Progress in research on the determination of entrapment efficiency of liposomes / 中国药科大学学报

@#Liposome, a new dosage form, has become important in improving in vivo behavior of drugs or realizing targeted drug delivery. Study and control of its critical processes and quality attributes are the main challenges in the current research on liposomes. The degree of encapsulation can determine drug''s effect in vivo directly, thus entrapment efficiency (EE) has turned into one of the critical quality attributes of liposome.In this paper some methods commonly used for the determination of EE and their characteristics are summarized and analyzed, and the main factors to be considered for the determination are discussed.

Formulation, Optimization And Characterization Of Nanostructured Lipid Carrier Of Nitrofurantoin

Nitrofurantoin is effective against many urinary tract pathogens. It acts as bacteriostatic and/or bactericidal by inhibiting DNA-RNA protein& cell wall synthesis. Nanostructured Lipid Carriers (NLCs) of NFT was prepared by Hot Homogenization Process. Glyceryl Monostearate and Miglyol 812 were heated at 80ºC temperature on hot plate. In the melted lipid, drug was added with continuous stirring at high speed homogenization. Formulation NLC12B has % Entrapment efficiency 89.1 ± 0.5, PDI 0.11 ± 0.01 and mean particle size 237 ± 7nm represents narrow particle size distribution. Spherical feature of NLCs with better uniformity without aggregation of Nitrofurantoin loaded NLC was confirmed by TEM. Moreover, efficient miscibility of drug in lipids was confirmed by the absence of intense and characteristic peak of NFT in XRPD. After 6 month storage at 2-8°C there was no significant changes in the PDI as well as mean particle size.

Preparation of glabridin ethosomes and their bioactivity evaluation / 中草药

Objective: To compare the effects of softeners including ethanol, propylene glycol and mixed alcohol (ethanol-propylene glycol 2:8) on the preparation of glabridin ethosomes (GLA-ES), and provide the selection basis of the softeners for studying the ethosomes of insoluble drugs. Methods: GLA-ES were prepared by injection-ultrasonic binding method with ethanol, propylene glycol and mixed alcohol (ethanol-propylene glycol, 2:8) as softeners. The morphology, size, Zeta potential, entrapment efficiency, stability, and in vitro drug release of GLA-ES were investigated. Tyrosinase activity on melanoma B16-OVA cells were detected to evaluate the inhibition of GLA-ES on the synthesis of melanin, the experiment of potassium ferricyanide reducing power was performed to evaluate the antioxidant effect of GLA-ES, and human epidermal HaCaT cells and rat skin were used for preliminary safety evaluation. Results: GLA-ES were yellow translucent liquid, containing vesicular phospholipid bilayer structure, the average particle size of GLA-Et-ES, GLA-PG-ES and GLA-MA-ES were (34.24 ± 0.29), (62.31 ± 1.66) and (41.20 ± 1.13) nm, respectively; The Zeta potential were (-41.0 ± 1.8), (-32.9 ± 0.2) and (-35.8 ± 1.6) mV, the entrapment efficiency were (91.47 ± 2.39)%, (87.33 ± 1.31)% and (91.39 ± 3.59)%, respectively, which had good stability of storage at 4 ℃ for 20 d, in vitro drug release behaviors of GLA-ES fitted Higuchi equation, implying their sustained release properties. Compared with the glabridin suspension, the inhibitory effects of GLA-Et-ES, GLA-PG-ES and GLA-MA-ES on tyrosinase activity in melanoma B16-OVA cells were increased by 38.07%, 19.58% and 40.42%, respectively. The results of potassium ferricyanide reducing power also showed that GLA-ES had a stronger in vitro antioxidant effect than the glabridin suspension; GLA-ES were nearly nontoxic on normal cells and had no irritation to rat skin. Conclusion: GLA-ES can be obtained by hree kinds of softeners, which can inhibit the synthesis of melanin and enhance the antioxidant effect with good safety. The present research will provide the basis for further developing skin-whitening cosmetics or pharmaceutical external preparation. For the insoluble drugs such as glabridin, when mixed alcohol (ethanol-propylene glycol) was selected as the softener to prepare ethosome, it exhibited better encapsulation efficiency and stability than that of ethanol or propylene glycol as the softener alone.

