Vitamin C as a shelf-life extender in liposomes

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

Nanotechnology as a tool to overcome the bariatric surgery malabsorption.

Obesity is a metabolic disease that affects all ages; it is considered life-threatening condition as it leads to fatal complications such as; cardiovascular diseases and diabetes. The therapeutic options include; life-style modifications, pharmacotherapy intervention, and surgical intervention. Bariatric surgery (BS) is considered as the most effective option among the others for its rapid weight loss, maintaining the lost mass, and improving the quality of life of the patients. Nevertheless, BS leads to severe changes in the bioavailability of medications, especially for chronic diseases, which may reach to limit where the patient's life endangers. Recently, pharmaceutical formulations had developed several methods to improve the drug bioavailability of drugs though the implying of nanotechnology. Nonotechnology is responsible for reducing the size of the drugs to the nano range (<1000 nm), which increase the drug surface area, dissolution, absorption, and, most importantly, the bioavailability of these drugs. It is believed that BS malabsorption and drugs bioavailability problems can be solved using nanotechnology for its advantages in overcoming BS complications.

Preparation, characterization and in vitro evaluation of PEGylated nanoliposomal containing etoposide on lung cancer.

Introduction and objective: Lung cancer is the most common one in terms of outbreak and mortality. Since most modern treatments have many side effects, finding an effective and alternative therapy seems necessary. The present study aimed to determine the effect of PEGylated liposomal etoposide nanoparticles on the lung cancer (A-549 and Calu6 cell lines). Materials and methods: The PEGylated liposomal etoposide nanoparticles were prepared by reverse-phase evaporation method. The particle size and zeta potential of the nanoparticles were measured by Zetasizer. The nanoparticle cytotoxicity was examined by MTT method. The vesicular drug release pattern was examined by dialysis method. The amount of loaded drug and the encapsulation efficiency (EE) was also measured and calculated. Apoptosis test was performed using flow cytometry with Annexin V kit. Results: The mean particle size, size distribution, and zeta potential of PEGylated liposomal etoposide nanoparticles were 122.5 ± 4.8 nm, 0.252 ± 0.12 and -13.7 ± 0.51 mv, respectively. The etoposide release in prepared formulations was detected to be about 15.64% after 50 hr. The cytotoxic effect of etoposide nanoparticles on lung cancer A-549 and Calu6 cell lines showed more anti-tumour activity compared to the free drug used. Conclusion: The results showed that the PEGylated liposomal nanoparticles were used as a suitable nanocarrier for etoposide injection. It was also found that the drug effect on the nanodrug formulations was higher than that of the free drug.

Preparation Process of Baicalin Liposomes by Reverse Phase Evaporation / 中国药学杂志

OBJECTIVE: To study the preparation technology of baicalin glycosides liposomes. METHODS: Baicalin liposomes modified by vitamin E and Tween 80 were prepared by reverse phase evaporation method. The free drug was separated by ultracentrifugation and the encapsulation rate was determined by UV spectrophotometry. Based on the results from single factor tests, orthogonal experimental design was used to investigate the factors influencing the envelopment rate of liposomes. The baicalin liposomes prepared by the optimized process were characterized for particle size, Zeta potential, and morphology. RESULTS: The optimum conditions for the preparation of liposomes were as follows: the ratio of water phase to organic phase 1∶3, the concentration of baicalin 3 mg•mL-1, the ratio of cholesterol to soy lecithin 1∶6, dosage of vitamin E 2 mg,dosage of Tween 80 120 μL. The mean diameter was 52.2 nm, Zeta potential was -51.9 mV, the encapsulation rate was 70.22% and drug loading capacity was 3.18%. Transmission Electr Microscope(TEM) results showed that the shape of the liposomes was good, the particle size was relatively uniform and consistent with the results of laser granulometry. CONCLUSION: The stability of baicalin liposomes can be improved by the addition of vitamin E and Tween 80.

