环孢素A双连续型微乳在大鼠皮肤中的药物滞留量考察

目的考察环孢素A双连续型微乳经大鼠皮肤给药的可行性及对药物体内分布的影响,并与大鼠灌胃给予新山地明比较。方法将环孢素A双连续型微乳非封闭的应用于大鼠皮肤,给药皮肤用胶带剥离法分离角质层,得到的全血、肾脏、肝脏、皮肤(除去角质层)经提取后用RP-HPLC法测定药物的含量,观察药物在血液中质量浓度的经时变化以及在肾脏、肝脏和皮肤的分布状况。结果与灌胃给予同剂量新山地明的体内行为相比,微乳经皮给药后皮肤中药物的含量显著高于口服组(P<0.01),而血液及肝脏、肾脏中药物的含量明显低于口服组。结论双连续型微乳能够有效的提高环孢素A在大鼠皮肤中的滞留量,同时可以降低药物在肝肾的蓄积。     

Leucinostatin-A loaded nanospheres: characterization and in vivo toxicity and efficacy evaluation

Leucinostatin A (Leu-A) is a nonapeptide exerting a remarkable activity especially against Candida albicans and Cryptococcus neoformans; nevertheless, its employment is limited due its toxicity. Therefore, we recently developed liposomal formulations, as suitable delivery systems, in order to increase its therapeutic index. However, liposomes present disadvantages related to their long-term instability. For this reason poly(lactic-co-glycolic) nanospheres (NS) were chosen as alternative colloidal carriers for Leu-A delivery. NS were formulated by spontaneous emulsification solvent diffusion method. This study investigates the effects of different parameters on drug encapsulation efficiency and particle size as well. The best preparation obtained was also characterized for its in vitro release, in vivo acute toxicity (LD50), and effectiveness against C. albicans in mice. In vitro release was performed over 100 h and resulted sufficiently sustained with more than 93% of the peptide released. Acute toxicity showed that the LD50 was increased more than 18-fold and the study on systemic candidiasis models revealed high effectiveness of the NS in reducing either the growth of fungal colonies in infected mice liver or in the mortality index. In conclusion, we can propose that Leu-A loaded NS could represent a new promising therapeutic system against Candida infection.     

罗替戈汀原位形成植入剂的制备及体内药动学考察

目的:制备抗帕金森病药物罗替戈汀原位形成植入剂(R-ISFI),并对其体内长效释药行为进行考察。方法:以N-甲基-二吡咯烷酮(NMP)为溶剂、聚乳酸-羟基乙酸共聚物(PLGA)为载体材料,制备R-ISFI。采用摇床法进行体外释放度的考察,采用大鼠体内药动学实验考察罗替戈汀的体内释药特性。大鼠皮下注射R-ISFI,HPLC法测定不同时间血浆中药物浓度。结果:高分子材料的类型、高分子材料与溶剂比、药物与高分子材料的用量比及ISFI的形状均对药物体外释放有显著的影响。R-ISFI体外释药平缓,30 d可累积释放85%,体内药动学结果表明,R-ISFI在体内缓释效果良好,突释小,可持续释放30 d。结论:制备的R-ISFI可持续平稳释放达一个月,是一种很有开发应用前景的长效缓释制剂。     

醋酸地塞米松聚乙二醇化纳米粒的制备及兔体内药动学研究

目的：制备醋酸地塞米松聚乙二醇（PEG）化纳米粒,并测定其在兔体内的药动学参数。方法：以高压均质法制备醋酸地塞米松PEG化纳米粒,用扫描电镜观察纳米颗粒的形态,用激光粒度分析仪测定粒径。建立检测血浆中醋酸地塞米松浓度的HPLC法,以醋酸地塞米松溶液和普通纳米粒作为对照,测定醋酸地塞米松PEG化纳米粒在兔体内的药动学参数。结果：PEG化纳米粒平均粒径为（180±7）nm。体内半衰期为4.79h,AUC0～12为11.81mg.min.L-1,平均滞留时间为3.15h,重要药动学参数比普通纳米粒及溶液剂增加近1倍。结论：醋酸地塞米松PEG化纳米粒可以延长醋酸地塞米松在兔体内的半衰期,达到体内长循环的目的;其表观特征与普通载药纳米粒无明显差异。     

