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Abstract Polymersomes are nanometric vesicles that can encapsulate large and hydrophilic biomolecules, such as proteins, in the aqueous core. Data in literature show large variation in encapsulation efficiency (%EE) values depending on the method used for calculation. We investigated different approaches (direct and indirect) to quantify the %EE of different proteins (catalase, bovine serum albumin-BSA, L-asparaginase and lysozyme) in Pluronic L-121 polymersomes. Direct methods allow quantification of the actual payload of the polymersomes and indirect methods are based on the quantification of the remaining non-encapsulated protein. The protein-loaded polymersomes produced presented approximately 152 nm of diameter (PDI ~ 0.4). Higher %EE values were obtained with the indirect method (up to 25%), attributed to partial entanglement of free protein in the polymersomes poly(Ethylene Glycol) corona. For the direct methods, vesicles were disrupted with chloroform or proteins precipitated with solvents. Reasonable agreement was found between the two protocols, with values up to 8%, 6%, 17.6% and 0.9% for catalase, BSA, L-asparaginase and lysozyme, respectively. We believe direct determination is the best alternative to quantify the %EE and the combination of both protocols would make results more reliable. Finally, no clear correlation was observed between protein size and encapsulation efficiency.
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Photothermal therapy has the characteristics of minimal invasiveness, controllability, high efficiency, and strong specificity, which can effectively make up for the toxic side effects and tumor resistance caused by traditional drug treatment. However, due to the limited tissue penetration of infrared light, it is difficult to promote and apply in clinical practice. The eye is the only transparent tissue in human, and infrared light can easily penetrate the eye tissue, so it is expected that photothermal therapy can be used to treat fundus diseases. Here in, a new nano-platform assembled by liposome and indocyanine green (ICG) was used to treat retinoblastoma. ICG was assembled in liposomes to overcome some problems of ICG itself. For example, ICG is easily quenched, self-aggregating and instability. Moreover, liposomes can prevent free ICG from being cleared through the systemic circulation. The construction of the nano-platform not only ensured the stability of ICG in vivo, but also realized imaging-guide photothermal therapy, which created a new strategy for the treatment of retinoblastoma.
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Hepatitis B virus core protein (HBc) has become a hot spot in drug carrier protein research due to its natural particle self-assembly ability and ease of modification. The truncation of the C-terminal polyarginine domain (CTD, aa 151-183) of HBc does not affect the self-assembly of the particles. However, it does affect the internal and external charges of the particles, which may subsequently affect drug encapsulation. Thus, the truncated C-terminal polyarginine domain (CTD) of HBc and the inserted RGD peptide were selected to construct and express three HBc variants (RH) encapsulated with ICG (RH/ICG) with different C-terminal lengths to compare the stability and drug activity of their nanoformulations. RH160/ICG was found to have a great advantages in encapsulation efficiency and biological imaging. Compared with other HBc variants, RH160/ICG significantly improved encapsulation efficiency, up to 32.77%±1.23%. Cytotoxicity and hemolysis assays further demonstrated the good biocompatibility of RH160/ICG. Cell uptake and in vivo imaging experiments in mice showed that RH160/ICG could efficiently deliver ICG in tumor cells and tumor sites with good imaging effect. This research provides a new direction for further expanding the diagnosis and treatment application of ICG and development of HBc-based nanoparticle drug carrier platform.
