口服胸腺五肽乳酸-羟基乙酸共聚物纳米粒的制备及物理性质考察

目的制备供口服给药的胸腺五肽乳酸-羟基乙酸共聚物(thymopentin-poly lactic-co-glycolicacid;TP5-PLGA)纳米粒,并对纳米粒的物理性质进行考察。方法用复乳-溶剂挥发法制备TP5-PLGA纳米粒,以包封率为评价指标,用L16(45)正交设计优选纳米粒制备的处方工艺条件,用HPLC法测定胸腺五肽的含量,用激光粒度仪测定纳米粒的粒径,用透射电镜观察纳米粒的形态,用动态透析法考察纳米粒的体外释药特征。结果正交设计确定纳米粒制备的最优处方工艺条件为胸腺五肽质量浓度50 g.L-1,载体材料PLGA质量浓度100 g.L-1,乳化剂PVA质量浓度20 g.L-1;优化处方与工艺制备的纳米粒为规整的圆球形,平均粒径为(150.3±9.6)nm,载药量与包封率分别为(2.403±0.066)%与(28.12±0.60)%;体外释药结果表明,前5 h药物释放(31.27±1.5)%,存在一定突释,4 d累积释药量为(43.60±2.3)%。结论以乳酸-羟基乙酸共聚物为载体材料制备胸腺五肽纳米粒工艺简便,制剂具有良好的物理性质和体外释药特征。     

胸腺五肽脂质体的研制

目的:制备胸腺五肽脂质体并进行质量评价。方法:采用复乳法制备胸腺五肽脂质体,以聚乳酸-羟基乙酸共聚物(PLGA)及卵磷脂为成球材料、以胸腺五肽为主药制备脂质体。以明胶浓度、PLGA浓度和卵磷脂浓度为考察因素,以包封率和载药量为考察指标设计L(934)正交试验优化基质处方并进行验证试验。通过测定优化处方所制脂质体粒径、包封率、体外累积释放百分率等评价脂质体质量。结果:优化基质处方为明胶、PLGA和卵磷脂浓度分别为100、200、100mg.mL-1。所制脂质体形态完整,平均粒径为(9.03±0.83)μm,载药量与包封率分别为(1.81±0.03)与(74.4±1.4),20d的累积释药百分率达90以上。结论:所制胸腺五肽脂质体工艺简单、重现性好,包封率和载药量高,具有显著的缓释作用。     

右美沙芬树脂口服缓释混悬液的制备及其释药特性研究

目的：制备右美沙芬树脂口服缓释混悬液，并考察其释药特性。方法：采用离子交换树脂为载体制备含药树脂微粒，用流化床进行包衣，并通过处方优化制备右美沙芬树脂口服缓释混悬液。对含药树脂微粒、含药树脂包衣微粒及含药树脂缓释混悬液进行释药特性研究。结果：含药树脂微粒的释放度随着释放介质离子强度的增加而增大，其释药动力学过程可用Viswanathan方程表征；采用含药树脂包衣微粒制备的右美沙芬树脂口服缓释混悬液的物理稳定性良好，其释药动力学过程符合Higuchi模型。结论：采用离子交换树脂为药物载体，并对该含药树脂微粒进行流化床包衣，可以制备符合Higuchi模型释药的右美沙芬树脂口服缓释混悬液。     

球面对称设计优化胸腺五肽三甲基壳聚糖纳米粒的制备条件

目的探讨以三甲基壳聚糖为材料制备胸腺五肽纳米粒的制备条件。方法离子胶凝法制备胸腺五肽三甲基壳聚糖纳米粒(Tp5-TMC-NP),用球面对称设计优化制备条件,以粒径和包封率为评价指标,考查TMC浓度(X1)、海藻酸钠浓度(X2)、Tp5加入量(X3)三个指标对制备条件的影响,将实验结果用数学方法处理并进行方程模型拟合,根据拟合方程及由此绘制的反应曲面图(Response Surface Plot)考察指标的最优值和各因素相对应的最佳取值范围。结果以优化条件制得纳米粒粒径110.6 nm,药物包封率78.8%。结论制备方法简便,具有工业化生产的可行性。     

