Lipid Film Hydration Method Research Articles

Engineering of exosome-liposome hybrid-based theranostic nanomedicines for NIR-II fluorescence imaging-guided and targeted NIR-II photothermal therapy of subcutaneous glioblastoma

Exosome-liposome hybrid-based vehicles (ELV) are promising carriers for cancer treatment, but there are rare efficient theranostic probes to label their lipid bilayer membrane for precisely tracing biodistribution and execute potent therapy. As both fluorescence imaging and photothermal therapy in the second near-infrared window (NIR-II) has intrinsically deep penetration and high efficacy to ablate tumors, herein the design and synthesis of lipophilic NIR-II cyanine dyes with strong donor strength is reported to label lipid bilayer membrane of ELV for NIR-II fluorescence image-guided and targeted NIR-II photothermal treatment of subcutaneous glioblastoma. Via lipid film hydration and subsequent extrusion method, the synthesized ELV (NIR-C12-EL) is formulated with NIR-C12 labeling, cyclic arginylglycylaspartic acid decoration, liposomal PEGylation, and biological exosome function. NIR-C12-EL exhibits excellent colloidal stability, good biocompatibility, strong light harvesting capability, high NIR-II photoconversion efficiency (62.28 %), and targeting capability to diagnose and ablate tumors, which together contribute to the extended life-span of the mice treatment with NIR-C12-EL and continuous 1064 nm laser irradiation. This study provides insight into not only designing of lipophilic NIR-II fluorescence probes for labeling of exosome-liposome hybrid-based vehicles but also the engineering of theranostic nanoplatforms for precise treatment of glioblastoma.

Long circulating liposomal platform utilizing hydrophilic polymer-based surface modification: preparation, characterisation, and biological evaluation

Liposomes are one of the most important drug delivery vectors, nowadays used in clinics. In general, polyethylene glycol (PEG) is used to ensure the stealth properties of the liposomes. Here, we have employed hydrophilic, biocompatible and highly non-fouling N-(2-hydroxypropyl) methacrylamide (HPMA)-based copolymers containing hydrophobic cholesterol anchors for the surface modification of liposomes, which were prepared by the method of lipid film hydration and extrusion through 100 nm polycarbonate filters. Efficient surface modification of liposomes was confirmed by transmission electron microscopy, atomic force microscopy, and gradient ultracentrifugation. The ability of long-term circulation in the vascular bed was demonstrated in rabbits after i.v. application of fluorescently labelled liposomes. Compared to PEGylated liposomes, HPMA-based copolymer-modified liposomes did not induce specific antibody formation and did not activate murine and human complement. Compared with PEGylated liposomes, HPMA-based copolymer-modified liposomes showed a better long-circulating effect after repeated administration. HPMA-based copolymer-modified liposomes thus represent suitable new candidates for a generation of safer and improved liposomal drug delivery platforms.

Ceftazidime and Usnic Acid Encapsulated in Chitosan-Coated Liposomes for Oral Administration against Colorectal Cancer-Inducing Escherichia coli.

Escherichia coli has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ), co-encapsulated in liposomes, could be an alternative. Coating the liposomes with chitosan (Chi) could facilitate the oral administration of this nanocarrier. Liposomes were prepared using the lipid film hydration method, followed by sonication and chitosan coating via the drip technique. Characterization included particle size, polydispersity index, zeta potential, pH, encapsulation efficiency, and physicochemical analyses. The minimum inhibitory concentration and minimum bactericidal concentration were determined against E. coli ATCC 25922, NCTC 13846, and H10407 using the microdilution method. Antibiofilm assays were conducted using the crystal violet method. The liposomes exhibited sizes ranging from 116.5 ± 5.3 to 240.3 ± 3.5 nm and zeta potentials between +16.4 ± 0.6 and +28 ± 0.8 mV. The encapsulation efficiencies were 51.5 ± 0.2% for CAZ and 99.94 ± 0.1% for UA. Lipo-CAZ-Chi and Lipo-UA-Chi exhibited antibacterial activity, inhibited biofilm formation, and preformed biofilms of E. coli. The Lipo-CAZ-UA-Chi and Lipo-CAZ-Chi + Lipo-UA-Chi formulations showed enhanced activities, potentially due to co-encapsulation or combination effects. These findings suggest potential for in vivo oral administration in future antibacterial and antibiofilm therapies against CRC-inducing bacteria.

