Intrapericardial administration of novel DNA formulations based on thermosensitive Poloxamer 407 gel

Inherited cardiopathies are leading to life-threatening conditions such as heart failure. Moreover, treatments currently available fail in altering the cardiac phenotype. Thus, gene therapy appears as an attracting alternative to conventional treatments. However, gene delivery remains a major hurdle in achieving this goal. To obtain regional delivery of plasmid DNA, intrapericardial administration seems to be an interesting approach. In order to improve retention time at the site of injection, formulations based on a thermosensitive gel of Poloxamer 407 were assessed. Protection and condensation of plasmid DNA was initially performed through complexation with polyethyleneimine (PEI), a widely used polymer. Characterization of the size and zeta potential of the complexes suggested interactions between the polyplexes and the Poloxamer gel through significant increase of the size of the polyplexes and shielding of the surface charges. In vivo evaluation has highlighted the toxicity of PEI/DNA polyplexes toward the myocardium. However, feasibility of intrapericardial injection of Poloxamer based formulations as well as their very low toxicity has been established.     

Release of flurbiprofen from poloxamer 407 gel

Release rates of flurbiprofen from transdemal gels made of poloxamer 407 were evaluated using a membraneless diffusion cell in order to study the effects of formulation variables on flurbiprofen release such as poloxamer 407 (17.5–25%), drug (0.1–1.0%), ethanol (10–20%), PG or PEG 300 (5–15%) concentrations and gel pH (3–7). Isopropyl myristate was employed as a receptor medium for the drug released from the gel. The diffusion coefficient of flurbiprofen decreased linearly as the amount of poloxamer 407 and the drug in the gel increased. The release rate of flurbiprofen was gel pH-dependent and the diffusion coefficient of the drug in the gel increased as the pH of the gel increased. The addition of more ethanol in the gel increased the drug release, resulting from the increase of the thermodynamic activity of the drug in the aqueous phase of the gel. However, the concentration effects of PG and PEG 300 on the release rate of flurbiprofen were negligible over the concentration range used.     

Evaluation of selected micronized poloxamers as tablet lubricants

The primary objective of this study was to compare the lubrication properties of micronized poloxamer 188 (Lμ trol micro 68^®) and micronized poloxamer 407 (Lμ trol micro 127^®) with certain conventional lubricants such as magnesium stearate and stearic acid. The secondary objective was to use these micronized poloxamers as water-soluble tablet lubricants in preparation of effervecsent tablets. The results showed that these micronized poloxamers have superior lubrication properties compared with stearic acid, with no negative effect on tablet hardness, friability, disintegration, or dissolution. Moreover, lubricant mixing time had no significant effect on tablet properties when poloxamers were used as lubricants. Effervescent tablets also were produced successfully using micronized poloxamers as lubricants. The micronized poloxamers had a better lubrication effect in compariason with that of water-soluble lubricant l-leucine.     

The antitumor effect of novel docetaxel-loaded thermosensitive micelles

To further evaluate the novel docetaxel-loaded micelle based on the biodegradable thermosensitive copolymer poly(N-isopropylacrylamide-co-acrylamide)-b-poly(dl-lactide) that we had synthesized before, in this paper, we studied its in vitro cytotoxicity in three different tumor cell lines by standard MTT assays using different tumor cell lines, followed by studies of acute toxicity and the tumor distribution studies which were conducted in Kunming mice. Meanwhile, the in vivo antitumor efficacy as well as toxicity of the micelle was evaluated in C57BL/6 mice. According to our findings, the in vitro cytotoxicity of docetaxel-loaded micelles was lower than that of the conventional docetaxel formulation at 37 degrees C, while hyperthermia greatly enhanced the efficacy of drug-loaded micelles. The acute toxicity study showed reduced toxicity of docetaxel-loaded micelle compared to that of conventional docetaxel formulation. Moreover, docetaxel-loaded micelle enabled a prominent higher docetaxel concentration in tumor than conventional docetaxel formulation. Furthermore, a significantly higher antitumor efficacy was observed in mice treated with docetaxel-loaded micelles accompanied by hyperthermia; docetaxel-loaded micelles also caused less body weight loss of mice. This study demonstrates an increased antitumor efficacy and reduced toxicity of the novel docetaxel-loaded micelle and indicates its prospect of clinical applications.     