球面对称设计优化胸腺五肽三甲基壳聚糖纳米粒的制备条件

目的探讨以三甲基壳聚糖为材料制备胸腺五肽纳米粒的制备条件。方法离子胶凝法制备胸腺五肽三甲基壳聚糖纳米粒(Tp5-TMC-NP),用球面对称设计优化制备条件,以粒径和包封率为评价指标,考查TMC浓度(X₁)、海藻酸钠浓度(X₂)、Tp5加入量(X₃)三个指标对制备条件的影响,将实验结果用数学方法处理并进行方程模型拟合,根据拟合方程及由此绘制的反应曲面图(Response Surface Plot)考察指标的最优值和各因素相对应的最佳取值范围。结果以优化条件制得纳米粒粒径110.6 nm,药物包封率78.8%。结论制备方法简便,具有工业化生产的可行性。     

胸腺五肽囊泡型磷脂凝胶的制备及体外性质的研究

目的 制备胸腺五肽囊泡型磷脂凝胶(TP5 VPGs).方法 采用直接载药法制备TP5 VPGs,测定包封率、体外释药行为及其对家兔的皮下刺激性.结果 制备的TP5 VPGs包封率为80.58％±2％;脂质含量为300 mg·g-1的TP5 VPGs在48 h时累积释放率达94.89％±3.56％;当脂质浓度增大为400 mg·g-1时,其48 h内累积释放率为61.76％±9.6％;该制剂具有明显的缓释效应,释药时间随脂质浓度的增加而延长,且无突释现象;皮下刺激试验表明所制备的磷脂凝胶无刺激性.结论 通过直接载药法制备的TP5 VPGs工艺简便可行,包封率较高,有明显的缓释特征,其释药时间同脂质浓度相关,有望成为一种新的缓释载体.     

胰岛素微粒剂的体外释药、小鼠体内分布与绝对生物利用度

采用放射免疫分析方法测定了胰岛素微粒剂的体外释药性 .用放射性标记技术制备了12 5Ⅰ 胰岛素微粒制剂 ,且以微粒剂中12 5Ⅰ 胰岛素的放射性计数为指标 ,研究了12 5Ⅰ 胰岛素在小鼠体内的生物利用度与组织分布 .研究表明 :微粒剂在不同pH值的磷酸盐缓冲液中 ,释药规律接近一级动力学方程 :ln(Q∞ -Q) =bt +A ,相关系数为rpH 2 5=- 0 .9398、rpH 7 0 =- 0 .9933,但更好地符合自拟释药方程 :Q =Q∞ bt/(1+bt) ,相关系数为rpH 2 5=- 0 .995 2、rpH 7.0 =- 0 .996 9.小鼠口服绝对生物利用度为 11.5 1%± 4.41% .12 5Ⅰ 胰岛素在小鼠脏器的同位素强度分布依次为肝、肾、心、肺、脾 .     

疏水性药物昔奈酸沙美特罗纳米粒-微粒系统的研制

目的:制备疏水性药物昔奈酸沙美特罗的纳米粒-微粒给药系统。方法:以壳聚糖为载体材料,采用离子交联法联合喷雾干燥工艺制备昔奈酸沙美特罗纳米粒-微粒给药系统,并考察其体外释药及沉降特性。结果:制得的纳米粒-微粒粉末外观较为圆整、规则,粒径分布主要集中在2～8μm范围内,堆密度和休止角分别为(217.28±1.47)mg/ml和(30.24±0.77)°,粉末流动性较好,包封率和载药量分别为(71.40±2.88)%和(7.67±0.31)%。昔奈酸沙美特罗纳米粒-微粒和昔奈酸沙美特罗原药在体外释放初期均表现出一定的突释效应(2h累积释药百分数达到50%以上),24h达到95%以上,其中昔奈酸沙美特罗纳米粒-微粒的体外释药速度与其原药相比较慢。微粒粉末的有效部位沉积百分比为22.07%。结论:本研究可以成功制得昔奈酸沙美特罗纳米粒-微粒给药系统,其载药量和包封率较高,体外释药可控,可吸入性良好,为进一步的载体修饰奠定了基础。     

胸腺五肽多囊脂质体的制备及体外释放的考察

目的 制备胸腺五肽多囊脂质体,并考察其包封率和体外释放情况.方法 采用复乳法制备胸腺五肽多囊脂质体,并用单因素、正交实验对处方进行优化.结果 制备的胸腺五肽多囊脂质体的外观圆整均匀,形态良好,包封率为80.15%±3%.体外释放的零级动力学方程为:Y=0.536X+20.431(r2=0.9814),132 h的累积释放率为92.01%.结论 复乳法制备的胸腺五肽多囊脂质体的工艺可行,包封率较高,有明显的缓释特征.     

