马来酸噻吗洛尔眼用温敏凝胶的处方筛选与体外释放评价

目的:筛选马来酸噻吗洛尔眼用温敏型凝胶优化处方,并对其体外释放进行评价。方法:选用泊洛沙姆P407、P188为载体材料制备眼用温敏凝胶,测定不同处方的凝胶前体溶液分别在未经处理和经人工泪液稀释条件下,从溶液态转变为凝胶态的胶凝温度,通过星点设计-效应面法筛选优化处方,并考察胶凝时间和释放行为。结果:根据温敏凝胶保存和使用的温度要求,筛选出优化处方为P407:P188(24.25%:1.56%)。前体溶液能够在34℃人工泪液中迅速形成凝胶,并在体外缓慢释放6 h以上。结论:经过筛选并制备出的噻吗洛尔温敏型凝胶具有良好的载药能力、稳定性及释放性能,满足眼用制剂质量要求和实际应用要求。     

Sustained release of lidocaine from Poloxamer 407 gels

In this work, we show that alteration of P407 gel content can affect drug release rates. The inorganic salts and PEG 400 commonly included in the formulation of P407 gels can also change the rate at which a drug is released. Lidocaine was selected as a model drug because, although widely used in the treatment of pain, its use is limited by short duration of its effects. The use of P407 gels prolongs the residence time of the lidocaine at the injection site, sustains drug release and increases therapeutic efficacy. Release studies were performed in a diffusion system. During release, data followed the Higuchi square root law time kinetic (r>0.98). Increased polymer concentration in the gel increases viscosity and reduces lidocaine release rates and diffusion coefficients via extended gel dissolution time and prolonged drug diffusion through the gel matrix. Lidocaine release rates and diffusion coefficients increased in gels composed of NaCl or PEG 400 aqueous solution. Because these additives are hydrophilic, they reduce gel dissolution time, thereby accelerating drug diffusion. Poloxamer is biocompatible and the results support the possibility of using Poloxamer gel as a sustained release injectable formulation.     

阿昔洛韦壳聚糖眼用温敏性原位凝胶的研制及其体外释药研究

目的 制备阿昔洛韦（ACV）壳聚糖（CS）眼用温敏性原位凝胶（ISG）,并对其体外释药特性进行考察.方法 以CS为增黏剂及吸收促进剂,以泊洛沙姆407和188（P407,P188）为基质,制备ACV-CS-ISG,以胶凝温度为指标,筛选P407与P188的最佳配比;采用无膜溶出模型对ACV-CS-ISG的体外释药特性进行考察.结果 当P407与P188的处方用量分别为21%及6%时,ACV-CS-ISG胶凝温度为（33.6±0.4）℃,人工泪液稀释后变为（34.2±0.3）℃,与人眼表温度（34℃）相似;体外释药及凝胶溶蚀均呈现零级动力学特征,且两者相关性良好.结论 ACV-CS-ISG具有理想的胶凝温度及较好的缓释效果,值得进一步研究.     

眼用盐酸倍他洛尔脂质体-原位凝胶的研制及体外释药的研究

目的制备盐酸倍他洛尔(BH)眼用脂质体-原位凝胶(ISG),并对其体外释药特性进行考察。方法采用逆向蒸发法制备BH脂质体(BHL);以泊洛沙姆407和188(P407,P188)为温敏性ISG基质,以胶凝温度为指标,筛选P407与P188的最佳配比;采用无膜溶出模型对BHL的体外释放行为进行考察。结果 BHL的平均包封率为(88.24±5.46)%(n=3);当P407与P188的处方用量分别为21%及6%时,胶凝温度最接近人眼表温度(34℃);BHL-ISG体外药物释放和凝胶溶蚀均呈现零级释放特征,两者相关性良好。结论 BHL-ISG结合脂质体和原位凝胶的特点,延缓药物释放,为其角膜滞留性研究奠定了基础。     

