Reverse-phase Evaporation Method Research Articles

Preparation of liposomes containing benzophenanthridine alkaloid sanguinarine and evaluation of its cytotoxic activity

Sanguinarine is a plant alkaloid with relatively low toxicity and high antiangiogenic, antitumour and antiviral potential. In order to increase its bioavailability and effectiveness, sanguinarine liposomes were prepared by a reverse phase evaporation method and characterised. Dynamic light scattering showed mean liposome size of 65 ± 11 nm, zeta-potential equal to -54 ± 1.2 mV, and polydispersity index equal to 0.26. The encapsulation efficiency was 78.6 ± 5.1%. The study on experimental models showed a prolonged sanguinarine release from liposome preparations. Liposomal sanguinarine showed dose-dependent cytotoxic activity in vitro on B16 (murine melanoma) and HeLa (human cervical carcinoma) cell lines. The highest cytotoxicity was observed on B16 cell line (IC50 6.5 μM). HeLa cell line cytotoxicity was relatively lower, equal to 8.03 μМ. Compared with free sanguinarine, liposomal sanguinarine may have advantages for in vivo anticancer therapy, due to its lower toxicity and 'passive targeting' as a result of enhanced permeability of tumour vessels.

Synthesis of nano‐niosomal deferoxamine and evaluation of its functional characteristics to apply as an iron‐chelating agent

AbstractDeferoxamine has been widely used as an iron‐chelating agent in patients with primary or secondary iron overload deficiency. Deferoxamine is typically administered subcutaneously, intramuscularly, or intravenously by the constant infusion of the drug over 8–12 h. This process is lengthy and uncomfortable for the patients. A nano‐niosomal form of deferoxamine was prepared using the reverse phase evaporation method and evaluated on the basis of morphology, drug release, cytotoxicity, and iron‐chelating efficacy to compare with free drug formulation. The unique structure of niosome enables sustained release of the drug over extended periods. The average particle size was 136 nm and the entrapment efficiency was about 96 %. The biocompatibility of the drug‐loaded nanoparticles showed that the encapsulation of the drug in nano‐niosomes reduces the toxicity of the drug significantly. Our results indicate that the iron‐chelating ability of the entrapped deferoxamine in hepatocytes is higher than the free drug. The nano‐niosomal drug form showed more efficacies versus the free one and it could be a promising clinical intravenous system for delivery of iron‐chelating drugs such as deferoxamine.

Construction and evaluation in vitro and in vivo of tedizolid phosphate loaded cationic liposomes

First, the SA-TDZA-Lips were prepared by reverse-phase evaporation method. Then, the drug release behaviour was evaluated by dynamic membrane dialysis in vitro and the preliminary safety was evaluated by haemolysis method. Finally, with tedizolid phosphate injection (TDZA-Inj) and tedizolid phosphate loaded liposomes (TDZA-Lips) as the control groups, the pharmacokinetic characteristic and tissues distribution of SA-TDZA-Lips were evaluated after intravenous injection. As a result, the stearylamine modified tedizolid phosphate liposomal delivery system was constructed successfully and the particle size was 194.9 ± 2.93 nm. The encapsulation efficiency (EE) was 53.52 ± 2.18%. The in vitro release of SA-TDZA-Lips was in accordance with Weibull equation. And there was no haemolysis happened, which indicated good preliminary safety for injection. The results of pharmacokinetics showed that the t1/2β increased by 0.74 times and 0.51 times higher than that of TDZA-Inj group and TDZA-Lips group, respectively. The MRT of SA-TDZA-Lips was 1.30 and 1.09 times higher than that of TDZA-Inj group and TDZA-Lips group, respectively. The AUC was 2.40 times and 0.23 times higher than that of TDZA-Inj group and TDZA-Lips group, respectively. The tissue distribution results showed that the relative uptake rate (Re) of TDZA in the lung was 1.527, which indicated the targeting. In conclusion, the SA-TDZA-Lips prepared in this study had several advantages like positive charge, strong cell affinity, prolonged circulation time in vivo, sustained release effect, and increased drug concentration in lungs. All advantages above provided significant clinical value of application for the treatment of bacterial pneumonia with tedizolid phosphate.