用体外释放度优选硝酸咪康唑缓释凝胶基质的研究

目的：优选硝酸咪康唑缓释凝胶剂的处方。方法：采用正交设计法,以聚卡波菲、甘油、山嵛酸甘油酯的用量为因素,以累积释放度作为考查指标,对硝酸咪康唑缓释凝胶剂的处方进行优选。结果：优选的凝胶剂最佳处方为聚卡波菲1.5 g、甘油5 mL、山嵛酸甘油酯2.0 g。结论：体外累积释放试验筛选硝酸咪康唑凝胶剂处方可行,所得缓释凝胶的质量符合2015年版《中国药典》有关规定。     

硝酸咪康唑凝胶剂的研制

目的：制备硝酸咪康唑凝胶剂，并建立质量控制方法。方法：用卡波姆-940为基质制备凝胶剂，用紫外分光光度法测定硝酸咪康唑含量，并考察其稳定性。结果：含量测定平均回收率97.79%、RSD为0.43%(n=3，凝胶稳定性良好。结论：该凝胶剂制备工艺可行，性质稳定，质控方法简便。     

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。     

硝酸毛果芸香碱眼用凝胶有关物质研究

目的建立高效液相色谱法测定硝酸毛果芸香碱眼凝胶有关物质的方法.方法采用C18色谱柱(150mm×4.6mm,5μm),pH=4.5的醋酸盐缓冲液(2.94g醋酸钠与稀醋酸38.4mL加水溶解成600mL,混匀,即得)-甲醇(85∶15)为流动相,检测波长为230nm.结论本方法简便、准确,适用于硝酸毛果芸香碱凝胶的有关物质检查.     

Enhanced bioavailability of metoclopramide HCl by intranasal administration of a mucoadhesive in situ gel with modulated rheological and mucociliary transport properties

The prolonged residence of drug formulation in the nasal cavity is of utmost importance for intranasal drug delivery. The objective of the present investigation was to develop a mucoadhesive in situ gel with reduced nasal mucociliary clearance in order to improve the bioavailability of the antiemetic drug, metoclopramide hydrochloride (MCP HCl). The in situ gelation upon contact with nasal mucosa was conferred via the use of the thermogelling poloxamer 407 whereas mucoadhesion and drug release enhancement were modulated via the use of mucoadhesive and polyethylene glycol (PEG) polymers respectively. The results revealed that the different mucoadhesives augmented the gel viscosity but reduced its sol–gel transition temperatures (T_sol–gel) and the drug release. The inclusion of PEG counteracted the effect of the mucoadhesive polymers whereby it decreased the gel consistency and increased the T_sol–gel as well as the in vitro drug release. The formulations with favorable sol–gel transition temperatures (25–32 °C) and high in vitro drug release (100% release in 60 min) were also rheologically stable upon storage. The mucoadhesiveness test was performed in vivo in rats, results showed that the carbopol-containing in situ gel prolonged the mucociliary transport time from 10 min (control solution) to 52 min (mucoadhesive gel) and maintained nasal mucosal integrity after 14-days application. The bioavailability study in rabbits revealed that the absolute bioavailability of MCP HCl was significantly increased from 51.7% in case of the oral drug solution to 69.1% in case of the nasal in situ gel. The study point to the potential of mucoadhesive nasal in situ gel in terms of ease of administration, accuracy of dosing, prolonged nasal residence and improved drug bioavailability.     