吡嘧司特钾眼用原位温度敏感凝胶的制备及其体外释放度的研究

目的：以吡嘧司特钾为模型药物,制备眼用原位温度敏感凝胶,考察其体外释放度。方法：以泊洛沙姆407/188为基质,筛选最佳处方以达到合适的胶凝温度,建立高效液相色谱法测定吡嘧司特钾含量并以无膜溶出模型考察体外释放度。结果：处方中以5%甘露醇为溶媒,0.1%吡嘧司特钾（w/v）、0.01%苯扎溴铵（v/v）、6%泊洛沙姆188（w/v）和20%泊洛沙姆407（w/v）的组成可以达到最适胶凝温度,经影响因素试验考察证明该制剂性质稳定,体外释放度考察结果表明药物的释放与时间成线性关系。结论：本文制备的吡嘧司特钾眼用原位温度敏感凝胶具有很好的温度敏感性,能够延长药物在眼部停留时间且给药方便,有望开发成为一种新型眼用给药制剂。     

In vivo and in vitro anti-cancer activity of thermo-sensitive and photo-crosslinkable doxorubicin hydrogels composed of chitosan–doxorubicin conjugates

Doxorubicin was chemically conjugated to acrylated chitosan in order to obtain sustained-release profiles of doxorubicin from thermo-responsive and photo-crosslinkable hydrogels. Chitooligosaccharide was acrylated with glycidyl methacrylate and subsequently conjugated to doxorubicin via an amide linkage. A mixture of doxorubicin–chitosan conjugates, acrylated Pluronic, and doxorubicin formed physical gels at 37 °C. Photo-irradiation was subsequently performed to chemically crosslink the physical hydrogel at 37 °C. Chitooligosaccharide–doxorubicin conjugates in the doxorubicin hydrogels significantly reduced burst release of free doxorubicin from doxorubicin hydrogels compared hydrogels without the conjugates. Upon incubating doxorubicin hydrogels at 37 °C, chitosan–doxorubicin conjugates were confirmed to be degraded into more hydrophilic oligomers by reversed-phase chromatography. In vitro cytotoxicity assay using released media from doxorubicin hydrogels showed that degraded chitosan–doxorubicin had cytotoxicity comparable to free doxorubicin. Athymic nude mice bearing human lung adenocarcinoma were subjected to intra-tumoral injections of physical hydrogels. After photo-crosslinking injected hydrogels using surgical catheters, tumor sizes, body weights, and survivals were measured for 1 month. Released media from doxorubicin hydrogels exerted similar cytotoxicities to free doxorubicin, and the tumor volume was significantly reduced for 1 month compared to other samples. Thus, doxorubicin hydrogels containing doxorubicin conjugates can be employed as a novel injectable anti-cancer drug aiming to achieve sustained release of doxorubicin for several weeks against solid tumors.     

Design and development of an injectable in situ forming drug delivery system of methotrexate for the treatment of rheumatoid arthritis

Methotrexate (MTX) is the drug of choice for the treatment of rheumatoid arthritis (RA). At present there exists a lacuna in delivering methotrexate in suitable dosage form to maintain optimum plasma concentration to achieve therapeutic efficacy during the treatment period. Exposure of MTX at higher concentrations resulted in severe side effects. Moreover, the treatment modality (initial and maintenance dose) of RA is not clinically uniform. Biodegradable injectable in situ gels offer versatility in delivering drug at predetermined rates, and maintaining plasma concentration with a possibility of dose adjustment. They can be developed to optimize the therapeutic properties of a drug product, render them safe, effective and reliable during therapy. The aim of the present study was to formulate a biodegradable injectable in situ gel system for methotrexate sodium in the treatment of rheumatoid arthritis. The formulations were prepared by "cold technique" using thermosensitive polymer, Pluronic F-127 (20 %) and varying concentration of co-polymers, Pluronic F-68 (2–6 %) and Carbopol 934 (1.0-1.5 %). The prepared in situ gels were evaluated in vitro for drug interactions by FT-IR, sterility, gelation characteristics, content uniformity, viscosity, syringeability and in vitro drug release. MTX was evenly distributed in all formulations, which were sterile and syringeable through an 18 gauze needle. The gels were thermosensitive and thermoresponsive, and were dependent on the concentration of co-polymers. Drug release from in situ gels was sustained for 96 h to 120 h, and influenced by the type and concentration of co-polymers employed. Drug release was significantly higher in dynamic diffusion state in comparison with static state as ascertained by student t-test. The drug release was by non-fickian diffusion mechanism and followed first-order kinetics. These findings suggested that in situ gels can be effectively used to achieve controlled drug release; are easy to administer, are effective with reduced frequency of dosage, and result in increased patient compliance and comfort. It may be concluded that methotrexate in situ gels are ideally suitable in the treatment of RA.     

