A detailed analysis of biodegradable nanospheres by different techniques--a combined approach to detect particle sizes and size distributions

Poly(d,l-lactide-co-glycolide) nanosupensions as intravenous nanosphere systems were produced by solvent deposition in aqueous Poloxamer 188 solutions. Light scattering techniques were applied to these colloidal systems to characterize particle sizes. Regularly shaped spherical particles were received as proved by freeze fracture replica and small-angle X-ray scattering (SAXS). SAXS was performed using intensive synchrotron radiation. Particle sizes were calculated from the small-angle part of scattering curve that were in good agreement with z-average values received from photon correlation spectroscopy (PCS). The flow field-flow fractionation (FlFFF) fractograms in combination with multi-angle light scattering (MALS) allowed an easy detection of maximum particle sizes what is most important for parenteral systems. Furthermore, high quality size distributions were received due to the separation step prior to size characterization. The calculated average size values exhibited a good correlation with z-averages determined by PCS. Only for suspensions of broader size distributions, higher deviations were observed. Comparing particle sizes with and without Poloxamer, differences in diameters resulted that were quantified. The additional Poloxamer shell was not able to be removed by an intensive washing during FlFFF focusing and separation. Especially FlFFF/MALS proved to be a valuable tool to characterize the pharmaceutical nanosuspensions in detail what is of great importance especially for controlled drug delivery systems.     

Novel Tanshinone II A ternary solid dispersion pellets prepared by a single-step technique: In vitro and in vivo evaluation

Novel Tanshinone II A (TA) ternary solid dispersion (tSD) pellets with the combination of polyvinylpyrrolidone and poloxamer 188 as dispersing carriers were prepared by a single-step technique. A formulation screening study showed that the addition of poloxamer 188 to binary TA-PVP system could remarkably promote the dissolution rate of TA from 60% to 100% after 60 min. Scanning electron microscopy study revealed a smooth surface and a tightly packed coating structure. Differential scanning calorimetry analysis confirmed the formation of solid dispersions. In vivo test showed that TA tSD pellets presented significantly larger AUC_0-t, which was 0.76 times more than that of binary solid dispersion (bSD) pellets, 2.87 times more than that of physical mixtures (PMs) and 5.40 times more than that of TA. C_max of TA tSD pellets also increased by 1.82-8.97-fold as that of bSD pellets, PMs and TA. TA tSD pellets generated obviously shortened T_max of (3.80 ± 0.398) h, compared to bSD pellets with (4.15 ± 0.456) h, PMs with (4.65 ± 0.226) h and TA with (5.52 ± 0.738) h. In conclusion, the addition of poloxamer 188 to pellets containing PVP-based solid dispersions could achieve complete dissolution, accelerated absorption rate and superior oral bioavailability. The fluid-bed technique becomes an alternative approach to obtain solid dispersion-coated pellets.     

钨酸钠对泊洛沙姆407诱导高血脂昆明小鼠模型血脂的影响

【目的】研究钨酸钠对泊洛沙姆407诱导的高血脂昆明小鼠模型血脂的影响。【方法】昆明小鼠给予钨酸钠（100或200mg/kg）灌胃,连续3 d,末次给药1 h后,腹腔注射泊洛沙姆407 0.3 g/kg,于注射后的4、24及48 h,取血测定甘油三酯和胆固醇含量,注射泊洛沙姆407后24 h血样同时测定高密度脂蛋白-胆固醇的含量。【结果】与正常组的甘油三酯（6.30±0.87）mmol/L相比,泊洛沙姆407腹腔注射4 h后,诱导昆明小鼠出现明显的高甘油三酯血症（233.99±37.94）mmol/L,预先给予钨酸钠处理,能明显降低血清甘油三酯水平[低剂量钨酸钠组：（207.13±29.85）mmol/L;高剂量钨酸钠组：（131.50±46.07）mmol/L,P〈0.05],此作用可持续到造模后的48 h。造模后的24 h,钨酸钠的降血清胆固醇的作用最明显[对照组：（6.07±0.70）mmol/L;低剂量钨酸钠组：（3.04±0.40）mmol/L;高剂量钨酸钠组：（1.81±0.40）mmol/L,P〈0.05]。造模后的24 h,预处理钨酸钠能明显升高血清高密度脂蛋白-胆固醇水平[对照组：（1.97±0.40）mmol/L;低剂量钨酸钠组：（2.70±0.42）mmol/L;高剂量钨酸钠组：（3.73±0.81）mmol/L,P〈0.05]。【结论】钨酸钠对于泊洛沙姆407诱导的高血脂昆明小鼠模型具有降脂作用。     

