The impact of metal ions on the phase behavior of phosphatidylcholine (PC) was investigated at the air/water interface by surface pressure-area (pi-A) isotherm measurements. The analysis of the pi-A isotherms showed that with the metal ionic radius decreasing, the concentration of the metal ions C increasing, and the valence of metal ions Q increasing, the amount of the corresponding curves of A0 decreases, the phase transition point would change more apparently, the collapse pressure would become larger subsequently, and the curve would be extended outside. The phenomenon could be approached when the metal ion concentration C became great enough. These experiments were identified with the rules on Langmuir films, by a variety of properties of metal ions (ion radius, ion concentration, ion valence, etc.). Among all the factors, the ionic valence showed the greatest impact on the phase changes, followed by the ion concentration, while the ionic radius influences were less on the phase-change characteristics.
Air ; Ions ; chemistry ; Membranes, Artificial ; Metals ; chemistry ; Phase Transition ; Phosphatidylcholines ; chemistry ; Surface Properties ; Water ; chemistry

This study aimed to evaluate the rheological characteristic of W/O microemulsion. Using the Low Shear-30 Sinus Rheometer, we assessed the effects of water percentage in microemulsion on the apparent viscosity of microemulsion at different shear rates and temperature, and on the viscoelasticity of microemulsion. The results demonstrated that with the increase of water, the apparent viscosities at four different shear rates increased exponentially. The fitted curve between water percentage and the apparent viscosity (eta) at low shear rate was steeper than the others. We found that viscous component (eta') and elastic component (eta") also increased exponentially when water percentage was increasing. This communication addressed the relationship between water percentage and eta, and discussed the physical meaning of the elastic component. The results suggest that both the viscous component and the elastic component present qualitatively physical nature, but the viscous component is more accurate than the other.
Chemical Phenomena ; Chemistry, Physical ; Elasticity ; Emulsions ; Phosphatidylcholines ; chemistry ; Rheology ; Shear Strength ; Viscosity

AIMTo prepare solid lipid nanoparticles by microemulsion technique.

METHODSStearic acid was used as the oil phase, lecithin as surfactant, alcohol as cosurfactant and distilled water as the aqueous phase. Microemulsion was prepared by mixing the above component in proper ratio. The corresponding pseudoternary phase diagram monitored Microemulsion formation field of different lecithin/alcohol. Solid lipid nanoparticles (SLN) were prepared by dispersing warm microemulsion in cold water under magnetic stirring. Then appropriate microemulsions that can contain more water phase and suitable oil phase were selected to prepare SLN. The influence of formulation, process variables on the preparation and quality of SLN were studied. Based on the investigation of single factors, orthogonal design was used to optimize SLN formulation and preparation process, and more, the reproducibility of the optimized results were studied.

RESULTSThe results showed that the device temperature (Ti), water temperature (Tw), and delivery rate (Rd) were the key factors that influence the preparation process of SLN, and Tw was extremely important. The ratio of microemulsion formulation, the ratio of microemulsion and distilled water had also influence on its quality.

CONCLUSIONMicroemulsion technique can be used to prepare solid lipid nanoparticles.

Alcohols ; Drug Carriers ; Emulsions ; Lipids ; chemical synthesis ; chemistry ; Nanotechnology ; Particle Size ; Phosphatidylcholines ; Solubility ; Technology, Pharmaceutical ; methods

AIMTo increase the solubility and bioavailability of all-trans retinoic acid (ATRA).

METHODSUsing the principle of lecthin/bile salt mixed micelle to prepared ATRA injection. The best formulation was obtained by the turbidity and three-phase figure.

RESULTSATRA mixed micelles injection is stable. The average size of the mixed micelle is 17.8 nm, poly. index 0.495, zeta potential -16.5 mV.

CONCLUSIONThe method can be used to prepare the stable injection.