Injectable PAMAM dendrimer-PEG hydrogels for the treatment of genital infections: formulation and in vitro and in vivo evaluation

Local intravaginal drug therapy is preferred for treatment of ascending genital infections during pregnancy. In the present study, an in situ forming biodegradable hydrogel for sustained release of amoxicillin in the cervicovaginal region is described. A generation 4 poly(amidoamine) [G4-(NH(2))(64)] dendrimer with peripheral thiopyridyl terminations is cross-linked with 8-arm polyethylene glycol (PEG) bearing thiol terminations. The hydrogels were formulated and tested in vivo in a pregnant guinea pig model for volume, retention times, biodegradation, tolerability and transport across fetal membrane. The physicochemical characterization of the hydrogels was carried out using differential calorimetry, SEM, and confocal imaging. The hydrogels offer antibacterial activity arising from sustained release of amoxicillin from gels. The in vivo studies in guinea pig showed that 100-200 μL of gel sufficiently covered the cervicovaginal region with a residence time of at least 72 h and gel was primarily retained in the maternal tissues without crossing the fetal membranes into the fetus. The dendrimer gels were stable up to 72 h, and the in vivo biodegradation of gel occurred after 72 h; this correlated well with the in vitro degradation pattern. The pH of the vagina was not altered upon application of the gel, and none of the animals aborted up to 72 h after application of gel. The histological evaluation of the cervical tissues showed absence of edema in the epithelial cell layer, no sloughing of the epithelial or superficial mucous layer, and absence of necrosis and infiltration of inflammatory cells in the submucosal layers, confirming that tissues were tolerant to the gel. The immunohistofluorescence images showed the localization of the gel components on the superficial mucified epithelial layer. The cross-linking density and swelling of hydrogels was impacted by the polymer content, and the 10% hydrogels exhibited the highest cross-link density. The in vitro drug release studies carried out using Franz diffusion cells showed that amoxicillin release from 6 and 10% gels was sustained for 240 h as compared to 3% gels. As the polymer concentration increased to 10%, the release pattern from gels approached diffusion controlled mechanism with diffusional exponent n = 0.49. In conclusion, the biodegradable in situ forming hydrogels of the present study offer a therapeutic option to provide sustained localized delivery of amoxicillin intracervically to the pregnant woman for the treatment of ascending genital infections.     

盐酸利多卡因鼻用温敏型凝胶的制备及其体外释放度研究

目的：研制盐酸利多卡因温敏凝胶并考察其释药机制。方法：以泊洛沙姆P407为凝胶材料,以泊洛沙姆P188、PEG6000调节胶凝温度,并采用正交试验筛选处方,采用数学模型拟合释放曲线。结果：盐酸利多卡因温敏凝胶在32～33℃胶凝,释药行为符合Higuchi方程。结论：盐酸利多卡因温敏凝胶处方设计合理,可进一步研究开发。     