Development and in vitro antiviral activity of ivermectin liposomes as a potential drug carrier system.

This study aimed to assess and compare diverse formulations of ivermectin-loaded liposomes, employing lipid film hydration and ethanol injection methods. Three lipids (DOPC, SPC, and DSPC) were used in predetermined molar ratios. A total of 18 formulations were created, and a factorial design determined the optimal formulation based on particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency. The average mean particle size, PDI and zeta potential of the selected formulations (F1, F2, F7, F9, and F11) was, respectively, 196.40 ± 44.60 nm, 0.39 ± 0.09, and -40.24 ± 9.17. The encapsulation efficiency exceeded 80%, with a mean loading capacity of 4.00 ± 1.70%. In vitro studies included transmission electron microscopy, Fourier transform infrared spectroscopy, drug release, and antiviral activity assessments against SARS-CoV-2. The liposomal formulations demonstrated superior antiviral activity compared to free ivermectin, as indicated by lower IC50 values. The results of this study emphasize the effectiveness of ivermectin-loaded liposomes in inhibiting viral activity, highlighting their potential as promising candidates for antiviral therapy. The findings suggest that the strategic use of liposomes as drug carriers can significantly modulate and improve the antiviral properties of ivermectin, offering a novel approach to harnessing its full therapeutic potential. Collectively, these results provide a robust foundation for further exploration of ivermectin as a viral protection tool and optimization of its delivery mechanisms.

Methods for obtaining phospholipid vesicles to improve the bioavailability of sparingly soluble active pharmaceutical ingredients

Low bioavailability of practically insoluble pharmaceutical substances is a serious issue in the field of drug development. The article provides an overview of the main methods for preparing liposomal drugs, such as the lipid film hydration method, ultrasonication method, extrusion method, high pressure homogenization method, solvent injection method, detergent removal method, and the reversephase evaporation method.

Liposomes versus microemulsions: Two novel nanosystems achieved an increased latanoprost hypotensive effect compared to traded medication

Aims/Purpose: The design of new topical ophthalmic nanosystems is linked to obtain non‐harmful carriers capable of increasing drug bioavailability and reduce the frequency of its instillations. Hypotensive actives such as latanoprost (L) are used to decrease intraocular pressure (IOP) in glaucoma patients. Two novel formulations, L‐loaded liposomes (LL) and L‐loaded microemulsions (LME), both including hyaluronic acid for its mucoadhesive properties were elaborated. The efficacy in reducing IOP of both formulations (48 h) was compared to a traded L‐ophthalmic solution (TM).Methods: LL were manufactured by the lipid film hydration method using synthetic phospholipids and cholesterol. LME were produced according to the self‐emulsification method by employing well‐tolerated oils and co‐solvents. Both LL and LME were characterized in terms of pH, osmolarity, size distribution, viscosity, and surface tension. Their hypotensive effect was evaluated up to 48 h in normotensive male albino New Zealand rabbits (n = 6, 12 eyes) using a tonometer following a single 25 μL topical administration and related to TM (n = 6). Draize test was performed before and 4 h after the instillation to establish LL, LME and TM tolerance.Results: Both LL and LME displayed proper physicochemical properties for the parameters evaluated. According to Draize test, both formulations resulted well‐tolerated without any sign of conjunctival hyperaemia, chemosis or discharge. Both LL and LME showed at least a 24‐h longer IOP reduction compared to TM, with the higher decrease at 3 h for LL and TM (24.02 ± 8.26% LL; 21.94 ± 10.14% TM) and 28 h for LME (30.40 ± 6.50%). Whilst at 24 h animals treated with TM (101.68 ± 5.27%) recuperated basal values, LL (91.08 ± 7.89%) and LME (80.14 ± 7.19%) rabbits still showed IOP decrease effect.Conclusions: Liposomes and microemulsions showed a longer hypotensive effect compared to traded medication, which makes them encouraging novel compliance‐friendly eye drops for glaucoma treatment.Acknowledgments: PID2020‐113281RB‐C21 funded by MCIN/AEI/10.13039/501100011033; 813440‐ORBITAL‐H2020‐MSCA‐ITN‐2018.