Evaluation of pluronic nanosuspensions loading a novel insoluble anticancer drug both in vitro and in vivo

To improve the solubility, stability and the antitumor activity of a novel anticancer drug, 3-(4-bromopheny l)-2-(ethyl-sulfonyl)-6-methylquinoxaline1,4-dioxide (Q39), a poloxamer nanosuspension was developed by precipitation combined with high pressure homogenization in present study. In vitro characterizations of Q39 nanosuspension (Q39/NS), including particle size, polydispersity index (PI), morphology, crystalline, saturation solubility, stability and releases were evaluated. BABL/c nude mice bearing HepG2 cells were used as in vivo tumor models to evaluate the anti-tumor activity of Q39/NS after intravenous administration. The particle size and PI for Poloxamer188 nanosuspension (P188/NS) were (304 ± 3) nm, and (0.123 ± 0.005) respectively, and it was (307 ± 5) nm and (0.120 ± 0.007) for Poloxamer85 nanosuspension (P85/NS) correspondingly. The morphology of P188/NS was spherical shape while elliptoid shape for P85/NS. The crystalline of Q39/NS did not change as shown by the X-ray diffraction analysis. The stability of Q39/NS improved compared with the solution. The solubility of Q39 in P188/NS was 7.3 times higher than the original solubility, while it was 6 times for P85/NS. Sustained release as shown from the in vitro release test, together with the tumor-targeting as shown from in vivo NS distribution, may contribute to the enhanced in vivo antitumor activity of Q39/NS.     

非那沙星眼用温敏凝胶的家兔眼刺激性试验及药效学研究

目的 研究非那沙星眼用温度敏感型原位凝胶(FTGE)对兔眼刺激性及药效学.方法 用Draize兔眼刺激性实验考察FTGE的眼部刺激性;以大肠杆菌及金黄色葡萄球菌感染的兔用FTGE进行局部治疗,观察其经过治疗后的细菌清除率.结果 FTGE无明显刺激性,符合眼用制剂的要求;FTGE的细菌清除率超过80%,药效优于氧氟沙星滴眼液.结论 FTGE在实验中无明显刺激性,且治疗角膜炎临床疗效明显,可供临床使用.     

In-situ gel formulations of econazole nitrate: preparation and in-vitro and in-vivo evaluation

Objectives This study describes the in‐situ gelling of econazole nitrate containing thermosensitive polymers composed of poloxamer 407 and 188 as a novel treatment platform for vaginal candidiasis. Methods Aqueous thermosensitive formulations containing 1% of econazole nitrate and poloxamer 407 and/or 188 were prepared and their rheological, mechanical and drug‐release properties determined at 20 ± 0.1°C and/or 37 ± 0.1°C. Based on their biologically suitable thermorheological properties, formulations containing the mixtures of poloxamer 407 and 188 in ratios of 15:15 (F1), 15:20 (F2) and 20:10 (F3) were chosen for comprehensive analysis. Key findings Formulations based on F3 exhibited typical gel‐type mechanical spectra (G′ > G″) at 37°C whereas formulations based on F1 and F2 exhibited properties akin to weakly cross‐linked gels. Texture profile analysis demonstrated that F3 showed the highest cohesiveness, adhesiveness, hardness and compressibility. No statistically significant differences (P > 0.5) were observed in the release of econazole nitrate from the formulations at pH 4.5, which in all cases followed anomalous diffusion kinetics. Formulations based on 20% poloxamer 407:10% poloxamer 188 were chosen for in‐vivo studies and were shown to be effective for the treatment of the vaginal candidiasis. Histopathologic evaluation also supported the effectiveness of the thermosensitive formulation administered intravaginally. Conclusion By careful engineering of the rheological properties, in‐situ thermosensitive gel formulations of econazole nitrate were prepared and were shown to be efficacious in the treatment of vaginal candidiasis.     

新型抗真菌药硝酸舍他康唑的药理作用及临床评价

硝酸舍他康唑(sertaconazole nitrate)是一种新的局部用抗真菌药,具有抗菌谱广、疗效好、安全性高等特性,并在临床实践中显示出较好的应用前景.现对其作用机制、药动学、临床应用和药物不良反应等进行综述.     

