耦合剂的处方及配制改进

耦合剂是作超声显像检查时涂抹于皮肤上，使之与电极探头黏合，起介质作用的一种胶浆剂，用量逐年倍增，通常按照羧甲基纤维素钠（CMCNa）胶浆的处方热法配制。但黏稠度太高，在冬季和早春有羟苯乙酯结晶析出，配制时CMC-Na溶胀缓慢，耗时费力，又浪费电汽资源。因此，我们将处方的药量和配制方法进行了改进，现介绍如下。     

处方和工艺因素对氨茶碱魔芋胶骨架片体外释放度的影响

目的：考察处方和工艺因素对魔芋胶骨架片体外释放度的影响，评价魔芋胶作为新型载体材料用于缓释骨架片制备的可行性。方法：以氨茶碱为模型药物，采用粉末直接压片法和湿法制粒压片法制备魔芋胶骨架片，考察魔芋胶粒度、黏度和用量，填充剂种类，主药粒度，压片工艺，压片压力等对其体外药物释放的影响。结果：氨茶碱魔芋胶骨架片可缓慢释放药物；随魔芋胶粒度降低，骨架材料用量或主药粒度增加，药物释放减慢；与淀粉、微晶纤维素和乳糖相比，Eudragit L100作为填充剂，可明显延缓药物释放；压片工艺，压片压力和魔芋胶黏度对药物释放影响不大。结论：魔芋胶可作为一种新型载体材料用于缓释骨架片的制备，魔芋胶粒度、用量，主药粒度和填充剂种类是影响骨架片体外药物释放的主要因素。     

5个喝汤＂老理儿＂需更新

我们一定听说过“老火出靓汤”“骨头汤最补钙”等老理儿，但是随着科学的发展以及人们饮食结构的变化，营养专家和医学专家们已经发现，有些常规老理儿已经不能适应今天的生活，必须及时更新。     

骨质增生症患者补钙是否会加重病情？

我今年46岁。前不久，我患上了骨质增生症。去医院检查后，医生建议我补钙。可我认为骨质增生是指人的骨骼长出了多余的部分，而补钙会促进人体骨骼的生长。因此，患了骨质增生症后再补钙岂不使病情加重吗？     

E2CA医用胶黏合手术切口的愈合效果和安全性研究

目的　研究 E2 CA医用胶黏合伤口的实验治疗学基础。方法　观察 E2 CA医用胶黏合大鼠模拟手术切口的愈合效果和皮肤伤口刺激反应 ,并进行了豚鼠皮肤过敏试验。结果　 E2 CA医用胶可使大鼠手术切口良好愈合 ,对皮肤切口的刺激较小 ,外用对豚鼠无皮肤和全身黏膜过敏反应。结论　 E2 CA医用胶黏合手术切口具有安全有效的特点     

补钙又补血你能做到吗？

不是所有的补钙剂都能够同时做到补血，但是阿胶钙做到了。做为能补血的补钙剂，在市场已流行了15个年头，无论在新疆还是广东、江苏、广西……阿胶钙，正以自身独特的“标签”——钙血同补，笑傲市场。     

切除部分真皮缝合、医用胶黏合伤口对减少切口瘢痕的改善作用

目的探讨手术切口选择切除部分真皮缝合加医用胶黏合切口与直接缝合加医用胶黏合切口的效果比较。方法选取2011年²013年我院200例进行外科手术的患者作为研究对象,并将全部患者按其伤口的处理方法分成观察组和对照组,每组各100例,观察组患者采用切除部分真皮缝合加医用胶黏合切口,对照组采用直接缝合加医用胶黏合切口,对比比较两组患者切口愈合后效果。结果两组患者切口愈合均良好,观察组切口愈合后瘢痕增生较少,痒感比对照组轻,切口美容满意度高,两组患者比较差异具有统计意义(P<0.05);观察组合对照组患者在切口疼痛程度、切口甲级愈合率和愈合时间比较差异无统计学意义(P>0.05)。结论外科手术切口应用切除部分真皮缝合加医用胶黏合切口,能显著减少术后早、中、远期瘢痕形成,减少痒感,缩短手术时间,并降低切口感染发生率和避免了患者拆线的痛苦,同时患者对体表美容的要求得到了满足,值得临床推广应用。     