Subject(s)
Animals , Mice , Hepatitis B/drug therapy , Hepatitis B Core Antigens , Indocyanine Green/chemistry , Nanoparticles/chemistry , Viral Core ProteinsABSTRACT
Millions of people are affected globally by alzheimer’sdisease and it is regarded as a dangerous progressive medical and socio-economic burden. The drug delivery to brain is hindered due to the presence of blood brain barrier. Nanoparticle mediated drug delivery is a promising approach in this regard. Chitosan is a hydrophilic polysaccharide polymer of N-acetylglycosamine and glucosamine. Owing to its biodegradability, nontoxicity and biocompatibility it is regarded as a safe excipient. The aim of the study was to fabricate donepezil-loaded sustained release chitosan nanoparticles as a simple way to deliver nano-drugs to the brain. The nanoparticles were fabricated using ionic gelation method using different concentrations of Sodium tripolyphosphate (TPP) and chitosan. The fabricated nanoparticles were assessedfor particle size, zeta potential, encapsulation efficiency and in vitrodrug release. The effect of sonication time on the particle size of nanoparticles was also studied. The nanoparticles exhibited mean particle size (between 135-1487nm) and zeta potential (between +3.9-+38mV) depending on chitosan and TPP concentration used. The rise in the sonication time from 25 to 125 sec exhibited a decrease in particle size. The encapsulation efficiency was found to be in the range of 39.1-74.4%. Sustained and slow release of donepezil at a constant rate was exhibited from nanoparticles. The nanoparticles show potential to deliver donepezil to brain with enhanced encapsulation efficiency
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OBJECTIVE: To establish a mini-column centrifugation method to determine the encapsulation efficiency (EE) of novel solid lipid nanoparticles containing oleic acid-CAT3 conjugates (OA-CAT3-SLN) and normal CAT3 SLN (CAT3-SLN). METHODS: Sephadex G-50 mini-columns were used to separate the encapsulated drug and free drug in the solid lipid nanoparticles (SLN) with the help of centrifugation. The boundary point of the elution between the encapsulated drug and free drug was established by the elution curve. The encapsulated drug in the SLN was eluted with 1 mL water for three times. Then 2 mL of ethanol was used to elute the separated free drug for three times. The eluted CAT3 was quantified by the verified HPLC-UV method and used to calculate the EE. The method was verified with the recovery and repeatability test. Finally, the EE of three batches of OA-CAT3-SLN and CAT3-SLN were determined. RESULTS: The mini-column centrifugation method could effectively separate the free drug from the encapsulated drug in SLN. The column recovery was (99.64±1.97)% (n=9), and the result of EE repeatability test of OA-CAT3-SLN was (83.71±0.70)% (n=5). The EE of OA-CAT3-SLN and CAT3-SLN were (86.26±2.65)% and (72.22±4.52)%, respectively (n=3). CONCLUSION: The established separation method is simple and reliable, with high recovery and good repeatability, and can distinguish different preparation processes.
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OBJECTIVE: To prepare matrine solid lipoid nanoparticle,establish preparating method and determine the encapshlation efficiency. METHODS: Matrine solid lipoid nanoparticle was prepared by microemulsion-probe ultrasonic method and its quality was evaluated by particle size, Zeta potential, microscopic morphology and in vitro release. The encapsulation efficiency of the carrier was measured by different methods and their effect was compared. RESULTS: The diameter of matrine solid lipoid nanoparticle was (116.7±2.6) nm and its Zeta potential was (-45±1.7)mV. Transmission electron micrographs showed that the solid lipoid nanoparticle was uniform in size and spherical. The in vitro release result suggested the carrier exhibited control release character. Dextran gel microcolumn centrifugation can effectively separate free drugs and carriers, and the measured encapsulation efficiency data has little difference in stability. CONCLUSION: Matrine solid lipoid nanoparticle is successfully prepared and their particle size, Zeta potential and in vitro release quality are evaluated.Dextran gel microcolumn method is effective in the measurement of matrine solid lipoid nanoparticle, providing a reliable reference for the determination of water-soluble drug encapsulation efficiency.
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Objective: To prepare glycyrrhizic acid (GL)-Pluronic F127 (F127)/polyethylene glycol 1000 vitamin E succinate (TPGS) mixed nanomicelles (MMs) and improve oral absorption of GL. Methods: GL-F127/TPGS-MMs was prepared by thin film dispersion method. The encapsulation efficiency and drug loading of MMs were used as evaluation indexes. The formulation and process, including the ratio of F127 to TPGS, the concentration of polymer and GL, hydration temperature and time, were optimized by the single factor experiment. The morphology of MMs was investigated by transmission electron microscopy. The single-pass perfusion model was established in rats to investigate the intestinal absorption characteristics of GL-F127/TPGS-MMs with absorption rate constant (Ka) and apparent absorption coefficient (Papp) as evaluation indexes. Results: The optimal formulation and process of GL-F127/TPGS-MMs were as follows: TPGS 180 mg, F127 270 mg, GL 70 mg, hydration temperature 50 ℃ and hydration time 3 h. The prepared GL-F127/TPGS-MMs had good clarity and the particle size, polydispersity index, and Zeta potential were (28.20 ± 5.63) nm, 0.20 ± 0.06, and (-5.24 ± 1.55) mV, respectively. The encapsulation efficiency and drug loading were (97.57 ± 5.29) % and (13.13 ± 0.71) %, respectively. The MMs were spherical with distinct vesicle structure. The absorption of GL in the jejunum segment was significantly higher than that in the ileum segment (P < 0.05). Compared with raw GL, GL-F127/TPGS-MMs had a statistically significant higher absorption rate in the intestinal segment (P < 0.05). Conclusion: The prepared GL-F127/TPGS-MMs could significantly improve the absorption of GL in vivo.