阿霉素-DS-PLGA自组装纳米粒的制备、表征和药物动力学

目的制备以葡聚糖硫酸钠-聚乳酸-羟基乙酸共聚物为疏水内核,二硬脂酰磷脂酰胆碱和聚乙二醇-磷脂酰乙醇胺包裹的阿霉素载药纳米粒,并进行表征和药物动力学研究。方法采用乳化溶剂挥发法制备阿霉素-葡聚糖硫酸钠-聚乳酸-羟基乙酸共聚物复合纳米粒。透射电镜观察纳米粒的外观形态、粒径测定仪测定粒径、粒径分布和Zeta电位,葡聚糖凝胶柱法测定包封率,动态透析法考察体外释放情况。通过大鼠尾静脉注射阿霉素溶液和阿霉素载药纳米粒,进一步考察其体内药动学特征。结果包载阿霉素的纳米粒外观多呈球形,粒径分布均匀,平均粒径为155.5 nm,Zeta电位为-(11.6±1.0)m V,包封率为99.4%。纳米粒中药物的释放缓慢,且呈p H依赖性,在p H7.4时,72 h累积释放达到27.4%,在p H 4.5时,72 h累积释放达到80.0%。与阿霉素溶液相比,纳米粒的AUC0-t和ρmax分别增加了8.3和6.2倍,t1/2延长了3.6倍。结论利用阴离子聚合物葡聚糖硫酸钠与阳离子阿霉素之间形成静电聚合物,制备成纳米粒后,药物在体内的血药浓度时间曲线下面积增大,循环时间延长。     

Formulation,characterization, and in vitro/ex vivo evaluation of quercetin-loaded microemulsion for topical application

The aim of this study was to develop a new microemulsion formulation for topical application of poorly soluble drug named quercetin. In order to design suitable microemulsion system, the pseudo-ternary phase diagrams of microemulsion systems were constructed at different surfactant/co-surfactant ratios using tween 80 as surfactant, transcutol^® P as a co-surfactant and oleic acid as an oil phase. Some physicochemical properties such as droplet size, density, refractive index, electrical conductivity, pH, surface tension, and viscosity of the microemulsion systems were measured at 298.15 K. The average hydrodynamic droplet size of the optimized microemulsions was obtained by dynamic light scattering method. Morphology assessment of the optimized quercetin-loaded microemulsion by transmission electron microscopy analysis indicated that the particles have the size of about 25?nm and spherical with narrow size distribution. Equilibrium solubility, in vitro drug release at a 24?h time period, release kinetic evaluation as well as ex vivo permeation and retention of quercetin-loaded microemulsions through rat skin has been investigated. The obtained results showed a slow release behavior without any transdermal delivery. Most of the formulations fitted best with zero-order kinetic model with a non-Fickian mechanisms. This study illustrated that the proposed QU-microemulsion has a good potential for use in sunscreen formulations.

     

Gelatin-stabilised microemulsion-based organogels facilitates percutaneous penetration of Cyclosporin A in vitro and dermal pharmacokinetics in vivo

Gelatin-stabilised microemulsion-based organogels (MBGs) are very useful in transdermal and topical delivery of hydrophobic drugs because of their lipophilic nature. MBGs systems possessing a potentially improved skin bioavailability of Cyclosporin A were designed and explored for some characteristics. The release characteristics of drug from MBGs were studied according to drug concentration. As the concentration of drug increased, the release of drug from gel increased, showing concentration dependency. Percutaneous penetration studies using rat skin in vitro showed that the deposition of Cyclosporin A was significantly improved by MBGs compared to the control. We also evaluated the therapeutic advantage of dermal administration of Cyclosporin A in rat model. Local (subcutaneous and skin), systemic concentrations and organ distribution (liver and kidney) were evaluated serially following topical and oral application of the drug. In rat dermal applied with the MBGs containing Cyclosporin A, the deposition of the drug into skin and subcutaneous fat was, respectively, almost 55- and 3-fold higher than the concentrations compared with oral administration. Systemic distribution in blood, liver and kidney was much lower following topical than following oral administration. With high local concentrations and minimal distribution to other organs via the circulation, topical applied MBGs loaded with Cyclosporin A might deliver maximal therapeutic effect to local tissue while avoiding the side effects seen with systemic therapy. The histopathological findings revealed that the new MBGs vehicle was a safe vehicle for topical drug delivery systems.     