硝苯地平-海藻酸钠缓释片的制备和性能研究

目的 制备硝苯地平-海藻酸钠缓释片,考察海藻酸钠的含量对其抗张强度、体外释放性能和稳定性的影响.方法 以直接压片法制备硝苯地平-海藻酸钠缓释片;在海藻酸钠含量为60、100、140 mg的条件下,测定其厚度和抗张强度;建立硝苯地平的体外分析方法,测定硝苯地平-海藻酸钠缓释片在人工胃液(前2 h)和人工肠液(后22 h)中的释放曲线,考察片剂的稳定性,并探讨海藻酸钠含量对片剂释放性能和稳定性的影响.结果 海藻酸钠含量为60、100、140 mg片剂的抗张强度依次为2.86、2.71、2.67 MPa,无显著性差异.在胃液环境中释放2h后,3种片剂累积释放率依次为60.3％、46.7％、35.6％,随海藻酸钠含量升高而降低(P＜0.05).在肠液环境中释放10 h后,3种片剂累积释放率依次为86.5％、74.6％和61.6％,随海藻酸钠含量升高而下降(P＜0.05).释放24 h后3种片剂累积释放率达到98.3％、91.3％、85.6％,片剂3的释放率比片剂1和2降低(P＜0.05).片剂对高湿、高温环境稳定性强,但对光的稳定性弱.结论 硝苯地平-海藻酸钠缓释片的厚度和抗张性能与海藻酸钠含量无关,海藻酸钠能够降低其在胃液中的突释效应,提高其在肠液环境中的缓释性能和对光的稳定性.     

黑枸杞花青素胃内漂浮微球的制备工艺

目的采用离子胶凝-干燥法制备黑枸杞花青素胃内漂浮微球,实现黑枸杞花青素胃内定位释药。方法以天然多糖海藻酸钠和壳聚糖为主要载体材料,以碳酸氢钠为起泡剂,采用正交试验法设计优化黑枸杞花青素胃内漂浮微球制备工艺,对其体外漂浮性能、包封率和体外释放度等进行考察。结果黑枸杞花青素胃内漂浮微球的最优工艺条件为海藻酸钠质量浓度为47.50 g·L~(-1),氯化钙质量浓度为40.00 g·L~(-1),壳聚糖质量浓度为3.75 g·L~(-1),碳酸氢钠质量浓度为15.00 g·L~(-1)。微球能在模拟胃液中漂浮12 h,漂浮率为94%,包封率为84.01%,具有缓释性能。结论制备的微球漂浮满足胃内漂浮制剂的要求。     

硝苯地平-海藻酸钠骨架缓释片的制备及处方工艺优化

目的：研制硝苯地平-海藻酸钠骨架缓释片并优化处方工艺。方法：以海藻酸钠为缓释骨架材料,乳糖为填充剂,硬脂酸镁为润滑剂,乙醇为黏合剂,湿法制粒并制备硝苯地平骨架缓释片。在处方单因素考察的基础上,选择对缓释片释放行为影响较大的3个处方因素——海藻酸钠用量、磷酸氢钙用量和海藻酸钠黏度,以累积释放度为指标,利用正交实验设计L9（34）对缓释片处方进行优化。考察制备的硝苯地平骨架缓释片的释放机制。将自制缓释片的体外释放行为和大鼠体内药动学与市售缓释片进行比较。结果：在3个处方因素中,磷酸氢钙用量对硝苯地平-海藻酸钠骨架缓释片的体外释放度影响最大,最佳处方组成为45%海藻酸钠、20%磷酸氢钙和黏度为105m Pa·s的海藻酸钠。处方优化的硝苯地平骨架缓释片体外释放行为符合一级动力学方程,属于Baker-Lonsdale球形扩散机制。与市售产品相比,自制缓释片的缓释效果更好;其经口给予大鼠后,硝苯地平的tmax明显延长,药物作用时间延长及生物利用度提高。结论：自制的硝苯地平-海藻酸钠骨架缓释片具有明显的缓释效果,并优于市售产品。     

Design and in vitro evaluation of floating drug delivery system for an antipsychotic agent: a technical report

Floating drug delivery systems are used to target drug release in the stomach or to the upper parts of the intestine. The oral delivery of the anti-psychotic agent carbamazepine was facilitated by preparing a non-disintegrating floating dosage form which can increase its absorption in the stomach by increasing the drug's gastric residence time. The polymers used were HPMC (low and high viscosity), guar gum, and carbopol, along with sodium bicarbonate as the gas-generating agent. The prepared tablets were evaluated for their physicochemical properties and drug release. In vitro release studies indicated that the carbamazepine release from the floating dosage forms was uniform and followed a zero-order release. It was observed that the devices containing higher proportions of HPMC (high viscosity) showed slower release than those containing lower proportions while also maintaining the integrity of the device (> or = 24 h). The incorporation of guar gum helps to maintain the device's integrity, and due to its viscolysing property also affects the drug's release profile. Sodium bicarbonate which was used as the gas-generating agent causes the tablet to float for the required time (> or = 24 h).     