Preparation, characterization and pharmacokinetics of dihydromyricetin phospholipids complex loaded by nanostructured lipid carriers / 中草药

Objective: To prepare dihydromyricetin (DMY) phospholipids complex (DMY-PC) and its nanostructured lipid carriers (DMY-PC-NLC), and carry out in vitro and in vivo evaluation. Methods: DMY-PC was prepared by solvent evaporation method. High pressure homogenization method was used to prepare DMY-PC-NLC. Orthogonal test was employed to optimize the ratio of solid/liquid lipid, dose of lipids materials, dose of DMY-PC and the concentration of emulsifier of poloxamer. The lyophilized powder of DMY-PC-NLC was prepared with 5% of mannitol as protective agent. The comparation of in vitro release and pharmacokinetics between DMY-PC and DMY-PC-NLC was also studied. Results: DMY was in an amorphous state in DMY-PC. The results of 1HNMR showed that the structure of DMY was not changed. The optimized prescription of DMY-PC-NLC determined by orthogonal test was as follow: The ratio of solid/liquid lipid was 5:1, dose of lipids materials was 325 mg, dose of DMY-PC was 45 mg and the concentration of emulsifier of poloxamer was 0.9%. The average size, Zeta potential, entrapment efficiency and drug loading of DMY- PC-NLC was (197.25 ± 4.42) nm, (-18.2 ± 2.1) mV, (71.68 ± 1.36)% and (3.94 ± 0.24)%, respectively. The in vitro release model was accord with Weibull model and the equation was lnln(1-Mt/M∞)=0.700 1 lnt-1.954 1 (r = 0.971 4). The relative bioavailability of DMY-PC and DMY-PC-NLC were enhanced to 1.63 and 3.22 times compared to DMY, respectively. Conclusion: Compared with DMY-PC, the absorption was promoted by DMY-PC-NLC in further, and the bioavailability of DMY was enhanced effectively.

Preparation and Quality Evaluation of Pogostone Transfersomes / 中国药房

OBJECTIVE： To prepare pogostone transfersomes， and to evaluate its quality. METHODS： Film dispersion method was used to prepare pogostone transfersomes. Using the accumulative penetration volume （Qn） and accumulative penetration ratio （PR） of pogostone as evaluation indexes， the types of surfactant， formulation were screened in respects of the dosage of surfactant and the dosage of pogostone. The pogostone transfersomes were prepared with optimal formulation； the morphology， particle size distribution and Zeta potential were observed and the entrapment efficiency was measured. RESULTS： The optimal formulation was as follows as the sodium cholate was selected as surfactant； the dosage of sodium cholate was 0.25 g； the dosage of pogostone was 15 mg. The optimal pogostone transfersomes were ivory-white suspension； average particle size was （115.6±3.65） nm （RSD＝3.20％，n＝3）； PDI was 0.185±0.008 （RSD＝4.30％， n＝3）； Zeta potential was （－13.76±0.225） mV （RSD＝1.70％，n＝3）； entrapment efficiency of pogostone was （46.01±0.40）％ （RSD＝0.87％，n＝3）； Qn was （378.76±0.61）   μg/cm2 （RSD＝0.20％，n＝3）； PR was （89.02±0.96）％ （RSD＝1.10％，n＝3）. CONCLUSIONS： Prepared pogostone transfersomes are in line with quality requirements， which can provide reference for the further study of new dosage form of pogostone.

