Vesicle Size Research Articles

Box–Behnken design for the development of fluconazole-loaded classical ethosomes

Introduction: Ethosomes are soft and flexible vesicles mainly composed of phospholipids, ethanol and water. The presence of a high amount of ethanol ensure deeper drug penetration; however, an optimal formulation is necessary. This study aims to develop and characterize Fluconazole loaded classical ethosomes using Box-Behken design, in order to achieve to an optimal formulation having a minimal vesicle size, low polydispersity index, high zeta potential and good entrapment efficiency (% EE). Methods: Fluconazole ethosomes were prepared using cold method and tested for vesicle size, polydispersity index, zeta potential and EE%. Box-Behken design was created using Design Expert® Software, where the impact of sonication time and amount of ethanol and soybean lecithin on resulting formulation were investigated. Results: It was determined that increasing the concentration of ethanol up to an optimized limit reduces vesicle size and improves % EE. It was also observed that soybean lecithin concentrations affected positively vesicle size but negatively % EE. Whereas sonication time had an inverse effect both on, vesicle size and EE%. All prepared formulations showed a low polydispersity index and a good zeta potential indicating homogeneity and high stability. Therefore, the optimal formulation had % EE of 80.05±0.306 % and vesicular size of 226.501±5.34 nm with polydispersity index of 0.487±0.0078. Conclusion: In summary, using Box-Behnken design can enhance the understanding of the correlations between the variables involved in ethosome formation and their effects on vesicle size, polydispersity index and % EE. The optimal formulation obtained can be incorporated into drug delivery systems to enhance skin permeation and antifungal activity.

Optimization of the experimental design parameters for synthesis of Fluconazole loaded transethosomes as nano-based antifungal vesicles

Introduction: Antifungal drugs formulated in conventional pharmaceutical forms are not fully effective due to various factors. New approaches have focused on transdermal delivery drugs, including transethosomes, where the mixture of ethanol and surfactant allows a deeper drug skin’s penetration. Formulation parameters and process variables can make their optimization a considerable challenge. This study aimed to formulate Fluconazole-loaded transethosomes using a full-factorial design with the goal of optimizing formulation and process variables. Method: Fluconazole transethosomes were developed using the cold Method. A 21,31 full-factorial design was created by Design Expert® Software, where the impact of surfactant’s type and soy lecithin to surfactant ratio on resulting formulation were investigated. The formulations were tested for vesicle size, polydispersity index, zeta potential and entrapment efficiency. Results: Formulations containing Tween®80 presented the smaller particle sizes and showed a considerable entrapment efficiency for Fluconazole, they were more homogenous and highly stable compared to those prepared with Span®80. The optimized soy lecithin to surfactant ratio of 90:10 with Tween®80 was deemed apt for the synthesis of transethosomes giving the optimal formulation with a small particle size (300.2±5.57 nm), a low PDI (0.203±0.004), a good zeta potential (−31.75±0.68 mV) and a high entrapment efficiency (88.11±0.74 %). Conclusion: This study enabled the in-depth identification and optimization of the key factors involved in the experimental process, such as the type of surfactant used and the soybean lecithin-to-surfactant ratio. To ensure safety and effectiveness in use, this work provides the perspective of continuing the study by evaluating the antifungal activity, long-term stability and safety of Fluconazole-loaded transethosomes.

Modulation of chondroprotective hyaluronic acid and poloxamer gel with Ketoprofen loaded transethosomes: Quality by design-based optimization, characterization, and preclinical investigations in osteoarthritis

Osteoarthritis (OA) is a chronic joint disease that results in biomechanical and morphological changes that contribute to cartilage degradation. Ketoprofen (KP), used in the treatment of OA, is a selective inhibitor of cyclooxygenase-2 (COX-2). Topical administration of KP bypasses gastric irritation as well as first-pass metabolism and increases localized delivery. The research intricates fabrication and optimization of KP-loaded transethosomes (KP-TEs) via Taguchi orthogonal array design and Central composite design (CCD). The optimized KP-TEs depicted an average vesicle size of 110.0 ± 1.70 nm, poly dispersibility index (PDI) of 0.103 ± 0.01, zeta potential −6.08 ± 0.27 mV, and conductivity of 0.049 ± 0.0001 mS/cm. The optimized KP-TEs were loaded in composite hyaluronic acid (HA) and poloxamer 407 (Px407) for an improvement of osteotrophic and chondroprotective transethosomal gel. The drug content of KP-TEs-HA/Px407 gel was found to be 90.08 ± 1.25 %. Preclinical research has been carried out by using the monosodium iodoacetate to develop model for osteoarthritis in male wistar rats. The X-ray imaging of KP-TEs-HA/Px407 gel treated group showed intact meniscus, healthy articular joint, and normal synovial lining same as the healthy control group. The IL − 1β IL-6, IL-22, TNF-α, and IL-10, levels, X-ray imaging, and studies on histopathology demonstrated the effectiveness of transethosomal gel in reducing pain and inflammation.