Evaluation the Anti-Cancer Effect of PEGylated Nano-Niosomal Gingerol, on Breast Cancer Cell lines (T47D), In-Vitro

Background: Cancer is a significant problem in modern medicine, also is the most common cause of death after cardiovascular diseases, and in need of targeted drug release. Although, chemotherapy is an important candidate in cancer treatment, but it has many side effects on healthy tissues of the body. Therefore, Nano technology is used for specific function, by the least side effects and damage to normal cells. Materials and method: In this study, the pharmacological properties of PEGylated Nano-niosomal Gingerol was examined. Noisome were prepared using reverse phase evaporation method, which contains specific proportion of cholesterol, span60 and polyethylene glycol. Then, PEGylated the prepared formulation by PEG6600. The amount of release and encapsulation of the drug was investigated. The percentage of remains of cancer cell line T47D treated with PEGylated niosomal Gingerol. Results: The average diameter of the nanoparticles, size distribution and zeta potential were reported for PEGylated niosomal sample 35.65 nm, 0.17 and 21 mv, and for PEGylated niosomal drug sample 256.9 nm, 0.23 and 28 mv, respectively. The amount of OD for encapsulated drug was 0.198, also the amount of concentration of the drug which is not encapsulated, was 0.77947 µl of the drug per ml. This value of encapsulated drug was 76.38 percent. Conclusion: The results showed that IC50 of the formulation of PEGylated nanoniosomal Gingerol is less than the standard drug. It seems, the cause of this phenomenon is due to the effect of Polyethylene glycol, in more stability and slower drug release, in the formulation of PEGylated niosome. Also, Polyethylene glycol makes increase in the drug dealing and its greater influence with the target cell. In this study, more than 76% of the Gingerol drug in PEGylated nanoniosomal formulation were enclose. Also, we could reduce the amount of drug release, as much as possible.

Formulation and statistical optimization of intravenous temozolomide-loaded PEGylated liposomes to treat glioblastoma multiforme by three-level factorial design.

The aim of the presented study was to develop PEGylated liposomes of Temozolomide (TMZ) that provide optimum drug concentration at tumor site. Reverse phase evaporation (REV) method was used to prepare TMZ-loaded PEGylated liposomes. Formulation was optimized by using design expert software by 32 factorial design. The physicochemical properties including size, morphology, entrapment efficiency, drug loading, etc. of formulated liposomes were evaluated. Finally, the optimized formulation was selected for in vitro drug release and stability study. In vivo pharmacokinetic study in rats showed that TMZ-loaded PEGylated liposomes leads to 1.6-fold increase in AUCTotal in blood and 4.2-fold increase in brain as compared to free drug solution. This formulated PEGylated liposomes offers a promising approach for treatment of Glioblastoma Multiforme.

Anti-inflammatory activity of liposomes of Asparagus racemosus root extracts prepared by various methods.

Asparagus racemosus root extracts (AR) have been reported to possess a variety of pharmacological properties. The aim of the present study was to develop liposomes of AR and to assess their physicochemical characteristics and anti-inflammatory activity in the monocytic leukemia cell line THP-1. Liposomes containing various ratios of AR to lipid and a phosphatidylcholine to cholesterol molar ratio of 7:3 were prepared by thin-film hydration (TF), reverse-phase evaporation (REV) and polyol dilution (PD). The results showed that AR liposomes prepared by TF had a multilamellar structure and a large size, whereas those prepared by REV and PD were oligolamellar in structure, and of a smaller size. The particle sizes and zeta potentials of the liposomes ranged from 196.5 to 456.6 nm and from -4.34 to -18.94 mV, respectively. The AR to lipid ratio was shown to have no significant influence on particle size, while the zeta potential generally increased with increasing AR to lipid ratio. The highest entrapment efficiency values were detected in liposomes with an AR to lipid ratio of 1:5, and for liposomes prepared by TF, REV and PD methods, the entrapment efficiencies were 55.71±2.04, 56.21±3.59 and 67.68±1.37%, respectively. AR was found to exert no toxicity on THP-1 cells. The maximum anti-inflammatory activities of AR and AR liposomes, evaluated in terms of the percentage inhibition of tumor necrosis factor-α in THP-1 cells, were ~52% at a concentration of 1 µg/ml. It can be concluded from the present study that AR liposomes have the potential to be used a formulation for topical and/or transdermal drug delivery to provide anti-inflammatory activity.

