Penetration Of Liposomes Research Articles

Enhancing tumor penetration: GSH-sensitive paclitaxel liposomes modified with Dermaseptin-PP

The dense structure of solid tumor tissues and the selective permeability of cell membranes impede the effective penetration of chemotherapeutic agent-loaded liposomes into tumors and their subsequent uptake by cells. Dermaseptin-PP, a cationic antimicrobial peptide, has demonstrated the ability to enhance the penetration and accumulation of drugs within solid tumors due to its unique membrane-breaking action. Based on this, we designed glutathione (GSH)-sensitive paclitaxel liposomes modified with Dermaseptin-PP. Dermaseptin-PP was modified through disulfide bonding, which could be broken at the tumor site due to high GSH levels. This cleavage resulted in the release of Dermaseptin-PP, thereby enhancing the permeability of the paclitaxel liposomes within the tumor. We found that the paclitaxel liposomes modified with Dermaseptin-PP were extensively distributed to the tumor site, and the Dermaseptin-PP modification significantly enhanced liposome penetration within the tumor. Our study significantly increased the anti-tumor efficacy of paclitaxel liposomes. Our study confirms that paclitaxel liposomes modified with Dermaseptin-PP is an effective anti-tumor therapy that enhances deep penetration into tumors. Additionally, this broadens the applications of cationic antimicrobial peptides.

Mucosa-penetrating liposomes for esophageal local drug delivery

Local drug delivery to the esophagus is hampered by rapid transit time and poor permeability of the mucosa. If some strategies aimed to improve the residence time have been proposed, non-invasive approaches to increase the drug penetration in the mucosa have not been described so far. Herein, we designed mucosa-penetrating liposomes to favor the penetration and retention of curcumin (CURC) in the esophagus. A novel mucosa penetrating peptide (MPP), SLENKGP, was selected by Phage Display and conjugated to pegylated liposomes at different PEG and MPP’s surface densities. Pegylation assured a long residence time of liposomes (at least 30 min) in the esophagus in vivo, but it did not favor the penetration of CURC in the mucosa. MPP-decorated liposomes instead delivered a significant higher amount of CURC in the mucosa compared to naked pegylated liposomes. Confocal microscopy studies showed that naked pegylated liposomes remain confined in the superficial layers of the mucosa whereas MPP-decorated liposomes penetrate the whole epithelium. In vitro, MPP reduced the interaction of PEG with mucin, meanwhile favoring the paracellular penetration of liposomes across epithelial cell multilayers. In conclusion, pegylated liposomes represent a valid approach to target the esophagus and the surface functionalization with MPP enhances their penetration in the mucosa.

A lava-inspired proteolytic enzyme therapy on cancer with a PEG-based hydrogel enhances tumor distribution and penetration of liposomes

The enhanced permeability and retention (EPR) effect has become the guiding principle for nanomedicine against cancer for a long time. However, several biological barriers severely resist therapeutic agents’ penetration and retention into the deep tumor tissues, resulting in poor EPR effect and high tumor mortality. Inspired by lava, we proposed a proteolytic enzyme therapy to improve the tumor distribution and penetration of nanomedicine. A trypsin-crosslinked hydrogel (Trypsin@PSA Gel) was developed to maintain trypsin’s activity. The hydrogel postponed trypsin’s self-degradation and sustained the release. Trypsin promoted the cellular uptake of nanoformulations in breast cancer cells, enhanced the penetration through endothelial cells, and degraded total and membrane proteins. Proteomic analysis reveals that trypsin affected ECM components and down-regulated multiple pathways associated with cancer progression. Intratumoral injection of Trypsin@PSA Gel significantly increased the distribution of liposomes in tumors and reduced tumor vasculature. Combination treatment with intravenous injection of gambogic acid-loaded liposomes and intratumoral injection of Trypsin@PSA Gel inhibited tumor growth. The current study provides one of the first investigations into the enhanced tumor distribution of liposomes induced by a novel proteolytic enzyme therapy.Graphic