聚N-异丙基丙烯酰胺类温敏凝胶的制备及其对萘普生钠的缓释作用

目的：制备聚N-异丙基丙烯酰胺类的两种温敏凝胶：聚N-异丙基丙烯酰胺均聚水凝胶和N-异丙基丙烯酰胺-甲基丙烯酰胺共聚水凝胶，并考察其性质和对萘普生钠的缓释作用。方法：在氮气保护下制备两种水凝胶，测定和比较交联剂和甲基丙烯酰胺含量对凝胶溶胀度及临界相转变温度的影响。并以两种水凝胶为载体，在模拟人体肠液环境下进行萘普生钠的体外释放实验。结果和结论：交联剂用量增大时，凝胶溶胀度下降；甲基丙烯酰胺含量增加时，共聚水凝胶溶胀度增加，临界相转变温度提高。亲水性共聚水凝胶对药物的释放稳定持久，释药量大，具缓释作用。     

Injectable in situ forming drug delivery system for cancer chemotherapy using a novel tissue adhesive: characterization and in vitro evaluation.

Injectable polymers that are biocompatible and biodegradable are important biomaterials for drug delivery system (DDS) and tissue engineering. We have already developed novel tissue adhesives consisting of biomacromolecules and organic acid derivatives with active ester groups. The resulting tissue adhesive forms in situ as a gel and has high bonding strength for living tissue as well as it has good biocompatibility and biodegradability. Here, we report on the physicochemical properties and in vitro evaluation of this novel tissue adhesive consisting of human serum albumin (HSA) and tartaric acid derivative (TAD) containing doxorubicin hydrochloride (DOX). The results of the measurement of physicochemical characteristics indicate that the gelation time and gel strength of HSA-TAD gels can be controlled according to the material composition. The bonding strength of HSA-TAD adhesives was found to be sufficient to adhere at focus and to correspond with the cross-linking density of HSA-TAD gels. Furthermore, the release of DOX from HSA-TAD gels was sustained for approximately 100 h in an in vitro evaluation. The novel tissue adhesive, therefore, is expected to be applicable for use as an injectable in situ forming DDS.     

氟尿嘧啶-羟丙基-β-环糊精包合物温敏凝胶生物黏附力及溶出度研究

目的：考察不同生物黏附材料对氟尿嘧啶-羟丙基-β-环糊精包合物温敏凝胶剂粘附性及溶出度的影响。方法：以羟丙基甲基纤维素（HPMC）、海藻酸钠、透明质酸钠、卡波姆、聚卡波菲为生物黏附材料制备氟尿嘧啶-羟丙基-β-环糊精包合物温敏凝胶剂,测定各处方的黏附力,并在溶出介质p H 7.2磷酸盐缓冲液中,用透析袋法进行体外释药试验。结果：以0.2%聚卡波菲为生物黏附材料的处方黏附力为32.3 g·ml^-1,药物释放时间延长至8 h,采用不同的生物黏附材料对制剂溶出行为没有显著影响。结论：以0.2%聚卡波菲为生物黏附材料,制备氟尿嘧啶-羟丙基-β-环糊精包合物温敏凝胶剂黏附力高,且具有良好的缓释效果。     

可注射硫酸延胡索总碱温度敏感型原位凝胶的 制备及其体外释药评析

 目的：研究可注射硫酸延胡索总碱原位凝胶的制备方法及其体外释药特性。方法：以泊洛沙姆407为载体材料制备注射用硫酸延胡索总碱温敏型原位凝胶制剂;采用高效液相色谱法测定释放介质中药物含量,考察凝胶体外释放特性;并对制剂进行评价。结果：原位凝胶最佳配方为：16%泊洛沙姆407、11%泊洛沙姆188、0.2%壳聚糖、0.5%硫酸延胡索总碱,该原位凝胶在室温下为流体,在体温下发生相转变形成凝胶;药物在48 h释放了88.4%,无突释现象,释药规律符合Higuchi方程;凝胶属Ostwald流体。结论：可注射硫酸延胡索总碱原位凝胶制备工艺简便,有良好的缓释作用,为研究中药植入型给药系统提供了依据。     

星点设计法优化布南色林-泊洛沙姆温敏水凝胶处方及含量测定

目的 优化泊洛沙姆温敏水凝胶体系负载布南色林,并对凝胶中布南色林含量进行测定.方法 采用直接混合法配备含药温敏水凝胶体系,倒置小管法测定胶凝温度(Tgel).以Tgel为因变量,25％泊洛沙姆407体积(X1)、50％泊洛沙姆188体积(X2)和1％布南色林药物混悬液(X3)为考察因素,通过星点设计法优化制剂处方.采用...     