Chitosan-associated SLN: in vitro and ex vivo characterization of cyclosporine A loaded ophthalmic systems

The aim of this study was to develop cyclosporine A (CsA) loaded solid lipid nanoparticles (SLN) associated with chitosan (CS), to improve interaction and internalization in corneal cells. The SLN were prepared using high shear homogenization and ultrasound methods with CS in the aqueous phase. The lipid phase was based on Compritol or Precirol. The SLN were characterized for particle size, polydispersity index, morphology, zeta potential and encapsulation efficiency. The systems were freeze-dried to increase physical stability and trehalose was used as a cryo/lyo-protector to stabilize the SLN. The penetration and permeation properties of the SLN were assessed in vitro (cell culture) and ex vivo (excised pig cornea). The cell uptake of SLN was studied by means of confocal laser scanning microscopy. CS-associated SLN based on Compritol were biocompatible and enhanced the permeation/penetration of CsA along with a possible mechanism of internalization/uptake of the nanoparticles both in vitro and ex vivo.     

In vivo sustained dermal delivery and pharmacokinetics of interferon alpha in biphasic vesicles after topical application

Biphasic vesicles, a novel nanostructured lipid-based delivery system show potential for topical application of interferon alpha (IFN α) for the treatment of human papillomavirus (HPV) infections (anogenital warts). Dermal delivery of IFN α encapsulated in biphasic vesicles (BPV-IFN α), applied topically to the skin, was characterized in a guinea pig model.BPV-IFN α (1 g, 2 MIU/g) was topically applied either as a single or multiple treatments on the skin of guinea pigs. As a comparison with currently used regimens, IFN α solution was administered intravenously or intradermally. Skin and serum samples were collected over 96 h, IFN α levels were determined by an antiviral assay, and half-life (t_1/2) and elimination (k) rates were calculated.Topical BPV-IFN α treatment resulted in maximum skin levels (about 100,000 U/100 cm²) of IFN α within 6 h and maintained for 72–96 h. Clearance from the skin after intradermal injections was initially fast (t_1/2 0.62 h, k 1.1179 h⁻¹), followed by a slower steady decrease after 6 h. After intravenous and intradermal administration, IFN α was rapidly cleared from the serum, t_1/2 0.75 h, k 0.9271 h⁻¹ and t_1/2 1.28 h, k 0.5421 h⁻¹, respectively, whereas after topical application, IFN α levels remained below 100 U/mL. Topical application of BPV- IFN α resulted in sustained delivery of biologically active IFN α locally into skin with minimal systemic exposure.     

A propofol microemulsion with low free propofol in the aqueous phase: Formulation, physicochemical characterization, stability and pharmacokinetics

The purpose of this study was to develop a propofol microemulsion with a low concentration of free propofol in the aqueous phase. Propofol microemulsions were prepared based on single-factor experiments and orthogonal design. The optimal microemulsion was evaluated for pH, osmolarity, particle size, zeta potential, morphology, free propofol in the aqueous phase, stability, and pharmacokinetics in beagle dogs, and comparisons made with the commercial emulsion, Diprivan(?). The pH and osmolarity of the microemulsion were similar to those of Diprivan(?). The average particle size was 22.6±0.2nm, and TEM imaging indicated that the microemulsion particles were spherical in appearance. The concentration of free propofol in the microemulsion was 21.3% lower than that of Diprivan(?). Storage stability tests suggested that the microemulsion was stable long-term under room temperature conditions. The pharmacokinetic profile for the microemulsion showed rapid distribution and elimination compared to Diprivan(?). We conclude that the prepared microemulsion may be clinically useful as a potential carrier for propofol delivery.     

Colon targeted beads loaded with pterostilbene: Formulation,optimization, characterization and in vivo evaluation

Background

Pterostilbene has a proven chemopreventive effect for colon carcinogenesis but suffers low bioavailability limitations and therefore unable to reach the colonic tissue.