Antineoplastic Agents ; administration & dosage ; chemistry ; Bile Acids and Salts ; Drug Stability ; Micelles ; Phosphatidylcholines ; Solubility ; Technology, Pharmaceutical ; methods ; Tretinoin ; administration & dosage ; chemistry

The temperature-sensitive liposomes were constructed by poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives that were synthesized for partially modification of carboxylic groups. The thermal characteristics of liposomes were investigated by using fluorescent indicator, particle size device and fluorescence spectrophotometer system. The results showed that the liposome made of fatty amine-modified poly(2-ethylacrylate) had a marked thermal sensitive release of drugs, which is correlated with the structure of molecular of polymer and the initial ratio of composition of phospholipid. The PEAA-associated-liposomes were also shown pH-sensitive drug release under acidic condition. The poly (2-ethylacrylate) for the preparation of medium-induced thermal liposomes in vitro experiments showed a good thermal characteristics and the methods of preparing temperature-sensitive liposomes were convenient and stability.
Acrylates ; chemistry ; Cholesterol ; chemistry ; Drug Carriers ; Drug Delivery Systems ; methods ; Fluoresceins ; analysis ; Hydrogen-Ion Concentration ; Liposomes ; chemistry ; Particle Size ; Phosphatidylcholines ; chemistry ; Polymers ; chemistry ; Temperature

OBJECTIVETo formulate gentamicin liposphere by solvent-melting method using lipids and polyethylene glycol 4 000 (PEG-4 000) for oral administration.

METHODSGentamicin lipospheres were prepared by melt-emulsification using 30% w/w Phospholipon® 90H in Beeswax as the lipid matrix containing PEG-4 000. These lipospheres were characterized by evaluating on encapsulation efficiency, loading capacity, change in pH and the release profile. Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Salmonella paratyphii and Staphylococcus aureus using the agar diffusion method.

RESULTSPhotomicrographs revealed spherical particles within a micrometer range with minimal growth after 1 month. The release of gentamicin in vitro varied widely with the PEG-4 000 contents. Moreover, significant (P>0.05) amount of gentamicin was released in vivo from the formulation. The encapsulation and loading capacity were all high, indicating the ability of the lipids to take up the drug. The antimicrobial activities were very high especially against Pseudomonas compare to other test organisms. This strongly suggested that the formulation retain its bioactive characteristics.

CONCLUSIONSThis study strongly suggest that the issue of gentamicin stability and poor absorption in oral formulation could be adequately addressed by tactical engineering of lipid drug delivery systems such as lipospheres.

Anti-Bacterial Agents ; chemistry ; pharmacokinetics ; pharmacology ; Bacteria ; drug effects ; Gentamicins ; chemistry ; pharmacokinetics ; pharmacology ; Liposomes ; chemistry ; Microbial Sensitivity Tests ; Particle Size ; Phosphatidylcholines ; chemistry ; Polyethylene Glycols ; chemistry

Sonogenic microbubble agent is a newly developed drug targeting delivery system, which uses ultrasonic beam to enhance the delivery of drug and gene to targeted cells and tissues. In this paper, the preparation of sonogenic phospholipids-based microbubbles was optimized by using central composite experimental design (CCD) and response surface methodology (RSM). Hydrogenated egg phosphatidylcholine (EPC), Tween 80 and polyethylene glycol 1500 (PEG 1500) were important components affecting the concentration of 2 - 8 microm microbubbles in the preparation. The combined effects of these three factors were analyzed by CCD and optimized by RSM. Evaluation variable was the concentration of 2 - 8 microm microbubbles. Overall desirability was fitted to a second-order polynomial equation, through which three dimensional response surface graphs were produced. Optimal experimental conditions were selected from the stationary point of the response surfaces. The stability of the sonogenic phospholipids-based microbubbles by the optimal formulation was investigated by accelerated experiment. The contrast effect in vivo of the optimal formulation was investigated. Foreign market product SonoVue was used as the control. From the results, all the three factors had positive effects on the concentration of 2 - 8 microm microbubbles. The optimal condition in the preparation of phospholipids-based microbubbles was obtained as following: EPC 8.35 mg, Tween 80 21.68 mg and PEG 1500 201 mg. The mean value of the concentration of 2 - 8 microm microbubbles in rechecking experiment reached 8.60 x 10(9) x mL(-1). From the accelerated experiment, phospholipids-based microbubbles showed good physical stability. The intensity (relative unit) and duration of the contrast effect by the optimal formulation were 4.47 +/- 0.15 and (302 +/- 7) s respectively, which showed little difference with foreign market product SonoVue [4.28 +/- 0.13, (309 +/- 8) s]. The optimal formulation selected by CCD and RSM showed high microbubble concentration, good physical stability and effective sonogenic contrast effect.
Animals ; Contrast Media ; Drug Carriers ; Drug Compounding ; Drug Delivery Systems ; Drug Design ; Male ; Microbubbles ; Particle Size ; Phosphatidylcholines ; chemistry ; Polyethylene Glycols ; chemistry ; Polysorbates ; chemistry ; Rabbits ; Ultrasonics