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Objective: To establish a vitamin K1(VK1)-delivery system with red blood cells as carrier. Methods: The VK1 self-emulsifying nano-emulsion, micelle and plasma solution were prepared to investigate the VK1 loading on red blood cells. The VK1- chitosan(CS)nanoparticles were prepared with different particle size by the 3 different preparation methods, and the effect of the particle size and charge property on the VK1-loading on red blood cells was investigated with the prepared VK1-CS nanoparticles. The encapsulation efficiency and drug loading were used as main indicators to investigate the appropriate drug loading method. Results: Due to the solubility of VK1 or the charge properties of nanoparticles, the drug loading and encapsulation efficiency of the red blood cell-encapsulated VK1 were quite low, and a large amount of drugs could not be loaded on the red blood cells. The ability of red blood cells to load VK1 was likely related to its Zeta potential. The VK1-CS nanoparticles prepared by the ion condensation method showed a good drug loading performance. Each milliliter of red blood cells could load 174.46 μg VK1 in the nanoparticles, and the loading rate was 85.11%. Conclusion: The VK1 loading by the red blood cells could be achieved by the electrostatic interaction between the positively charged chitosan nanoparticles and the negatively charged erythrocyte membrane.
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Objective To develop a method to determine the encapsulation efficiency of doxorubicin hydrochloride and timosaponin AIII co-loaded liposomes. Methods In this paper, the thin-film rehydration method was used to prepare doxorubicin hydrochloride and timosaponin AIII co-loaded liposomes. Liposomes and free drugs were separated by dialysis, gel microcolumn centrifugation, and ultra-high speed centrifugation. The content of free drugs and drugs in liposomes was determined by HPLC, and the entrapment efficiency of doxorubicin hydrochloride and timosaponin AIII co-loaded liposomes was calculated. Results The optimal formulation of doxorubicin hydrochloride and timosaponin AIII co-loaded liposomes was DPPC-DSPE-PEG2000-TAIII-DOX with a molar ratio of 5:1:1:1. The liposomes prepared using thin-film rehydration method had a well-defined spherical shape with a size of (55.4 ± 0.40) nm, a PDI of (0.20 ± 0.02), and a weakly negative zeta potential of (-17.4 ± 0.6) mV. The excipients in the liposomal formulation can be well separated from doxorubicin hydrochloride and timosaponin AIII in the selected chromatographic conditions. The calibrated linear curve of doxorubicin hydrochloride was within 24.9-498.0 μg/mL (r = 0.999 9) and that of timosaponin AIII was within 50.55-1 011.0 μg/mL (r = 0.999 6). Free doxorubicin hydrochloride and timosaponin AIII were well separated from liposome by gel microcolumn centrifugation, and the encapsulation efficiency of doxorubicin hydrochloride and timosaponin AIII was (85.12 ± 1.27)% and (76.51 ± 0.46)% respectively. Conclusion The thin-film dispersion- method can be used for the preparation of doxorubicin hydrochloride and timosaponin AIII co-loaded liposomes. The method of gel microcolumn centrifugation is accurate, reproducible, simple, and suitable for determination of the encapsulation efficiency of co-loaded liposomes.
