Modified Ethanol Injection Method Research Articles

Nanoethosomal formulation of gammaoryzanol for skin-aging protection and wrinkle improvement: a histopathological study

Background: Free radical scavengers and antioxidants, with the main focus on enhanced targeting to the skin layers, can provide protection against skin ageing.Objective: The aim of the present study was to prepare nanoethosomal formulation of gammaoryzanol (GO), a water insoluble antioxidant, for its dermal delivery to prevent skin aging.Methods: Nanoethosomal formulation was prepared by a modified ethanol injection method and characterized by using laser light scattering, scanning electronic microscope (SEM) and X-ray diffraction (XRD) techniques. The effects of formulation parameters on nanoparticle size, encapsulation efficiency percent (EE%) and loading capacity percent (LC%) were investigated. Antioxidant activity of GO-loaded formulation was investigated in vitro using normal African green monkey kidney fibroblast cells (Vero). The effect of control and GO-loaded nanoethosomal formulation on superoxide dismutase (SOD) and malondialdehyde (MDA) content of rat skin was also probed. Furthermore, the effect of GO-loaded nanoethosomes on skin wrinkle improvement was studied by dermoscopic and histological examination on healthy humans and UV-irradiated rats, respectively.Results: The optimized nanoethosomal formulation showed promising characteristics including narrow size distribution 0.17 ± 0.02, mean diameter of 98.9 ± 0.05 nm, EE% of 97.12 ± 3.62%, LC% of 13.87 ± 1.36% and zeta potential value of –15.1 ± 0.9 mV. The XRD results confirmed uniform drug dispersion in the nanoethosomes structure. In vitro and in vivo antioxidant studies confirmed the superior antioxidant effect of GO-loaded nanoethosomal formulation compared with control groups (blank nanoethosomes and GO suspension).Conclusions: Nanoethosomes was a promising carrier for dermal delivery of GO and consequently had superior anti-aging effect.

Using Factorial Experimental Design To Prepare Size-Tuned Nanovesicles

The aim of this work was to prepare size-tuned nanovesicles using a modified ethanol injection method (EIM) by applying factorial experimental design. Stable size-tuned nanovesicles (liposomes and niosomes) with controlled sizes and high EE values for hydrophobic compounds (Sudan Red 7B and vitamin D3) were achieved. Equations that were able to predict the mean particle sizes, in the ranges of 55–156 nm for liposomes and 224–362 nm for niosomes with PDI values between 0.032 and 0.378, were obtained. These customized soft nanoparticles could be suitable in food, cosmetic, pharmaceutical, or medical applications, such as diagnosis or therapy.

Iron-entrapped niosomes and their potential application for yogurt fortification

Several formulations were tested for iron-entrapped niosomes with high stability and encapsulation efficiency. A modified ethanol injection method was selected for niosomes preparation.Niosomes formulated with Glycerol monooleate, Polyglyceryl-3 dioleate or Sorbitan monooleate as food-grade surfactants and dodecanol as membrane stabilizer showed iron encapsulation efficiencies in the 72–84% range.Niosomes stability against simulated gastric fluid and simulated intestinal fluid was evaluated by measuring the entrapment efficiency and oxidation of iron.The best formulations were selected for preparation of iron-fortified yogurts. Sensory, rheological and stability properties of the control yogurt were only slightly affected by iron-entrapped niosomes. These results demonstrated that yogurt could be a suitable vehicle for the iron-entrapped niosomes formulated in this work.