Mucosal vaccination against tuberculosis using Ag85A-loaded immunostimulating complexes.

Tuberculosis (TB) is one of the major devastating diseases in the world, mainly caused by Mycobacterium tuberculosis. Furthermore, multi-drug resistant TB and extremely drug resistant TB are becoming big problems globally. Bacillus Calmette-Guerin (BCG) is the only available vaccine which provides protection against TB. The BCG vaccine is effective in children but not recommended in adults and elderly patients due to an associated low risk of infection with Mycobacterium tuberculosis and variable effectiveness of the vaccine. The main aim of this research study is to develop such a vaccine which will provide a better and safer profile in children and adults, as well as in elderly patients. In this present study, we prepared pulmonary tubercular vaccine by using an Antigen 85 complex (Ag85)-loaded nanocarrier such as the immunostimulating complex (ISCOM). Immunological outcomes clearly indicated significant improvement in humoral as well as cellular immune responses after pulmonary immunization with ISCOMs containing Quil A in mice.

Microencapsulation of (deoxythymidine)20-DOTAP complexes in stealth liposomes optimized by Taguchi design.

Stealth liposomes encapsulating oligonucleotides are considered as promising non-viral gene delivery carriers; however, general preparation procedures are not capable to encapsulate nucleic acids (NAs) efficiently. In this study, the lyophobic complexes of deoxythymidine20 oligonucleotide (dT20) and DOTAP were used instead of free dT20 for nano-encapsulation process by reverse phase evaporation method. Regarding the various factors that can potentially affect the liposome characteristics, Taguchi design was applied to analyze the simultaneous effects of factors comprising PEG-lipid (%), dT20/total lipid molar ratio, cholesterol (Chol%) and organic-to-aqueous phase ratio (o/w) at three levels. The response variables, hydrodynamic diameter, loading efficiency (LE%) and capacity (LC%), were studied by dynamic light scattering and ethidium bromide exclusion assay, respectively. The optimum condition described by minimum particle size as well as high LE% and LC% was obtained at 5% PEG-lipid, dT20/total lipid of 7, 20% Chol and o/w of 3 with an average size of 84 nm, LE% = 83.4% and LC% = 11.6%. Moreover, stability assessments in presence of heparin sulfate revealed the noticeable resistance, unlike DOTAP/dT20 lipoplexes, to premature release of NA. Transmission electron microscopy confirmed formation of discrete and circular vesicles encapsulating dT20.

Formulation design and characterization of a non-ionic surfactant based vesicular system for the sustained delivery of a new chondroprotective agent

Diacerein is used for symptomatic relief and cartilage regeneration in osteoarthritis. Due to gastrointestinal side effects, poor aqueous solubility and low bioavailability, its clinical usage has been restricted. The objective of the present study was to enhance its dissolution profile and to attain sustained release by designing a novel delivery system based on niosomes. Five niosomal formulations (F1-F5) with non-ionic surfactant (sorbitan monostearate) and cholesterol in varying ratios of 5:5, 6:4, 7:3, 8:2 and 9:1 were developed by the reverse-phase evaporation technique. The size and polydispersivity index (PDI) were found in the range of 0.608 µm to 1.010 µm and 0.409 to 0.781, respectively. Scanning electron microscopy (SEM) of the selected formulation (F3) revealed spherical vesicles, and 79.8% entrapment was achieved with F3 (7:3). Dissolution studies using the dialysis method showed sustained release behaviour for all formulations. The optimized surfactant-to-cholesterol concentration (7:3) in formulation F3sustained the drug-release time (T50%) up to 10 hours. Kinetic modelling exhibited a zero-order release (R2=0.9834) and the release exponent 'n' of the Korsmayer-Peppas model (n=0.90) confirmed non-fickian and anomalous release. The results of this study suggest that diacerein can be successfully entrapped into niosomes using sorbitan monostearate and that these niosomes have the potential to deliver diacerein efficiently at the absorption site.