NANO-VESICLES OF SALBUTAMOL SULPHATE IN METERED DOSE INHALERS: FORMULATION, CHARACTERIZATION AND IN VITRO EVALUATION

Objective: The present work was aimed to prepare niosomes entrapping salbutamol sulphate (SS) using reversed phase evaporation method (REV).Methods: Niosomes were prepared by mixing span 60 and cholesterol in 1:1 molar ratio in chloroform, SS in water was then added to organic phase to form niosomal SS. Formulations after evaporation of chloroform, freeze centrifuged then lyophilized, were evaluated for particles size, polydispersity index (Pdi), zeta-potential, morphology, entrapment efficiency (EE%) and in vitro release. For pulmonary delivery; metered dose inhalers (MDI) were prepared by suspending SS niosomes equivalent to 20 mg SS in hydrofluoroalkane (HFA). The metered valve was investigated for leakage rate, the total number of puffs/canister, weight/puff, dose uniformity and particle size.Results: The results showed spherical niosomes with 400-451 nm particles that entrapped 66.19% of SS. 76.54±0.132% SS release from niosomes that showed a controlled release profile for 8h. The leakage test was not exceeding 4 mg/3 d, the number of puffs were up to 200puffs/canister, the dose delivered/puff was 0.1 mg and 0.64-4.51μm niosomal aerosol.Conclusion: The results indicate an encouraging strategy to formulate a controlled drug delivery by entrapping (SS) in niosomes which could be packaged into (MDI) that met the requirements of (USP) aerosols guidelines which offering a novel approach to respiratory delivery.

Preparation, Characterization, and Preliminary In Vitro Testing of Nanoceria-Loaded Liposomes.

Cerium oxide nanoparticles (nanoceria), well known for their pro- and antioxidant features, have been recently proposed for the treatment of several pathologies, including cancer and neurodegenerative diseases. However, interaction between nanoceria and biological molecules such as proteins and lipids, short blood circulation time, and the need of a targeted delivery to desired sites are some aspects that require strong attention for further progresses in the clinical application of these nanoparticles. The aim of this work is the encapsulation of nanoceria into a liposomal formulation in order to improve their therapeutic potentialities. After the preparation through a reverse-phase evaporation method, size, Z-potential, morphology, and loading efficiency of nanoceria-loaded liposomes were investigated. Finally, preliminary in vitro studies were performed to test cell uptake efficiency and preserved antioxidant activity. Nanoceria-loaded liposomes showed a good colloidal stability, an excellent biocompatibility, and strong antioxidant properties due to the unaltered activity of the entrapped nanoceria. With these results, the possibility of exploiting liposomes as carriers for cerium oxide nanoparticles is demonstrated here for the first time, thus opening exciting new opportunities for in vivo applications.

Simple nanoliposomes encapsulating Lycium barbarum polysaccharides as adjuvants improve humoral and cellular immunity in mice.

The success of subunit vaccines has been hampered by the problems of weak or short-term immunity and the lack of availability of nontoxic, potent adjuvants. It would be desirable to develop safe and efficient adjuvants with the aim of improving the cellular immune response against the target antigen. In this study, the targeting and sustained release of simple nanoliposomes containing Lycium barbarum polysaccharides (LBP) as an efficacious immune adjuvant to improve immune responses were explored. LBP liposome (LBPL) with high entrapment efficiency (86%) were obtained using a reverse-phase evaporation method and then used to encapsulate the model antigen, ovalbumin (OVA). We demonstrated that the as-synthesized liposome loaded with OVA and LBP (LBPL-OVA) was stable for 45 days and determined the encapsulation stability of OVA at 4°C and 37°C and the release profile of OVA from LBPL-OVA was investigated in pH 7.4 and pH 5.0. Further in vivo investigation showed that the antigen-specific humoral response was correlated with antigen delivery to the draining lymph nodes. The LBPL-OVA were also associated with high levels of uptake by key dendritic cells in the draining lymph nodes and they efficiently stimulated CD4+ and CD8+ T cell proliferation in vivo, further promoting antibody production. These features together elicited a significant humoral and celluar immune response, which was superior to that produced by free antigen alone.

Ethosomes and Transfersomes: Principles, Perspectives and Practices.