Lipid nanoemulsions loaded with doxorubicin-oleic acid ionic complex: characterization, in vitro and in vivo studies

This study aimed at developing a novel lipid nanoemulsion formulation of doxorubicin (DOX) which is feasible for scale-up production, exhibits good parenteral acceptability, and further improves the therapeutic index of the drug. Oleic acid was used to form ionic complex with DOX in order to enhance its lipophilicity. The lipid nanoemulsions loaded with doxorubicin-oleic acid complex (DOX-OA-LNs) were prepared using a simple high-pressure homogenization method and fully characterized from physicochemical and in vitro release standpoint. Afterwards, the DOX-OA-LNs and free DOX were compared with respect to their in vitro cellular uptake and cytotoxicity, and their in vivo pharmacokinetics and biodistribution behavior in mice were also investigated. The obtained DOX-OA-LNs could achieve high encapsulation efficiency of 93.7 +/- 1.2% under optimal conditions. The in vitro release behavior displayed biphasic drug release pattern with rapid release at the initial stage and prolonged release afterwards. The DOX-OA-LNs exhibited higher growth inhibitory effect than free DOX by MTT assay. Flow cytometry and confocal microscopy studies showed that the cellular uptake of free DOX and DOX-OA-LNs were comparable. Pharmacokinetics and in vivo distribution studies in mice showed that DOX-OA-LNs demonstrated significantly higher DOX level in blood and longer circulation time than free DOX. Moreover, DOX-OA-LNs significantly decreased DOX concentration in heart, lung and kidney. These results suggested that DOX-OA-LNs could be a promising formulation for the delivery of DOX in tumor chemotherapy.     

Water/oil type microemulsion systems containing lidocaine hydrochloride: in vitro and in vivo evaluation

Abstract

The purpose of this study was to develop a water/oil microemulsion containing lidocaine hydrochloride (4%) and to compare its local anaesthetic efficacy with commercial products. A pseudoternary diagram (K_m:1/1 or 1/2) was constructed using lecithin/ethanol/oil/water. The droplet size, viscosity and release of the microemulsions were evaluated. Tail flick tests were conducted for in vivo effectiveness; the initiation time of effect, maximum effect, time to reach maximum effect, and relative efficacy were evaluated. The drug caused a significant increase in droplet size. The use of olive oil resulted in a decrease in the solubilisation parameter, as well as a reduction in the release. The droplet size and viscosity of the microemulsion composed of Miglyol/lecithin/ethanol/water/drug (K_m:1/2) was lower than other microemulsions (8.38?nm, 6.9 mPa), and its release rate (1.61?mg/h) was higher. This system had a faster and more efficient anaesthetic effect than the other microemulsions and commercial products. Results indicate that a water/oil type microemulsion (Miglyol/lecithin/ethanol/water) has promising potential to increase the local anaesthetic effect.     

Preparation, characterization and in vivo distribution of solid lipid nanoparticles loaded with syringopicroside

A solvent emulsification evaporation method was employed to prepare solid lipid nanoparticles (SLN) loaded with syringopicroside. The conventional broad-spectrum antibacterial and antiviral drug syringopicroside was incorporated into SLN to improve drug targeting. The SYR-SLNs were spherical and uniform in transmission electron microscopy (TEM). The mean particle size and potential were 180.31 +/- 10 nm, and -41.9 +/- 10.3 mV, respectively. Also, a sephadex column chromatography was adopted to investigate the encapsulation efficiency (EE %) of the SLN. This method is based on the principle of molecular sieve effect, and the EE% of the optimal formulation was 42.35 %. Drug-loading capacity was 5.33 %. The in vitro release profile revealed that syringopicroside was released from SLN efficiently and completely in normal saline (NS) compared with other release media. A HPLC method was established for in vivo assay of syringopicroside. A tissue distribution study was conducted in rats after iv administration of 15 mg/kg SYR-SLN and syringopicroside NS, and it was found that SYR-SLN has improved delivery to the liver compared with any other organizations. These results indicated that solvent emulsification evaporation is a simple, easy, available and effective method for preparing SYR-SLN.     