Comparison of guar gum from different sources for the preparation of prolonged-release or colon-specific dosage forms

The aim of the present study was to compare some physicochemical properties of guar gum samples from different sources and thus to investigate the suitability of these samples for the formulation of either prolonged-release or colon-specific dosage forms. Twelve different guar gum samples from India, Pakistan and the USA were used. Theophylline was chosen as a model drug. The flow type of the guar gum samples was determined as pseudoplastic. The viscosity and the particle size of the guar gum samples were found to be the main parameters which could affect the drug release from matrix tablets. All of the guar gum samples are suitable for use in the preparation of prolonged-release matrix tablets. But, three of them, obtained from India and the USA, may be potentially the most suitable guar gum samples for the preparation of colon-specific dosage forms.     

Interaction of preservatives with macromolecules: Part I--Natural hydrocolloids.

Antibacterial activity of methyl-p-hydroxybenzoate against Ps. aeruginosa was evaluated in the presence of varying concentrations of acacia, tragacanth, sodium alginate, guar gum and carrageenin. All these hydrocolloids reduced the antibacterial activity to varying degrees. Tragacanth and guar gum inhibited the activity to a greater extent than acacia, sodium alginate and carrageenin. Hydrocolloids reduce the antibacterial activity of preservatives in two ways. Interaction of the preservative with hydrophilic macromolecules and subsequent reduction in the availability of preservative appears to be the predominant mechanism by which tragacanth and guar gum reduce the activity of methyl-p-hydroxybenzoate. Acacia, sodium alginate and carrageenin apparently act by offering physical protection to microbial cells from the action of the preservative. It is also probable that these hydrocolloids provide more favourable media for microbial growth thereby increasing the preservative requirement for adequate preservation.     

Effect of steam sterilization on the rheology of polymer solutions

The effect of steam sterilization (dwell@121 degrees C) on the apparent viscosity of solutions of carbomer 940P, guar gum, hydroxyethylcellulose (HEC), and xanthan gum was studied. Guar gum and carbomer 940P could be steam sterilized for 30 min without any change in the apparent viscosity. Steam sterilization of HEC and xanthan gum resulted in a substantial decrease in the apparent viscosity and the desirable shear-thinning rheology. The addition of sodium chloride to either polymer prior to steam sterilization diminished the effect of sterilization on the rheology. The apparent viscosity of xanthan solutions was not significantly affected if the solution was made isotonic with sodium chloride (0.15 M). The addition of sodium chloride to xanthan gum after steam sterilization resulted in full recovery of the initial rheological properties. Carbomers, guar gum, and xanthan (in 0.15 M NaCI) are candidates for use in pharmaceutical solutions/suspensions that are subjected to steam sterilization.     

Effect of Steam Sterilization on the Rheology of Polymer Solutions

The effect of steam sterilization (dwell@121°C) on the apparent viscosity of solutions of carbomer 940P, guar gum, hydroxyethylcellulose (HEC), and xanthan gum was studied. Guar gum and carbomer 940P could be steam sterilized for 30 min without any change in the apparent viscosity. Steam sterilization of HEC and xanthan gum resulted in a substantial decrease in the apparent viscosity and the desirable shear-thinning rheology. The addition of sodium chloride to either polymer prior to steam sterilization diminished the effect of sterilization on the rheology. The apparent viscosity of xanthan solutions was not significantly affected if the solution was made isotonic with sodium chloride (0.15 M). The addition of sodium chloride to xanthan gum after steam sterilization resulted in full recovery of the initial rheological properties. Carbomers, guar gum, and xanthan (in 0.15 M NaCl) are candidates for use in pharmaceutical solutions/suspensions that are subjected to steam sterilization.     

Ethanol-resistant ethylcellulose/guar gum coatings – Importance of formulation parameters

Recently, ethylcellulose/guar gum blends have been reported to provide ethanol-resistant drug release kinetics from coated dosage forms. This is because the ethanol insoluble guar gum effectively avoids undesired ethylcellulose dissolution in ethanol-rich bulk fluids. However, so far the importance of crucial formulation parameters, including the minimum amount of guar gum to be incorporated and the minimum required guar gum viscosity, remains unclear. The aim of this study was to identify the most important film coating properties, determining whether or not the resulting drug release kinetics is ethanol-resistant. Theophylline matrix cores were coated in a fluid bed with blends of the aqueous ethylcellulose dispersion “Aquacoat® ECD 30” and guar gum. The polymer blend ratio, guar gum viscosity, and degree of dilution of the final coating dispersion were varied. Importantly, it was found that more than 5% guar gum (referred to the total polymer content) must be incorporated in the film coating and that the apparent viscosity of a 1% aqueous guar gum solution must be greater than 150 cP to provide ethanol-resistance. In contrast, the investigated degree of coating dispersion dilution was not found to be decisive for the ethanol sensitivity. Furthermore, all investigated formulations were long term stable, even upon open storage under stress conditions for 6 months.     

pH sensitive alginate-guar gum hydrogel for the controlled delivery of protein drugs