Development and characterization of ivermectin loaded liposomes prepared by lipid film hydration and ethanol injection method

Development and characterization of ivermectin loaded liposomes prepared by lipid film hydration and ethanol injection method

Liposomes containing azithromycin and green tea as an anti-acne treatment: Formulation and Characterization

Liposomes and other novel drug delivery carriers are highly adaptable, allowing for the distribution of a wide range of pharmacological compounds. The antibiotic azithromycin is widely regarded as the most effective treatment for acne. Lower efficacy or higher negative effects have led to decreased use of topical azithromycin. In this study, liposomes have been chosen because it is hypothesised that this may lessen the drug's side effects when used in conjunction with Azithromycin. Traditional herbal therapies have been intensively investigated as alternatives to conventional treatments for many ailments due to the possibility for side effects and antibiotic resistance from conventional pharmaceuticals. Thanks to its antibacterial qualities, green tea is one of the most effective natural therapies for acne. The lipid film hydration method was used to create drug-loaded liposomes, and the optimal component ratios were established. Liposomes were studied for their in-vitro drug release properties and characterised for their vesicle size, shape, encapsulation effectiveness, and drug content. Formulations F1 and F6, which included a 1:1 ratio of fat to cholesterol, showed the highest levels of encapsulation efficiency (69.5% and 66.2%, respectively) and in-vitro drug release (82.5 and 82.2 percent, respectively). Carbopol gel has been modified to include liposomal formulations, and the results have been compared to those of commercially available gels that do not use liposomes. Within 24 hours, the release of azithromycin (90.5%) was greater in the non liposomal marketed gel than in the liposomal gel (77.5% and 74.8%) of green tea. Green tea liposomes used in the formulation had a MIC value that was comparable to that of commercially available, non-liposomal gel. It was discovered that azithromycin was more effective than green tea in killing Micrococcus luteus.

Novel Liposomal Formulation with Azelaic Acid: Preparation, Characterization, and Evaluation of Biological Properties

Azelaic acid (AA), as a natural product, was proven to be effective in targeting multiple causes of acne and related dermatological conditions, as it is well tolerated using different classical formulations (gel, cream, etc.). However, its limited aqueous solubility and inadequate penetration across the stratum corneum might be related to different possible side effects such as itching and burning. The aim of our work was to elaborate a novel liposomal formulation based on azelaic acid, with enhanced biocompatibility, bio-availability, antimicrobial, antigenotoxic, and anti-inflammatory properties. The liposomal formulations were prepared by the lipid film hydration method with different concentrations of azelaic acid (15%, 20%, 25%) and characterized in terms of morphological features, physico-chemical properties, antimicrobial, cytotoxic, and in vitro wound healing effect. Successful encapsulation with 80.42% efficiency, with a size of up to 500 nm and good stability, was achieved, as demonstrated by FTIR spectroscopy (Fourier Transform Infrared Spectroscopy), DLS (dynamic light scattering), and zeta-potential measurements. In terms of antibacterial activity, all the liposomal formulations exhibited a better effect compared to free AA solution against Staphylococcus aureus and Enterococcus faecalis. Cytotoxicity assays and an in vitro “scratch” test performed with normal human dermal fibroblasts revealed an accelerating healing effect, while a comet assay evidenced the protective effect of AA liposomal formulations against hydrogen-peroxide-induced DNA damage in fibroblasts. The optimum formulation in terms of both the antimicrobial and wound healing effect was AALipo20% (liposomes with 20% azelaic acid included).

