Reverse-phase Evaporation Method Research Articles

Transfersomes: An Innovative Vesicular Carrier for Boosted Transdermal Delivery System

One may find difficulties with oral and parenteral drug delivery systems in a routine of clinical practice because they do not have sufficient compliance and bioavailability for patients. So, nowadays transdermal route is a greater area of interest of pharmaceutical research for delivering drug. But skin is the most challenging area to cross in transdermal delivery of drug as the stratum corneum & the outer layer of the skin have tight intracellular junctions. Researchers have developed various approaches like micro needle, sonophoresis, electrophoresis, and iontophoresis etc to overcome those complications for the transdermal delivery of drugs. Chemical permeation enhancers are needed in vesicular drug delivery system such as niosomes, liposomes, elastic liposomes (transfersomes and ethosomes) to improve their penetration property. Transferosomes can be prepared by a number of methods like vortexing, sonication method, freeze–thaw method, ethanol injection method, Reverse-phase evaporation method, etc. Transfersomes can carry wide ranges of drugs having a wide range of solubility within it as they are constructed of hydrophobic as well as hydrophilic moieties. The main property of transferosome is deformability. This flexible nature of the vesicle membrane helps transfersome to go across the narrow pores with a maximum amount of drugs present within it. They have high deformable capacity which exhibits advanced penetration capability of intact vesicles. Both high and low molecular weight drugs like albumin, insulin, corticosteroids, sex hormones, anesthetic, anticancer, analgesic can be fused within transfersome.

Preparation and evaluation of niosomal chitosan-based in situ gel formulation for direct nose-to-brain methotrexate delivery

Achieving effective treatments for various brain disorders due to the blood-brain barrier existence and the brain's complex structure has become a challenging goal. To overcome these challenges, one of the non-invasive strategies aimed at direct brain drug delivery is the use of the intranasal route. Novel drug delivery systems can be used to overcome the limitations in this administration route. This study suggested niosomal methotrexate (MTX) in situ gel formulation, which could be a suitable candidate for drug delivery to the brain. Here, niosomal MTX was prepared by a modified reverse-phase evaporation method, optimized with the aid of the design expert® software, and characterized. Optimum niosomal MTX with particle size, zeta potential, and entrapment efficiency (EE%), equal to 130.5 nm, −38.5 mV, and 91.39 %, respectively, were added into the temperature-sensitive in situ gel formulation composed of chitosan and Poloxamer 407. This study demonstrates that the simultaneous use of niosome and in situ gel formulations causes long-term persistence in the nasal cavity and helps us to have a more controlled drug release system with higher brain concentration, lower plasma concentration, higher Kp, and lower side effects compared to the free drug (MTX solution), MTX-gel (MTX-loaded in situ gel), and niosomal MTX formulations.

Carboplatin Niosomal Nanoplatform for Potentiated Chemotherapy

This study aimed to characterize a stable nano-niosome formulation, which could reduce the adverse effects of carboplatin (CB) and improve its therapeutic efficacy in the treatment of breast cancer. For this purpose, CB-loaded polyethylene glycol (PEG)ylated niosome nanoparticles (PEG-NS-CB) were synthesized using the reverse-phase evaporation method. PEG-NS-CB (226.0 ± 10.6 nm) could release CB in a controlled manner and, compared to CB and CB-loaded non-PEGylated niosome (NS-CB), caused higher cytotoxicity effects against mouse breast cancer 4T1 cells (IC50: 83.4, 26.6, and 22.5 µM for CB, NS-CB, and PEG-NS-CB, respectively). Also, PEG-NS-CB demonstrated higher stability, in which its profile of drug release, cytotoxicity, and LE% did not change significantly three months after preparation compared to those at the production time. In addition, the in vivo results demonstrated that PEG-NS-CB caused higher therapeutic (the number of alive mice: 12, 15, and 17 out of 20 in CB, NS-CB, and PEG-NS-CB receiver groups, respectively) and less toxicity effects (weight loss of 17, 12.5, and 10% in CB, NS-CB, and PEG-NS-CB receiver groups, respectively), compared to NS-CB and CB in breast cancer-bearing mice. Overall, the results of this study suggest that PEG-NS-CB could be a promising formulation for the treatment of breast cancer.

In Vitro Nephrotoxicity and Permeation of Vancomycin Hydrochloride Loaded Liposomes.