The success story of liposomes in the treatment of systemic infectious diseases and various carcinomas lead the scientists to the innovation of elastic vesicles to achieve similar success through transdermal route. In this direction, ethosomes and transfersomes were developed with the objective to design the vesicles that could pass through the skin. However, there is a lack of systematic review outlining the principles, method of preparation, latest advancement and applications of ethosomes and transfersomes. This review covers various aspects that would be helpful to scientists in understanding advantages of these vesicular systems and designing a unique nano vesicular delivery system. Structured search of bibliographic databases for previously published peer-reviewed research papers was explored and data was culminated in terms of principle of these vesicular delivery systems, composition, mechanism of actions, preparation techniques, methods for their characterization and their application. A total of 182 papers including both, research and review articles, were included in this review in order to make the article comprehensive and readily understandable. The mechanism of action and composition of ethosomes and transfersomes was extensively discussed. Various methods of preparation such as, rotary film evaporation method, reverse phase evaporation method, vortex/ sonication method, ethanol injection method, freeze thaw methods, along with their advantages has been discussed. It was also discussed that both these elastic nanocarriers offer unique advantages of ferrying the drug across membranes, sustaining drug release as well as protecting the encapsulated bio actives from external environment. The enhanced bioavailability and skin penetration of ethosomes as compared to conventional vesicular delivery systems is attributed to the presence of ethanol in the bilayers while that for transfersomes accrues due to their elasticity along with their ability to retain their shape because of the presence of edge activators. Successful delivery of synthetic drugs as well as phytomedicines has been extensively reported through these vesicles. Though these vesicular systems offer a good potential for rational drug delivery, a thoughtfully designed process is required to optimize the process variables involved. Industrial scale production of efficacious, safe, cost effective and stable formulations of both these delivery systems appears to be a pre-requisite to ensure their utility as the trans-dermal vehicles.

Liposomes Containing Gadodiamide: Preparation, Physicochemical Characterization, and In Vitro Cytotoxic Evaluation.

The aim of this study was to develop, characterize and assess the cytotoxic activity of pHsensitive (pHL-Gd), stealth pH-sensitive (SpHL-Gd), and conventional (convL-Gd) liposomes containing gadodiamide (Gd-DTPA-BMA). Formulations were prepared by reverse-phase evaporation method and their physicochemical properties were evaluated by means of particle size, zeta potential, and Gd-DTPA-BMA entrapment. SpHL-Gd was considered being the most promising liposome, since it combines stealth and fusogenic characteristics that might contribute to achieve higher therapeutic efficiency. Their drug encapsulation percentages have been optimized satisfactorily. The addition of Gd-DTPA-BMA at 125 μmol/mL in the SpHL-Gd preparation allowed obtaining liposomes with appropriate encapsulation percentage (20.3 ± 0.1%) and entrapment (25.4 ± 0.1 μmol/mL). The cytotoxic studies on the 4T1 breast cancer cell line demonstrated that liposomes-loaded with Gd-DTPA-BMA inhibited cancer cell. pHL-Gd and SpHL-Gd liposomes showed higher activity than convL-Gd and free Gd-DTPA-BMA, indicating that the pH-sensitive characteristic was important to improve intracellular delivery. The presence of polyethylene glycol (PEG) in the SpHL-Gd formulation did not affect the pH-sensitivity and internalization. Therefore, the results of this study suggest the feasibility of liposomes containing Gd-DTPA-BMA as a new promising controlled delivery system.

Enhancing Lysozyme Loading in Powderized Liposomes by Controlling Encapsulation Processes

Liposomes have demonstrated great potentials as protein carriers in various pharmaceutical applications. However, low loading amount of proteins in liposomes have been a major challenge for maximizing the therapeutics potential of the proteins. We thus aimed to enhance the loading amount of a model protein, lysozyme, in liposomes by controlling key experimental variables of a reverse phase evaporation method. The loading amount of lysozyme in liposomes was evaluated with changing type of organic solvents used, weight ratio of lysozyme/phosphatidylcholine, and volume ratio of aqueous to organic phase along with particle characterization before and after freeze‐drying procedure. As a result, the loading amount of lysozyme in liposomes was considerably enhanced and the physical stability of the liposomes was maintained without any significant changes in the particle characteristics for 7 days. The findings of this study would be useful for highly efficient loading of protein therapeutics in liposomes, leading to improved therapeutic effects of the drugs.

Preparation of liposomes containing small gold nanoparticles using electrostatic interactions

The development of liposome-nanoparticle colloid systems offers a versatile approach towards the manufacture of multifunctional therapeutic platforms. A strategy to encapsulate small metallic nanoparticles (<4nm) within multilamellar vesicles, effected by exploiting electrostatic interactions was investigated. Two liposome-gold nanoparticle (lipo-GNP) systems were prepared by the reverse-phase evaporation method employing cationic or anionic surface functionalised particles in combination with oppositely charged lipid compositions with subsequent post-formulation PEGylation. Structural characterisation using electron microscopy and elemental analysis revealed a regular distribution of GNPs between adjacent lipid bilayers of intact liposomes. Nanoparticle encapsulation efficacy of the two lipo-GNP systems was revealed to be significantly different (p=0.03), evaluated by comparing the ratio of measured lipid to gold concentration (loading content) determined by a colorimetric assay and atomic emission spectroscopy, respectively. It was concluded that the developed synthetic strategy is an effective approach for the preparation of liposome-nanoparticle colloids with potential to control the relative concentration of encapsulated particles to lipids by providing favourable electrostatic interactions.