Preclinical toxicity assessment of anionic nanoliposomes

AimTo evaluate the in vivo toxicity of the anionic nanoliposome formulation containing [hydrogenated soy phosphatidylcholine (HSPC)] and [1,2-distearoyl-sn-glycero-3- phosphoglycerol (DSPG)]. MethodsThe anionic nanoliposome formulation was prepared by the lipid film hydration method. To assess the toxicity of anionic nanoliposomes, male and female albino mice were weakly treated with intravenous injection of the formulation (100 μmol/kg) for four weeks. The toxicity study was performed by the subacute protocol, four weeks after the last injection. To this end, the plasma levels of lipid indexes, urea, creatinine, AST, ALT, ALP, and fasting blood glucose (FBG) were measured. To evaluate histopathological alterations, the tissues of the vital organs including the heart, liver, kidneys, spleen, and brain were studied using hematoxylin & eosin (H&E) staining. ResultsThe results showed nonsignificant changes in total cholesterol, LDL-C, HDL-C, creatinine, urea, AST, ALP, and ALT in the liposome-treated mice when compared with control mice. However, plasma levels of triglycerides were significantly decreased (by 64.5 ± 15.3 mg/dL, p = 0.001) and (by 58.75 ± 15.3 mg/dL, p = 0.002) in the liposome-treated male and female mice, respectively, when compared with corresponding control mice. The FBG level was significantly increased by154 ± 20 mg/dL, p = 0.001 in the liposome-treated male mice when compared with the control male mice. The PAB level was significantly decreased by 12 ± 4.2 HK, p = 0.03 in the liposome-treated male mice when compared with the control male mice. Histological examination of vital organs indicated no significant differences in tissue damage between the liposome-treated and control mice. ConclusionThe findings of the present study indicated that DSPG-containing nanoliposome formulation exerted no significant adverse effects on the function of vital organs and blood levels of biochemical biomarkers in healthy mice. However, further investigations are needed to find a safe dose of DSPG liposomes concerning the risk of diabetes.

Vortioxetine liposomes as a novel alternative to improve drug stability under stress conditions: toxicity studies and evaluation of antidepressant-like effect.

Vortioxetine hydrobromide (VXT), a new therapeutic option in the treatment of major depressive disorder, is a poorly soluble drug, and instability under stress conditions has been reported. The aim of the present study was to prepare VXT liposomes (VXT-Ls) with an antidepressant-like effect, to improve drug stability and reduce toxicity of the free drug. Liposomes were prepared using the thin lipid film hydration method and properly characterized. Forced degradation studies were conducted in photolytic and oxidative conditions. The cytotoxicity was evaluated in VERO cells through MTT assay and in vivo toxicity was assessed in mice. The antidepressant-like effect in mice was confirmed using the open-field test paradigm and tail suspension test. The optimized VXT-Ls have multilamellar vesicles with an average size of 176.74nm ± 2.43. The liposomal formulation increased the stability of VXT. VERO cell viability was maintained at around 40% when the VXT-Ls were tested at higher concentrations and no signs of acute toxicity were observed in mice. The antidepressant-like effect was effective, for VXT-Ls, at doses ranging from 2.5mg/kg to 10mg/kg, measured by the tail suspension test in mice. The non-liposomal formulation was effective at a dose of 10mg/kg. The open field test was performed and any unspecific changes in locomotor activity were revealed. Liposomes seem to be a promising alternative for an oral VXT formulation at lower doses (2.5mg/kg).

Enhanced biological activity of liposomal methylated resveratrol analog 3′-hydroxy-3,4,5,4′-tetramethoxystilbene (DMU-214) in 3D patient-derived ovarian cancer model

3′-hydroxy-3,4,5,4′-tetramethoxystilbene (DMU-214) belongs to methoxystilbenes family and is an active metabolite of 3,4,5,4′-tetramethoxystilbene (DMU-212). In several of our previous studies, the anti-apoptotic activity of DMU-214 was significantly higher than that of the parent compound, especially in ovarian cancer cells. Due to increased lipophilicity and limited solubility, methoxystilbenes require a solubilization strategy enabling DMU-214 administration to the aqueous environment. In this study, DMU-214-loaded liposomes were developed for the first time, and its antitumor activity was tested in the ovarian cancer model. First, several liposomal formulations of DMU-214 were obtained by the thin lipid film hydration method followed by extrusion and then characterized. The diameter of the resulting vesicles was in the range of 118.0-155.5 nm, and samples presented monodisperse size distribution. The release of DMU-214 from the studied liposomes was governed by the contribution of two mechanisms, Fickian diffusion and liposome relaxation. Subsequently, in vitro activity of DMU-214 in the form of a free compound or liposome-bound was studied, including commercial cell line SK-OV-3 and patient-derived ovarian cancer cells in monolayer and spheroid cell culture models. DMU-214 liposomal formulations were found to be more potent (had lower IC50 values) than the free DMU-214 both in the monolayer and, more significantly, in both examined spheroid models. The above results, with particular emphasis on the patient-derived ovarian cancer model, indicate the importance of further development of liposomal DMU-214 as a potential anticancer formulation for ovarian cancer treatment.