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Objective To optimize the formulation ratio and preparation process of the APGA modified artemether liposomes, and evaluate its physical and chemical properties. Methods The encapsulation efficiency of artemether was evaluated as index, and the preparation method of APGA modified artemether liposomes was optimized. The preparation process of APGA modified artemether liposomes was optimized by orthogonal experiments. Laser particle analyzer and transmission electron microscopy were used to evaluate the particle size, Zeta potential, and appearance of liposomes, and dialysis method was used to study the release of liposomes in vitro. Results The best prescription was as follow: EPC-Chol-TPGS at 95:0.5:3, 5% APGA-PEG-DSPE, the artemether-lipid ratio at 1:20, film-forming temperature 30 ℃, probe ultrasound time 8 min. The resulting liposomes exhibited a pale blue opalescent appearance. The average particle size, polydispersity index, and zeta potential of artemether liposomes was (99.97 ± 1.67) nm, 0.185 ± 0.021, and (-0.023 ± 0.080) mV, respectively. Transmission electron micrograph image showed that artemether liposomes were spherical vesicles with uniform sizes. The encapsulation efficiency of artemether in liposomes was (90.06 ± 1.15)%. In vitro cumulative release rate of artemether from the liposomes in the simulated body fluids was (57.07 ± 6.09)% after 48 h. Conclusion The optimized APGA modified artemether liposomes was successfully developed. It had the following characters: round shape, uniform particle size, high drug encapsulation efficiency and good sustained-release effect.
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Objective: To integrate the toxic component of cantharidin (CTD) into a novel nanostructured lipid carrier (NLC) and optimize the cantharidin nanostructured lipid carrier (CTD-NLC) formulation process to reduce the toxicity of CTD and enhance its targeting. Methods: CTD-NLC was prepared by emulsified ultrasonic dispersion method. The encapsulation efficiency was determined by dialysis method. The average particle size, particle size distribution (polydispersity index, PDI), Zeta potential, encapsulation efficiency, and drug loading were taken as indicators. Univariate investigation and central composite design-response surface methodology (CCD-RSM) were used to optimize the prescription process of CTD-NLC. Multivariate quadratic fitting was used to evaluate the model equation between indicators and factors. The fitted equation was analyzed by the variance analysis and the optimal prescription was predicted by the resonse surface. Results: The optimized CTD-NLC prescriptions were as follow: mass of total lipid was 453.66 mg, solid to liquid lipid ratio of 1:2, total stable dose of 16.9 mg/mL, ratio of Pluronic F68 to egg yolk lecithin (Lipoid E PC S) of 3.88:1, with ultrasound for 30 min (working 2 s, stopping 2 s). The prepared CTD-NLC was clear clarification in appearance with light blue opalescence, the average particle size was (85.99 ± 0.49) nm, PDI was 0.280 ± 0.002, Zeta potential was (-8.21 ± 0.24) mV, encapsulation efficiency was (98.57 ± 0.05)%, and drug loading was (0.65 ± 0.01)%. Conclusion: The fitting model established by CCD-RSM is accurate and reliable. The optimized CTD-NLC distribution is concentrated, with high encapsulation efficiency and good physical stability. It lays a foundation for the subsequent in vitro and in vivo studies of CTD-NLC.
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Objective: To optimize the formulation of syringopicrosides poly (lactic-co-glycolic acid, PLGA) nanoparticles (Syr-NPs). Methods: Syr-NPs were prepared by nanoprecipitation method. The encapsulation efficiency (EE), drug loading (DL), average particle size and general evaluation "normalized value" were used as evaluation indexes. The central composite design was used to inspect the effects of the concentration of PLGA (A), the concentration of syringopicrosides (B), the ratio of aqueous phase to organic phase (C) on three evaluation indexes mentioned above and the "normalized value" ofgeneral evaluation. Prediction and analysis for selecting the best prescription condition were carried out by using the central composite design-response surface method. Results: The concentration of PLGA, the concentration of syringopicrosides and the ratio of aqueous phase to organic phase according to the optimized prescription were 9.63 mg/mL, 12.88 mg/mL and 1:9.46, respectively; And the EE, drug loading and average particle diameter of Syr-NPs prepared according to the optimized prescription were (27.86 ± 0.87)%, (7.02 ± 0.15)%, and (110.0 ± 1.20) nm, respectively. Conclusion: This method is stable and feasible and can be used to optimize the formulation and preparation process of syringopicrosides wrapped inside with PLGA nanoparticles.