Novel dual VES phospholipid self-assembled liposomes with an extremely high drug loading efficiency

Vitamin E succinate (VES), a unique selective anti-cancer drug, has attracted much attention for its ability to induce apoptosis in various cancer cells. Importantly, it has been reported that VES is largely non-toxic to normal cells. However, poor aqueous solubility and bioavailability extensively restricted its clinical utility. In this report, dual VES phospholipid conjugate (di-VES-GPC) prodrug based liposomes were prepared in order to develop an efficient delivery system for VES. Di-VES-GPC was first synthesized by conjugating VES with l-α-glycerophosphorylcholine (GPC) using N,N′-dicyclohexylcarbodiimide (DCC) as a coupling agent. The di-VES-GPC prodrug was able to self-assemble into liposomes by reverse-phase evaporation method. The structure of the liposomes was characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and cryo-TEM. The results showed that di-VES-GPC assembled liposomes were spherical with an average diameter approximately 183nm. Cryo-TEM data confirmed the formation of multilamellar liposomes with the bilayer thickness about 5nm by the assembly of the conjugate without any excipient. The VES drug loading highly reaches up to 82.8wt% in the liposomes after a simple calculation. Furthermore, the in vitro release behavior of di-VES-GPC liposomes was evaluated in different media. It was found that the liposomes could release free VES at a weakly acidic microenvironment but exhibited good stability under a simulated biological condition. The cellular uptake and intracellular drug release tests demonstrated that di-VES-GPC liposomes could be internalized effectively and converted into parent drug VES in cancer cells. Furthermore, in vitro antitumor activities of the di-VES-GPC liposomes were evaluated by MTT assay and flow cytometry. It was revealed that the liposomes presented comparable cytotoxicities to free VES. Taken together, the di-VES-GPC liposomes might provide an excellent formulation of VES which have potential in the treatment of cancers.

Optimization of Glycyrrhiza polysaccharide liposome by response surface methodology and its immune activities

Glycyrrhiza polysaccharide liposome (GPSL) was prepared by reverse-phase evaporation method and optimized with response surface methodology. As a result, the optimum preparation conditions were as follows: the ratio of soybean phosphatide to Glycyrrhiza polysaccharide (GPS) of 24:1, temperature of drug incubation of 46°C, the ultrasound time of 16min. Confirmation experiments and transmission electron micrograph (SEM) exhibited the entrapment efficiency of liposome as 78.33±0.25%, with spherical shape and uniform sizes. Furthermore, proliferation assay, allogeneic mixed lymphocyte reaction and supernatant cytokines of chBM-DCs were performed by MTT and ELISA methods to investigate the immune-modulating effects of GPSL and GPS. The results showed that GPSL could significantly promote the proliferation of immature chBM-DCs, enhance the ability of mature chBM-DCs to induce T-cell proliferation and modulate the mature chBM-DCs to secret cytokines such as IL-2, IFN-γ and IL-10. These evidences indicated that the immune-modulating activity of GPS was significantly improved after encapsulated with liposome.

Retinal gene delivery enhancement by lycopene incorporation into cationic niosomes based on DOTMA and polysorbate 60

The present study aimed to evaluate the incorporation of the natural lipid lycopene into niosome formulations based on cationic lipid DOTMA and polysorbate 60 non-ionic surfactant to analyze the potential application of this novel formulation to deliver genetic material into the rat retina. Both niosomes with and without lycopene were prepared by the reverse phase evaporation method and physicochemically characterized in terms of size, zeta potential, polydispersity index and capacity to condense, release and protect the DNA against enzymatic digestion. In vitro experiments were performed in ARPE-19 cells after complexion of niosomes with pCMS-EGFP plasmid at appropriate cationic lipid/DNA ratios. At 18/1 mass ratio, nioplexes containing lycopene had nanometric size, positive zeta potential, low polydispersity and were able to condense, release and protect DNA. Percentage of transfected cell was around 35% without compromising cell viability. The internalization pathways studies revealed a preference to caveolae mediated endocytosis and macropinocytosis, which could circumvent lysosomal degradation. Both subretinal and intravitreal administrations to the rat retina showed that nioplexes were able to transfect efficiently the outer segments of the retina, which offer reasonable hope for the treatment of many inherited retinal diseases by a safe non-viral vector formulation after the less invasive intravitreal administration.