Comprehensive analysis of the influence of physicochemical properties and tumor-associated environments on liposome intratumoral penetration

Poor tumor penetration is the most significant barrier to the clinical translation of nanomedicines. Despite numerous studies, little is known about how the physicochemical properties and tumor-associated environments impact liposome intratumoral penetration from a multi-factorial perspective. Thus, we developed a set of model liposomes to explore the laws of their intratumoral penetration. Our comprehensive analysis revealed that zeta potential, membrane fluidity, and size of liposomes could influence their penetration in the peripheral, intermediate, or central areas of the tumor, respectively. Moreover, protein corona and stromal cells primarily impeded liposome penetration in the tumor periphery, while the vascular vessels had a similar effect in the tumor center. Our results also revealed a non-monotonic relationship, indicating that the best condition for a single factor may not necessarily be the optimal choice when considering all the factors. The preferred size, zeta potential, and membrane fluidity for excellent tumor penetration are within the ranges of 52-72nm, 16-24mV, and 230-320 mp, respectively. Our study provides a comprehensive understanding of the influence of physicochemical properties and tumor-associated environments on liposome intratumoral penetration, offering explicit guidance for the precise design and rational optimization of anti-tumor liposomes.

Representative Inorganic Nanomaterials and Liposomes in Cosmetics

Nanomaterials are defined as materials ranging from 1nm to 100nm in at least one dimension or with internal nanostructures in bulk materials but showing distinct properties. Since the 20th century, when the feasibility of nanotechnology had been attested, nanomaterials’ applications have radiated to various fields involving electronics, physics, chemistry, processing, biology, and measurement. Moreover, inspired by the physicochemical properties and targeted effects of nanomaterials in therapy and medicine, the anticipated applications in cosmetics are well-developed. Herein, the transparency and enhanced absorption of nano titanium dioxide/zinc oxide, the antibacterial property of nanosilver/nanogold, and the stability, increased penetration, and biocompatibility of liposomes in cosmetics are summarized. Besides, the existing problems such as security assessment, elevatable loading efficiency, and usage are classified. Particularly, the focus is on the mechanism of liposomes, preparation, routes of penetration, and liposome-cell interactions. This article intended better to understand the principles of nanomaterials behind cosmetic applications and get alerted to the inconclusive security.

Extracellular matrix degrading enzyme with stroma-targeting peptides enhance the penetration of liposomes into tumors.

Various anti-tumor nanomedicines have been developed based on the enhanced permeability and retention effect. However, the dense extracellular matrix (ECM) in tumors remains a major barrier for the delivery and accumulation of nanoparticles into tumors. While ECM-degrading enzymes, such as collagenase, hyaluronidase, and bromelain, have been used to facilitate the accumulation of nanoparticles, serious side effects arising from the current non-tumor-specific delivery methods limit their clinical applications. Here, we report targeted delivery of bromelain into tumor tissues through its covalent attachment to a hyaluronic acid (HA)-peptide conjugate with tumor ECM targeting ability. The ECM targeting peptide, collagen type IV-binding peptide (C4BP), was chosen from six candidate-peptides based on their ability to bind to frozen sections of triple-negative breast cancer, 4T1 tumor ex vivo. The HA- C4BP conjugate showed a significant increase in tumor accumulation in 4T1-bearing mice after intravenous administration compared to unmodified HA. We further demonstrated that the systemic administration of bromelain conjugated C4BP-HA (C4BP-HA-Bro) potentiates the anti-tumor efficacy of liposomal doxorubicin. C4BP-HA-Bro decreased the number and length of collagen fibers and improved the distribution of doxorubicin within the tumor. No infusion reaction was noted after delivery of C4BP-HA-Bro. C4BP-HA thus offers a potential for effective and safe delivery of bromelain for improved intratumoral delivery of therapeutics.

Oxime Therapy for Brain AChE Reactivation and Neuroprotection after Organophosphate Poisoning.