Box-Behnken Design Optimization of Captopril-Loaded Transferosomes: Formulation and Characterization.

This study aimed to overcome the limitations of oral delivery and enhance the permeation of Captopril (CPL) by developing transferosomes. Transferosomes encapsulating CPL were prepared using a thin film hydration method. Seventeen formulations were prepared, varying Soya lecithin, Tween-20, and sonication speed. The formulations were evaluated for vesicle size (VS), polydispersity index (PDI), and entrapment efficiency (EE%). The optimized formulation’s discharge profile was compared with that of the CPL suspension. Transferosomes exhibited VS ranging from 244 to 376 nm and EE% from 65 to 91%, with zeta potentials ranging from -51 to -26 MV. In-vitro and ex-vivo permeation studies demonstrated superior drug permeation for transferosomal formulations compared to plain CPL suspension. CPL transferosomes represent a promising delivery system for prolonged and controlled drug discharge, offering potential improvements in hypertension management.

Creation and Expansion of Bioadhesive Transdermal Gel of Levobupivacaine Loaded Nanoparticles for Enhancement of Anesthetic Effect.

The present research work aimed to prepare a bioadhesive gel containing Levobupivacaine-loaded nanoparticles (NPs) to improve local anesthesia as transdermal patches were patient-friendly and easy to therapy. This study focuses on developing a The NPs were created using the ionotropic gelation method and assessed for particle charge, vesicle size and its distribution, and surface morphology. The improved NPs were incorporated into a gel and evaluated for their physicochemical assets. Among the NPs, NP4 was identified as the best based on its physicochemical properties. The NG-6 bioadhesive gel formulation stood out as the top gel among those tested. The NG-6 gel exhibited superior skin permeation ended 14 hours compared to other NPs. This bioadhesive transdermal gel with Levobupivacaine nanoparticles offers a promising approach to enhancing anesthetic effects.

A one-platform comparison study of brinzolamide-loaded liposomes, niosomes, transfersomes, and transniosomes for better management of glaucoma

Ocular drug delivery presents significant challenges due to various anatomical and physiological barriers. Ultradeformable vesicles have emerged as better vesicular systems for achieving deeper corneal penetration and enhanced ocular bioavailability. This research aims to develop a hybrid vesicular system with improved deformability and compare it to conventional vesicular carriers. The ultradeformable vesicle, termed “transniosomes,” is a combination of niosomes, liposomes, and transfersomes, loaded with brinzolamide as model drug. The brinzolamide-loaded transniosomes (BRZ-TN) was formulated and compared with different vesicular systems through in vitro, ex vivo, and in vivo characterizations. The optimized BRZ-TN demonstrated a vesicle size of 112.06 ± 4.13 nm and an entrapment efficiency of 93.63 ± 0.30 %. With a deformability index of 6.405, the BRZ-TN exhibited a permeability of 86.68 ± 2.51 % over 10 h, which is approximately 1.3 times higher than other conventional vesicular systems. Additionally, the BRZ-TN showed a drug flux of 0.247 ± 0.01 mg/cm2/h and an apparent permeability of 0.09 ± 1.21 cm/s. Pre-clinical experiments confirmed the superiority of the optimized BRZ-TN, achieving a 37 % reduction in intraocular pressure (IOP), post 6hr of administration, indicating its prolonged therapeutic effect and improved ocular bioavailability. The findings of this study suggest that transniosomes are superior to other carriers and hold great promise as a nanocarrier for ocular drug delivery.

Development and Evaluation of Voriconazole Loaded Invasomes Gel for Enhanced Antifungal Activity.