The potential use of novel chitosan-coated deformable liposomes in an ocular drug delivery system

In this study, novel chitosan-coated deformable liposomes (DL-CS) were proposed as an ocular drug delivery system to prolong pre-corneal retention, and improve transcorneal penetration and absorption. Flurbiprofen-loaded deformable liposomes (FP-DL) were prepared by a modified ethanol injection method and then coated with chitosan. Both DL and DL-CS exhibited a homogeneous particle size distribution, high encapsulation efficiency and good stability. After coating with 0.1% CS, the zeta potential was shifted from negative to positive. The apparent permeability coefficient of FP-DL-0.1% CS evaluated using isolated rabbit corneas was 1.29-, 1.95- and 4.59- fold greater than that of uncoated FP-DL, conventional liposomes and FP solution (P<0.01), respectively. The in vivo pre-corneal retention time and elimination dynamics were assessed using gamma scintigraphy technology. The area under the remaining activity-time of FP-DL-0.1% CS was prolonged 2.84- and 1.53-fold compared with that of the FP solution and FP-DL groups, respectively. Moreover, the ocular irritation test in vivo revealed that DL-0.1% CS produced no ocular damage or abnormal clinical signs. These results indicate that DL-CS appears to be a novel ophthalmic drug delivery strategy with the potential to overcome the limitations of conventional eye drops.

PH-sensitive, polymer modified, plasma stable niosomes: promising carriers for anti-cancer drugs.

The aim of this study was the design and evaluation of a novel plasma stable, pH-sensitive niosomal formulation of Mitoxantrone by a modified ethanol injection method. Cholesterol hemisuccinate was added instead of cholesterol in order to produce pH-sensitivity property and using PEG-Poly (monomethyl itaconate)-CholC6 (PEG-PMMI-CholC6) copolymer introduced simultaneously pH-sensitivity and plasma stability properties in prepared niosomes. The pH-sensitivity and cytotoxicity of Mitoxantrone niosomes were evaluated in vitro in phosphate buffer with different pHs as well as using human ovarian cancer cell line (OVCAR-3), human breast cancer cell line (MCF-7) and human umbilical vein endothelial cells (HUVEC). Results showed that both cholesterol derivatives bearing formulations had pH-sensitive property and were found to release their contents under mild acidic conditions rapidly. In addition, the PEG-PMMI-CholC6-based niosomes could reserve the pH-sensitivity after incubation in plasma. Both Mitoxantrone-loaded pH-sensitive niosomes showed higher cytotoxicity than the conventional niosomes on OVCAR-3 and MCF-7 cell lines. However, both pH-sensitive niosomes exhibited lower cytotoxic effect on HUVEC cell line. Plasma stable, pH-sensitive niosomes could improve the cytotoxic effect and reduce the side effects of anti-tumor drugs.

Fusogenic liposomal formulation of sirolimus: improvement of drug anti-proliferative effect on human T-cells

Context: Fusogenic liposomes are unique delivery vehicles capable of introducing their contents directly and efficiently into the cytoplasm.Objective: The objective of this study was to evaluate the potential of fusogenic liposomes containing Sirolimus to improve its anti-proliferative effect on T-lymphocyte cells.Materials and methods: Conventional liposomes containing Sirolimus were prepared from Dipalmitoylphosphatidylcholine (DPPC) and cholesterol using the modified ethanol injection method. To prepare fusogenic liposomes, dioleoylphosphatidylethanolamine (DOPE) was added to the conventional liposome formulation. The liposomes were characterized by their size, zeta potential, encapsulation efficiency percent (EE%) and chemical stability during 6 months. The in vitro release of liposomes, anti-proliferative effect and liposome uptake of both types of liposomes with optimized formulations were studied on human T-lymphocyte cells employing the MTT assay and fluorescein isothiocyanate-loaded liposomes.Results and discussion: The particle size of the liposomes was evaluated between 138 and 650 nm and mean zeta potential was in the range of −32.95 to −45.60 mV. The average EE% of the prepared conventional and fusogenic liposomes were 76.9% and 80.5%, respectively. Liposomal formulations released only 10–20% of encapsulated drug without any burst effect. In vitro immunosuppressive evaluation on T-cells showed that fusogenic liposomes have the best anti-proliferative effects and uptake on T-lymphocyte cell compared to the conventional liposomes.Conclusion: Our results indicated that fusogenic liposomes can be useful carriers for improving the inhibition of T-cell proliferation.