One of the main problems in the treatment of poisoning with organophosphorus (OPs) inhibitors of acetylcholinesterase (AChE) is low ability of existing reactivators of AChE that are used as antidotes to cross the blood-brain barrier (BBB). In this work, modified cationic liposomes were developed that can penetrate through the BBB and deliver the reactivator of AChE pralidoxime chloride (2-PAM) into the brain. Liposomes were obtained on the basis of phosphatidylcholine and imidazolium surfactants. To obtain the composition optimized in terms of charge, stability, and toxicity, the molar ratio of surfactant/lipid was varied. For the systems, physicochemical parameters, release profiles of the substrates (rhodamine B, 2-PAM), hemolytic activity and ability to cause hemagglutination were evaluated. Screening of liposome penetration through the BBB, analysis of 2-PAM pharmacokinetics, and in vivo AChE reactivation showed that modified liposomes readily pass into the brain and reactivate brain AChE in rats poisoned with paraoxon (POX) by 25%. For the first time, an assessment was made of the ability of imidazolium liposomes loaded with 2-PAM to reduce the death of neurons in the brains of mice. It was shown that intravenous administration of liposomal 2-PAM can significantly reduce POX-induced neuronal death in the hippocampus.

Application and Efficacy of Melatonin Elastic Liposomes in Photoaging Mice

Transdermal drug delivery system is a preferable choice to overcome the low bioavailability of oral medication. Elastic liposomes have shown great effectiveness for percutaneous transport of melatonin (MLT). In this study, the elastic liposomes loaded with MLT were prepared using thin-film dispersion method and optimized through the central composite design (CCD) approach. The physicochemical properties and skin permeation against UV-induced skin photoaging efficacy of the developed MLT-ELs were assessed. The average size of the MLT-ELs was about 49 nm with a spherical shape and high encapsulation efficiency (73.91%) and drug loading (9.92%). The results of FTIR, DSC, and XRD revealed that the chemical structure of MLT was not changed after prepared elastic liposomes, and the drug was successfully encapsulated in the elastic liposome membrane material. In vitro skin permeation evaluation showed that the cumulative penetration of elastic liposomes was 1.5 times higher than that of conventional liposomes, highlighting that the elastic liposomes more easily penetrated into the body. The photoaging experiment results indicated that topical MLT-EL treatment ameliorated the skin elasticity, enhanced the skin hydration level, and preserved the integrity of dermal collagen and elastic fibers. It could be concluded that the elastic liposomes might serve as a promising platform for the transdermal delivery of melatonin.

Effective Penetration of a Liposomal Formulation of Bleomycin through Ex-Vivo Skin Explants from Two Different Species.

Simple SummaryBleomycin, a chemotherapy drug, is currently injected into patients, but this can damage healthy tissues. Ideally, we would like to apply bleomycin directly onto a skin tumour but bleomycin is a big molecule and cannot pass through the skin or directly enter into cancer cells to kill them. Therefore, we need to find new ways of packaging the drug to get it inside cancer cells. Liposomes are small artificial bubbles made of from the same building blocks as our skin and cell membranes that can be filled with pharmaceutical drugs. In this study we propose that liposomes can assist with the delivery of bleomycin by improving penetration through the skin. We are using a new compound called Bleosome, which contains liposomes packed with bleomycin. We found that Bleosome penetrated more through the healthy skin of dogs and horses than bleomycin. These are promising results, indicating that Bleosome may be an effective treatment, with easy application and limited side-effects, to treat skin cancer.Bleomycin is a chemotherapy agent that, when administered systemically, can cause severe pulmonary toxicity. Bleosome is a novel formulation of bleomycin encapsulated in ultra-deformable (UD) liposomes that may be applicable as a topical chemotherapy for diseases such as non-melanoma skin cancer. To date, the ability of Bleosome to effectively penetrate through the skin has not been evaluated. In this study, we investigated the ability of Bleosome to penetrate through ex vivo skin explants from dogs and horses. We visualized the penetration of UD liposomes through the skin by transmission electron microscopy. However, to effectively image the drug itself we fluorescently labeled bleomycin prior to encapsulation within liposomes and utilized multiphoton microscopy. We showed that UD liposomes do not penetrate beyond the stratum corneum, whereas bleomycin is released from UD liposomes and can penetrate to the deeper layers of the epidermis. This is the first study to show that Bleosome can effectively penetrate through the skin. We speculate that UD liposomes are penetration enhancers in that UD liposomes carry bleomycin through the outer skin to the stratum corneum and then release the drug, allowing diffusion into the deeper layers. Our results are comparative in dogs and horses and warrant further studies on the efficacy of Bleosome as topical treatment.