Preparation, characterization and in vivo distribution of solid lipid nanoparticles loaded with cisplatin

An emulsification dispersion-ultrasonication method was employed to prepare solid lipid nanoparticles (SLN) loaded with cisplatin. The conventional antitumor drug cisplatin (CDDP) was incorporated into SLN to obtain a targeted and less toxic drug delivery system. The CDDP-SLNs were spherical and uniform in transmission electron microscopy (TEM) photography. The mean particle size and zeta potential were 121 +/- 15 nm, and -46.4 +/- 10.3 mV, respectively. Also, a novel cation exchange resin method was adopted to investigate the encapsulation efficiency (EE%) of the SLN. This method is based on the principle of cation exchange between drugs and resins, and the EE% of the optimal formulation was 82.3%. The in vitro release profile revealed that CDDP was released from SLN efficiently and completely in normal saline (NS) compared with other release media. A pre-column derivatization HPLC method was established for in vivo assay of cisplatin. A tissue distribution study was conducted in male rats after iv administration of 8 mg mL(-1) CDDP-SLN and cisplatin NS, and it was found that CDDP-SLN has a targeted effect to the liver as well as a low concentration in the kidney in rats. These results indicated that emulsification dispersion-ultrasonication is a simple, easy, available and effective method for preparing CDDP-SLN, and the cation exchange resin method is a feasible and suitable method to evaluate the EE% of CDDP-SLN. CDDP-SLN prepared by this method was proved to be a targeted and less toxic drug delivery system.     

Multidrug resistance modulation in vivo: The effect of cyclosporin A alone or with dexverapamil on idarubicin pharmacokinetics in acute leukemia

Objective: To determine the effect of the coadministration of the multidrug resistance (MDR) modulators cyclosporin A (CyA) alone or plus dexverapamil (D-Ver) on idarubicin (IDA) pharmacokinetics in patients with acute leukemia. Methods: Pharmacokinetic studies were performed in 27 patients with a diagnosis of acute myelogenous leukemia (AML), who were being treated with a combination chemotherapy regimen including idarubicin and cytarabine for the induction of a first remission (n = 14), or of a second remission (n = 7), or for remission consolidation (n = 6). Of these 27 patients, nine were coadministered CyA and seven were coadministered CyA plus D-Ver as MDR modulators. Blood was sampled at appropriate intervals after each of the three IDA daily administrations. IDA and idarubicinol (IDAOL) were assayed by HPLC. Pharmacokinetic evaluations were performed by means of a two-compartment open model with zero-order absorption and first-order elimination using the WinNonlin pharmacokinetic software package. Results: CyA markedly increased the area under the concentration time-curve (AUC) of both IDA [558.26 (197.25) μg · h · l⁻¹ vs 315.44 (158.28) μg · h · l⁻¹; P < 0.01] and IDAOL [2896.60 (736.38) μg · h · l⁻¹ vs 1028.49 (603.95) μg · h · l⁻¹; P < 0.001] when coadministered as a single modulator, due to a lower total body clearance (CL) [83.51 (52.44) l · h⁻¹ · m⁻² vs 139.65 (69.45) l · h⁻¹ · m⁻²; NS]. When patients received two MDR modulators simultaneously (D-Ver plus CyA), IDA exposure was essentially the same as in those of the no inhibitor group [331.29 (95.49) μg · h · l⁻¹ vs 315.44 (158.28) μg · h · l⁻¹; NS], whereas the IDAOL total body exposure was greater than in the no inhibitor group [2030.32 (401.11) μg · h · l⁻¹ vs 1028.49 (603.95) μg · h · l⁻¹; P < 0.01], even if less than in patients receiving CyA as a single MDR modulator (IDA + CyA group) [AUC 2030.32 (401.11) μg · h · l⁻¹ vs 2896.60 (736.38) μg · h · l⁻¹; P < 0.05], suggesting an antagonistic effect against those of CyA on IDA and IDAOL elimination and/or an unpredictable redistribution. The main pharmacokinetic parameters of IDA, such as CL and volume of distribution at steady state (Vd_ss), were remarkably affected by the coadministration of CyA or CyA plus D-Ver, but no statistically significant difference was noted because of IDA pharmacokinetic interpatient variation. Conclusion: The results show that CyA alone at a dose of 10 mg · kg⁻¹ daily significantly increased systemic body exposure to both IDA and IDAOL in acute leukemia, and suggest that these pharmacokinetic effects were at least partially decreased when D-Ver was coadministered with CyA. Our findings raise important questions concerning the need for a dosage adjustment of IDA when MDR modulators are coadministered. Received: 2 June 1998 / Accepted in revised form: 3 December 1998     