Optimization of Conditions for Cyanidin-3-OGlucoside (C3G) Nanoliposome Production by Response Surface Methodology and Cellular Uptake Studies in Caco-2 Cells.

We aimed to optimize the formulation of C3G nanoliposomes using response surface methodology. Additionally, we evaluated the stability, particle change, and encapsulation efficiency (EE) of C3G nanoliposomes under different temperatures and storage durations, as well as in simulated gastrointestinal juice (SGF) and simulated intestinal fluid. The morphology of C3G nanoliposomes was observed by transmission electron microscope. The ability of C3G nanoliposomes to affect cancer cell morphology and inhibit cancer cell proliferation was studied with Caco-2 cells. Reverse-phase evaporation method is a simple and efficient method for liposome preparation. The optimal preparation conditions for this method were as follows: C3G concentration of 0.17 mg/mL, phosphatidylcholine/cholesterol ratio of 2.87, and rotary evaporation temperature of 41.41 °C. At optimal conditions, the particle size and EE of the C3G nanoliposomes were 165.78 ± 4.3 nm and 70.43% ± 1.95%, respectively. The C3G nanoliposomes showed an acceptable stability in SGF at 37 °C for 4 h, but were unstable under extended storage durations and high temperatures. Moreover, our results showed that different concentrations of C3G nanoliposomes affected the morphology and inhibited the proliferation of Caco-2 cells.

Comparison Between Effects of Free and Niosomal Formulations of Artemisia annua L. (Asteraceae) on Chronic Myelogenous Leukemia (K562) Cell Line

Artemisia annua L. (Asteraceae) (artemisinin) has special antitumor activity against melanoma, breast, ovarian, prostate, central nervous system and renal cancer cell lines. The present study was conducted to compare effects of free and niosomal formulation of artemisinin on Chronic Myelogenous Leukemia (CML) using K562 cell line. Materials and Methods: Different concentrations of artemisinin were prepared using spectrophotometer in 195 nm wavelength. Two different methods of reverse phase evaporation and ether injection were adopted to prepare the niosomes formulations. Encapsulation, in vitro release, in vitro cytotoxicity determination and the K562 cells viability rates were assessed. Results: The percentage of encapsulation for niosome formulation obtained with reverse phase evaporation and ether injection methods were 87.27±0.93 and 74.9±4.2, respectively. The rate of the artemisinin release across the dialysis membrane was significantly slower for artemisinin-loaded niosomes than that of the free artemisinin (p<0.05). The percentage of K562 cells apoptosis in free artemisinin was significantly higher than that of the niosomal formulations (p<0.05). The niosomal formulations showed significantly more influence than that of the free artemisinin (p<0.05). Conclusion: The use of niosomal formulation of artemisinin could effectively improve its therapeutic index, release rate and apoptosis influence

Nanoformulation of dual bexarotene-tailed phospholipid conjugate with high drug loading

Bexarotene (Bex), a synthetic retinoid X receptor-selective activator, has been proved to be an efficacious chemotherapeutic agent. But, its clinical application is limited due to the poor solubility. In this report, dual bexarotene-tailed phospholipid (DBTP) conjugate based nanovesicles were prepared in order to develop new nanoformulation. DBTP conjugate was first synthesized by conjugating two Bex molecules with glycerophosphorylcholine (GPC) through facial esterification. The amphiphilic DBTP nanovesicles were prepared without any additive by reverse-phase evaporation method. They were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results revealed that the DBTP nanovesicles have a spherical structure with an average diameter approximately 138.7nm and a negatively charged surface (−33.3±2.5mV). The loading efficiency of Bex is 76wt% after a simple calculation. In vitro degradation of DBTP nanovesicles and the release of Bex were further studied in detail. The results demonstrated that DBTP nanovesicles were stable in neutral environment but degraded in a weakly acidic condition and released parent drug Bex effectively. Cellular uptake was investigated by confocal laser scanning microscope (CLSM) and liquid chromatography-mass spectroscopy (LC-MS). The results demonstrated the successful internalization and intracellular release of DBTP nanovesicles. Furthermore, the cytotoxicity analysis and apoptosis of the nanovesicles showed higher antitumor activities compared with free Bex. In a conclusion, DBTP nanovesicles could be an effective nanoformulation of Bex.