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Objective: To prepare total alkaloids of Strychni Semen (TASS) - total glucosides of paeony (TGP) lipid-based cubic liquid crystalline nanoparticles (TASS-TGP LLCN) and investigate its percutaneous absorption behavior. Methods: TASS-TGP LLCN was prepared by precursor injection method, and the encapsulation efficiency (EE) was determined by ultrafiltration centrifugation. The prescription of TASS-TGP LLCN was optimized by uniform design with the encapsulation efficiency as the index, and the basic properties of the optimized TASS-TGP LLCN were evaluated. Meanwhile, Poloxamer 407 (F127) was used as matrix to prepare gel, Franz diffusion method was used to compare the in vitro percutaneous permeability of TASS-TGP LLCN gel with TASS-TGP ordinary gel. Results: The optimal formula of TASS-TGP LLCN was glycerol monooleate (GMO) 1.0 g, F127 0.25 g, dispersed phase 60 mL. The EE of brucine, strychnine and paeoniflorin were all more than 50%, the average particle size was about (245.3 ± 16.4) nm, the pH value was 6.62, and the cubic structure was uniform in size under transmission electron microscope. The cumulate osmotic quantities in 24 h, the permeation rate and the skin retention volume of TASS-TGP LLCN gel were all better than ordinary gel of TASS-TGP. Conclusion: TASS-TGP LLCN has dual effects of promoting permeability and skin reservoir, which has a potential development prospect.
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Objective: To prepare pegylated long-circulating liposomes co-encapsulated by costunolide (Cos) and dehydrocostus lactone (DL), optimize the formulation and process, and evaluate the quality. Methods: The pegylated long-circulating liposomes co-encapsulated by Cos and DL were prepared by film hydration method. Single factor test and Box-Behnken response surface methodology were used to optimize the preparation process with encapsulation efficiency of Cos and DL as the index. The particle size, surface potential, encapsulation efficiency and in vitro release of the liposomes were evaluated. Results: The optimal preparation conditions were as follows: drug-to-lipid ratio was 0.14, ratio of cholesterol to phospholipid was 0.05, mPEG-2000-DSPE addition amount was 6%, hydration time was 30 min, and probe ultrasonic time was 4 min. The obtained liposome was round and uniform in distribution, with an average particle size of (104.8 ± 2.48) nm, a polydispersity index (PDI) of (0.245 ± 0.031), and a Zeta potential of (-9.7 ± 0.23) mV, the encapsulation efficiency of Cos and DL were (91.9 ± 2.6)% and (94.41 ± 1.23)%, respectively. Conclusion: The PEGylated long-circulating liposome prepared by the process and prescription optimization has good appearance and high encapsulation efficiency, which can meet the application requirements.
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Objective: To screen the optimal formulation of puerarin nanoparticles (Pur-NPs) by self-assembly of chitosan/alginate by Box-Behnken response surface method. Methods: Puerarin chitosan/sodium alginate nanoparticles (Pur-CS/SA-NPs) were prepared by self-assembly method. Taking chitosan concentration, chitosan pH, sodium alginate concentration, stirring speed, stirring time, ultrasonic power, and dosage as investigation factors, the encapsulation rate, drug loading, particle size, and polydispersity index (PDI) were used as evaluation index to investigate the optimal prescriptions using the Box-Behnken response surface design method, and the optimal formulation was characterized and released in in vitro experiments. Results: The optimal formulation from the optimized self-assembly method was as following: chitosan concentration of 0.45 mg/mL, sodium alginate concentration of 0.07 mg/mL, chitosan pH of 4.33, and rotation speed of 316.49 r/min. For the convenience of experimental operation, the most optimal prescription was determined to be chitosan concentration of 0.45 mg/mL, sodium alginate concentration of 0.07 mg/mL, chitosan pH of 4.3, and rotation speed of 300 r/min. The results were verified by three parallel experiments, and the encapsulation efficiency, drug loading, average particle diameter, and PDI of obtained nanoparticles were (89.056 ± 1.680)%, (44.528 ± 0.840)%, (208.327 ± 1.870) nm and 0.131 ± 0.006, respectively. After characterization, the morphology of the nanoparticles was intact. It can be seen from the in vitro release experiments that the equation fitted by the nanoparticles was Higuchi model, and there was no burst release during the release process, indicating that the nanoparticles were released well in vitro. Conclusion: The prescription of puerarin chitosan/sodium alginate nanoparticles was optimized by Box-Behnken response surface method. The model was evaluated by average particle size, PDI, encapsulation efficiency and drug loading, and the characterization results and in vitro release test showed that the model had good predictability.