Liposomes Dispersed Within a Thermosensitive Gel: A New Dosage Form for Ocular Delivery of Oligonucleotides

Purpose. The main goal of this study was to develop an ocular controlled release formulation of a model oligonucleotide (pdT16), contained within liposomes dispersed within a thermosensitive gel composed by poloxamer 407. Methods. The influence of the poloxamer concentration 2% or 27% on the stability of the liposomes (PC: CHOL and PC: CHOL: PEG-DSPE) was investigated. The in vitro release profiles of pdT16 from various poloxamer formulations (free pdT16 dispersed within 20% and 27% poloxamer gels, pdT16 encapsulated within liposomes dispersed within 20% and 27% poloxamer gels) were realized using a membrane-free release model. Results. The dispersion of liposomes within a dilute 2% poloxamer solution resulted in a great leakage of pdT16 from liposomes. However, the destabilization effect of poloxamer was reduced when higher concentration (27%) was used. Poloxamer dissolution was found to control the release process of pdT16, whereas the dispersion of liposomes within 27% poloxamer gel was shown to slow down the diffusion of pdT16 out from the gel. Conclusions. The dispersion of liposomes within a 27% poloxamer gel presented an interesting system to control the release of a model oligonucleotide compare to a simple gel.     

In-vivo anti-tumor activity of a novel poloxamer-based thermosensitive in situ gel for sustained delivery of norcantharidin

In order to develop a novel norcantharidin (NCTD) delivery system with slow drug release and specific targeting characteristics, we have developed a Poloxamer-based NCTD thermosensitive in situ gel. The evaluation of the characteristics of this system using both in vitro and in vivo methods was previously reported. However, its anti-tumor activity in vivo is still not confirmed. Thus, the potential anti-tumor activity and relative mechanism were investigated in a murine H22 hepatoma model. Tumor-bearing mice were treated with different dose of NCTD thermosensitive in situ gel (3.3?mg/kg, 6.6?mg/kg, and 9.9?mg/kg, respectively by intra-tumor injection once every three days, totaling 5 injections per group. Control groups included untreated or NCTD injection (2.2?mg/kg, qd) or blank in situ gel. The expression of vascular endothelial growth factor (VEGF) and CD44 in tumor tissue was examined by immunohistochemistry (IHC) staining. Treatment with middle or high dose of NCTD thermosensitive in situ gel significantly induced tumor regression, inhibited VEGF and CD44 expression and improved survival of tumor-bearing mice. The efficacy of NCTD thermosensitive in situ gel is higher than that of free NCTD injection. Therefore, NCTD thermosensitive in situ gel is a novel NCTD delivery approach for chemotherapeutic treatment of cancer.     

Evaluation of the Antimicrobial Activity of Ammoniacum Gum from Dorema ammoniacum

Antimicrobial activity of the dichloromethane-methanol (1 : 1) extract of ammoniacum gum (from Dorema ammoniacum D. Don) was evaluated against 14 microorganisms which included seven Gram-positive bacteria (Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Micrococcus luteus, Staphylococcus epidermidis, Staphylococcus aureus and Streptococcus faecalis), four Gram-negative bacteria (Escherichia coli, Pseudomonas aereuginosa, Klebsiella pneumoniae and Bordetella bronchiseptica), one yeast (Saccharomyces cereviseae) and two fungi (Aspergillus niger and Candida albicans). The extract of ammoniacum gum exhibited a of broad spectrum antimicrobial activity by inhibiting all the seven Gram-positive bacterium, one Gramnegative bacterium, one yeast and one fungus, with a minimum inhibitory concentration (MIC) of 40µg/ml. To overcome the solubility problem often faced when herbal extracts are added to aqueous medium, we employed a modified broth method where the broth cultures were agitated at 150 rpm in an orbital shaking incubator. This method reduced the MIC of the extract considerably, to 5-20µg/ml, against B. bronchiseptica, S. aureus and S. epidermidis.     