Inhalable,large porous PLGA microparticles loaded with paclitaxel: preparation,in vitro and in vivo characterization

Abstract

Large porous particles (LPPs) could be used as a useful carrier for non-invasive delivery to the deep lung. Pulmonary delivery of paclitaxel-loaded LPPs (PTX-LPPs) can help to eliminate the highly complicated and harmful solvent used in PTX parenteral formulations. PTX-LPPs with mass median aerodynamic diameter (MMAD) of 5.74?±?0.09?μm, high encapsulation efficiency and good aerosolisation properties were produced using ammonium bicarbonate as porogen. Cytotoxicity of PTX-LPPs on A549 and Calu-6 cell lines was comparable with Free-PTX. Endotracheal administration of PTX-LPPs in rats exhibited PTX plasma concentration in the therapeutic range which lasted 4-fold longer than i.v. injection. The bioavailability was measured as 51?±?7.1%. The lung targeting efficiency (T_e) of PTX-LPPs was 11.9-fold higher than i.v. administration. PTX-LPPs could deliver a higher PTX to lung with a non-toxic plasma level in a longer duration which shows their pulmonary delivery suitability.     

Electrosteric stealth Rivastigmine loaded liposomes for brain targeting: preparation,characterization, ex vivo,bio-distribution and in vivo pharmacokinetic studies

Being one of the highly effective drugs in treatment of Alzheimer’s disease, Rivastigmine brain targeting is highly demandable, therefore liposomal dispersion of Rivastigmine was prepared containing 2?mol% PEG-DSPE added to Lecithin, Didecyldimethyl ammonium bromide (DDAB), Tween 80 in 1:0.02:0.25 molar ratio. A major challenge during the preparation of liposomes is maintaining a stable formulation, therefore the aim of our study was to increase liposomal stability by addition of DDAB to give an electrostatic stability and PEG-DSPE to increase stability by steric hindrance, yielding what we called an electrosteric stealth (ESS) liposomes. A medium nano-sized liposome (478?±?4.94?nm) with a nearly neutral zeta potential (ZP, ?8?±?0.2?mV) and an entrapment efficiency percentage of 48?±?6.22 was prepared. Stability studies showed no major alteration after three months storage period concerning particle size, polydispersity index, ZP, entrapment efficiency and in vitro release study confirming the successful formation of a stable liposomes. No histopathological alteration was recorded for ESS liposomes of the sheep nasal mucosa. While ESS liposomes showed higher % of drug permeating through the sheep nasal mucosa (48.6%) than the drug solution (28.7%). On completing the in vivo pharmacokinetic studies of 36 rabbits showed 424.2% relative bioavailability of the mean plasma levels of the formula ESS compared to that of RHT intranasal solution and 486% relative bioavailability of the mean brain levels.     

Quercetin in w/o microemulsion: In vitro and in vivo skin penetration and efficacy against UVB-induced skin damages evaluated in vivo.

The present study evaluated the potential of a w/o microemulsion as a topical carrier system for delivery of the antioxidant quercetin. Topical and transdermal delivery of quercetin were evaluated in vitro using porcine ear skin mounted on a Franz diffusion cell and in vivo on hairless-skin mice. Skin irritation by topical application of the microemulsion containing quercetin, and the protective effect of the formulation on UVB-induced decrease of endogenous reduced glutathione levels and increase of cutaneous proteinase secretion/activity were also investigated. The w/o microemulsion increased the penetration of quercetin into the stratum corneum and epidermis plus dermis at 3, 6, 9 and 12h post-application in vitro and in vivo at 6h post-application. No transdermal delivery of quercetin occurred. By evaluating established endpoints of skin irritation (erythema formation, epidermis thickening and infiltration of inflammatory cells), the study demonstrated that the daily application of the w/o microemulsion for up to 2 days did not cause skin irritation. W/o microemulsion containing quercetin significantly prevented the UVB irradiation-induced GSH depletion and secretion/activity of metalloproteinases.