Preparation and detection of VEGF chitosan microspheres with different concentrations / 中华医学美学美容杂志

Objective To evaluate the effects of chitosan microspheres as the ball wall,pre pared by emulsion cross-linked VEGF chitosan microspheres.Methods 1 ％ chitosan aqueous solution as the aqueous solution and genipin as a cross-linking agent were used to detect the drug loading rate and cumulative release rate of drug-loaded microspheres by ELISA.Results VEGF chitosan microsphere size was about 5.25-20.34 μm;electron microscopy showed that microspheres surface was smooth,decentralized,and had small adhesions each other.The highest encapsulation efficiency was (56.33±3.42) ％ and the highest drug loading rate was (18.75±0.32) ng/mg.In vitro release experiments showed that the concentration of VEGF increased gradually with the passage of time.The release rate of microspheres was (32.32±2.31)％ on the first day and (86.42±1.68)％ on the 21st day.The cumulative release rate was 88.7％.Conclusions Genipin can be used to prepare chitosan microspheres loaded with different concentrations of VEGF with good performance and simple preparation process.The drug-loading rate and entrapment efficiency of the obtained microspheres are both high.

Formulation optimization of rutaecarpine lipid liquid crystalline nanoparticles by Box-Behnken design-response surface methodology / 中草药

Objective To optimize the formulation of rutaecarpine lipid liquid crystalline nanoparticles (Rut-LLCN) by Box-Behnken design-response surface methodology. Methods Rut-LLCN were prepared by precursor injection-high pressure homogenization method. A three factor and three-level Box-Behnken design was employed with the glyceryl monoolein quality, percentage of poloxamer in glyceryl monoolein and the rutaecarpine quality as independent variables, the entrapment efficiency, drug loading, mean particle size and polydispersity index as the dependent variables to sereen the optimal formaula. Results Optimized prescription was GMO 450 mg, F127-GMO 12%, and Rut 20 mg. All items of optimized prescription were similar to target values. According to the optimized prescription, the entrapment efficiency, drug loading, average particle size, and PDI of Rut-LLCN were (84.02 ± 7.99)%, (3.24 ± 0.30)%, (186.90 ± 13.50) nm, and 0.313 ± 0.020, respectively. Conclusion The prescription optimization model of Rut-LLCN was optimized by Box-Behnken designs-response surface methodology, and entrapment efficiency, drug loading, mean particle size, and PDI of Rut-LLCN are measured to investigate the model.

Optimization of preparation of curcumin-loaded TPGS/F127/P123 mixed micelles by uniform design methodology / 中草药

Objective: The preparation process of curcumin-loaded TPGS/F127/P123 mixed micelles was optimized with uniform design method to improve the poor solubility of curcumin in water, aiming to increase entrapment efficiency (EE), drug-loading (DL), and reduce the precipitated drug (PD). Methods: Curcumin-loaded TPGS/F127/P123 mixed micelles were prepared by thin-film hydration method with modification. Before using the uniform design, a number of preliminary experiments were conducted to identify the controlled factors such as the amount of curcumin, the dosage of TPGS, and the ratio of F127/P123. The formulation was operated by uniform design of three factors and seven levels, and its results were fitted by polynomial linear equation, the response surface, and the contour line in order to choose and verify the optimal preparation process. Results: In the optimum formulation, the dosage of curcumin was 14.0 mg, TPGS 150.0 mg, and the ratio of F127/P123 was 68: 32. The solubility of optimum formulation was (3.47 ± 0.14) mg/mL, EE (87.15 ± 4.39)%, DL (4.70 ± 0.17)%, and PD (0.33 ± 0.12)% in 48 h. Conclusion: The solubility of curcumin in TPGS/F127/P123 mixed micelles was improved after the optimization of the uniform design method, and EE and DL were also improved.

Study on preparation and storage stability of ginsenoside Re liposomes / 中草药

Objective To establish and optimize preparation technology of ginsenoside Re liposomes, therefore to improve storage stability. Methods Ginsenoside Re liposomes were prepared by the method of film dispersion-mechanical vibration, which were collected by separating liposome from disclosed free drug by dialysis method. Measure entrapment efficiency by HPLC. Prepare freeze-dried liposome preparations by freezing-drying technology. Taking entrapment efficiency as the main screening index, optimize liposome formulation and freezing-drying technology by orthogonal test design. Results The entrapment efficiency of ginsenoside Re lipidosomes prepared by the method of film dispersion-mechanical vibration is the highest. The best formulation technology is: Mass ratio of drug and phospholipid is 1∶30, mass ratio of phospholipid and cholesterol is 16∶1, ice-water bath ultrasound is 30 min, and double distilled water is hydration solution; The best freezing-drying technology is: Taking sucrose as the freeze-drying protective agent, mass ratio of disaccharide-water is 1∶10, pre-freezing temperature is −20 ℃, and normal saline of 0.9% is reconstitution solution. Conclusion The preparation technology of liposome is stable and practicable. The ginsenoside Re liposome prepared by taking the sucrose as the freeze-drying protective agent has good indexes, which can extend the storage period.