A novel elastic liposome for skin delivery of papain and its application on hypertrophic scar

This study aims to investigate the therapeutic effects of papain elastic liposomes (PEL) on hypertrophic scar through topical application. PEL were prepared using the reverse-phase evaporation method and optimized by response surface methodology. The transdermal absorption of optimized PEL was tested by vertical Franz diffusion cells in vitro. The effects of PEL were investigated in rabbit model of hypertrophic scar in vivo, histological analysis and scar-related proteins were detected to reveal potential scar repair mechanism. The best formulation of PEL had EE (43.8±1.4%), particle size (100.9±2.2nm), PDI (0.037±0.003), zeta potential (-26.3±1.3mV), and DI (21.9±3.1). PEL gave the cumulative amounts and steady state fluxes in the receiver solution of 381.9±32.4μg/cm2, 11.4±1.5μg/cm2/h, and showed drug deposition in skin of 19.1±3.2% after 24h. After topical application, the scar elevation index, microvascular density, and collagen fiber were significantly decreased with regular arrangement. The expressions of TGF-β1, P-Smad-3, P-NF-κB p65, and P-IKBa in hypertrophic scar were significantly down regulated in contrast with those in model group. PEL were proven as an excellent topical preparation for hypertrophic scar treatment.

The role of nanoparticles in the albumin-cytarabine and albumin-methotrexate interactions

Understanding the interactions which occur between nanomaterials and biomolecules is one of the most important issues in nanotechnology. Determining the properties of nanoparticles obtained through the use of novel methods and defining the scope of their application as drug carriers has important practical significance. Nanoparticles containing methotrexate and cytarabine obtained by a modified reverse-phase evaporation method (mREV) were characterized through the use of the UV/Vis and NMR methods. Obtained results confirmed high degree of analysed drugs encapsulation. The encapsulation efficiencies of cytarabine (AraC) and methotrexate (MTX) in LDPPC/AraC/MTX were found to be 86.30% (AraC) and 86.00% (MTX). The increased permeability of the phospholipid membranes, resulting from physico-chemical properties and the location of the drug, as well as from the physico-chemical properties of the phospholipids themselves, has been confirmed by increase in the length of the T1 relaxation time of protons in the N+(CH3)3 group. The study of analysed drugs release process from the liposomes has been made for bovine serum albumin, both in the absence (dBSA) and in the presence of fatty acid (BSA). Moreover two types of kinetic models (Bhaskar equation and Rigter-Peppas equation) have been used. Based on the study it has been concluded that mathematical modelling of drug release can be very helpful in speeding up product development and in better understanding the mechanisms controlling drug release from advanced delivery systems.

Self-assembled nanostructures formed by phospholipids and anticancer drugs. Serum albumin-nanoparticle interactions

The future of nanomedicine is related to the possibilities regarding the elimination of traditional therapies effects and targeted treatment of cancer at the molecular level. Nanooncology with modern diagnostics and personalized therapy can be a chance for cancer patients.Nanoparticles containing prednisone and cytarabine, obtained by a modified reverse-phase evaporation method (mREV), were characterized spectrometrically. Mathematical modelling of drug release can be very helpful in speeding up product development and in forming a better understanding of the mechanisms controlling drug release from advanced delivery systems. The in vitro release study of cytarabine and prednisone from nanoparticles in pH7.4 phosphate buffered saline (PBS) was explored, and the parabolic diffusion model simulated the progress of the release best, showing that the release process belongs to the group of multiphase diffusion processes.

A comparison between conventional liposome and drug-cyclodextrin complex in liposome system

A drug-cyclodextrin complex in liposome system was prepared in order to make a comparison with conventional risperidone-loaded liposome. Thin film hydration, reverse phase evaporation and ethanol injection methods were taken as preparation means to obtain the two types of liposome. Differential thermal analysis (DTA) and transmission electron microscopy (TEM) were used to investigate the thermal characters of inclusion complexes and morphology of liposome, respectively. Particle size, zeta potential and encapsulation efficiency were studied by light scattering analysis and ultrafiltration. In vitro release was carried out in the pH 7.4 phosphate buffer solution and samples were collected at the certain time. As a result, drug-cyclodextrin complex in liposome prepared by various methods displayed lower encapsulation efficiency than conventional liposome. However, size was larger and its stability was better than the latter. The second release phase of novel delivery system was slightly slower after initial burst release at the first phase, while the conventional liposome displayed a more regular trait. Thus, the novel liposome have potential to be developed as co-administration formulation with long-acting injection.