Drugs can be toxic to the fetus depending on the amount that permeates across the maternal–fetal barrier. One way to limit the amount which penetrates this barrier is to increase the molecular size of the drug. In this study, we have achieved this by encapsulating our model antibiotic (vancomycin hydrochloride, a known nephrotoxic agent) in liposomes. PEGylated and non-PEGylated liposomes encapsulating vancomycin hydrochloride were prepared using two different methods: thin-film hydration followed by the freeze–thaw method and the reverse-phase evaporation method. These liposomes were characterized by their hydrodynamic size and zeta potential measurements, CryoTEM microscopy, loading and encapsulation efficiency studies, in vitro release measurements and in vitro cytotoxicity assays using NRK-52 E rat kidney cells. We also determined the in vitro permeability of these liposomes across the human placental cell and dog kidney cell barriers. Vancomycin hydrochloride-loaded PEGylated liposomes (VHCL-lipo) of a size less than 200 nm were prepared. The VHCL-lipo were found to have the faster release of vancomycin hydrochloride and resulted in greater viability of NRK-52E cells. In vitro, the VHCL-lipo permeated the human placental cell and dog kidney cell barriers to a lesser extent than the free vancomycin hydrochloride. The data suggest a reduction in nephrotoxicity and permeability of vancomycin hydrochloride after encapsulation in PEGylated liposomes.

Design and physicochemical characterization of novel hybrid SLN-liposome nanocarriers for the smart co-delivery of two antitubercular drugs

In the present work a novel hybrid system for the delivery of two first-line antitubercular drugs, rifampicin (RIF) and isoniazid (INH), was designed. In order to control the release of the drugs and improve the efficiency of conventional carriers, like liposomes or solid lipid nanoparticles (SLNs), the new systems were developed by embedding SLNs into lecithin-based liposomes through the reverse-phase evaporation method. The hybrid system was characterized and compared to SLNs and liposomes in terms of size, encapsulation efficiency, morphology, and drug release. Detailed structural data and further evidence of the successful formation of the hybrid nanoparticles were obtained by applying small-angle neutron scattering (SANS). The hybrid system displayed a particle size comparable to liposomes and a high encapsulation efficiency. Morphological results obtained by atomic force microscopy (AFM) highlighted the possible presence of SLNs into the phospholipid bilayer; this hypothesis was supported by the slower in vitro release of the hydrophilic drug INH compared to liposomes and SLNs. Moreover, scattering differences of the inner core of the nanoparticles, evidenced in the SANS analysis, further corroborated the successful formation of the hybrid carrier. These novel systems were able to release their content as expected from an efficient dosage form in a perspective of an inhaled administration, improving the stability and the drug release profile with respect to plain liposomes. The physicochemical characterization of our systems opens new avenues towards a better understanding of the formulation of vesicles encapsulating SLNs.

Vitamin C as a shelf-life extender in liposomes

The objective of this study was to evaluate the influence of vitamin C (VC) on the stability of stored liposomes under different climatic conditions. Liposomal formulations containing 1 mg/mL of VC (LIP-VC) and blank formulations (LIP-B) were prepared by the reverse-phase evaporation method. After preparation, they were characterized according to their refractive index, average vesicle diameter, polydispersity index (PDI), zeta potential, pH, content, encapsulation efficiency (EE%), morphology, stability and antioxidant activity. For stability, LIP-VC and LIP-B were stored in different climatic conditions (4 °C, 25 °C and 40 °C) for 30 days. The LIP-VC presented 1.3365 refractive index, 161 nm of mean diameter, 0.231 PDI, -7.3 mV zeta potential, 3.2 pH, 19.4% EE%, spherical morphology, 1 mg/mL of VC content, and antioxidant activity of 12 and 11.4 μmol of TE/mL for the radical DPPH and ABTS+, respectively. During stability, the LIP-B stored in 40 °C showed an instability in the parameters: PDI, vesicle size and zeta potential after 15 days, while the LIP-VC remained stable in its size and PDI for 30 days. After that, it is shown that VC can be used as an antioxidant and stabilizer in liposomes to increase the stability and shelf-life of vesicles.