A novel osmoprotective liposomal formulation from synthetic phospholipids to reduce in vitro hyperosmolar stress in dry eye treatments

Dry eye disease (DED) is a worldwide, multifactorial disease mainly caused by a deficit in tear production or increased tear evaporation with an increase in tear osmolarity and inflammation. This causes discomfort and there is a therapeutic need to restore the homeostasis of the ocular surface. The aim of the present work was to develop a biodegradable and biocompatible liposomal formulation from the synthetic phospholipids 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) that is able to reduce the effects of hypertonic stress by helping to restore the lipid layer of the tear film. Liposomes were made using the lipid film hydration method with synthetic phospholipids (10 mg/mL) with and without 0.2% HPMC. They were characterised in terms of size, osmolarity, pH, surface tension, and viscosity. Additionally, the in vitro toxicity of the formulation at 1 and 4 h in human corneal epithelial cells (hTERT-HCECs) and human conjunctival cells (IM-HConEpiC) was determined. Furthermore, osmoprotective activity was tested in a corneal model of hyperosmolar stress. In vivo acute tolerance testing was also carried out in albino New Zealand rabbits by topical application of the ophthalmic formulations every 30 min for 6 h. All the assayed formulations showed suitable physicochemical characteristics for ocular surface administration. The liposomal formulations were well-tolerated in cell cultures and showed osmoprotective activity in a hyperosmolar model. No alterations or discomfort were reported when they were topically administered in rabbits. According to the results, the osmoprotective liposomal formulations developed in this work are promising candidates for the treatment of DED.

PH-Sensitive Liposomes for Enhanced Cellular Uptake and Cytotoxicity of Daunorubicin in Melanoma (B16-BL6) Cell Lines.

Daunorubicin (DNR) was delivered using a pH-sensitive liposomal system in B16-BL6 melanoma cell lines for enhanced cytotoxic effects. DNR was encapsulated within liposomes and CL as a component of the lipid bilayer. PEGylated pH-sensitive liposomes, containing CL, were prepared in the molar ratio of 40:30:5:17:8 for DOPE/cholesterol/DSPE-mPEG (2000)/CL/SA using the lipid film hydration method and loaded with DNR (drug: lipid ratio of 1:5). The CL liposomes exhibited high drug encapsulation efficiency (>90%), a small size (~94 nm), narrow size distribution (polydispersity index ~0.16), and a rapid release profile at acidic pH (within 1 h). Furthermore, the CL liposomes exhibited 12.5- and 2.5-fold higher cytotoxicity compared to DNR or liposomes similar to DaunoXome®. This study provides a basis for developing DNR pH-sensitive liposomes for melanoma treatment.

Evaluation of liver specific ionizable lipid nanocarrier in the delivery of siRNA

Hepcidin, a key regulator of iron homeostasis, has been implicated in the pathogenesis of various iron-related diseases. Although small interfering RNA (siRNA) are potent to modulate the expression of hepcidin, their bioavailability remains a major issue. The β-galactopyranoside-conjugated liposomes (GAL-liposome) targeting liver synthesized hepcidin were prepared by thin lipid film hydration method to encapsulate siRNA and the conjugation of β-galactopyranoside to the lipid nanocarrier was achieved by covalent chemistry. The prepared siRNA loaded GAL-lip were spherical with around 50 nm radius in size as observed by HR-TEM. The zeta potential and polydispersity index of the prepared liposomes were − 19.9 ± 0.96 mV and 0.44 ± 0.05, respectively. The encapsulation efficiency as determined by dialysis bag method was around 91.76 ± 1.74%. The cell viability and cellular uptake analysis was examined in HepG2 cells by MTT assay and flow cytometry, respectively. The stability and cumulative release of siRNA was also assessed. The hepcidin mRNA expression on administration of siRNA loaded GAL-lip was determined in HepG2 cells and in lipopolysaccharide-induced mice model followed by examining itsin vivo biodistribution by fluorescence microscopy. The results suggested thatsiRNA loaded GAL-lip reduced the hepcidin levels, thus, highlighting a novel ligand conjugated ionizable lipid-based nanocarrier for inducing RNA interference.