Injectable and biodegradable poly(organophosphazene) gel containing silibinin: its physicochemical properties and anticancer activity

The biodegradable poly(organophosphazene) hydrogels were developed as a locally injectable drug carrier for a hydrophobic silibinin to overcome its limited bioavailability. The aqueous solution of poly(organophosphazene) enhanced the solubility of silibinin up to 2000 times compared with that of phosphate buffered saline (0.0415 vs. 84.55 mg/mL). Both aqueous polymer solutions with and without silibinin showed a sol-gel transition as a function of temperature. A faster in vitro degradation rate of the gel and drug release rate from the gel at pH 6.8 than those at pH 7.4 were observed when the degradation and release study on hydrogels were conducted at 37 °C. Silibinin was sustainedly released from the hydrogel mainly by a diffusion-controlled mechanism. The silibinin released from the hydrogel was shown to be effective considering the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In the HT-29 xenografted mice model, the intratumorally injected hydrogel containing silibinin exhibited a good antitumor effect in comparison with the control groups. The Western blotting indicated that one of the reasons for the enhanced antitumor effect of the hydrogel system was the sustained antiangiogenic effect of silibinin. The poly(organophosphazene) gels are expected to be an effective candidate of the locally injectable drug carrier for silibinin.     

Development and characterisation of levosulpiride-loaded suppositories with improved bioavailability in vivo

The purpose of this study was to develop and characterize levosulpiride loaded liquid suppository with improved bioavailability. The content of levosulpiride-loaded liquid suppositories were optimized in a series of experiments using various weight ratios of P188, P407, Tween 80, and drug. The suppositories were liquid at room temperature, however, when rectally administered, they became gel at body temperature. Their rheological properties and release characteristics were determined in vitro while pharmacokinetic study was performed after its rectal administration in rats and compared with drug suspension. Poloxamer 188 and Twee 80 decreased the gelation temperature and gelation time, but increased the gel strength and mucoadhesive force of liquid suppositories. Liquid suppository composed of [Levosulpiride/P 188/P 407/Tween 80 (1/15/17/3%)] with a gelation temperature of about 30.7?°C remained liquid at 25?°C, but converted to gel at 30–36.5?°C, resulting in easy administration and rapid gelation inside the body. This liquid suppository gave a considerably increased dissolution rate reflected in a meaningfully higher plasma concentration and 7.1-fold AUC values of levosulpiride in rats as compared to the drug suspension. Hence, liquid suppository system could be used for enhanced bioavailability of levosulpiride-loaded pharmaceutical products.     

Enhanced rectal bioavailability of ibuprofen in rats by poloxamer 188 and menthol

To improve the bioavailability of poorly water-soluble ibuprofen in the rectum with poloxamer and menthol, the effects of menthol and poloxamer 188 on the aqueous solubility of ibuprofen were investigated. The dissolution and pharmacokinetic study of ibuprofen delivered by the poloxamer gels composed of poloxamer 188 and menthol were then performed. In the absence of poloxamer, the solubility of ibuprofen increased until the ratio of menthol to ibuprofen increased from 0:10 to 4:6 followed by an abrupt decrease in solubility above the ratio of 4:6, indicating that four parts menthol formed eutectic mixture with six parts ibuprofen. In the presence of poloxamer, the solutions with the same ratio of menthol to ibuprofen showed abrupt increase in the solubility of ibuprofen. The poloxamer gel with menthol/ibuprofen ratio of 1:9 and higher than 15% poloxamer 188 showed the maximum solubility of ibuprofen, 1.2mg/ml. Menthol improved the dissolution rates of ibuprofen from poloxamer gels. Release mechanism showed that the release rate of ibuprofen from the poloxamer gels without menthol was independent of the time but the drug might be released from the poloxamer gels with menthol by Fickian diffusion. Furthermore, the poloxamer gel with menthol (poloxamer/menthol/ibuprofen (15%/0.25%/2.5%)) gave significantly higher initial plasma concentrations, C(max) and AUC of ibuprofen than did solid suppository, indicating that the drug from poloxamer gel could be more absorbed than that from solid one in rats. Thus, the poloxamer gel with poloxamer 188 and menthol was a more effective rectal dosage form for ibuprofen.     