番茄红素-泊洛沙姆188固体分散体的制备及溶出度和生物利用度研究

目的 ： 采用固体分散体技术,提高番茄红素在水中的溶解度和体外溶出度,从而提高其体内的生物利用度。 方法 ： 以泊洛沙姆188为载体,溶剂法制备番茄红素固体分散体,应用光谱分析和DSC考察其分散特征,溶出度试验测定其体外溶出度,大鼠灌胃后测定其体内生物利用度,用HPLC法测定血药浓度,采用Kinetica软件计算药动学参数。 结果 ： 番茄红素可能以分子复合物状态存在于固体分散体中,且显著提高了番茄红素的溶出度,与市售番茄红素油混悬液为对照,其相对生物利用度为(312.2±96.9)%。 结论 ： 番茄红素-泊洛沙姆188固体分散体制备工艺简单,成本较低,能显著改善难溶性药物番茄红素的生物利用度,具有较好的实际应用价值。     

烟酸对poloxamer 407诱导的昆明小鼠血脂的影响

【目的】研究烟酸对poloxamer 407(P407)诱导的昆明小鼠高血脂动物模型血脂的影响。【方法】昆明小鼠给予烟酸(0.5或1 g/kg)灌胃,连续3 d,末次给药1 h后,给予动物腹腔注射P407 0.3 g/kg,于注射后的4、24、48 h取血测定甘油三酯和胆固醇含量,注射P407后24 h的血样同时测定高密度脂蛋白-胆固醇的含量。【结果】在造模前给予烟酸处理,能明显降低高血脂动物的血清甘油三酯和胆固醇水平,且剂量关系明显,此作用可维持至造模后的48 h。高血脂造模后的24 h,烟酸能明显升高模型动物的血清高密度脂蛋白-胆固醇水平。【结论】烟酸对于P407诱导的高血脂昆明小鼠模型具有降脂作用。     

布洛芬眼用在体凝胶的制备及体外特性研究

目的制备布洛芬眼用在体凝胶,并考察其体外特性,为其临床应用奠定基础。方法以泊洛沙姆407为基质制备布洛芬温度敏感在体凝胶,应用动态流变实验测定温敏凝胶相变过程的流变学性质,并采用无膜溶出模型考察其体外溶蚀及释药情况。结果泊洛沙姆407凝胶经人工泪液稀释后相变温度提高7℃左右。布洛芬在体凝胶稀释后相变温度为32℃,其相转变表现为模量和动态黏度呈指数增长,体外释药呈现良好的零级释放特征。结论布洛芬在体凝胶兼具液体剂型和凝胶剂型的优点,是一种具有良好应用前景的新型眼用制剂。     

A lyophilized surfactant-based rutin formulation with improved physical characteristics and dissolution for oral delivery

Rutin (RUT) is a phytochemical flavonoid with numerous therapeutic potentials including antihypertension, cardioprotective, neuroprotective, and anti-cancer activities. Its clinical use is inhibited due to its poor aqueous solubility and permeability over oral administration. The present study aimed to overcome these problems through micellization and entrapment of RUT in solid dispersion (SD) using Poloxamer (POL) 407 and 188 as surfactant-based matrices. The RUT/SD formulations were prepared in serial drug loading concentrations in weight percentage to the total solid. The physical properties of the formed RUT/SD solids were characterized by several methods including polarizing microscopy, differential thermal analysis (DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and dissolution study. The dissolution test was performed using a paddle dissolution apparatus and samples were analyzed using UV spectrophotometry. Polarized microscope confirmed that the optical behaviors of the RUT/SD implied a formation of miscible RUT with POL matrices. The morphology of RUT/SDs varied from porous matrices with craters to smoother surfaces as a function of RUT concentrations. XRD and DTA data exhibited that RUT existed as partially amorphous. These data indicated that the higher concentration of RUT in the RUT/SD formulations, the higher amorphous proportion of the RUT in the solid state. Henceforth, this led to an increase in the percentage of dissolved RUT from the developed RUT/SD formulations at 94 to 100% compared to pure RUT at only < 35% within an hour. The present study disclosed the successful improvements in the physical characteristics of the RUT/SD formulations and their potencies for the future development for oral formulation.     

