehensive overview of state-of-the-art polysaccharide-based hydrogel platforms designed for artificial and natural vesicles with application in drug delivery to the skin. We discuss their various physicochemical and biological properties and try to create a sound basis for the optimization of EV-embedded hydrogels as versatile therapeutic avenues.

Preparation, characterization, and pharmacodynamic study on deep second degree burns of total flavonoids composite phospholipids liposome gel of Oxytropis falcata Bunge

Wound healing is the treatment problem after deep second degree (II°) burns. The p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-κB/inhibitory factor-κB (NF-κB/IκB) signal pathways play significant role in angiogenesis and wound repair after burns.This study aimed to investigate the preparation, characterization and pharmacodynamics of the total flavonoids composite phospholipids liposome of Oxytropis falcata Bunge (TFOFB-CPL) on deep II° burns to research its biological activity and underlying mechanism. The TFOFB-CPL was prepared by thin-film dispersion method and the preparation process was optimized via central composite design. The TFOFB-CPL was then characterized by using particle size, polydispersity indexes (PDIs), zeta potential, encapsulation efficiency (EE) and morphology. Moerover, in vitro transdermal test and in vivo pharmacodynamic study included wound healing rate, hematoxylin-eosin (HE) staining, masson staning, western blotting and RT-PCR. The results showed that the therapeutic effects of TFOFB-CPL gel on deep II° burns, especially during wound healing were significant. TFOFB-CPL gel has a sustained-release effect during the treatment of deep II° burns with forming drug depot in the dermis layer. The wound healing rate of TFOFB-CPL gel group was near positive group and better than the other groups. TFOFB-CPL gel could promote the growth of epidermis, skin appendages, fibrovascular and collagen fibers, and had obvious anti-inflammatory effects. Moreover, TFOFB-CPL gel inhibited the activation of p38MAPK and the degradation of IκBα, and promoted the neonatal wounds during the early stage. Therefore, TFOFB-CPL gel could be considered as a novel preparation for treating deep II° burns.

Going skin deep: A direct comparison of penetration potential of lipid-based nanovesicles on the isolated perfused human skin flap model

Phospholipid-based nanocarriers are attractive drug carriers for improved local skin therapy. In the present study, the recently developed isolated perfused human skin flap (IPHSF) model was used to directly compare the skin penetration enhancing potential of the three commonly used nanocarriers, namely conventional liposomes (CLs), deformable liposomes (DLs) and solid lipid nanoparticles (SLNs). Two fluorescent markers, calcein (hydrophilic) or rhodamine (lipophilic), were incorporated individually in the three nanosystems. The nanocarrier size ranged between 200 and 300nm; the surface charge and entrapment efficiency for both markers were dependent on the lipid composition and the employed surfactant. Both carrier-associated markers could not penetrate the full thickness human skin, confirming their suitability for dermal drug delivery. CLs exhibited higher retention of both markers on the skin surface compared to DLs and SLNs, indicating a depo formation. DLs and SLNs enabled the deeper penetration of the two markers into the skin layers. In vitro and ex vivo skin penetration studies performed on the cellophane membrane and full thickness pig/human skin, respectively, confirmed the findings. In conclusion, efficient dermal drug delivery can be achieved by optimization of a lipid nanocarrier on the suitable skin-mimicking model to assure system's accumulation in the targeted skin layer.

Elastic liposomes as novel carriers: recent advances in drug delivery

Elastic liposomes (EL) are some of the most versatile deformable vesicular carriers that comprise physiologically biocompatible lipids and surfactants for the delivery of numerous challenging molecules and have marked advantages over other colloidal systems. They have been investigated for a wide range of applications in pharmaceutical technology through topical, transdermal, nasal, and oral routes for efficient and effective drug delivery. Increased drug encapsulation efficiency, enhanced drug permeation and penetration into or across the skin, and ultradeformability have led to widespread interest in ELs to modulate drug release, permeation, and drug action more efficiently than conventional drug-release vehicles. This review provides insights into the versatile role that ELs play in the delivery of numerous drugs and biomolecules by improving drug release, permeation, and penetration across the skin as well as stability. Furthermore, it provides future directions that should ensure the widespread use of ELs across all medical fields.

Current Trends in Development of Liposomes for Targeting Bacterial Biofilms

Biofilm targeting represents a great challenge for effective antimicrobial therapy. Increased biofilm resistance, even with the elevated concentrations of very potent antimicrobial agents, often leads to failed therapeutic outcome. Application of biocompatible nanomicrobials, particularly liposomally-associated nanomicrobials, presents a promising approach for improved drug delivery to bacterial cells and biofilms. Versatile manipulations of liposomal physicochemical properties, such as the bilayer composition, membrane fluidity, size, surface charge and coating, enable development of liposomes with desired pharmacokinetic and pharmacodynamic profiles. This review attempts to provide an unbiased overview of investigations of liposomes destined to treat bacterial biofilms. Different strategies including the recent advancements in liposomal design aiming at eradication of existing biofilms and prevention of biofilm formation, as well as respective limitations, are discussed in more details.

In vitro models to estimate drug penetration through the compromised stratum corneum barrier

OBJECTIVES

The phospholipid vesicle-based permeation assay (PVPA) is a recently established in vitro stratum corneum model to estimate the permeability of intact and healthy skin. The aim here was to further evolve this model to mimic the stratum corneum in a compromised skin barrier by reducing the barrier functions in a controlled manner.

METHODS

To mimic compromised skin barriers, PVPA barriers were prepared with explicitly defined reduced barrier function and compared with literature data from both human and animal skin with compromised barrier properties. Caffeine, diclofenac sodium, chloramphenicol and the hydrophilic marker calcein were tested to compare the PVPA models with established models.

RESULTS AND DISCUSSIONS

The established PVPA models mimicking the stratum corneum in healthy skin showed good correlation with biological barriers by ranking drugs similar to those ranked by the pig ear skin model and were comparable to literature data on permeation through healthy human skin. The PVPA models provided reproducible and consistent results with a distinction between the barriers mimicking compromised and healthy skin. The trends in increasing drug permeation with an increasing degree of compromised barriers for the model drugs were similar to the literature data from other in vivo and in vitro models.

CONCLUSIONS

The PVPA models have the potential to provide permeation predictions when investigating drugs or cosmeceuticals intended for various compromised skin conditions and can thus possibly reduce the time and cost of testing as well as the use of animal testing in the early development of drug candidates, drugs and cosmeceuticals.