Comparison of three synthetic transferrin mimetic small peptides to promote the blood–brain barrier penetration of vincristine liposomes for improved glioma targeted therapy

The existence of the blood–brain barrier (BBB) makes the clinical chemotherapy of glioma a formidable challenge, because it hinders the passage of different chemotherapeutics into the brain and reduces the overall therapeutic efficiency. Therefore, it is necessary to design a drug delivery system in way that would favor the transportation of anti-cancer agents across the BBB and increase their selective accumulation within the tumor cells without affecting the normal tissues. Transferrin receptor (TfR) that shows an elevated level of expression on the BBB and glioma cells emerges as a promising tool for brain targeted delivery and glioma therapy. However, only a limited number of studies have comparatively evaluated the functionally of TfR targeting ligands. Herein, a series of liposomal formulations modified with the most well-known TfR targeting peptides including T12 (also known as THR), B6, and T7 was developed and their brain targeting capability and selective glioma accumulation was comparatively evaluated in vitro and in vivo. Among all TfR targeting or non-targeting groups, T7-modified liposomes (T7-LS) showed the highest BBB penetration capacity and brain distribution and displayed an enhanced accumulation in glioma cells. When loaded with vincristine (VCR), as a model chemotherapeutic, T7-LS/VCR could achieve the best anti-glioma outcome by means of targeted cytotoxicity and apoptosis in vitro. The obtained results suggested T7-LS as a potential platform for effective brain targeted delivery and glioma therapy in clinic.

Facile Biofilm Penetration of Cationic Liposomes Loaded with DNase I/Proteinase K to Eradicate Cutibacterium acnes for Treating Cutaneous and Catheter Infections.

BackgroundThe biofilm produced by Cutibacterium acnes is a major infection threat for skin and implanted catheters. Nanoparticles provide a new approach to eradicate biofilms. The present study evaluated the capability of cationic liposomes loaded with DNase I (DNS) and proteinase K (PK) to remove preformed C. acnes biofilms.MethodsDNS and PK were able to target and disassemble the biofilm by degrading extracellular polymer substances (EPS). Soyaethyl morpholinium ethosulfate (SME) was used to render a positive charge and enhance the antibacterial activity of the liposomes.ResultsThe cationic liposomes containing enzymes yielded monodisperse nanovesicles ranging between 95 and 150 nm. The entrapment efficiency of the enzymes in the liposomes achieved a value of 67–83%. All liposomal formulations suppressed planktonic C. acnes growth at a minimum inhibitory concentration (MIC) equal to the free SME in the solution. The enzyme in the liposomal form inhibited biofilm growth much better than that in the free form, with the dual enzyme-loaded liposomes demonstrating the greatest inhibition of 54% based on a crystal violet assay. The biofilm-related virulence genes PA380 and PA1035 were downregulated by the combined enzymes in the liposomes but not the individual DNS or PK. Scanning electron microscopy (SEM) and confocal microscopy displayed reduced C. acnes aggregates and biofilm thickness by the liposomal system. The liposomes could penetrate through about 85% of the biofilm thickness. The in vitro pig skin permeation also showed a facile delivery of liposomes into the epidermis, deeper skin strata, and hair follicles. The liposomes exhibited potent activity to eliminate C. acnes colonization in mouse skin and catheters in vivo. The colony-forming units (CFUs) in the catheter treated with the liposomes were reduced by 2 logs compared to the untreated control.ConclusionThe data suggested a safe application of the enzyme-loaded cationic liposomes as antibacterial and antibiofilm agents.