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Objective: To prepare oxymatrine phospholipid complex solid lipid nanoparticles(OMT-PC-SLN) lyophilized powder and evaluate its pharmaceutical properties. Method: Pseudo-ternary phase diagram was employed to optimize the formula of microemulsion;single factor experiments were adopted to optimize the formulation process of OMT-PC-SLN lyophilized powder with encapsulation efficiency as index;the morphology of this preparation was observed by transmission electron microscope(TEM).The particle size was measured by particle size analyzer and the in vitro release performance of OMT-PC-SLN lyophilized powder was examined. Result: Optimal formulation process was as following:taking soybean phospholipid and polyethylene glycol 15-hydroxystearate(Kolliphor HS 15) as the emulsifier,ethanol as co-emulsifier,ratio of emulsifier to co-emulsifier(Km)=3:2,oil phase:(emulsifier+co-emulsifier)=1:9,oxymatrine phospholipid complex-stearic acid-soybean phospholipid-Kolliphor HS 15-ethanol(30:100:180:360:360);taking 50 mL of 4%mannitol solution as the external aqueous phase,ice bath stirring at 1 000 r·min-1 and solidifying for 1 h,precooled at -20℃ for 24 h,took out and dried for 24 h.OMT-PC-SLN lyophilized powder was spherical in appearance with encapsulation efficiency of (38.09±1.24)%,average particle size of 785.5 nm,polydispersity coefficient(PDI) of 0.456 and the Zeta potential of -24.82 mV.The cumulative release rates of OMT-PC-SLN lyophilized powder were 72.63%at 2 h and 98.42%at 12 h;the cumulative release rate of oxymatrine(crude drug) was 98.60%at 2 h. Conclusion: This optimized formulation process of OMT-PC-SLN lyophilized powder is stable with good repeatability;compared with oxymatrine,OMT-PC-SLN lyophilized powder has a certain sustained-release effect.
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Objective: To study on the physical and chemical properties of dichroa alkali hydrochloride and to establish a method for the determination of entrapment efficiency of dichroa alkali hydrochloride liposomes. Method: HPLC was used to determine the content of dichroa alkali hydrochloride with mobile phase of acetonitrile-water-triethylamine-glacial acetic acid(9:91:0.35:0.75) and detection wavelength at 265 nm.The oil-water partition coefficient of this compound in different pH range was measured by shake flask method.The stability of the dichroa alkali hydrochloride in phosphate buffer solution with different pH after sterilization at 125℃ for 30 min was investigated.Ammonium sulfate gradient method was used to prepare dichroa alkali hydrochloride liposomes.The microcolumn was prepared by dextran gel and cation exchange resin,respectively.Then the free drug and liposome were separated by centrifugation,the drug content was measured,and the encapsulation efficiency was calculated.The t-test was performed using SPSS 20.0 software,the differences between these two methods were compared. Result: In the pH 6-9,the oil-water partition coefficient of dichroa alkali hydrochloride increased with increasing of pH,which was between 0.016 and 1.44;the recovery rate of dichroa alkali hydrochloride after sterilization was 37.16%-57.91%.Between the dextran gel microcolumn centrifugation and the cation exchange resin microcolumn centrifugation,there was no significant difference in the entrapment efficiency of the liposomes. Conclusion: Dichroa alkali hydrochloride is suitable for preparation of liposomes.However,its stability is not ideal,so the experimental temperature should be strictly controlled in the preparation process.Dextran gel microcolumn centrifugation and cation exchange resin microcolumn centrifugation can be used to determine the entrapment efficiency of dichroa alkali hydrochloride liposomes,and the cation exchange resin microcolumn centrifugation is suggested after comparison.