Preparation and evaluation of novel purine derivative F7 thermosensitive liposome / 国际药学研究杂志

Objective To prepare F7 thermosensitive liposome and evaluate its physicochemical properties, then investigate its cytotoxicity against tumor cells in vitro. Methods The F7 thermosensitive liposome was prepared by the pH gradient active drug loading method using dipalmitoyl phosphatidylcholine myristoyl lyso-phosphocholine and 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy (polyethylene glycol)-2000 as membrane materials. The encapsulation efficiency and drug loading were determined for the F7 thermosensitive liposome by HPLC. The phase transition temperature of F7 thermosensitive liposome was investigated by differential scanning calorimetry;the liposome morphology was observed by atomic force microscopy;the drug release of liposome was examined by dialysis;and the particle size and zeta potential were measured through Malvern particle size analyzer. The cytotoxicity of F7 and F7 thermosensitive liposome was determined by the MTT method, and the freeze-drying process was optimized using the designexpert software. Results The encapsulation efficiency of F7 thermosensitive liposomes was (97.56±0.22) ％, and the drug loading ratio was (1.51±0.01) ％. The phase transition temperature of F7 thermosensitive liposome was 39.9℃, the zeta potential was (-15.10±0.85) mV, the particle size was (86.94±1.21) nm, and the poly disperse coefficient was 0.17±0.01. Compared with the F7 injection, the F7 thermosensitive liposomes showed a stronger, dose-dependent inhibitory effect on the growth of lung cancer H1299 and breast cancer MCF-7 cells. The freeze-dried powder of liposomes dissolved well with the encapsulation efficiency of 95％ and the particle size of approximately 130 nm. Conclusion The F7 thermosensitive liposome prepared by the pH gradient active drug loading method has high encapsulation efficiency and good stability. The preparation method is simple and feasible for further development of the F7 preparation.

Formulation and Efficacy of Liposome-encapsulated Afatinib for Therapy of Non-small Cell Lung Cancer / 中国肺癌杂志

BACKGROUND@#Afatinib, a second-generation irreversible epidermal growth factor inhibitor receptor for the development of non-small cell lung cancer and secondary drug resistance, has low bioavailability and adverse reactions due to current oral administration. The aim of this study was to prepare a novel drug delivery system, afatinib liposome, and to establish a method for the determination of encapsulation efficiency.@*METHODS@#Four different preparation methods were used to prepare afatinib liposomes, and the optimal preparation process was determined by comparing the encapsulation efficiency and particle size.@*RESULTS@#It has been verified that sephadex microcolumn centrifugation can be used to purify afatinib liposomes, and UV spectrophotometry can be employed to determine the entrapment efficiency of liposomes. Among different preparation methods, the encapsulation efficiency of afatinib liposomes prepared by ammonium sulfate gradient method was 90.73% and the average particle size was 108.6 nm.@*CONCLUSIONS@#Ammonium sulfate gradient method can be successfully applied to prepare afatinib liposomes that performed higher encapsulation efficiency and smaller particle size. The UV spectrophotometry employed to determine the liposome encapsulation efficiency was easy operation and with high accuracy.