FORMULATION AND CARACTERIZATION OF QUERCETIN NIOSOME WITH CONCENTRATION VARIATIONS OF SPAN 20 SURFACTANT

Quercetin has low solubility, absorption and bioavailability which limits its practical use as a drug or supplement. Therefore, it is important to formulate a quercetin niosome system with various concentrations of span 20 as a surfactant. This investigation aimed to formulate and analyse a quercetin niosome preparation with span 20 variations to provide optimal quercetin solubility. Niosomes were prepared using various concentrations of span 20. In the present study, the quercetin niosome used the reverse phase evaporation (RPE) method. Quercetin niosome is characterised by its organoleptic properties, pH value, particle morphology comprising the particle shape and size, and encapsulation efficiency. Organoleptic observations of the quercetin niosome included a yellow colour, distinctive quercetin odour and thick consistency for all formulas. The pH remained within the physiological pH range of skin. Quercetin niosome morphology was close to spherical while the niosome particle size results were 2.13 µm (F1), 2.99 µm (F2) and 3.31 µm (F3). The quercetin niosome encapsulation efficiency results were 81.86 ± 0.47% (F1), 84.02 ± 0.26% (F2) and 88.24 ± 0.10% (F3). Quercetin niosome were successfully prepared using multiple span 20 concentrations below the cholesterol concentration characterised by the measurement results of organoleptic, pH, particle morphology and encapsulation efficiency.

Pressure-Controlled Encapsulation of Graphene Quantum Dots into Liposomes by the Reverse-Phase Evaporation Method.

Ultrasmall nanoparticles (USNPs) with sizes below 10 nm have shown great potentials in medical applications owing to their outstanding physical, chemical, optical, and biological properties. However, they suffer from a rapid renal clearance and biodegradation rate in the biological environment due to the small size. Liposomes are one of the most promising delivery nanocarriers for loading USNPs because of their excellent biocompatibility and lipid bilayer structure. Encapsulation of USNPs into liposomes in an efficient and controllable manner remains a challenge. In this study, we achieved a high loading of graphene quantum dots (GQDs, ∼4 nm), a typical USNP, into the aqueous core of liposomes (45.68 ± 1.44%), which was controllable by the pressure. The GQDs-loaded liposomes (GQDs-LPs) exhibited a very good aqueous stability for over a month. Furthermore, indocyanine green (ICG), an efficient near-infrared (NIR) photothermal agent, was introduced in the GQDs-LP system that could convert NIR laser energy into thermal energy and break down the liposomes, causing the release of GQDs in 6 min. Moreover, this NIR light-controlled release system (GQDs-ICG-LPs) also exhibited a good photothermal therapeutic performance in vitro, and 75% of cancer cells were killed at a concentration of 200 μg/mL. Overall, the successful development of the NIR light-controlled release system has laid a solid foundation for the future biomedical application of USNPs-loaded liposomes.

Fabrication and Characterization of Azithromycin-Loaded Niosomes for Periodontitis Treatment

Azithromycin (AZM) is a potential drug for periodontitis treatment, but its poor water solubility could be problematic for local delivery to periodontal tissues. Entrapping AZM, which is a hydrophobic drug into niosomes, could effectively deliver drugs to the target site. This study aimed to design and fabricate azithromycin-loaded niosomes (NAZ) with desirable properties for intra-periodontal pocket administration. Span 60 and cholesterol were used to prepare niosomes with modified reverse phase evaporation method. NAZ were characterized and the effects of niosome composition were investigated. In vitro release and cell viability were evaluated. The results of this study indicated that with the specific ratio of Span 60 and cholesterol, the particle sizes of niosomes were in nano-sized (319 nm) with optimal zeta potential (-39.57 mV). Controlled release of AZM was achieved with release kinetic followed zero order model. NAZ exhibited low toxicity as cell viability was comparable to negative control.

Improving Dermal Delivery of Rose Bengal by Deformable Lipid Nanovesicles for Topical Treatment of Melanoma