Recent advances with liposomes as drug carriers for treatment of neurodegenerative diseases.

A major challenge in treating neurogenerative diseases is delivering drugs across the blood-brain barrier (BBB). In this review, we summarized the development of liposome-based drug delivery system with enhanced BBB penetration for efficient brain drug delivery. We focused on the liposome-based therapeutics targeting Alzheimer's disease and Parkinson's disease because they are most common types of adult chronic neurodegenerative disorders. A variety of liposome with surface modification of BBB-targeting ligands have been created to cross the BBB via transcytosis to the therapeutic efficacy of Alzheimer's disease and Parkinson's disease drugs. Recent advances in liposome are providing alternatives to overcome BBB for more efficient therapeutic strategy. To improve the BBB penetration of liposomes, we need to completely understand the pathophysiological changes at the BBB.

Size-Dependent Absorption through Stratum Corneum by Drug-Loaded Liposomes

Topical treatment of various skin disorders requires drug absorption and penetration through the stratum corneum (SC) into the epidermis and dermis tissues. The use of nano-drug delivery systems including liposomes and lipid nanoparticles (SLNs) have been shown to facilitate SC penetration. The goal of this work was to study the impact of liposome sizes and the resulted drug distribution inside various skin tissue. All trans retinoic acid (ATRA) was used as the model drug and loaded into gel phase HSPC/CHOL/DSPE-PEG liposomes (lipo-ATRA) with sizes ranging from 80nm to more than 300nm. The percutaneous drug absorption process was monitored and analyzed. There were significant differences in percutaneous absorption and tissue distribution resulted from liposomes smaller than 100nm and those bigger than 200nm. Lipo-ATRA with a mean diameter of 83nm can deliver the content to epidermis and dermis. But for 200nm - 300nm liposomes, the resulted epidermis and dermis ATRA levels were less than about one third, suggesting bigger liposomes had poor penetration through the brick and mortar structure of SC. Gel phase liposomes with sizes under 100nm improved encapsulated drug absorption and distribution into the epidermis and dermis tissues. A size dependent mechanism for liposome penetration of the stratum corneum was proposed.

Enhanced treatment for cerebral ischemia-reperfusion injury of puerarin loading liposomes through neutrophils-mediated targeted delivery

The recovery of blood circulation following cerebral infarction-associated thrombolysis brings new damage to the brain, which is cerebral ischemia-reperfusion injury (CIRI). Inflammation is the main pathological mechanism of CIRI. The inflammatory response triggered by cerebral ischemia-reperfusion provides neutrophils with a special opportunity to facilitate drug delivery to the site of ischemic penumbra through the chemotaxis of inflammatory factors by neutrophils. Puerarin is an isoflavone derivative with a significant neuroprotective effect in vitro. But the blood-brain barrier (BBB) impedes its therapeutic efficacy on CIRI within the brain. Inspired by the pathological process, we have used neutrophils as carriers to enhance the BBB penetration of liposomes loaded with puerarin and improve the concentration of puerarin in the brain parenchyma in this study. These results showed that puerarin-containing liposomes were released in response to inflammatory conditions associated with brain injury to enhance the neuroprotection effect at the ischemic penumbra.

Candesartan treatment enhances liposome penetration and anti-tumor effect via depletion of tumor stroma and normalization of tumor vessel.