Determination of the Entrapment Efficiency and Drug Loading Capacity of Curcumin and Quercetin Loaded Self-microemulsifying Drug Delivery System / 中国药师

Objective:To establish an HPLC method to determine the entrapment efficiency (EE) and drug loading (DL) of curcumin (CUR)and quercetin (QUE)loaded self-microemulsifying drug delivery system.Methods:A centrifugation method was used to isolate the free drug.The content of drug was determined by HPLC.The analytical column was a Purospher STAR LP C18 column (250 mm×4.6 mm,5 μm) and the column temperature was 30 ℃.The mobile phase was acetonitrile-4% acetic acid (50∶50) and the flow rate was 1.0 ml·min-1.The UV detection wavelength was set at 370 nm and the injection volume was 10 μl.Results:CUR and QUE were linear within the range of 10.728-96.552 μg·ml-1 (r=0.999 8) and 1.08-9.72 μg·ml-1 (r=0.999 9),respectively.The average recovery was 99.98%(RSD=1.46%,n=9) and 100.34%(RSD=1.06%,n=9),respectively.In CUR-QUE-SMEDDS,the EE of curcumin and quercetin was (95.97±0.50)% and (95.91±2.52)%,and the DL was (25.82±0.15) mg·g-1 and (1.80±0.05)mg·g-1,respectively.Conclusion:The method is accurate,rapid and simple,and suitable for the determination of DL and EE in CUR-QUE-SMEDDS.

Excipient Formula Research of Nicotinate-Curcumin nanoparticles Prepared by Film Ultrasonic Method / 中国药学杂志

OBJECTIVE: To optimize the film-ultrasonic technique for preparing nicotinate-curcumin nanoparticles. METHODS: An HPLC method was established for determination of nicotinate-curcumin. Using the entrapment efficiency of nicotinate-curcumin as the evaluation indicator, the optimum excipient formula was selected through the Box-Bebnken reponse surface design of three factors (amounts of nicotinate-curcumin and lecithin and concentration of tween-80) at three levels. RESULTS: With the established optimal formula, ie 80 mg stearic acid, 150 mg lecithin and 20 mL tween-80 (0.6%), the entrapment efficiency of nicotinate-curcumin approached 65%. The mean particle size was 190 nm. CONCLUSION: The nicotinate-curcumin nanoparticles prepared by the film ultrasonic technique optimized by central composite design test have high entrapment efficiency, indicating that the technique is feasible.

Effect of curcumin-micelles adopting vitamin E-TPGS and Solutol HS 15 as carriers on solubility and oral bioavailability of curcumin / 中草药

Objective: To prepare curcumin-micelles adopting vitamin E-TPGS (VE-TPGS) and Solutol HS15 (SHS15) as carriers, and study the effect on solubility and oral bioavailability of curcumin (Cur). Methods: Cur was loaded into micelles between VE-TPGS and SHS15 by thin film dispersion method. Particle size, loading efficiency, entrapment efficiency, and in vitro release were carried on to estimate the influence of micelles on Cur; Moreover, oral bioavailability in rats was also evaluated. Results: The particle size was (35.79 ± 1.23) nm with polydispersity index (PDI) of 0.12 ± 0.03 when the optimized micelles ratio was at 3:7 of VE-TPGS and SHS15, which increased the solubility of Cur to 2.03 mg/mL in water. The entrapment efficiency and drug loading were 90.03% and 9.34%, respectively. The in vitro release profile showed a sustained release property compared with that of Cur. In addition, the relative bioavailability of micelles (AUC0~∞) compared with that of Cur (AUC0~∞) was 303.5% (P < 0.01). Conclusion: The Cur-micelles combined use of VE-TPGS and SHS15 shows great potential clinical application.