胰岛素壳聚糖胶态纳米粒的制备及体外释药性能

采用离子趋向凝胶化法制备了胰岛素壳聚糖胶态微粒,并考察了外观、粒径和体外释药性能.所得产品呈球形,表面光滑圆整,平均粒径为276nm,多分散系数为0.08.体外释药呈pH依赖性,释药速度受载药量及泊洛沙姆188含量的影响.     

Preparation and evaluation of poly-butylcyanoacrylate nanoparticles for oral delivery of thymopentin

Thymopentin (Tp5) was loaded in poly-butylcyanoacrylate (PBCA) nanoparticles (NP) in order to enhance the oral bioavailability of Tp5. PBCA-Tp5-NP was prepared by nanoprecipitation methods. Dialyzing membrane method was employed to examine the in vitro release of PBCA-Tp5-NP in PBS, and Tp5 samples in the release medium were detected by HPLC. The cell proliferation test ((3)H-thymidine) was conducted to verify the PBCA-Tp5-NP bioactivity in vitro. The pharmacodynamical studies were performed on preimmunoinhibited rats and in flow cytometer. The size and the entrapment efficiency of PBCA-Tp5-NP were 178 +/- 39 nm and 92.21 +/- 1.08%, respectively. In vitro release data show that less than 60% Tp5 was released from lyophilized PBCA-Tp5-NP while 80% Tp5 was released from the colloidal PBCA-Tp5-NPs in 48 h. The proliferation test showed that PBCA-Tp5-NP had the similar effect as Tp5. The in vivo data showed that oral PBCA-Tp5-NPs had similar function as what intravenous Tp5 did. The oral bioavailability of Tp5 could be enhanced by PBCA nanoparticles. PBCA-Tp5-NP had the property of sustained-release and the efficacy of Tp5 was not changed after formulation.     

Preparation and evaluation of N(3)-O-toluyl-fluorouracil-loaded liposomes

This study was aimed at developing a liposome delivery system for a new and potential antitumor lipophilic prodrug of 5-fluorouracil (5-Fu)-N(3)-O-toluyl-fluorouracil (TFu), intended to improve the bioavailability and therapeutic efficacy of 5-Fu by oral and intravenous administration. TFu-loaded liposomes were prepared by a modified film dispersion-homogenization technique, the formulation and manufacture parameters were optimized concerning the drug encapsulation efficiency. TFu-loaded liposomes were characterized according to particle size, size distribution, zeta potential, drug entrapment efficiency, drug loading and physical stability, respectively. In vitro release characteristics, in vivo pharmacokinetic properties and bioavailabilities were also investigated. The formulated liposomes were found to be relatively uniform in size (400.5 +/- 9.6 nm) with a negative zeta potential (-6.4 +/- 0.8 mV). The drug entrapment efficiency and loading were (88.87 +/- 3.25%) and (8.89 +/- 0.19%), respectively. The physical stability experiments results indicated that lyophilized TFu-loaded liposomes were stable for at least 9 months at 4 degrees C. In vitro drug release profile of TFu-loaded liposomes followed the bi-exponential equation. The results of the pharmacokinetic studies in mice indicated that the bioavailability of TFu-loaded liposomes was higher than the suspension after oral administration, and was bioequivalent comparing with TFu 50% alcohol solution after intravenous (i.v.) administration. These results indicated that TFu-loaded liposomes were valued to develop as a practical preparation for oral or i.v. administration.     

Research on thymopentin loaded oralN-trimethyl chitosan nanoparticles

Peptides, although high efficacy and specificity in their physiological function, usually have low therapeutical activities due to their poor bioavailability when administrated orally. Nanoparticles have been regarded as a useful vector for targeted drug delivery system because they can protect drug from being degraded quickly and pass the gastrointestinal barriers. Here we described a novel oral N-trimethyl chitosan nanoparticles formulation containing thymopentin (Tp5-TMC-NP). N-trimethyl chitosan (TMC) was synthesized and then used to prepare Tp5-TMC-NP by ionotropic gelation. A three-factor, five-level CCD (Central Composite Design) design was used in the optimization procedure, with HPLC as the analyzing method. The resulting Tp5-TMC-NP had a regular spherical surface and a narrow particle size range with a mean diameter of 110.6 nm. The average entrapment efficiency was 78.8%. The lyophilized Tp5-TMC-NP formulation was stable in 4 degrees C or -20 degrees C after storage of 3 months without obvious changes in morphology, particle size, pH and entrapment ratio. The results of the flow cytometer determination showed that the ratio of CD4+/CD8+ of Wistar female rat givenTp5-TMC-NP (ig) was 2.59 time that of the group given Tp5 (ig).     