Enhanced corneal permeation and antimycotic activity of itraconazole against Candida albicans via a novel nanosystem vesicle

The objective of this study was to investigate the potential of spanlastics as an ophthalmic delivery system to improve the corneal permeability and antimycotic activity of itraconazole (ITZ). Spanlastics containing edge activators, including Tween 20 or 80, were produced by modified ethanol injection method and exhibited a particle size of approximately 287 nm and an entrapment efficiency of more than 88%. Less than 13% ITZ was released from spanlastics over 6 h compared to 35% from conventional niosomes. Spanlastics exerted a 1.34-fold increase in the amount of ITZ permeated through excised bovine cornea after 24 h compared to conventional niosomes. Antimycotic study revealed a significant (p < 0.05) increase in the zone of inhibition of Candida albicans culture demonstrated by spanlastics compared to ITZ powder at the same concentration level (10 mg). In vivo Draize test showed no signs of acute ocular toxicity upon application of the selected spanlastic formulation to the rabbit eye. Results revealed that spanlastics loaded with itraconazole could be a potential nanosystem in ocular drug delivery systems.

Fusogenic pH sensitive liposomal formulation for rapamycin: Improvement of antiproliferative effect

Context: Liposomes are increasingly employed to deliver chemotherapeutic agents, antisense oligonucleotides, and genes to various therapeutic targets.Objective: The present investigation evaluates the ability of fusogenic pH-sensitive liposomes of rapamycin in increasing its antiproliferative effect on human breast adenocarcinoma (MCF-7) cell line.Materials and methods: Cholesterol (Chol) and dipalmitoylphosphatidylcholine (DPPC) (DPPC:Chol, 7:3) were used to prepare conventional rapamycin liposomes by a modified ethanol injection method. Dioleoylphosphatidylethanolamine (DOPE) was used to produce fusogenic and pH-sensitive properties in liposomes simultaneously (DPPC:Chol:DOPE, 7:3:4.2). The prepared liposomes were characterized by their size, zeta potential, encapsulation efficiency percent (EE%), and chemical stability during 6 months. The antiproliferative effects of both types of rapamycin liposomes (10, 25, and 50 nmol/L) with optimized formulations were assessed on MCF-7 cells, as cancerous cells, and human umbilical vein endothelial cells (HUVEC), as healthy cells, employing the diphenyltetrazolium bromide (MTT) assay for 72 h.Results and discussion: The particle size, zeta potential, and EE% of the liposomes were 165 ± 12.3 and 178 ± 15.4 nm, −39.6 ± 1.3, and −41.2 ± 2.1 mV as well as 76.9 ± 2.6 and 76.9 ± 2.6% in conventional and fusogenic pH-sensitive liposomes, respectively. Physicochemical stability results indicated that both liposome types were relatively stable at 4 °C than 25 °C. In vitro antiproliferative evaluation showed that fusogenic pH-sensitive liposomes had better antiproliferative effects on MCF-7 cells compared to the conventional liposomes. Conversely, fusogenic pH-sensitive liposomes had less cytotoxicity on HUVEC cell line.

Nonionic surfactant-based vesicular system for transdermal drug delivery

Objective: The objective of this study was to formulate and evaluate the Ibuprofen niosomal formulation as a transdermal drug delivery system.Materials and methods: Niosomes were prepared by a modified ethanol injection method, using Span 60, Tween 60 and Tween 65 as well as cholesterol with various cholesterol:surfactant molar ratios. The prepared vesicles were characterized for entrapment efficiency (EE), particle size, zeta potential and in vitro release study. Skin permeation studies were conducted using modified Franz diffusion cell, and excised rat skin was treated with niosomal, liposomal and conventional Carbopol 914 gel of Ibuprofen.Results and discussion: The results showed that the type of surfactant and molar ratio of cholesterol:surfactant altered the EE, size and in vitro drug release of niosomes. Higher EE was obtained with the niosomes prepared with cholesterol and Span 60 at molar ratio of 0.5:1. It has been observed that both niosomal and liposomal formulations enhanced the drug permeation and the percentage of accumulated dose in the skin compared to control conventional gel formulation. However, niosomes prepared by Span 60 and Tween 65 exhibited higher permeation and retention of Ibuprofen, respectively.Conclusion: Our results suggested that niosomal formulations could be used as a promising carrier for the Ibuprofen transdermal delivery system.