The effect of the source and the concentration of polymers on the release of chlorhexidine from mucoadhesive buccal tablets

In the current work, two groups of chlorhexidine mucoadhesive buccal tablets were prepared, using either rod or irregularly-shaped spherical particles of hydroxypropyl methylcellulose and different ratios of poloxamer 407 (P407). The tablets were designed to release the drug over two hours. Their physicochemical properties and drug release profiles were investigated. The impact on dry granulation, the ex-vivo mucoadhesion, the swelling index, the morphology of swollen tablets and the drug release kinetic were investigated. Drug-polymers chemical interaction was studied using Fourier Transforms Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC). Due to different particle shapes, the preparation of dry granules required a 40 KN force for rod-shaped particles compared to 10 KN for the irregularly-shaped spherical particles. All formulations showed at least two-hours residence time using ex-vivo mucoadhesion. Statistically, there was no significant difference in the swelling index, drug release nor its kinetic for both groups. However, the microscopical morphology of the swollen tablet and the size of the pores were affected by particle shape. Increasing the ratio of P407 to 62.5% resulted in a pronounced increase in drug release from around 60% to >90% after two hours. Following the FTIR and DSC analyses, no chemical interaction was noted apart from the steric hindrance effect of P407, which was observed even with the physical mixtures.     

Development and characterization of a novel liposome-based formulation of SN-38

SN-38, 7-ethyl-10-hydroxycamptothecin, is the active metabolite of Irinotecan (CPT-11), a topoisomerase I inhibitor commercially available as Camptosar^®. SN-38 is approximately 200–2000-fold more cytotoxic than CPT-11. Despite its promising anticancer potential, SN-38 thus far has not been used as an anticancer drug due to its poor solubility in any pharmaceutically acceptable solvents. In addition, SN-38 has low affinity to lipid membranes; it tends to precipitate in aqueous phase resulting in a very low drug-to-liposome entrapment. SN-38 also reversibly converts to an inactive open lactone ring structure at physiological pH. We have developed a novel, liposome-based SN-38 formulation (LE-SN-38). The formulation contains liposomes of uniform size distribution (<200 nm), and it is easy-to-use. Drug entrapment efficiency of the formulation is>95%. Long-term stability studies indicate that the lyophilized LE-SN-38 is physically and chemically stable for at least 6 months at 2–8 °C. In preclinical studies, LE-SN38 has shown promising results in terms of increased cytotoxicity against various tumor cell lines and better therapeutic efficacy towards xenograft mouse models compared to CPT-11.     

羧甲基壳聚糖温敏凝胶对小鼠L929细胞增殖的影响及其生物相容性研究

目的：自制羧甲基壳聚糖温敏凝胶,研究其对L929细胞增殖的影响并且通过动物实验探讨其组织相容性,为进一步的临床应用提供基础实验依据。方法：用羧甲基壳聚糖与甘油磷酸盐互配, 制备羧甲基壳聚糖温敏凝胶。采用MTT法测定不同浓度的凝胶浸提液对体外培养的L929细胞增殖的影响;将凝胶植入小鼠皮下,然后分别在3、7、14天处死,常规组织切片,HE染色观察凝胶周围组织的炎症反应。结果：培养24h后,各浓度浸提液组对L929细胞的增殖均有一定促进作用,在48h、72h、96h时,各实验组都较阴性及阳性对照组显示出较明显的促进细胞增殖作用,其中0.4倍浸提液组促增殖效果最明显（P＜0.05）;凝胶植入后前3d,实验组以急性炎症为主,随着时间的延长各实验组炎症细胞逐渐减少至消失,说明羧甲基温敏凝胶具有很好的组织相容性。结论：羧甲基壳聚糖温敏凝胶对L929细胞有明显的促进作用且具有良好的组织相容性,在牙周病治疗中具有潜在的应用价值。     

The formulation and stability of erythromycin-benzoyl peroxide in a topical gel

The combination of benzoyl peroxide and erythromycin is used for the local treatment of acne and available as a commercial preparation. Because of the stability problems of erythromycin an extempore preparation is required. The influence of storage temperature and non active ingredients on the stability of benzoyl peroxide and erythromycin in topical gel preparations for extempore compounding is described. A microbiological and an HPLC method were used to determine the erythromycin and the benzoyl peroxide concentrations, respectively. For a formulation compounded with hydroxyethylcellulose no stability problems were observed. For the formulation containing Carbopol 940, the levels of erythromycin varied over a wide range due to precipitation and aggregation of the drug during compounding.