Release stability of 5-fluorouracil liposomal concentrates, gels and lyophilized powder

Possible leakage of 5-fluorouracil from stable plurilamellar vesicles was monitored during storage of the liposomal concentrates, gels and lyophilized powders. Changes in release profile of dibucaine were taken as indicator of instability. Release profiles were obtained using the dialysis technique for a freshly prepared liposomal concentrate, gel or reconstituted lyophilized powder (zero time) and storage for one, two and four weeks in well closed tubes at 4 degrees C for the liposomal concentrate or gel and at 25 degrees C for liposomal lyophilized powder. Aiming at increasing stability of 5-fluorouracil liposomal dispersion, freshly prepared liposomal concentrates were directly incorporated in hydroxypropyl methylcellulose gel. Stability release profiles of liposomal gels and concentrates indicated a significant increase in stability of liposomal formulations. Also, lyophilization increases the shelf life of liposomes by preserving it in a dry form as a lyophilized cake to be reconstituted immediately prior to administration or direct incorporation into a final dosage form. Release and physico-chemical stability studies showed superior potentials of the lyophilized product after reconstitution in comparison to concentrate and gel forms. It could be concluded that lyophilization of liposomes loaded with a water-soluble drug such as 5-fluorouracil could significantly increase the stability of the liposomal vesicles and decrease leakage from it.     

Effect of formulation design and freeze-drying on properties of fluconazole multilamellar liposomes

Fluconazole-entrapped multilamellar liposomes were prepared using the thin-film hydration method. The effects of cholesterol molar ratio, charge-inducing agents, and α-tocopherol acetate on encapsulation efficiency values and in vitro drug release of multilamellar liposomes were studied. Freeze-dried liposomal products were prepared with or without cryoprotectants. Results showed that incorporation of stearylamine resulted in an increased entrapment of fluconazole, whereas incorporation of dicetyl phosphate decreased the drug entrapment efficiency. The incorporation of α-tocopherol acetate into fluconazole multilamellar liposomes resulted in the increase of entrapment efficiency of fluconazole liposomes. In vitro release studies revealed that incorporation of cholesterol into multilamellar liposomal formulations decreased drug permeability from formulations. Positively charged fluconazole multilamellar liposomes gave rise to a slow release rate compared to neutral liposomes whereas negatively charged fluconazole liposomes showed a rapid release rate. Physical stability studies showed that lyophilized cake of liposomes without cryoprotectants was compact and difficult to reconstitute compared to fluffy easily reconstituted cakes upon using cryoprotectants. Fluconazole retained in freeze-dried liposomes without cryoprotectants was 63.452% compared to 91.877% using three grams of trehalose as a cryoprotectant per gram lipid in positively charged multilamellar liposomes. Physical stability studies showed superior potentials of the lyophilized product after reconstitution in comparison with those of a solution product.     

5-Fluorouracil in topical liposome gels for anticancer treatment--formulation and evaluation

Liposome gels bearing an antineoplastic agent, 5-fluorouracil, intended for topical application have been prepared and drug release properties in vitro have been evaluated. Different formulations of liposomes were prepared by the film hydration method by varying the lipid phase composition (PL 90H/cholesterol mass ratio) and hydration conditions of dry lipid film (drug/aqueous phase mass ratio). Topical liposome gels were prepared by incorporation of lyophilized liposomes into a structured vehicle (1%, m/m, chitosan gel base). Also, hydrogels containing different concentrations of 5-fluorouracil were prepared and drug release properties were investigated. The rate of drug release from liposome gels was found to be dependent on the bilayer composition and the dry lipid film hydration conditions. Also, liposomes embedded into a structured vehicle of chitosan showed significantly slower release than hydrogels. The drug release obeyed the Higuchi diffusion model, while liposomes acted as reservoir systems for continuous delivery of the encapsulated drug.     