Cutaneous melanoma is one of the most aggressive and metastatic forms of skin cancer. However, current therapeutic options present several limitations, and the annual death rate due to melanoma increases every year. Dermal delivery of nanomedicines can effectively eradicate primary melanoma lesions, avoid the metastatic process, and improve survival. Rose Bengal (RB) is a sono-photosensitizer drug with intrinsic cytotoxicity toward melanoma without external stimuli but the biopharmaceutical profile limits its clinical use. Here, we propose deformable lipid nanovesicles, also known as transfersomes (TF), for the targeted dermal delivery of RB to melanoma lesions to eradicate them in the absence of external stimuli. Considering RB’s poor ability to cross the stratum corneum and its photosensitizer nature, transfersomal carriers were selected simultaneously to enhance RB penetration to the deepest skin layers and protect RB from undesired photodegradation. RB-loaded TF dispersion (RB-TF), prepared by a modified reverse-phase evaporation method, were nanosized with a ζ-potential value below −30 mV. The spectrophotometric and fluorimetric analysis revealed that RB efficiently interacted with the lipid phase. The morphological investigations (transmission electron microscopy and small-angle X-ray scattering) proved that RB intercalated within the phospholipid bilayer of TF originating unilamellar and deformable vesicles, in contrast to the rigid multilamellar unloaded ones. Such outcomes agree with the results of the in vitro permeation study, where the lack of a burst RB permeation peak for RB-TF, observed instead for the free drug, suggests that a significant amount of RB interacted with lipid nanovesicles. Also, RB-TF proved to protect RB from undesired photodegradation over 24 h of direct light exposure. The ex vivo epidermis permeation study proved that RB-TF significantly increased RB’s amount permeating the epidermis compared to the free drug (78.31 vs 38.31%). Finally, the antiproliferative assays on melanoma cells suggested that RB-TF effectively reduced cell growth compared to free RB at the concentrations tested (25 and 50 μM). RB-TF could potentially increase selectivity toward cancer cells. Considering the outcomes of the characterization and cytotoxicity studies performed on RB-TF, we conclude that RB-TF represents a valid potential alternative tool to fight against primary melanoma lesions via dermal delivery in the absence of light.

Role of Penetration Enhancers in the Topical Delivery of Adapalene by Transfersomal Gel: An in vitro Investigation

<p style="text-align: justify;"><strong>Objectives: </strong>To formulate and investigate the role of various penetration enhancers in the transfersomal gel delivery of adapalene. <strong>Methods:</strong> Transfersomes were formulated by reverse-phase evaporation method and the influence of various parameters was investigated and optimized for particle size, PDI, zeta potential, and entrapment efficiency using the Design of Experiment approach. Optimized formulation was subjected to various characterizations such as Fourier Transform Infrared Spectroscopy, turbidity measurement, and deformability study, and then transfersomes were incorporated into a suitable gel (Carbopol 934). The transfersomal gel was then characterized for gel characteristics such as pH, spreadability, viscosity, homogeneity, extrudability, etc. Appropriate essential oils used as natural permeation enhancers like eucalyptus oil, menthol, peppermint oil, and turpentine oil were included in the transfersomal gel of adapalene, and then<em> in vitro</em> drug release,<em> ex vivo </em>permeation, and flux study was conducted and compared. <strong>Results:</strong> The adapalene loaded transfersomal gel showed particle size of 152.1 nm, PDI of 0.315, the zeta potential of -42.9 mV, and entrapment efficiency of 58.65 %. FTIR studies showed no interactions among the drug, lipids, and polymers used. Among the essential oils used as the permeation enhancers, the formulations containing peppermint oil displayed better <em>in vitro</em> drug release and <em>ex vivo</em> permeation than the other formulations containing remaining essential oils.<strong> Conclusion:</strong> From the present study, it can be concluded that the developed formulation can enhance the topical penetration of the drug and thereby improve therapy, which certainly adds quality to the transfersomal preparation. <p style="text-align: justify;"><strong>Key words:</strong> Transfersomes, Adapalene, Eucalyptus oil, Turpentine oil, Menthol oil, Peppermint oil.

Pueraria-flavones-loaded bile salt liposomes with improved intestinal absorption and oral bioavailability: in vitro and in vivo evaluation

Pueraria flavone (PF), the main component of Pueraria lobata, is a traditional Chinese medicine used for the treatment of cardiovascular and cerebrovascular diseases; however, it exhibits low oral bioavailability because of its poor membrane permeability. In this study, PF-loaded sodium deoxycholate-decorated liposomes (SDC-Lips) were prepared using the reverse-phase evaporation method and optimised using the Box–Behnken design method. The morphology, particle size, zeta potential, and entrapment efficiency of these PF-loaded SDC-Lips were evaluated. The release behaviours of PF-loaded SDC-Lips in simulated gastric and intestinal fluids were consistent with the Weibull kinetic model. In-situ intestinal perfusion studies showed that the absorption characteristics of free PF in rats were mainly passive diffusion and partly active transport, and the duodenum was the main absorption site. After encapsulated with SDC-Lips, the absorption of PF increased significantly. The in-vivo pharmacokinetic parameters of area under the plasma concentration-time curve (AUC)(0→12h) and AUC(0→ꝏ) of PF-loaded SDC-Lips after intragastric administration were 1.34-fold and 1.543-fold, respectively. Overall, the PF-loaded SDC-Lips improved the oral absorption of PF by increasing its solubility and might be considered a promising formulation strategy for prolonging the biological activity time of PF.