Active Tumor-Targeting Nano-formulations Containing Simvastatin and Doxorubicin Inhibit Melanoma Growth and Angiogenesis.

Primary melanoma aggressiveness is determined by rapid selection and growth of cellular clones resistant to conventional treatments, resulting in metastasis and recurrence. In addition, a reprogrammed tumor-immune microenvironment supports melanoma progression and response to therapy. There is an urgent need to develop selective and specific drug delivery strategies for modulating the interaction between cancer cells and immune cells within the tumor microenvironment. This study proposes a novel combination therapy consisting of sequential administration of simvastatin incorporated in IL-13-functionalized long-circulating liposomes (IL-13-LCL-SIM) and doxorubicin encapsulated into PEG-coated extracellular vesicles (PEG-EV-DOX) to selectively target both tumor-associated macrophages and melanoma cells. To this end, IL-13 was conjugated to LCL-SIM which was obtained via the lipid film hydration method. EVs enriched from melanoma cells were passively loaded with doxorubicin. The cellular uptake of rhodamine-tagged nano-particles and the antiproliferative potential of the treatments by using the ELISA BrdU-colorimetric immunoassay were investigated in vitro. Subsequently, the therapeutic agents were administered i.v in B16.F10 melanoma-bearing mice, and tumor size was monitored during treatment. The molecular mechanisms of antitumor activity were investigated using angiogenic and inflammatory protein arrays and western blot analysis of invasion (HIF-1) and apoptosis markers (Bcl-xL and Bax). Quantification of oxidative stress marker malondialdehyde (MDA) was determined by HPLC. Immunohistochemical staining of angiogenic markers CD31 and VEGF and of pan-macrophage marker F4/80 was performed to validate our findings. The in vitro data showed that IL-13-functionalized LCL were preferentially taken up by tumor-associated macrophages and indicated that sequential administration of IL-13-LCL-SIM and PEG-EV-DOX had the strongest antiproliferative effect on tumor cells co-cultured with tumor-associated macrophages (TAMs). Accordingly, strong inhibition of tumor growth in the group treated with the sequential combination therapy was reported in vivo. Our data suggested that the antitumor action of the combined treatment was exerted through strong inhibition of several pro-angiogenic factors (VEGF, bFGF, and CD31) and oxidative stress-induced upregulation of pro-apoptotic protein Bax. This novel drug delivery strategy based on combined active targeting of both cancer cells and immune cells was able to induce a potent antitumor effect by disruption of the reciprocal interactions between TAMs and melanoma cells.

Stealth Liposomes (PEGylated) Containing an Anticancer Drug Camptothecin: In Vitro Characterization and In Vivo Pharmacokinetic and Tissue Distribution Study.

Numerous attempts to overcome the poor water solubility of cam ptothecin (CPT) by various nano drug delivery systems are described in various sources in the literature. However, the results of these approaches may be hampered by the incomplete separation of free CPT from the formulations, and this issue has not been investigated in detail. This study aimed to promote the solubility and continuous delivery of CPT by developing long-lasting liposomes using various weights (M.W. 2000 and 5000 Daltons) of the hydrophilic polymer polyethylene glycol (PEG). Conventional and PEGylated liposomes containing CPT were formulated via the lipid film hydration method (solvent evaporation) using a rotary flash evaporator after optimising various formulation parameters. The following physicochemical characteristics were investigated: surface morphology, particle size, encapsulation efficiency, in vitro release, and formulation stability. Different molecular weights of PEG were used to improve the encapsulation efficiency and particle size. The stealth liposomes prepared with PEG5000 were discrete in shape and with a higher encapsulation efficiency (83 ± 0.4%) and a prolonged rate of drug release (32.2% in 9 h) compared with conventional liposomes (64.8 ± 0.8% and 52.4%, respectively) and stealth liposomes containing PEG2000 (79.00 ± 0.4% and 45.3%, respectively). Furthermore, the stealth liposomes prepared with PEG5000 were highly stable at refrigeration temperature. Significant changes were observed using various pharmacokinetic parameters (mean residence time (MRT), half-life, elimination rate, volume of distribution, clearance, and area under the curve) of stealth liposomes containing PEG2000 and PEG5000 compared with conventional liposomes. The stealth liposomes prepared with PEG5000 showed promising results with a slow rate of release over a long period compared with conventional liposomes and liposomes prepared with PEG2000, with altered tissue distribution and pharmacokinetic parameters.