A novel injectable local hydrophobic drug delivery system: Biodegradable nanoparticles in thermo-sensitive hydrogel

In this article, a novel local hydrophobic drug delivery system: nanoparticles in thermo-sensitive hydrogel, was demonstrated. First, honokiol, as a model hydrophobic drug, loaded poly(varepsilon-caprolactone)-poly(ethylene glycol)-poly(varepsilon-caprolactone) (PCEC) nanoparticles were prepared by emulsion solvent evaporation method, and then were incorporated into thermo-sensitive F127 hydrous matrix. The obtained injectable hydrophobic drug delivery system can act as a depot for sustained release of honokiol in situ. The lower critical solution temperature (LCST) of the composite matrix increases with increase in the mass of incorporated nanoparticles, or with decrease in the amount of residual organic solvent in the system. Honokiol release profile in vitro was studied, and the results showed that honokiol could be sustained released from the system. The described injectable drug delivery system might have great potential application for local delivery of hydrophobic drugs such as honokiol.     

Study of thermo-sensitive in-situ gels for ocular delivery

The aim of the present study was the development of thermo-sensitive in-situ gels for in-vitro evaluation of ophthalmic delivery systems of ketorolac tromethamine (KT), based on methylcellulose (MC) in combination with hydroxypropylmethyl cellulose (HPMC). The gel temperature of 1% MC solution was observed at 60°C. It was found that 6% oral rehydration salt without dextrose (ORS) was capable to reduce the gel temperature below physiological temperature. HPMC was added to increase viscosity and drug release time. The results indicated a large increase in viscosity at 37°C with addition of HPMC whch provided sustained release of the drug over a 4h period. From in-vitro release studies, it could be concluded that the developed systems were thus a better alternative to conventional eye drops.     

Novel Injectable Pentablock Copolymer Based Thermoresponsive Hydrogels for Sustained Release Vaccines

The need for multiple vaccinations to enhance the immunogenicity of subunit vaccines may be reduced by delivering the vaccine over an extended period of time. Here, we report two novel injectable pentablock copolymer based thermoresponsive hydrogels made of polyethyleneglycol-polycaprolactone-polylactide-polycaprolactone-polyethyleneglycol (PEG-PCL-PLA-PCL-PEG) with varying ratios of polycaprolactone (PCL) and polylactide (PLA), as single shot sustained release vaccines. Pentablock copolymer hydrogels were loaded with vaccine-encapsulated poly lactic-co-glycolic acid nanoparticles (PLGA-NP) or with the soluble vaccine components. Incorporation of PLGA-NP into the thermoresponsive hydrogels increased the complex viscosity of the gels, lowered the gelation temperature, and minimized the burst release of antigen and adjuvants. The two pentablock hydrogels stimulated both cellular and humoral responses. The addition of PLGA-NP to the hydrogels sustained immune responses for up to 49 days. The polymer with a higher ratio of PCL to PLA formed a more rigid gel, induced stronger immune responses, and stimulated effective anti-tumor responses in a prophylactic melanoma tumor model.

Electronic supplementary material

The online version of this article (doi:10.1208/s12248-015-9843-4) contains supplementary material, which is available to authorized users.KEY WORDS: nanoparticles, pentablock copolymers, sustained release, thermoresponsive hydrogels, vaccine delivery