Although it has limited solubility and poor permeability to the skin, voriconazole (VRC) is a viable choice for the topical treatment of fungal infections. Owing to these constraints, treating the inflection requires several injections over an extended period. The goal of this work was to produce a VRC invasome gel with improved topical antifungal activity. The Box-Behnken design (BBD) program was utilized to optimize the IVS after it was created using the thin-film hydration process. The optimized invasome formulation through BBD has 159.9 nm of vesicle size, 68.58% of entrapment efficiency, and 23.5 mV of zeta potential. The spherical shape of the vesicle was revealed using scanning microscopy. According to FTIR spectra, the medication and polymers do not interact. The optimized invasomal VRC gel exhibited an optimum of 345 to 589 cp. Ex-vivo permeation studies of IG4 exhibited a higher flux of 0.168 as compared to pure voriconazole. An antimicrobial study was accepted to check the antimicrobial efficiency of voriconazole gel (IG4). The study confirmed a good zone of inhibition of the fungus infection (C. albicans). The voriconazole invasome’s potential diffusion and antibacterial efficacy are demonstrated here. Invasomal gel was found to be an effective carrier and a desirable strategy for improving the topical distribution of VRC to treat fungal infections.

Improved Topical Delivery of Sorafenib-Meglumine Antimoniate: Elastic Nano-Liposomal Formulation for the Treatment of Cutaneous Leishmaniasis

Background: Cutaneous leishmaniasis (CL) is a widespread parasitic disease with significant health and social impacts. Current systemic treatments have severe side effects, highlighting the need for effective topical alternatives.Objective: This study aimed to develop and evaluate the effectiveness of sorafenib (SF) and meglumine antimoniate (MM) dual-loaded transferosomes (TRs) for topical treatment of CL.Methods: TRs were prepared using a thin film hydration method and incorporated into a carbopol gel. The formulations were characterized for vesicle size, zeta potential, entrapment efficiency, and deformability index. In vivo and ex vivo skin permeation studies were conducted, along with anti-leishmanial efficacy testing on an intramacrophage amastigote model using BALB/c mice.Results: The TRs exhibited a vesicle size of 186.1 ± 65.89 nm, zeta potential of -27.9 mV, and entrapment efficiency of 71.7 ± 3.9% for MM and 78.6 ± 4.2% for SF. Ex vivo studies showed enhanced skin permeation with cumulative permeation of 327.6 ± 29.4 µg/cm² for MM and 291.6 ± 28.3 µg/cm² for SF. In vivo results indicated a significant reduction in lesion size (0.1 ± 0.12 mm) and parasite load (2.7 ± 0.3 log scale).Conclusion: The MM-SF dual-loaded TRs demonstrated effective topical delivery and therapeutic potential for CL, providing a promising alternative to systemic treatments.

Design and Characterization of Liposomal-Based Carriers for the Encapsulation of Rosa canina Fruit Extract: In Vitro Gastrointestinal Release Behavior.

The increasing demand for natural compounds as an alternative to synthetic antioxidants and conservans has led to the utilization of secondary plant metabolites in the food industry, as these bioactive compounds possess great antioxidative and antimicrobial properties without side effects on human health. Despite this, the sensitivity of plant-derived compounds is a restrictive factor in terms of their full potential. The current research aimed to characterize rosehip-fruit-extract-loaded liposomes (non-treated and UV-irradiated) in terms of their density, surface tension, viscosity, chemical composition (FTIR and HPLC analyses), and thermal behavior. In the storage stability study, the vesicle size, polydispersity index (PDI), zeta potential, conductivity, and mobility of the liposomes were monitored. FTIR analysis confirmed that the plant compounds were successfully loaded within the carrier, while no chemical reaction between the rosehip fruit extract and phospholipids was detected. The results of the HPLC analysis evidence the high potential for liposomal encapsulation to protect sensitive bioactives in the rosehip fruit extract from the degrading effect of UV irradiation. The size of the rosehip-fruit-extract-encapsulated liposomes increased on the seventh day of storage from 250 nm to 300 nm, while the zeta potential values were between -21 mV and -30 mV in the same period and further stabilized over 60 days of monitoring. In Vitro release studies in water and simulated gastrointestinal fluids showed that the presence of enzymes and bile salts (in intestinal fluid) enhanced the rosehip-polyphenol permeability from liposomes (70.3% after 6 h) compared with their release in water after 24 h and in gastric fluid after 4 h (38.9% and 41.4%, respectively). The obtained results indicate that the proliposome method was an effective method for rosehip fruit extract liposomal encapsulation and for the delivery of these plant-derived bioactives in foods.