A diacereína é usada para o alívio sintomático e para a regeneração da cartilagem na osteoartrite. Devido aos efeitos adversos gastrointestinais, baixa solubilidade aquosa e biodisponibilidade, o seu uso clínico tem sido restrito. O objetivo do presente estudo foi melhorar o perfil de dissolução deste fármaco e obter liberação prolongada através do planejamento de um novo sistema de liberação designado de niossoma. Cinco formulações distintas de niossomas (F1 a F5) contendo tensoativos não iônicos (monoestearato de sorbitano) e colesterol, em diferentes proporções, de 5:5, 6:4, 7:3, 8:2 e 9:1, foram desenvolvidas através da técnica de evaporacão de fase reversa. Os tamanhos e índices de polidispersibilidade (PDI) obtidos variam entre 0,608 e 1,01 µm e entre 0,409 e 0,7781, respectivamente. Imagens de microscopia electrônica de varrimento (SEM) da formulação selecionada (F3) revelaram vesículas esféricas. Obteve-se encapsulação de 79,8% com a formulação F3 (7:3). Estudos de dissolução usando o método de diálise demonstraram padrão de liberacão prolongada para todas as formulações. A proporção de tensoativo e colesterol (7:3) na formulacão F3 prolongou o tempo de liberação do fármaco (T50%) até 10 horas. Estudos de modelação cinética demonstraram ordem de liberacão zero (R2=0,9834) e o expoente de liberação "n" do modelo de Korsmayer-Peppas (n=0.90) confirmou a liberação não-fickiana e anômala. Os resultados deste estudo sugerem que a diacereína pode ser encapsulada com sucesso no interior de niossomas, utilizando monostearato de sorbitano, o qual tem potencial para liberar, eficientemente, a diacereína no local de absorção.

Preparation technology of sinomenine hydrochloride liposomes / 中草药

Objective: To prepare sinomenine hydrochloride (SIN-HCl) liposomes with high entrapment efficiency (EE) and to illustrate the effects of drug quantity and particle size on EE. Methods: Centrifugation sedimentation-centrifugation ultrafiltration was employed to determine EE of liposomes. Thin film hydration (TFH), reverse phase evaporation (REV), and ether injection (EI) were screened based on EE and formability of liposomes. The effects of water type, pH value, ion concentration of hydration liquid, pH gradient active drug loading, lecithin-cholesterol ratio, and drug-lipid ratio on EE of liposomes were investigated. The relationship between EE and the factors affecting the drug quantity and particle size was probed with a comprehensive design experiment. The stability of typical liposomes was evaluated at 4 °C. Results: The optimal preparation technology was TFH for SIN-HCl liposomes and citrate buffer solution (CBS) was the best hydration liquid. The liposome EE increased with the increase of pH values of CBS. When the pH value of CBS was fixed, the EE increased as a result of decrease in the ion concentration of CBS. pH gradient active drug loading led to increase of EE. The preferable hydration liquid for liposomes was CBS with pH value of 2.5. The optimal ratio of soybean lecithin to cholesterol was 6:1. Increasing ratios of SIN-HCl to soybean lecithin from 1:6 to 6:6 led to a slight decrease in EE of liposomes without probe signification. A quantitative relationship was established between the EE and drug quantity and liposome size. The EE of SIN-HCl liposomes prepared by certain particle size and drug quantity could reach over 80%. The typical liposomes showed a good stability. Conclusion: The technology of pH gradient active drug loading is able to prepare SIN-HCl liposomes with high EE.

Preparation of curcumin liposome and preliminary study on its stability / 重庆医科大学学报

Objective:To prepare curcumin liposome and investigate its stability.Methods:Curcumin liposome was prepared by the reversed-phase evaporation method and purified by exclusion chromatography with Sephadex-50.The optimum formation was selected by means of orthogonal design of experiment;Centrifugal acceleration experiment and determination of leakling ration were served to proved the liposome stability.Results:The optimum formula was as follows:the ratio of lecithin to drug was 60∶1;lecithin:cholesterol was 4∶1;pH of PBS was 6.5,ultrasonic time was 5min.The average entrapment efficiency for curcumin was 95.06%.Conclusion:The selected formulation and preparation technique of curcumin liposome is reasonable in prescription,practicable in techniques,high in encapsulation efficiency and good in stability.