Plasma stable, pH-sensitive non-ionic surfactant vesicles simultaneously enhance antiproliferative effect and selectivity of Sirolimus

Objective: The purpose of the present investigation was to prepare a plasma stable, pH-sensitive niosomal formulation to enhance Sirolimus efficacy and selectivity.Materials and methods: pH-sensitive niosomal formulations bearing PEG-Poly (monomethyl itaconate)-CholC6 (PEG-PMMI-CholC6) copolymers and cholesteryl hemisuccinate (CHEMS) were prepared by a modified ethanol injection method and characterized with regard to pH-responsiveness and stability in human serum. The ability of pH-sensitive niosomes to enhance the Sirolimus cytotoxicity was evaluated in vitro using human erythromyeloblastoid leukemia cell line (K562) and compared with cytotoxicity effect on human umbilical vein endothelial cells (HUVEC).Results and discussion: This study showed that both formulations can be rendered pH-sensitive property and were found to rapidly release their contents under mildly acidic conditions. However, the CHEMS-based niosomes lost their pH-sensitivity after incubation in plasma, whereas, PEG-PMMI-CholC6 niosomes preserved their ability to respond to pH change. Sirolimus encapsulated in pH-sensitive niosomes exhibited a higher cytotoxicity than the control conventional formulation on K562 cell line. On the other hand, both pH-sensitive niosomes showed lower antiproliferative effect on HUVEC cells.Conclusion: Plasma stable, pH-sensitive PEG-PMMI-CholC6-based niosomes can improve the in vitro efficiency and also reduce the side effects of Sirolimus.

Preparation of optimized Naproxen nano liposomes using response surface methodology

The aim of this study was to prepare and optimize a liposomal delivery system for Naproxen (NPX), a practically water insoluble drug. NPX liposomes, which were consisted of cholesterol (CH) and phosphatidylcholine (PC) in different molar ratios, were prepared by modified ethanol injection method and optimized employing response surface methodology (RSM). Proportion of PC:CH and total lipid:drug ratio were selected as the independent variables while the particle size (PS), encapsulation efficiency percent (EE%) and drug release of the liposomes over 24 h (D24h) were considered as dependent variables. The effects of PC:CH and total lipid:drug ratios were studied and optimized to obtain the liposomal vesicles with desired quality. Graphical response surface and contour plots were also employed to understand the interaction of different variables. The optimum points for the variables were obtained from the optimization plot. The mean PS, EE% and D24h of NPX liposomes were about 178.11 nm, 53.14 and 46.62 % respectively. The results indicated that PC:CH and total lipids:drug ratios were the major contributing variables for EE% and D24h. However, only PC:CH ratio was the main contributing variable for PS. The optimum formulation of NPX liposomes, in which PC:CH ratio and lipids:drug ratio were 3.81 and 2.98 respectively, had high EE% (58 %) and D24h (>50 %) as well as appropriate PS (<162.4 nm). Ethanol injection method besides RSM, are simple, rapid and beneficial approaches for liposome preparation and optimization.