Pluronic gels for nasal delivery of Vitamin B12. Part I: preformulation study

Thermoreversible nasal gels of Vitamin B₁₂ using pluronic PF 127 were aimed to improve absorption and patient compliance. In the present research work, effects of Vitamin B₁₂ and gel additives, viz. PF concentration, osmolarity, polyethylene glycol (PEG 15000) on thermodynamic properties of phase transitions at gelation (T₁) and gel melting (T₂) is reported. Aqueous PF 127 gels prepared by cold method containing pluronic (20–24%, w/w), vitamin, sorbitol, PEG, and benzalkonium chloride. T₁ decreases and T₂ increases with vitamin and PF concentration. Gelation range narrows with sorbitol and PEG. Suppression of T₂ is significantly higher than T₁ with both the additives. The linearity was observed only for semilogarithmic plot of PF concentration and 1/T₂ for sorbitol and PEG, which reveals significant interaction of both at gel melting. Enthalpy of both transitions remains unchanged with vitamin indicating no interaction with polymer. Benzalkonium chloride decreased gelation onset temperature. Thermodynamic properties of PF 127 gels are significantly altered with polymer concentration and water-soluble formulation additives.     

Amino-functionalized poloxamer 407 with both mucoadhesive and thermosensitive properties: preparation,characterization and application in a vaginal drug delivery system

Lack of mucoadhesive properties is the major drawback to poloxamer 407 (F127)-based in situ hydrogels for mucosal administration. The objective of the present study was to construct a novel mucoadhesive and thermosensitive in situ hydrogel drug delivery system based on an amino-functionalized poloxamer for vaginal administration. First, amino-functionalized poloxamer 407 (F127-NH₂) was synthesized and characterized with respect to its micellization behavior and interaction with mucin. Then using acetate gossypol (AG) as model drug, AG-loaded F127-NH₂-based in situ hydrogels (NFGs) were evaluated with respect to rheology, drug release, ex vivo vaginal mucosal adhesion, in vivo intravaginal retention and local irritation after vaginal administration to healthy female mice. The results show that F127-NH₂ is capable of forming a thermosensitive in situ hydrogel with sustained drug release properties. An interaction between positively charged F127-NH₂ and negatively charged mucin was revealed by changes in the particle size and zeta potential of mucin particles as well as an increase in the complex modulus of NFG caused by mucin. Ex vivo and in vivo fluorescence imaging and quantitative analysis of the amount of AG remaining in mouse vaginal lavage all demonstrated greater intravaginal retention of NFG than that of an unmodified F127-based in situ hydrogel. In conclusion, amino group functionalization confers valuable mucoadhesive properties on poloxamer 407.     

用Box-Behnken效应面法优化穿心莲内酯纳米乳原位凝胶处方工艺研究

目的:采用Box-Behnken效应面法优化穿心莲内酯纳米乳原位凝胶的处方,为中药经皮给药制剂的研究与开发提供参考。方法:以泊洛沙姆188（P188）和泊洛沙姆407（P407）为凝胶基质,采用凝胶基质的质量分数为考察因素,凝胶温度为考察指标,通过二项式拟合分析得到方程,并建立胶凝温度与2个考察因素之间的数学关系,采用星点设计-效应面法优化穿心莲内酯纳米乳原位凝胶的处方,并对优化处方进行验证。结果:凝胶温度与考察因素存在可信定量关系,且二项式拟合方程置信度高。穿心莲内酯纳米乳原位凝胶的最佳处方为20.00%泊洛沙姆407和5.00%泊洛沙姆188;凝胶温度为（33.8±0.2）℃,处方制备重复性高。结论：该方法适用于穿心莲内酯纳米乳原位凝胶的处方优化,建立的模型预测性良好,优化的制备方法稳定,胶凝温度适宜,可为穿心莲内酯经皮给药制剂的开发提供参考。