Expression of miR-181a in Circulating Tumor Cells of Ovarian Cancer and Its Clinical Application.

Objective: To determine the possibility of early diagnosis and prognosis of ovarian cancer (OC) via detecting miR-181a in circulating tumor cells (CTCs) of OC and to solve clinical difficulties in OC tissue sample collection. Methods: EpCAM liposome magnetic beads (Ep-LMBs) were prepared by the reverse-phase evaporation method, and the performance of EpCAM was characterized. The cytotoxicity assay was detected by the MTT assay, and CTC capture efficiency was determined using OC cell lines. Blood and tissue samples were collected from 30 patients with OC and 30 normal ovarian tissue samples were selected. Expression of miR-181a in CTCs and tissue samples was measured by real-time fluorescence quantitative PCR (RT-qPCR) with U6 as an internal reference. Expression of miR-181a was interfered in OC cells and its relative expression was measured. Results: Ep-LMBs were successfully prepared with high stability. Cellular assays showed that these Ep-LMBs could capture up to 80% of OC cells. RT-qPCR showed that the expression of miR-181a was increased in OC tissues compared with that in normal ovarian tissues, and the relative expressions of miR-181a in cancerous tissues and CTCs were comparable. Correlation analysis with clinical characteristics revealed that miR-181a expression was correlated with the stage and metastasis of OC and the difference was statistically significant. Conclusion: MiR-181a may be involved in the development and progression of OC as an oncogene. Detection of miR-181a in Ep-LMB-captured CTCs is an effective and feasible alternative method for early diagnosis and prognostic evaluation of OC other than tissue tests.

Geniposide-Loaded Liposomes for Brain Targeting: Development, Evaluation, and In Vivo Studies.

Geniposide (GE) possesses excellent neuroprotective effects but with poor brain targeting and short half-life. Liposome was considered to have great potential for brain diseases. Therefore, this research aimed to develop a geniposide liposome (GE-LP) as a brain delivery system for cerebral ischemia reperfusion injury (CIRI) therapy and evaluate its characterization, pharmacokinetics, brain targeting, and neuroprotective effects in vivo. Then, a reverse-phase evaporation method was applied to develop the GE-LP and optimize the formulation. Notably, the GE-LP had suitable size, which was 223.8 nm. Subsequently, the pharmacokinetic behavior of GE solution and GE-LP in mice plasma was investigated, and the brain targeting was also researched. The results showed that GE in plasma of GE-LP displayed three folds longer distribution half-life and a higher bioavailability and brain targeting compared to GE solution. In vivo neuroprotective effects was evaluated through the middle cerebral artery occlusion (MCAO) rat model, and GE-LP exhibited a stronger tendency in preventing the injury of CIRI, which can significantly improve neurological deficits. Overall, this study demonstrates GE-LP as a new formulation with ease of preparation, sustained release, and high brain targeting, which has significant development prospects on CIRI; this is expected to improve the efficacy of GE and reduce the frequency of administration.

A transferosome-loaded bigel for enhanced transdermal delivery and antibacterial activity of vancomycin hydrochloride