Applying quality by design (QbD) concept for fabrication of chitosan coated nanoliposomes

In the present investigation, a quality by design (QbD) strategy was successfully applied to the fabrication of chitosan-coated nanoliposomes (CH-NLPs) encapsulating a hydrophilic drug. The effects of the processing variables on the particle size, encapsulation efficiency (%EE) and coating efficiency (%CE) of CH-NLPs (prepared using a modified ethanol injection method) were investigated. The concentrations of lipid, cholesterol, drug and chitosan; stirring speed, sonication time; organic:aqueous phase ratio; and temperature were identified as the key factors after risk analysis for conducting a screening design study. A separate study was designed to investigate the robustness of the predicted design space. The particle size, %EE and %CE of the optimized CH-NLPs were 111.3 nm, 33.4% and 35.2%, respectively. The observed responses were in accordance with the predicted response, which confirms the suitability and robustness of the design space for CH-NLP formulation. In conclusion, optimization of the selected key variables will help minimize the problems related to size, %EE and %CE that are generally encountered when scaling up processes for NLP formulations. The robustness of the design space will help minimize both intra-batch and inter-batch variations, which are quite common in the pharmaceutical industry.

An evaluation of the anti-tumor efficacy of oleanolic acid-loaded PEGylated liposomes

The effective delivery of oleanolic acid (OA) to the target site has several benefits in therapy for different pathologies. However, the delivery of OA is challenging due to its poor aqueous solubility. The study aims to evaluate the tumor inhibition effect of the PEGylated OA nanoliposome on the U14 cervical carcinoma cell line. In our previous study, OA was successfully encapsulated into PEGylated liposome with the modified ethanol injection method. Oral administration of PEGylated OA liposome was demonstrated to be more efficient in inhibiting xenograft tumors. The results of organ index indicated that PEG liposome exhibited higher anti-tumor activity and lower cytotoxicity. It was also found that OA and OA liposomes induced tumor cell apoptosis detected by flow cytometry. Furthermore, effects of OA on the morphology of tumor and other tissues were observed by hematoxylin and eosin staining. The histopathology sections did not show pathological changes in kidney or liver in tested mice. In contrast, there was a significant difference in tumor tissues between treatment groups and the negative control group. These observations imply that PEGylated liposomes seem to have advantages for cancer therapy in terms of effective delivery of OA.

Enhancement of Hepatoprotective Efficacy of Propolis by Fabrication of Liposomes, as a Platform Nano-Formulation for Multi-Component Natural Medicine

Lack of suitable formulations often obscures the potential of natural medicine. Moreover, the presence of myriad of constituents with varied physicochemical properties makes fabrication of stable phyto-formulation extremely difficult. Bee propolis is one such material that suffers inadequate clinical application, despite having diverse pharmacological activities, solely attributed to deficit of appropriate formulations. In this study, we have presented a possibility of fabricating liposomes as a platform nano-formulation for enhancement of hepatoprotective activity of propolis. Hepatoprotective efficacy of the propolis is limited by its poor oral absorption. Moreover, the exact composition of the propolis being yet undefined, indeed unconfined, it cannot be administered parenterally. In order to address the foregoing issue, propolis liposomes suitable for oral administration and having higher entrapment efficiency were formulated through a modified ethanol injection method. Effect of phospholipids (PL) and cholesterol (CH) concentration on the formulation characteristics was checked statistically by 3(2) factorial approach. Liposomes were characterized for vesicle diameter (Dv), entrapment efficiency (EE), zeta potential (ζ p), TEM and drug release kinetics. Clinical efficacy of the formulation was assessed using acetaminophen induced hepatotoxicity in rat model. Biochemical parameters such as AST, ALT, ALP and TBARS, as well as histopathological aspects were studied. Stable unilamellar vesicles were formed according to 3(2) factorial approach. Dv, EE and ζ p were ranging between 216 to 437 nm, 79.53 to 93.01% & -27.8 to -31.2 mV, respectively. Marked positive effect of PL and CH and propolis concentrations was seen on Dv as well as EE. Release of propolis in acidic media followed zero order kinetics while in alkaline media it followed 1(st) order kinetics. Formulation was able to suppress AST, ALT, ALP & TBARS levels in hepatotoxicity induced experimental animals and promote tissue healing, in a manner more effective than plain EEP as well as silymarin. In conclusion, suitability of liposomes as a fundamental formulation for enhancing hepatoprotective activity of multi-component propolis was justified.