美洛昔康纳米脂质载体的制备及表征

目的制备美洛昔康纳米脂质载体(MX-NLC)胶体溶液及冻干粉,并对二者理化性质和体外释放行为进行考察。方法应用高压均质法制备MX-NLC胶体溶液,并对其冷冻干燥。以外观、含量、包封率、粒径、zeta电位、释放度为评价指标,考察MX-NLC胶体溶液及冻干粉的理化性质。结果冻干前后的平均含量质量分数为99.8%和98.5%,平均包封率为73.6%和72.5%;MX-NLC冻干前后的粒径分别为137 nm和154 nm,zeta电位分别为-28.4 mV和-25.2 mV。体外释放结果表明,MX-NLC具有明显的缓释效果。结论通过高压均质法和冷冻干燥技术可以得到美洛昔康纳米脂质载体。所制得MX-NLC粒径在100～200 nm内,具有明显的缓释特征,有可能实现静脉注射给药并具备被动靶向特征。     

The effect of cryoprotectants on the physical properties of large liposomes containing sodium diclofenac

Large liposomes (1-10 microm) containing sodium diclofenac were prepared and lyophilized using lactose or mannitol (7.5% in respect to the lipid content) as cryoprotectants. The physical studies of liposomes were performed during 30 days of storage in a dry or resuspended form. Lyophilization of large liposomes and storage in the dry form at 5 degrees C increases their physical stability. Lactose is a cryoprotectant which does not influence changes of properties of liposomes regarding their size, encapsulation efficacy and release rate. Large liposomes lyophilized in the presence of mannitol tend to increase in size and encapsulation efficacy, but the lipid bilayers are stabilized and less permeable to the drug.     

Antitumor effect of adriamycin-encapsulated nanoparticles of poly(DL-lactide-co-glycolide)-grafted dextran

In this study, we prepared adriamycin (ADR)-encapsulated core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer and evaluated its antitumor activity in vitro and in vivo. The particle size of ADR-encapsulated DexLG nanoparticles was around 50-200 nm and the morphology was spherical shapes at transmission electron microscopy (TEM) observation. Since reconstitution of lyophilized nanoparticles is essential to practical use in vivo, ADR-encapsulated DexLG nanoparticles were lyophilized and reconstituted them into deionized water. Although reconstitution process caused increase of particle size, drug release behavior of nanoparticles was not significantly changed before and after reconstitution process. The ADR-encapsulated DexLG nanoparticles were less cytotoxic than free ADR plus empty nanoparticles at in vitro, while empty DexLG nanoparticles did not significantly affect cell viability. Even if free ADR plus empty nanoparticles are most effective to inhibit tumor growth at tumor-induced animal model using CT-26 cells, ADR-encapsulated DexLG nanoparticles showed increased survivability of mice. These results indicated that ADR-encapsulated DexLG nanoparticles are promising vehicles for antitumor drug delivery.     

Nasal administration of metoclopramide from different dosage forms: in vitro,ex vivo,and in vivo evaluation

Nasal drug delivery is an interesting route of administration for metoclopramide hydrochloride (MTC) in preventing different kind of emesis. Currently, the routes of administration of antiemetics are oral or intravenous, although patient compliance is often impaired by the difficulties associated with acute emesis or invasiveness of parenteral administration. In this perspective, nasal dosage forms (solution, gel, and lyophilized powder) of MTC were prepared by using a mucoadhesive polymer sodium carboxymethylcellulose (NaCMC). In vitro and ex vivo drug release studies were performed in a modified horizontal diffusion chamber with cellulose membrane and excised cattle nasal mucosa as diffusion barriers. The tolerance of nasal mucosa to the formulation and its components were investigated using light microscopy. In vivo studies were carried out for the optimized formulations in sheep and the pharmacokinetics parameters were compared with oral solution and IV dosage form. The release of MTC from solution and powder formulations was found to be higher than gel formulation (p?<?0.05). Histopathological examination did not detect any severe damage. Hydroxypropyl-β-cyclodextrin (HPβCD) used in powder formulations was found to be effective for enhancing the release and absorption of MTC. In contrast to in vitro and ex vivo experiments nasal bioavailability of gel is higher than those of solution and powder (p?<?0.05). In conclusion, the NaCMC gel formulation of MTC with mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.