Quality Investigation of Quercetin-loaded PLGA-TPGS Nanoparticles / 医药导报

Objective To prepare quercetin ( QT )-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate ( PLGA-TPGS) nanoparticles ( QPTN) and QT-loaded polylactic-co-glycolic acid ( PLGA) nanoparticles ( QPN) by using QT as model drug and PLGA-TPGS or PLGA as carrier materials, and to investigate the quality of the two nanoparticles. Methods QPTN and QPN were prepared by using the ultrasonic emulsification-solvent evaporation method, and their surface morphology,size and surface charge were detected by using a transmission electron microscope ( TEM) and a Nano ZS90 light scattering and laser Doppler anemometry, respectively. Drug loading ( DL) , entrapment efficiency ( EE) and in vitro drug release of QT in the two nanoparticles were determined by using a reverse phase-high performance liquid chromatography (RP-HPLC) on Hypersil C18 column (4.6 mm×250 mm, 5 μm) with methanol and 0.03% phosphoric acid (3︰2) as mobile phase, and the detective wavelength was 370 nm. Results TEM images exhibited that two nanoparticles were all spherical and regular. The average sizes of QPTN and QPN were (155.4±2.7) nm and (363.8±3.2) nm, while DL and EE of QPTN were approximately (21.6±2.8)%, (93.7±2.9)% (n=6), and DL and EE of QPN were approximately (15.0±1.5)%, (64.6± 1.6)% (n=6), respectively. Both of nanoparticles exhibited sustained release, and the cumulative QT release of QPTN and QPN reached (85.8±2.8)% and (68.6±1.4)% (n=6) at day 30, respectively, with a significant difference between them (P<0.05) . Conclusion QPTN gets smaller size, higher DL and EE, and exhibits sustained release, and the in vitro cumulative QT release is faster and more complete than QPN relatively.

Quality Investigation of Quercetin-loaded PLGA-TPGS Nanoparticles / 医药导报

Objective To prepare quercetin ( QT )-loaded polylactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate ( PLGA-TPGS) nanoparticles ( QPTN) and QT-loaded polylactic-co-glycolic acid ( PLGA) nanoparticles ( QPN) by using QT as model drug and PLGA-TPGS or PLGA as carrier materials, and to investigate the quality of the two nanoparticles. Methods QPTN and QPN were prepared by using the ultrasonic emulsification-solvent evaporation method, and their surface morphology,size and surface charge were detected by using a transmission electron microscope ( TEM) and a Nano ZS90 light scattering and laser Doppler anemometry, respectively. Drug loading ( DL) , entrapment efficiency ( EE) and in vitro drug release of QT in the two nanoparticles were determined by using a reverse phase-high performance liquid chromatography (RP-HPLC) on Hypersil C18 column (4.6 mm×250 mm, 5 μm) with methanol and 0.03% phosphoric acid (3︰2) as mobile phase, and the detective wavelength was 370 nm. Results TEM images exhibited that two nanoparticles were all spherical and regular. The average sizes of QPTN and QPN were (155.4±2.7) nm and (363.8±3.2) nm, while DL and EE of QPTN were approximately (21.6±2.8)%, (93.7±2.9)% (n=6), and DL and EE of QPN were approximately (15.0±1.5)%, (64.6± 1.6)% (n=6), respectively. Both of nanoparticles exhibited sustained release, and the cumulative QT release of QPTN and QPN reached (85.8±2.8)% and (68.6±1.4)% (n=6) at day 30, respectively, with a significant difference between them (P<0.05) . Conclusion QPTN gets smaller size, higher DL and EE, and exhibits sustained release, and the in vitro cumulative QT release is faster and more complete than QPN relatively.

Formula Optimization of Evodiamine Liposomes by Central Composite Design-Response Surface Methodol-ogy / 中国药师

Objective:To optimize the formula of evodiamine liposomes. Methods:Using phospholipids, cholesterol and vitamin E as the materials, the liposomes were prepared by a film dispersion method. The binomial model of mass ratio of phospholipid to drug, mass ratio of phospholipid to cholesterol and the concentration of phospholipid were fitted by design-response surface methodology using encapsulation efficiency as the index. The formula was optimized by three-dimensional response surface and contour plot. The predic-tive data was validated, and the morphology, particle size and pH were observed. Results:The optimized formula was as follows:the mass ratio of phospholipid to drug was 30. 58∶1, that of phospholipid to cholesterol was 15. 22∶1 and the concentration of phospholipid was 42. 26 mg·ml-1 . The average encapsulation efficiency of evodiamine liposomes was 92. 89%. The appearance was milky white and translucent with round or oval pellets, the particle size was 126 nm and the pH was 6. 94 ± 0. 17. Conclusion: The formula and preparation process of evodiamine liposomes are stable and feasible.