Investigations on feasibility of in situ development of amphotericin B liposomes for industrial applications

Amphotericin B (AmB) liposome formulations are very successful in the treatment of fungal infections and leishmaniasis. But higher cost limits its widespread use among people in developing countries. Therefore, we have developed a modified ethanol-injection method for the preparation of AmB liposomes. Two liposomal formulations were developed with dimyristoyl phosphatidylcholine [F-1a] and soya phosphatidylcholine [F-2a], along with egg phosphatidyl glycerol and cholesterol. AmB was dissolved in acidified dimethyl acetamide and mixed with ethanolic lipid solution and rapidly injected in 5% dextrose to prepare liposomes. Liposomes were characterized on the basis of size (~100 nm), zeta (–43.3 ± 2.8 mV) and percent entrapment efficiency (>95%). The in vitro release study showed an insignificant difference (P ≥ 0.05) for 24-hour release between marketed AmB liposomes (AmBisome) and F-1a and F-2a. Proliposome concentrate, used for the preparation of in situ liposomes, was physically stable for more than 3 months at experimental conditions. Similarly, AmB showed no sign of degradation in reconstituted liposomes stored at 2–8°C for more than 3 months. IC50 value of Ambisome (0.18 µg/mL) was comparatively similar to F-1a (0.17 µg/mL) and F-2a (0.16 µg/mL) against intramacrophagic amastigotes. Under experimental conditions, a novel modified method for AmB liposomes is a great success and generates interest for development as a platform technology for many therapeutic drug products.

Mucoadhesive liposomal delivery systems: the choice of coating material

Objective: Development of liposomal mucoadhesive drug delivery system, which is able to improve the bioavailability of poorly absorbed oral drugs by prolonging their gastric and intestinal residence time, through facilitating the intimate contact of the delivery system with the absorption membrane. Materials and methods: Liposomes containing model drug atenolol were prepared by the modified ethanol injection method. Liposomes containing atenolol were coated by different mucoadhesive polymers, for example, chitosan, Carbopol 974P, Eudragit L100, and Eudragit S100, to optimize the choice of coating material. The delivery systems were tested for their in vitro mucoadhesiveness. Results: Liposomes prepared by the ethanol injection method were of satisfactory size (around 100 nm, before coating). Through the coating of liposomes in the presence of unentrapped material, the entrapment efficiency for drug was increased. In vitro mucoadhesive test confirmed the mucoadhesive properties of the coated layer for all tested polymers; however, Eudragit S100-coated liposomes were superior to other coating materials. Discussion: Eudragit coating appeared to be an optimal polymer choice. These preliminary data indicate that polymer-coated mucoadhesive liposomes are able to carry sufficient amount of drug and to remain attached to the intestinal mucosa for a sufficient period of time to enable prolonged absorption of entrapped drug. Conclusion: While keeping in mind that the in vivo conditions may vary with the in vitro ones, we may recommend the system described in our work for possible oral delivery of peptides and phytochemicals.

Development and pharmacokinetics of nimodipine-loaded liposomes

In order to improve the water solubility of nimodipine and prolong the time of the drug in the circulation, nimodipine-loaded liposomes with a small size and high entrapment efficiency were prepared by a method that was easy to scale up (the modified ethanol injection method). The nimodipine liposome dispersions were characterized with respect to particle size distribution, zeta potential and entrapment efficiency. Liposomal nimodipine and nimodipine solution were intravenously administered to mice as a single dose of 4 mg kg-1. The pharmacokinetic parameters of nimodipine changed significantly when encapsulated in liposomes. The clearance of nimodipine encapsulated in liposomes was reduced and the elimination half-life was prolonged. The ratios of the area under the curve values of nimodipine liposomes to nimodipine solution were 1.78 and 1.90 in plasma and cerebral tissue, respectively. The drug concentration in cerebral tissue and in plasma showed a good linear correlation, which showed that liposomes could efficiently deliver nimodipine into brain tissue. These findings suggest that intravenous administration of liposomal nimodipine produces higher and more stable plasma and cerebral drug concentrations compared with nimodipine solution. In conclusion, liposomal nimodipine is a promising alternative to the solution preparation.