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OBJECTIVE： To prepare Zingiber officinale oil microcapsules and to evaluate its quality. METHODS： Z. officinale oil microcapsules were prepared by spray drying method with sodium starch octenyl succinate as capsule material. The preparation technology was optimized by orthogonal test with mixing temperature of capsule material and capsule core， mass ratio of capsule material and capsule core， stirring speed as factors， using encapsulation efficiency as index. The drug loading， encapsulation efficiency， appearance， particle size distribution and stability of light， heat and humidity （using iodine value and peroxide value as indexes） were evaluated. RESULTS： The optimal preparation technology of Z. officinale oil microcapsules was that the mixing temperature of capsule material and core was 60 ℃； mass ratio of capsule material and capsule core was 10 ∶ 1； stirring speed was 12 000 r/min. Average drug-loading amount and encapsulation efficiency of Z. officinale oil microcapsules prepared by optimal technology were 17.97％ and 73.57％ （n＝3）. The morphology of Z. officinale oil microcapsules was round， smooth， non-sticky and uniform in size distribution. The average diameter of microcapsules was （6.30±0.27） μm. Under light， heat and humidity conditions， the iodine value and peroxide value of Z. officinale oil microcapsules changed slightly. CONCLUSIONS： The optimal preparation technology of Z. officinale oil microcapsules is simple and reproducible. The prepared microcapsules have good encapsulation efficiency， high drug loading amount and good stability.
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OBJECTIVE： To establish a method for determining the content of tetracaine hydrochloride （TCH） ethosomes， and to optimize the preparation technology. METHODS： The content of TCH was determined by HPLC. TCH ethosomes were prepared with injection-ultrasonic method. Using drug-loading amount， egg lecithin concentration and ethanol volume fraction as factor， encapsulation efficiency as index， central composite design-response surface methodology was used to optimize the prescription based on the single factor test. The prepared ethosomes were characterized and the stability was evaluated. RESULTS： The linear range of TCH was 10-100 μg/mL （r＝0.999 5）； the limit of quantification was 0.045 μg/mL， and detection limit was 0.021 μg/mL. RSD of precision， stability and repeatability tests were less than 2％. The recoveries ranged 97.80％-103.20％ （RSD＝0.36％， n＝9）. The optimal preparation technology included that the adding amount of TCH control was 1 mg； the concentration of egg lecithin was 7 mg/mL， and ethanol volume fraction was 33％. Under this technology， the average encapsulation efficiency was 64.50％ （n＝3）， the relative error of which from the predicted value （64.92％） was 0.64％. TCH ethosome was a clear blue liquid with a blue opalescence. Its appearance was spherical， its shape was round， smooth， uniform in size； the average particle size was （80.33±2.24） nm， and the average Zeta potential was （－22.6±1.33） mV. TCH ethosome was stable during 10 days under 4 ℃， sealed and protected from light. CONCLUSIONS： The optimal preparation process is stable and feasible. Established method is simple and rapid.
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OBJECTIVE： To optimize the preparation technology of Oridonin A oral liposomes （ORI-LIP） by using supercritical fluidsolution-enhanced dispersion （SEDS） technology， and to investigate its advantage with routine liposome preparation technologies. METHODS： Using particle size as evaluation index， orthogonal design was employed to investigate the influence of pressure， temperature and flow rate on the preparation technology of ORI-LIP by SEDS. At the same time， thin film dispersion and reverse evaporation method were used to prepare ORI liposomes. The particle size， encapsulation efficiency， drug loading amount and stability （accelerated test for 6 months） were compared among 3 methods. Moreover， the difference in dissolution behavior in vitro of ORI crude drug and 3 kinds of liposomes was evaluated. RESULTS： The optimized preparation condition of ORI liposomes by SEDS included temperature of 50 ℃， pressure of 18 MPa， flow rate of 1 mL/min. Compared with thin film dispersion and reverse evaporation method， the liposomes prepared by the SEDS method exhibited smaller particle size [（147.4±4.8）nm]， better encapsulation efficiency （67.8％）， drug-loading amount （7.8％） and stability （particle size increased slightly， encapsulation efficiency decreased only by 4.4％）. Results of in vitro dissolution test showed that compared with crude drug， release rate of each liposome was slow and persistent， and the cumulative release rate was higher. The accumulative release rate of ORI-LIP prepared by SEDS could achieve to 67.2％， and reached to dissolution equilibrium at 24 h. CONCLUSIONS： ORI-LIP prepared by SEDS has smaller particle size， higher encapsulation efficiency， drug loading amount and stability， which can improve the in vitro release of ORI. Compared with conventional methods， SEDS technology has certain advantages.