Transdermal drug delivery is an attractive route of administration relative to other routes as it offers enhanced therapeutic efficacy. However, due to poor skin permeability of certain drugs, their application in transdermal delivery is limited. The ultra-deformable nature of transferosomes makes them suitable vehicles for transdermal delivery of drugs that have high molecular weights and hydrophilicity. However, their low viscosity, which leads to low contact time on the surface of the skin, has restricted their application in transdermal delivery. Therefore, this study aimed to deliver transferosomes loaded with a highly water-soluble and high molecular weight vancomycin hydrochloride (VCM-HCl) via a bigel for systemic delivery and treatment of microbial infections. VCM-HCl-loaded transferosomal formulations (TNFs) were prepared using a reverse-phase evaporation method and then loaded into a bigel. Both the TNFs and TNFs-loaded bigel (TNF-L-B) were characterized by a range of in vitro and ex vivo techniques. TNFs and TNF-L-B were tested for biosafety via the MTT assay and found to be biosafe. Prepared TNFs had sizes, zeta potential and entrapment efficiency of 63.02 ± 5.34 nm, −20.93 ± 6.13 mV and 84.48 ± 1.22% respectively. VCM-HCl release from TNF-L-B showed a prolonged release profile with 39.76 ± 1.6% after 24hrs when compared to bare VCM-HCl loaded in the bigel (74.81 ± 8.84%). Ex-vivo permeation of prepared TNF-L-B showed a higher permeation flux of 0.56 µg/cm2/h compared to the bare VCM-HCl-loaded bigel of 0.23 µg/cm2/h, indicating superior permeation and bioavailability of the drug. Additionally, the prepared TNF-L-B demonstrated improved antimicrobial activity. The TNF-L-B showed minimum inhibitory concentrations (MIC) of 0.97 μg/ml against Staphylococcus aureus (SA) and 1.95 μg/ml against methicillin-resistant SA (MRSA), which were 2-fold lower MIC values than the bare drug. The time-kill assay showed that both TNFs and TNF-L-B systems caused a 5.6-log reduction (100%) in MRSA compared to bare VCM-HCl after 24 hrs of incubation. Furthermore, as opposed to the bare VCM-HCl solution, the degree of biofilm reduction caused by TNFs (55.72%) and TNF-L-B (34.58%) suggests their dominance in eradicating MRSA biofilm. These findings indicate that TNF-L-B is a promising system for transdermal delivery of hydrophilic and high molecular weight drugs.

Identification of Novel Ligands for Targeted Antifibrotic Therapy of Chronic Pancreatitis.

PurposeChronic pancreatitis (CP) is an inflammatory disorder of the pancreas that leads to impaired pancreatic function. The limited therapeutic options and the lack of molecular targeting ligands or non-serum-based biomarkers hinder the development of target-specific drugs. Thus, there is a need for an unbiased, comprehensive discovery and evaluation of pancreatitis-specific ligands.MethodsThis study utilized a computational-guided in vivo phage display approach to select peptide ligands selective for cellular components in the caerulein-induced mouse model of CP. The identified peptides were conjugated to pegylated DOPC liposomes via the reverse-phase evaporation method, and the in vivo specificity and pharmacokinetics were determined. As proof of concept, CP-targeted liposomes were used to deliver an antifibrotic small molecular drug, apigenin. Antifibrotic effects determined by pancreatic histology, fibronectin expression, and collagen deposition were evaluated.ResultsWe have identified five peptides specific for chronic pancreatitis and demonstrated selectivity to activated pancreatic stellate cells, acinar cells, macrophages, and extracellular matrix, respectively. MDLSLKP-conjugated liposomes demonstrated an increased particle accumulation by 1.3-fold in the inflamed pancreas compared to the control liposomes. We also observed that targeted delivery of apigenin resulted in improved acini preservation, a 37.2% and 33.1% respective reduction in collagen and fibronectin expression compared to mice receiving the free drug, and reduced oxidative stress in the liver.ConclusionIn summary, we have developed a systematic approach to profile peptide ligands selective for cellular components of complex disease models and demonstrated the biomedical applications of the identified peptides to improve tissue remodeling in the inflamed pancreas.

Edible packaging coating of encapsulated thyme essential oil in liposomal chitosan emulsions to improve the shelf life of Karish cheese

Edible packaging materials of encapsulated essential oils in biopolymers have been investigated to provide an effective and safe approach for food preservation. In this study, chitosan-based emulsions made of liposomes loaded with thyme essential oil (TEO) were investigated to extend the shelf-life of Karish cheese. Liposomal chitosan emulsions were prepared via reverse-phase evaporation method and its macrostructure was demonstrated. Chitosan-based emulsions with TEO/liposomes, prepared by 2% wt/v chitosan solutions, are stable over 2 months. GC/MS analysis of TEO showed that thymol and p-cymene are the major compounds with 30 and 13.7% respectively.Antimicrobial activities were assessed via visible microbial growth method and total bacteria counts of mesophilic, phsychrotrophic bacteria, yeast and mould over 4 weeks. Visible microbial growth test showed an explicit microbial growth, by the second week, for all cheese samples that are not coated or coated with chitosan solutions. Cheese samples coated with chitosan containing TEO 1 and 2 % v/v stayed safe with accepted microbial counts till the end of third week. However, samples coated with liposomal chitosan emulsions encapsulated TEO 1and 2% v/v remained in acceptable appearance and microbial counts up to 4 weeks. Coatings showed neutral effects on moisture content, pH and titratable acidity.