The poor penetration of nanoparticles in solid tumors has been a critical factor limiting the clinical benefits of nanomedicine. Therefore, we depleted the dense extracellular matrix (ECM) and normalized tumor vessels to enhance drug delivery and therapeutic efficacy. We used candesartan as an angiotensin system inhibitor, which reduced ECM content and facilitated "vascular normalization" by targeting the angiotensin-signaling axis, resulting in improved anti-cancer therapeutic effects. We also combined candesartan with PEGylated liposome-encapsulated zoledronic acid (ZOL) (PEG-ZOL-LPs) to assess how this affected anti-tumor therapy. Our findings indicated that the migration of 4T1 mouse breast cancer cells was inhibited by candesartan. Moreover, the ECM depletion (including collagen I and hyaluronan) by candesartan was achieved through the downregulation of TGF-β1 in vitro, consistent with in vivo results. Furthermore, treatment groups that received candesartan also had significantly decreased tumor vessel permeability and proportions of circulating endothelial progenitor cells (CEPCs) in the serum, which resulted in normalization of tumor vasculature and improved delivery of PEG-ZOL-LPs. Finally, the positive effect candesartan in terms of tumor growth was found not to have an impact of the efficacy of the PEG-ZOL-LPs treatment. This unexpected lack of effect of candesartan on the performance of PEG-ZOL-LPs would be due to dynamics of the effect of both treatments. It might be possible that a different protocol of administration could lead to a synergistic effect. Graphical abstract The schematic illustration showed that candesartan favored depletion of tumor stroma and tumor vascular normalization to improve the anti-cancer efficacy of PEG-ZOL-LPs.

Analysis of the Effect of IL-1β on Blood-Brain Barrier Permeability in M6 Glioma Mouse Model Using Intravital Microscopy.

We studied the effect of IL-1β on the permeability of brain capillaries in healthy mice. Intravital microscopy demonstrated that parenteral administration of IL-1β was followed by an increase in vascular permeability ensuring passage of free Alexa488 fluorescent label through the capillary walls, but not sufficient for penetration of liposomes. In addition, experiments on mice with intracranial M6 glioma showed penetration of liposomes through the walls of tumor capillaries after parenteral administration of IL-1β in a concentration of 2 μg/ml. Thus, the use of proinflammatory cytokine IL-1β in the therapy of brain tumors can significantly increase the therapeutic efficacy of drug delivery systems, in particular, for drugs poorly crossing the blood-brain barrier.

Liposomal delivery of 5 Fluorouracil and Tretinoin: An Aspect of Topical treatment of skin warts

Background: Tretinoin and 5-fluorouracil are indicated for treatment of various skin disorders and actinic keratosis respectively. Objective: Present study was focused to design liposomes containing 5- fluorouracil and tretinoin. Design was further optimized by 32 full factorial design. Methods: Liposomes were prepared by ethanol injection method and evaluated by Transmission Electron Microscopy, percentage entrapment efficiency, zeta potential and in vitro drug release. Optimized formulation was subjected to histopathological and stability studies at 4ºC, 25ºC and 60ºC temperatures. Results: No drug crystals were visible in transmission electron microscopy, regardless of the preparation technique or the loaded drug. Formulation F9 showed maximum drug entrapment of 72.86% and 69.70% for 5-fluorouraciland tretinoin respectively. When phospholipid concentration was increased from 40 to 60 mg/ml, encapsulation efficiencies of formulation increased. Zeta potential and particle size were maintained within range of -19.14 to -25.61 and 100 to 200 nm respectively which facilitated good stability and penetration of liposomes. Dissolution profiles of formulations F1 to F6 showed high amount of drug release (30.6 to 67.42%) at 2 h. Liposomes were not stable at high temperature but formulations were most stable when stored at lower temperature i.e. 4oC. Conclusion: So, in liposomes both 5-fluorouracil and tretinoin were successfully incorporated and it can be further used for formulation development.