Changes in the Release of Endothelial Extracellular Vesicles CD144+, CCR6+, and CXCR3+ in Individuals with Acute Myocardial Infarction.

Acute myocardial infarction (AMI) results from vulnerable plaque rupture, causing ischemic cardiomyocyte necrosis and intense inflammation. Paradoxically, this inflammation releases factors that aid heart repair. Recent findings suggest a role for extracellular vesicles (EVs) in intercellular communication during post-AMI cardiac repair. However, EVs' tissue origin and chemokine profile in the blood of patients with AMI remains unclear. This study characterized the tissue origin and chemokine receptor profile of EVs in the coronary and peripheral blood of patients with AMI. The results reveal that vesicles isolated from coronary and peripheral blood plasma are enriched in tetraspanin (CD9) and express CD81+, CD90+, and CD144+. The vesicle size ranged between 145 and 162 nm, with the control group exhibiting smaller vesicles (D10) than the AMI group. Furthermore, all vesicles expressed CCR6 and CXCR3, whereas a small percentage expressed CCR4. In addition, a decrease in CXCR3 and CCR6 expression was observed in coronary and peripheral AMI blood vesicles compared with the control; however, no difference was found between AMI coronary and AMI peripheral blood vesicles. In conclusion, our study demonstrates, for the first time, changes in the number of extracellular vesicles expressing CD144+, CXCR3, and CCR6 in the peripheral circulation of patients with AMI. Extracellular vesicles present in the circulation of patients with AMI hold excellent promise as a potential diagnostic tool.

Stress increases sperm respiration and motility in mice and men

Semen quality and fertility has declined over the last 50 years, corresponding to ever-increasing environmental stressors. However, the cellular mechanisms involved and their impact on sperm functions remain unknown. In a repeated sampling human cohort study, we identify a significant effect of prior perceived stress to increase sperm motility 2-3 months following stress, timing that expands upon our previous studies revealing significant stress-associated changes in sperm RNA important for fertility. We mechanistically examine this post-stress timing in mice using an in vitro stress model in the epididymal epithelial cells responsible for sperm maturation and find 7282 differentially H3K27me3 bound DNA regions involving genes critical for mitochondrial and metabolic pathways. Further, prior stress exposure significantly changes the composition and size of epithelial cell-secreted extracellular vesicles that when incubated with mouse sperm, increase mitochondrial respiration and sperm motility, adding to our prior work showing impacts on embryo development. Together, these studies identify a time-dependent, translational signaling pathway that communicates stress experience to sperm, ultimately affecting reproductive functions.

Formulation, optimization and evaluation of ibuprofen loaded menthosomes for transdermal delivery

The study aimed to improve the transdermal permeation of IBU utilizing menthosomes as a vesicular carrier. IBU-loaded menthosomes were formulated by thin film hydration & optimized using 23 factorial designs (Design Expert® version 13 software). In vitro &ex vivo skin permeation analysis of IBU-encapsulated menthosomes was studied across the rat skin sample. In vivo pharmacodynamic activity was studied in an arthritis rat model. The optimized IBU-loaded menthosomes exhibited an optimum vesicle size of 214.2 ± 2.96 nm, Zeta potential of −21.1 ± 2.72 mV, (PDI) Polydispersity Index of 0.267 ± 0.018 with Entrapment efficiency (EE%) of 78.7 ± 2.73 %. The in vitro &ex vivo skin penetration study displayed enhanced release of drug of 77.02 ± 1.0 % and 40.91 ± 0.81 % respectively, compared to conventional liposomes. In vivo pharmacodynamic study on carrageenan-induced paw edema in Wistar albino rats demonstrated superior anti-inflammatory activity of the optimized IBU-encapsulated menthosomes (**p < 0.01) and effective inhibition of paw edema (34.04 ± 0.155 %). The formalin test indicated a significant analgesic effect of optimized formulation during the chronic phase of analgesia (*p < 0.05) compared to the control group. Thus, the developed and optimized drug-loaded menthosomes could serve as a suitable vesicular delivery carrier in enhancing the transdermal delivery of other NSAID drugs.