Osmotically balanced, large unilamellar liposomes that enable sustained bupivacaine release for prolonged pain relief in in vivo rat models

To efficiently prolong analgesic effects, we developed osmotically balanced, large unilamellar liposomes (~ 6 μm in diameter) in which highly concentrated bupivacaine (up to 30 mg/mL) was encapsulated, and their sustained bupivacaine release was highly effective in relieving postoperative pain over 24 h in a rat model. Our reverse-phase evaporation method based on non-toxic alcohol, ethanol, enabled simple and cost-effective production of bupivacaine-loaded liposomes, of which osmotic pressure was readily balanced to improve the structural stability of the enlarged unilamellar liposomes along with extension of their shelf life (> a month). The in vitro release profile verified that the release duration of the bupivacaine-loaded liposomes extended up to 6 days. For the in vivo study, male Sprague–Dawley rats were used for the incisional pain model, simulating postoperative pain, and the mechanical withdrawal threshold (MWT) was measured using a von Frey filament. Compared to the control group that received intraplantar administration of normal saline, the group of liposomal bupivacaine showed that the initially increased MWT gradually decreased up to 24 h, and importantly, the analgesic effect of the liposomal bupivacaine was maintained 6 times longer than that of bupivacaine only, proving the potential of effective long-acting anesthetics.

Transdermal Delivery of Lidocaine-Loaded Elastic Nano-Liposomes with Microneedle Array Pretreatment

This study aimed to improve the transdermal delivery of lidocaine hydrochloride (LidH) using elastic nano-liposomes (ENLs) and microneedle (MN) array pretreatment. LidH-containing ENLs were prepared using soybean phosphatidylcholine and cholesterol, with Span 80 or Tween 80, using a reverse-phase evaporation method. The ENL particle size, stability, and encapsulation efficiency (EE) were characterized and optimized based on the component ratio, pH, and type of surfactant used. In vitro transdermal diffusion study was performed on MN-pretreated mouse skin using Franz diffusion cells. The anesthetic effects of LidH in various formulations after dermal application were evaluated in vivo in rats by measuring the tail withdrawal latency after photothermic stimulation. Stable LidH-loaded Tween 80 or Span 80 ENLs were obtained with particle sizes of 115.8 and 146.6 nm and EEs of 27% and 20%, respectively. The formulations did not exert any cytotoxicity in HaCaT cells. Tween 80 and Span 80 ENL formulations showed enhanced LidH delivery on pretreated mice skin in vitro and prolonged the anesthetic effect in vivo compared to that by LidH application alone. LidH-loaded ENLs applied to MN-pretreated skin can shorten the onset time and prolong the anesthetic effect safely, which merits their further optimization and practical application.

Repetitive drug releases from light-activatable micron-sized liposomes.

In this work, a novel light activatable micron-sized liposomal drug carrier that has a unique capability to release drug repetitively in proportion to the cycle number of short irradiation (5 s) of near-infrared (NIR) pulsed laser is reported. We synthesized methotrexate (MTX)-loaded liposomes based on a modified reverse-phase evaporation method. Gold nanorods (AuNR) were attached to the liposomal surfaces, enabling the liposomes to release drug under short NIR irradiation via the photothermal effect. The concentrations of methotrexate (MTX) released from the liposomes were 10.6, 29.8, 43.7 and 65.9 μg/mL after one, two, three or four NIR laser cycles (1.1 W at 1064 nm, 5 s per cycle), respectively. The current finding will provide possible solution to the previously reported inconsistency in drug release from light activatable liposomal drug carriers at each activation cycle. The repeatability of drug release described in this work is believed to be due to reversible nature of the liposomes. The liposomes release drug via lipid bilayer melting when irradiated by laser due to gold nanorods' plasmonic heat on the lipid bilayer surface and quickly regain their original structure once the laser source is removed. We provided evidence of the reversible liposomal structures by monitoring the change of number densities of liposomes using a microelectrode sensor with different laser irradiation durations and powers. We also assessed the micron-sized liposome with respect to long-term stability, drug encapsulation efficiency, and drug-releasing efficiency, demonstrating the possibility of utilizing these liposomes as long-term drug delivery vehicles for various drugs.