The Use of a Staggered Herringbone Micromixer for the Preparation of Rigid Liposomal Formulations Allows Efficient Encapsulation of Antigen and Adjuvant

Anionic liposomal formulations have previously shown to have intrinsic tolerogenic capacity and these properties have been related to the rigidity of the particles. The combination of highly rigid anionic liposomes to deliver tolerogenic adjuvants and antigen peptides has potential applications for the treatment of autoimmune and inflammatory diseases. However, the preparation of these highly rigid anionic liposomes using traditional methods such as lipid film hydration presents problems in terms of scalability and loading efficiency of some costly tolerogenic adjuvants like 1-α,25-dihydroxyvitaminD3. Here we propose the use of an off-the-shelf staggered herringbone micromixer for the preparation of these formulations and performed a systematic study on the effect of temperature and flow conditions on the size and polydispersity index of the formulations. Furthermore, we show that the system allows for the encapsulation of a wide variety of peptides and significantly higher loading efficiency of 1-α,25-dihydroxyvitaminD3 compared to the traditional lipid film hydration method, without compromising their non-inflammatory interaction with dendritic cells. Therefore, the microfluidics method presented here is a valuable tool for the preparation of highly rigid tolerogenic liposomes in a fast, size-tuneable and scalable manner.

Formulation, characterization, optimization and in-vivo evaluation of methazolamide liposomal in-situ gel for treating glaucoma

The rationale of this study was to formulate topically effective sustained release ophthalmic Methazolamide (MTA) liposomal in-situ gel. Lipid film hydration method was employed for the preparation of MTA liposomes consisting of lecithin and cholesterol. Optimization of the MTA liposomes by Design-Expert software was done to evaluate the effect of cholesterol and drug in varying concentrations using a 32 factorial design. Encapsulation efficiency and particle size were considered as dependent variables. Drug encapsulation was increased by increasing cholesterol as well as drug concentration. The optimized batch showed encapsulation efficiency of 74.12 ± 0.52% and particle size was found 193.2 ± 1.34 nm. The liposomal gel was prepared by incorporating MTA liposomes in Carbopol 934 gel.The final formulation showed a pH of 7.1 ± 0.05, spreadability of 0.8 ± 0.1. In vitro release studies of MTA liposomes and MTA liposomal gel were compared. In comparison to MTA solution, MTA liposomal gel showed a significant reduction (p < 0.05) in intraocular pressure (IOP). Area under % decrease in IOP Vs time (hr) curve (AUC0–8hr) was found to be 58 ± 0.03, 174 ± 0.04, and 222 ± 0.03 hr−1 for MTA drug, MTA liposomes, and MTA liposomal gel respectively. MTA Liposomal gel, as opposed to traditional eye drops, may be a suitable delivery medium for ocular distribution, with the benefits of more intensive glaucoma treatment, lower dosage, and increased patient compliance.

Fabrication and Release Kinetics of Liposomes Containing Leuprolide Acetate

The present work is focused on the preparation and in vitro release kinetics of liposomal formulation of Leuprolide Acetate. In this work, “Thin Lipid Film Hydration Method” was used for preparation of Leuprolide Acetate loaded liposomes. Prepared liposomal formulations of Leuprolide acetate was evaluated by drug entrapment study, in-vitro drug release kinetics and stability studies. The percentage drug entrapment of Leuprolide acetate for F1 and F2 formulations were found to be 78.14 ± 0.67 and 66.70 ± 0.81% respectively. In-vitro drug release study of liposomal formulations had shown zero order release pattern. Regression co-efficient (R2) value of Zero order kinetics for F1 and F2 formulations were 0.9912 and 0.9676 respectively. After storing formulations for 1 month, stability testing was done at 40C.It was found that all batches were stable. These liposomal formulations of Leuprolide acetate can be formulated for parenteral application to treat prostate cancer and in women, to treat symptoms of endometriosis (overgrowth of uterine lining outside of the uterus) or uterine fibroids.