Statistical Optimization and Characterization of Nimodipine Transferosomes

Background: Nimodipine is a vasodilator that is used for the prevention of cerebral vasospasm after subarachnoid hemorrhage. The oral and intravenous administration of the drug is associated with undesirable side effects. So, transdermal delivery using lipid-based nanovesicles, also known as transferosomes, can be thought of as an alternative. Objective: To optimize the formulation of transferosomes using the statistical design of experiments, with the aim of obtaining the most suitable transferosomes for the transdermal delivery of nimodipine. Methods: In the Box-Behenken statistical design, the independent variables were the quantities of nimodipine, phospholipon 90%, and sodium deoxycholate, while the dependent variables were the vesicle size, entrapment efficiency for nimodipine and its flux through the rat's skin. The optimized formulation was characterized through transmission electron microscopy and the deformability index. Results: The optimized formulation of transferosomes suggested by the software consisted of 30 mg nimodipine, 150 mg phospholipon 90% and 15 mg sodium deoxycholate. The resulted values were 248 nm for vesicles size, 81% for entrapment, and 476 μg/cm2/h. Under transmission electron microscopy, transferosomes appeared as vesicles, with a 0.98 deformability index for the optimized formula. Conclusions: Nimodipine can be formulated as transferosomes and efficiently applied for transdermal delivery.

A central composite design-based targeted quercetin nanoliposomal formulation: Optimization and cytotoxic studies on MCF-7 breast cancer cell lines

This study aimed to enhance the efficacy of quercetin (QT) by formulating it into a liposomal drug delivery system utilizing the concept of central composite design. The drug:lipid ratio, cholesterol concentration, and sonication time were selected as independent variables in the study. The vesicle and percentage entrapment efficiency were selected as the dependent variables. Quercetin nanoliposomes (QT-NLs) were prepared via a combination of ethanol injection and thin film hydration. The vesicle size and entrapment efficiency of all formulations were within the ranges of 100 nm and >80 %, respectively. The zeta potential value indicated the stability of the optimized formulation. The contour plots were used to select the desired batch range. SEM studies revealed an imperfect crystalline morphology without any unwanted agglomeration. MTT assays on VERO cell lines indicated the safety of the developed formulation. MTT assays of MCF-7 cells revealed IC50 values of 5.8 μM and 7.9 μM for QT-NLs and QT, respectively. In our study, the optimized formulation exhibited late and early apoptosis and necrosis when used to treat MCF-7 cells. S and G2/M cell cycle phases of MCF-7 cell arrest were confirmed by the cell cycle report. At sub-G0/G1 phase, 2.10 ± 1.1 %; G0/G1 phase, 34.13 ± 1.9 %; S phase, 34.55 ± 0.98 %; and G2/M phase, 26.24 ± 1.7 % of cell arrest were observed. The results demonstrated the effectiveness of the proposed design for the development of corn starch-coated QT-NLs and their activity in breast cancer cell lines.

How the designed processing parameters affect the liquid mixture density and viscosity of the tretinoin-loaded niosomes at different temperatures?

The current study was conducted to present novel thermophysical data on tretinoin-loaded niosomes paired with a combination of span 60 and tween 80. Measurements were carried out to analyze the liquid mixture density and viscosity of the mentioned multilayered structures for the first time, with consideration given to the diverse molecular weights of surfactants and various stabilizers at different temperatures. Through the application of equations of state, this study has the ability to set the stage for thermodynamic modeling of solutions that involve niosomes, presenting a promising avenue for further research. So, tretinoin-loaded formulations were prepared by investigating the effects of different co-surfactants, including cholesterol or dodecanol, as well as the impact of surfactant molecular weight limited to 650.525–1090.175 g mol−1. This novel investigation was conducted to assess the superior stabilizing capabilities of dodecanol in comparison to cholesterol, with a specific emphasis on optimized vesicle size, highest incorporation efficiency, and lowest zeta potential. In particulars, the response surface methodology (RSM) was applied to optimize the operative factors and the number of experiments. The experimental evidence clearly indicates that the use of dodecanol in the manufacturing process significantly improves the stability of niosomes, while the inclusion of cholesterol leads to higher liquid mixture density and viscosity in the prepared niosomes.