Determination of Entrapment Efficiency of Levodopa-loaded PEGylated-Solid Lipid Nanoparticles by Mini-Column Centrifugation-HPLC / 医药导报

Objective To establish a mini-column centrifugation-HPLC method to determine the entrapment efficiency of levodopa-loaded PEGylated-solid lipid nanoparticles.Methods A dextran gel(Sephadex G-50) mini-column centrifugation was employed to separate the free drug from solid lipid nanoparticles.The content of levodopa was qualified by HPLC.Results Under the applied chromatographic condition,the excipients had no influence on the determination of levodopa.A calibrated linear of levodopa concentration was within 10.54-527.00 μg·mL-1.The recoveries of high,medium and low concentrations of levodopa were 99.13%,99.51% and 99.04%(RSD were 1.25%,1.91% and 1.71%), respectively.The free levodopa was well separated from solid lipid nanoparticles by using mini-column centrifugation.The addition of blank solid lipid nanoparticles recovery was 98.84% with RSD of 0.80%(n=3).The average adsorption rates of the three concentrations of free levodopa were 100.00%,98.75% and 98.56%(RSD were 0.00%,0.19% and 0.18%,n=3),respectively.The adsorption rate of the physical mixtures of three different concentrations of drugs and empty PEGylated solid lipid nanoparticles were 99.68%,98.46% and 99.21%(RSD were 1.52%,0.23% and 0.21%),respectively.Conclusion The method was simple,accurate and reproducible,which can be used for determination of the entrapment efficiency of levodopa-loaded PEGylated-solid lipid nanoparticles.

Determination of Content and Entrapment Efficiency of Transferrin Modified Vincristine-Tetrandrine Lipo-somes / 中国药房

OBJECTIVE:To establish the method for the determination of main components content and entrapment efficiency of transferrin modified vincristine-tetrandrine liposomes. METHODS:HPLC method was adopted to determine the content of vin-cristine. The determination was performed on ELITE C18 column with mobile phase consisted of methanol-15%triethylamine (70∶30)at a flow rate of 1.0 ml/min. The determination wavelength was set at 297 nm and column temperature was 30 ℃. The sample size was 20 μl. Free drug was isolated from liposomes by dextran gel column chromatography,and entrapment efficiency was deter-mined. RESULTS:The linear range of vincristine was 160-1 600 μg/ml (r=0.999 8,n=5) with average recovery of 99.20%(RSD=0.26%,n=9). RSD of precision test was 0.070%(n=5). The average content of vincristine in liposomes was 0.790 mg/ml(RSD=0.15%,n=3),and the average entrapment efficiency was 85.94%(RSD=2.08%,n=3). CONCLUSIONS:The method is accurate,reliable,simple and rapid,and can be used for the determination of the content and entrapment efficiency of vincristine in transferrin modified vincristine-tetrandrine liposomes.

Determination of Entrapment Efficiency of Buthionine Sulfoximine Nanoparticles in Different Entrapping Systems by HPLC / 中国药师

Objective:To establish an HPLC method to determine the entrapment efficiency of buthionine sulfoximine (BSO) nan-oparticles in different entrapping systems .Methods:Free BSO was separated from the loaded nanoparticles by high speed centrifugation in two entrapping systems and the entrapment efficiency of buthionine sulfoximine nanoparticles was determined by HPLC .A WondaSil C18 column (250 mm ×4.6 mm, 5 μm) was used and the mobile phase was methanol-water (20 ∶80).The flow rate was 0.4 ml· min-1 and the column temperature was 30℃.The detection wavelength was set at 210 nm and the volume of injection was 20 μl.Re-sults:BSO had a good linear relationship within the range of 2.0-320.0μg· ml-1(r=0.999 7).The average recovery was 101.05%and RSD was 0.74%(n=9).The average entrapment efficiency of HP/CaCO3/CaHPO4/BSO nanoparticles and HP/PS/CaCO3/BSO hydrid nanovesicles was 25.63% and 58.62%, respectively.Conclusion:The method has good repeatability and high accuracy and sensitivity, which is applicable to determine the entrapment efficiency of BSO nanoparticles .HP/PS/CaCO3/BSO hydrid nanovesicles entrapped system is superior to HP/CaCO3/CaHPO4/BSO nanoparticles entrapped system .