A simulated moving bed (SMB), equipped with eight silica-gel columns, was used to separate phosphatidylcholine (PC) from soybean phospholipids. The effects of flow rate in Sections 2 (Q(2)) and 3 (Q(3)), switching time, feed flow rate and feed concentration on the operating performance parameters: purity, recovery, productivity and desorbent consumption were studied. Operating conditions leading to more than 90% purity in both outlet streams have been identified, together with those achieving optimal performance. Regions leading to complete separation are observed and explained theoretically. As the mass-transfer effect was not considered, the triangle theory only gives initial guesses for the optimal operating conditions.
Chemical Fractionation ; methods ; Chromatography, High Pressure Liquid ; methods ; Computer Simulation ; Models, Chemical ; Phosphatidylcholines ; isolation & purification ; Phospholipids ; chemistry ; Plant Extracts ; isolation & purification ; Soybeans ; chemistry

In this paper, we address the preparation of the EPC and HEPC sterically stabilized doxorubicin liposomes and report the data collected from further studies on pharmacokinetics in blood for choosing a better carrier in delivering the drugs. The pharmacokinetics of EPC and HEPC sterically stabilized liposomes (EPC-SSL, and HEPC-SSL) in Wistar rats were investigated by HPLC. The results showed that the mean residence time of HEPC-SSL in blood is 23.3 h, while that of EPC-SSL is 12.0 h. In conclusion, HEPC-SSL is a better carrier in delivering the drugs to the extravascular sites when compared with EPC-SSL.
Animals ; Antibiotics, Antineoplastic ; administration & dosage ; pharmacokinetics ; Delayed-Action Preparations ; chemical synthesis ; pharmacokinetics ; Doxorubicin ; administration & dosage ; pharmacokinetics ; Drug Carriers ; chemistry ; Hydrogenation ; Liposomes ; Phosphatidylcholines ; chemistry ; pharmacology ; Rats

OBJECTIVETo investigate various methods for constructing soybean lecithin (SL)-based vesicles and evaluate the permeation-enhancing effect of SL-based vesicles on the penetration of insulin through buccal mucosa.

METHODSThe ultrasonic method, high speed shear method and high pressure homogenization method were respectively used to prepare the SL-based vesicles, and the particle size of the vesicles was measured with photon correlation spectrometry (PCS). The penetration rate of insulin through porcine buccal mucosa was investigated with the Valia-Chien diffusion cells.

RESULTSThe average particle sizes of 3 formulations of SL-based vesicles were 97.39, 85.60, and 100.60 nm when prepared by ultrasonic method, and were 58.7, 88.7, and 91.9 nm when prepared by high pressure homogenization method. Both vesicles presented good stability. However, the SL-based vesicles prepared by high speed shear method had larger average diameters and were found to be unstable. Transmission electron microscopy showed that SL-based vesicles had a spherical shape and the result accorded with PCS. The permeation flux of insulin of formulation 1 and control solution were 0.0024 and 0.0008 IU x ml(-1) x min(-1), respectively. The accumulative amount of formulation 1 at 180 min was (0.436 +/- 0.010 ) IU x ml(-1), which was 1.46 times higher than the control solution.

CONCLUSIONSThe SL-based vesicles obtained using high pressure homogenization method are characterized by small particle size, narrow distribution, good stability, and powerful permeation-enhancing effect, which enables them to be good carriers for the buccal delivery of insulin.

Absorption ; Administration, Topical ; Chemistry, Pharmaceutical ; Drug Carriers ; administration & dosage ; chemical synthesis ; pharmacokinetics ; Drug Delivery Systems ; methods ; Insulin ; metabolism ; Mouth Mucosa ; metabolism ; Nanotechnology ; methods ; Phosphatidylcholines ; pharmacokinetics ; Soybeans ; chemistry