Formulation and Comparative Characterization of Chitosan, Gelatin, and Chitosan–Gelatin-Coated Liposomes of CPT-11–HCl

Liposomes containing phosphatidylcholine and cholesterol (uncoated) and coated by chitosan, gelatin, and combination of chitosan and gelatin were prepared by the modified ethanol injection method. The aim of this work was to formulate and characterize liposomes of camptothecin (CPT)-11–HCl (Irinotecan HCl) containing chitosan, gelatin, and both polymers as coating materials; and also to increase its circulation longevity when compared with the free drug while maintaining the agent in its active lactone form. Size, shape, zeta potential, encapsulation efficiency, stability study, in vitro, and in vivo release study were used for characterization of liposomes. The size of liposomes was in the order of uncoated < chitosan coated < gelatin coated < combination of chitosan and gelatin coated. The zeta potential of liposomes was in the order of combination of chitosan and gelatin coated > chitosan coated > gelatin coated > uncoated. The formulations showed the long-term stability. The encapsulation efficiency of liposomes was in order of combination of chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated. The in vitro and in vivo release of drug was observed in the order of combination chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated.

Antioxidant evaluation and liposome formulation of Phyllanthus emblica extract

The DPPH radical scavenging activity of Phyllanthus emblica extract was determined along with its total phenolic content using gallic acid as a standard. The alcoholic extract showed high antioxidant activity with EC50 of 1.55µg/ml and total phenolic contents of 454.7±27.0mg/g. The effect of pH on antioxidant activity and total phenolic contents of the extract was evaluated at pH 2.0, 5.5 and 7.0. The solid state stability studies were performed at room temperature (25oC) and 45 °C under 75% RH for 2 months. The antioxidant capacity of the extract was pH dependent, the radical scavenging activity was about 70% at pH 2.4 and 5.5 and 40% at pH 7.2. Solid state stability of the extract showed no significant changes in both antioxidant activity and total phenolic contents. Liposomes of Phyllanthus emblica extract (1%) were prepared using modified ethanol injection method. The composition of liposome including types and ratios of lipids and additives was varied in order to obtain the liposomes with appropriate physical appearance, size and entrapment efficiency. The suitable liposome formulation is SPC (soybean phosphatidylcholine): Tween 80: DA (deoxycholic acid) (84:16:2.5). The formulation shows good physical appearance as a yellowish colloidal solution with high entrapment efficiency (70.67±2.66%) and suitable particle size (235.8±21.5nm).

Cationic liposome (DC-Chol/DOPE = 1:2) and a modified ethanol injection method to prepare liposomes, increased gene expression

Cationic liposomes composed of 3β-[ N-( N′, N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and dioleoylphosphatidylethanolamine (DOPE) (DC-Chol/DOPE liposome, molar ratio, 1:1 or 3:2) prepared by the dry-film method have been often used as non-viral gene delivery vectors. The formulation and preparation of DC-Chol/DOPE liposomes, as well as the formation of their lipoplexes were investigated in an attempt to improve transfection efficiency in vitro. A more efficient transfection in medium with serum was achieved using DC-Chol/DOPE liposomes (molar ratio, 1:2) than those (3:2), and preparation method by a modified ethanol injection than the dry-film. The most efficient DC-Chol/DOPE liposome for gene transfer was molar ratio (1:2) and prepared by a modified ethanol injection method. The enhanced transfection might be related to an increase in the release of DNA in the cytoplasm by the large lipoplex during incubation in optiMEM, not to an increased cellular association with the lipoplex. The use of a modified ethanol injection method might enhance the role of DOPE that is aid in destabilization of the plasma membrane and/or endosome. These findings suggested that cationic liposomes rich in DOPE prepared by a modified ethanol injection method will help to improve the efficacy of liposome vector systems for gene delivery.