Design of a pH sensitive alginate-guar gum hydrogel crosslinked with glutaraldehyde was done for the controlled delivery of protein drugs. Alginate is a non-toxic polysaccharide with favorable pH sensitive properties for intestinal delivery of protein drugs. Drug leaching during hydrogel preparation and rapid dissolution of alginate at higher pH are major limitations, as it results in very low entrapment efficiency and burst release of entrapped protein drug, once it enters the intestine. To overcome these limitations, another natural polysaccharide, guargum was included in the alginate matrix along with a cross linking agent to ensure maximum encapsulation efficiency and controlled drug release. The crosslinked alginate-guar gum matrix is novel and the drug loading process used in the study was mild and performed in aqueous environment. The release profiles of a model protein drug (BSA) from test hydrogels were studied under simulated gastric and intestinal media. The beads having an alginate to guar gum percentage combination of 3:1 showed desirable characters like better encapsulation efficiency and bead forming properties in the preliminary studies. The glutaraldehyde concentration giving maximum (100%) encapsulation efficiency and the most appropriate swelling characteristics was found to be 0.5% (w/v). Freeze-dried samples showed swelling ratios most suitable for drug release in simulated intestinal media ( approximately 8.5). Protein release from test hydrogels was minimal at pH 1.2 ( approximately 20%), and it was found to be significantly higher ( approximately 90%) at pH 7.4. Presence of guar gum and glutaraldehyde crosslinking increases entrapment efficiency and prevents the rapid dissolution of alginate in higher pH of the intestine, ensuring a controlled release of the entrapped drug.     

Optimization and pharmacotechnical evaluation of compression‐coated colon‐specific drug delivery system of triphala using factorial design

The purpose of the present investigation was to achieve successful delivery specifically to the colon using guar gum as a compression coat over a core tablet of triphala. In this study, guar gum along with hydroxy propyl methyl cellulose (HPMC) was used as a compression‐coating polymer. The drug delivery system was based on the gastrointestinal transit time concept, assuming colon arrival time to be 6 h. Rapidly disintegrating core tablets containing 100‐mg triphala extract were compression coated with guar gum and HPMC. A 3² full factorial design was applied for optimization of the formulation. Both variables, the proportion of guar gum in polymer blend (X₁) and coat weight of the tablet (X₂), had an influence on the percent drug release after 4 h of dissolution of tablet in the presence of rat cecal content (Y240) and difference in percent drug release between 4 h and 10 h of dissolution of tablet in the presence of rat cecal content (YD).The results revealed that for protecting the rapidly disintegrating core of triphala in the physiological conditions of stomach and upper intestine, the core tablet should be coated with 50% of guar gum in coat formulation and higher coat weight. The proportion of guar gum exhibited predominant action as compared to coat weight. In vivo performance was assessed via an x‐ray roentgenography study by placing barium sulfate as an x‐ray opaque material instead of triphala. The guar gum–HPMC coating was found to be a promising drug delivery system for drugs such as triphala and sennosides to be delivered to the colon. Drug Dev. Res. 65:34–42, 2005. © 2005 Wiley‐Liss, Inc.     

Study of complex coacervation of gelatin with sodium carboxymethyl guar gum: microencapsulation of clove oil and sulphamethoxazole

Complex coacervation of gelatin with sodium carboxymethyl guar gum was studied. The coacervation was studied as a function of pH, colloid composition and concentration. The efficiency of coacervation was followed by measuring viscosity, coacervate yield and turbidity of test solutions. All the measurements suggest that, as the amount of sodium carboxymethyl guar gum (CMGG) in the colloids increases, the pH at which maximum coacervation happens decreases. Effective coacervation could be realized over the pH range of 2.5-4.0 using different compositions. The efficiency of the CMGG/gelatin system to encapsulate oils and solid particles is demonstrated by successful encapsulation of oil of cloves and sulphmethoxazole.     

Impact of cross-linker on alginate matrix integrity and drug release

Sodium alginate, a biopolymer, was employed in the formulation of matrix tablets. They cracked or laminated at acidic pH, compromising their dissolution performance. Improved mechanical strength and reduced barrier permeability of calcium alginate gel provided the rationale for cross-linking the alginate matrix to sustain drug release. Studies had suggested that the incorporation of soluble calcium salts in alginate matrix tablets could sustain drug release at near-neutral pH due to in situ cross-linking. However, results from the present study showed otherwise when gastrointestinal pH conditions were simulated. Significant reduction in drug release rate was only observed when an external calcium source was utilized at low concentration. High calcium ion concentrations caused matrix disintegration. In contrast, matrices pre-coated by calcium alginate could sustain drug release at pH 1.2 followed by pH 6.8 for over 12h. The presence of cross-linked barrier impeded matrix lamination and preserved matrix structure, contributing to at least three-fold reduction in drug release at pH 1.2. Zero order release as well as delayed burst release could be achieved by employing appropriate grade of alginate and cross-linking conditions.