Design, development, and optimization of sumatriptan loaded ethosomal intra-nasal nanogel for brain targeting

Background: Sumatriptan is one of the most essential drugs for treating migraine. However, dosage-related side effects are still a worry despite its 14 % oral bioavailability and recurrence of migraine-associated diseases. Methodology: The fundamental focus of the study is to develop the sumatriptan intra-nasal nano-ethsomal gel by film hydration technique with the aid of QbD principles that govern the varied compositions and blends of polymers like HPMC K100M and Phospolipon 90G to develop a sustained release dosage form. Results and discussion: The preliminary FT-IR and DSC studies revealed no interactions between the drug and their physical mixtures. The present study considered three observable responses: vesicle size, zeta potential, and percent drug release after 24 h, taken into consideration during the optimization of the ethosomal formulations utilizing 32 central composite designs (CCD). The vesicle size (122.23 nm), zeta potential (-40.2 mV), and drug release percentage (92.61 %) for all formulations were seen in the F12 batch after 24h. The p-XRD and SEM studies indicated that the nano-ethosomal gel was stable. The stability studies indicated the preparation of a more stable formulation for the parameters under the study protocol. Conclusion: Using a novel intra-nasal brain targeting approach by adapting the film hydration technique, the current issues might be addressed, and the drug's duration of residence at the absorption site uptake substantially increase. To efficiently modify the drug's residence through the intra-nasal route, this work focuses on developing a nano-ethosomal gel loaded with sumatriptan.

Novel embelin-loaded transniosomes for topical delivery: comprehensive exploration of in vitro, ex vivo and dermatokinetic assessment for anti-cancer activity.

This study systematically designed and optimised a transniosomal formulation containing embelin for skin cancer management. The transniosomes were developed using a rotary evaporation method and then optimised using a Box-Behnken design. The optimized embelin-loaded transniosomes (Opt-EMB-TNs) exhibited a vesicle size of 149.01 nm, polydispersity index of 0.184, a zeta potential of -21.14 mV, an entrapment efficiency of 75.6 ± 0.65%, drug loading of 3.36 ± 0.03% and drug release of 80.88 ± 2.55%. The antioxidant potential of Opt-EMB-TNs was found to be 88.54% when compared to standard ascorbic acid. Dermatokinetic studies showed a greater drug deposition in targeted skin areas with Opt-EMB-TN gel compared to the embelin conventional gel (EMB-CF gel). In addition, the penetration depth study of the skin sample revealed that the transniosomal gel containing rhodamine B dye exhibited higher penetration than that of the rhodamine B dye containing hydroalcoholic solution. The efficacy of Opt-EMB-TNs for skin cancer was confirmed by cytotoxicity assay against the B16F10 melanoma cell line. The study concluded that the Opt-EMB-TN gel formulation is a promising and effective topical treatment for skin cancer, demonstrating significant potential for further development and clinical application. © 2024 Society of Chemical Industry.

A glance into factors affecting the possible combined entrapment of curcumin and methylene blue into niosomal formulations as a potential anticancer therapy

Niosomes are non-ionic surfactant vesicles that has successfully attracted a great deal of attention over the last few decades. The best ratio between main components is the key to creating the optimum formulations with substantial loading capacity. Therefore, this study investigated formulation factors that could affect the entrapment of two compounds with different solubilities, namely Methylene blue (MB) and curcumin (CUR) as model hydrophilic and hydrophobic compounds, respectively. The aim was to propose an optimum formula to encapsulate both compounds as a potential hybrid anticancer therapy. The factors with potential influence on the entrapment efficiency (EE) included the type of the non-ionic surfactants (Span 60 versus Span 65), cholesterol to surfactant ratio, and the concentrations of the co-surfactant (Cremophor RH40). Niosomes were prepared by thin film hydration technique and downsized using probe sonicator. The morphology, vesicle size and polydispersity index (PDI) of the prepared vesicles were inspected. The data showed the superiority of Span 65 over Span 60 in terms of higher encapsulation efficiency for MB and CUR. The results reflected positive impact of cholesterol and Cremophor RH40 concentration on EE of the two compounds. The optimum composition of Span 65:cholesterol:Ccremophor RH40 was at the mol% ratio of 45:45:10, respectively, with EE of 91.19 % for CUR alone, 51.70 % for MB alone, and 45.32 %/84.40 % for combined MB/CUR loaded formulations. The vesicle size of the formulations after probe sonication, fall into the range of 100–200 nm, ideal for parenteral delivery to the target sites.