Cholesterol-tuned liposomal membrane rigidity directs tumor penetration and anti-tumor effect

Recently, liposomes have been widely used in cancer therapeutics, but their anti-tumor effects are suboptimal due to limited tumor penetration. To solve this problem, researchers have made significant efforts to optimize liposomal diameters and potentials, but little attention has been paid to liposomal membrane rigidity. Herein, we sought to demonstrate the effects of cholesterol-tuned liposomal membrane rigidity on tumor penetration and anti-tumor effects. In this study, liposomes composed of hydrogenated soybean phospholipids (HSPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2000) and different concentrations of cholesterol were prepared. It was revealed that liposomal membrane rigidity decreased with the addition of cholesterol. Moderate cholesterol content conferred excellent diffusivity to liposomes in simulated diffusion medium, while excessive cholesterol limited the diffusion process. We concluded that the differences of the diffusion rates likely stemmed from the alterations in liposomal membrane rigidity, with moderate rigidity leading to improved diffusion. Next, the in vitro tumor penetration and the in vivo anti-tumor effects were analyzed. The results showed that liposomes with moderate rigidity gained excellent tumor penetration and enhanced anti-tumor effects. These findings illustrate a feasible and effective way to improve tumor penetration and therapeutic efficacy of liposomes by changing the cholesterol content, and highlight the importance of liposomal membrane rigidity.

Effects of surface charge and flexibility of liposomes on dermal drug delivery

Dermal drug delivery is noninvasive and improves patient's quality of life. However, the stratum corneum and tight junctions in the granular layer are barriers that impede the delivery of hydrophilic macromolecules. For use in the treatment of allergic diseases, the drug must be delivered to deep sites within the skin, where immune-competent cells are located. Several liposome preparations have been reported to improve dermal drug delivery. However, there are few systematic reports on intradermal penetration of liposomes that focused on liposomal characteristics. In the present study, we aimed to investigate the characteristics of liposomes, which facilitates effective intradermal penetration, by focusing on their surface charge and structural flexibility. Liposomes with various surface charges and structures were prepared and their physical properties, flexibility, intradermal penetration, cytotoxicity, skin irritation, and intracellular uptake ability were evaluated. Three types of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/cholesterol-based cationic, neutral, and anionic liposomes and another anionic 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)/cholesteryl hemisuccinate (CHEMS) liposome were tested. Cellular uptake and intradermal penetration of liposomes were affected by surface charge and flexibility. DOPE/CHEMS liposome showed the most effective intradermal penetration and lowest skin irritation induction. In conclusion, the combination of negative surface charge and flexible structure is required for effective dermal drug delivery using liposomes.

Design, preparation, and evaluation of liposomal gel formulations for treatment of acne: in vitro and in vivo studies

The study highlights the significance of co-application of bioactive components into liposomal gel formulations and their comparison to azithromycin for treatment of Acne. A Design of Experiments (DoE) approach was utilized to obtain optimized liposomal formulation encapsulating curcumin, with size and zeta potential of ∼100 nm and ∼14 mV, respectively, characterized by DLS, HR-TEM, FESEM, and AFM. The curcumin liposomal dispersion depicted excellent stability over the period of 60 days, which was further converted in gel form using Carbopol. Pharmacokinetics of curcumin-loaded liposomal gel showed that Tmax for curcumin was achieved within 1 h of post application in both stratum corneum and skin, indicating quick penetration of nano-sized liposomes. Stratum corneum depicted Cmax of 688.3 ng/mL and AUC0-t of 5857.5 h × ng/mL, while the skin samples displayed Cmax of 203.3 ng/gm and AUC0-t of 2938.1 h × ng/gm. Lauric acid and azithromycin liposomal gel formulations were prepared as per the optimum parameters obtained by DoE. In antibacterial activity using agar diffusion assay, lauric acid gel formulation revealed ∼1.5 fold improved antibacterial effect than curcumin gel formulation. Interestingly, their co-application (1:1) exhibited significantly enhanced antibacterial effect against both macrolide-sensitive (1.81 versus 1.25 folds) and resistant strains of P. acnes (2.93 versus 1.22 folds) than their individual counterparts. The in vivo studies in rat ear model displayed a ∼2 fold reduction in comedones count and cytokines (TNF-α and IL-1β) on co-application with curcumin and lauric acid liposomal gel compared to placebo treated group.