Presynaptic quantal size enhancement counteracts post-tetanic release depression.

Repetitive synaptic stimulation can induce different forms of synaptic plasticity but may also limit the robustness of synaptic transmission by exhausting key resources. Little is known about how synaptic transmission is stabilized after high-frequency stimulation.In the present study, we observed that tetanic stimulation of the Drosophila neuromuscular junction (NMJ) decreases quantal content, release-ready vesicle pool size and synaptic vesicle density for minutes after stimulation. This was accompanied by a pronounced increase in quantal size. Interestingly, action potential-evoked synaptic transmission remained largely unchanged. EPSC amplitude fluctuation analysis confirmed the post-tetanic increase in quantal size and the decrease in quantal content, suggesting that the quantal size increase counteracts release depression to maintain evoked transmission. The magnitude of the post-tetanic quantal size increase and release depression correlated with stimulation frequency and duration, indicating activity-dependent stabilization of synaptic transmission. The post-tetanic quantal size increase persisted after genetic ablation of the glutamate receptor subunits GluRIIA or GluRIIB, and glutamate receptor calcium permeability, as well as blockade of postsynaptic calcium channels. By contrast, it was strongly attenuated by pharmacological or presynaptic genetic perturbation of the GTPase dynamin. Similar observations were made after inhibition of the H+-ATPase, suggesting that the quantal size increase is presynaptically driven. Additionally, dynamin and H+-ATPase perturbation resulted in a post-tetanic decrease in evoked amplitudes. Finally, we observed an increase in synaptic vesicle diameter after tetanic stimulation. Thus, a presynaptically-driven quantal size increase, likely mediated by larger synaptic vesicles, counterbalances post-tetanic release depression, thereby conferring robustness to synaptic transmission on the minute time scale. KEY POINTS: Many synapses transmit robustly aftersustained activity despite the limitation of key resources, such as release-ready synaptic vesicles. We report robust synaptic transmission after sustained high-frequency stimulation of the Drosophila neuromuscular junction despite a reduction in release-ready vesicle number. An increased postsynaptic response to individual vesicles, likely driven by an increase in vesicle size due to endocytosis defects, stabilizes synaptic efficacy for minutes after sustained activity. Our study provides novel insights into the mechanisms governing synaptic stability after sustained neural activity.

HSPiP and QbD oriented optimized stearylamine-elastic liposomes for topical delivery of ketoconazole to treat deep seated fungal infections: In vitro and ex vivo evaluations

The study explored stearylamine containing cationic elastic liposomes to improve topical delivery and efficacy of ketoconazole (KETO) to treat deeply seated fungal infections. Stearylamine was used for dual functionalities (electrostatic interaction and flexibility in lipid bilayer). Hansen solubility program (HSPiP) estimated Hansen solubility parameters (HSP) based on the SMILE file and structural properties followed by experimental solubility study to validate the predicted values. Various formulations were developed by varying phosphatidylcholine and surfactants (tween 80 and span 80) concentration. To impart cationic properties, stearylamine (1.0 %) was added into the organic phase. Using quality by design (QbD) method, we optimized the formulations and evaluated for vesicle size, polydispersity index, zeta potential, morphology (scanning electron microscopy), in vitro drug release (%), and ex vivo permeation profiles. Result showed that there is a good correlation (0.65) between HSPiP predicted and actual experimental solubility of KETO in water, chloroform, S80, and tween 80. Spherical OKEL1 showed an established correlation between the predicted and the actual formulation parameters (size, zeta potential, and polydispersity index) (259 nm vs 270 nm, +2.4 vs 0.21 mV, and 0.24 vs 0.27). OKEL1 was associated with the highest value of %EE (83.1 %) as compared to liposomes. Finally, OKEL1 exhibited the highest % cumulative permeation (49.9 %) as compared to DS (13 %) and liposomes (25 %). Moreover, OKEL1 resulted in 4-fold increase in permeation flux as compared to DS which may be attributed to vesicular mediated improved permeation and gel based compensated trans epidermal water loss in the skin. The drug deposition elicited OKEL1 and OKEL1-gel as suitable carriers for maximum therapeutic benefit to treat deeply seated fungal infections.