格列吡嗪缓释微丸生产工艺改进研究

目的 将原格列吡嗪缓释微丸在离心包衣锅中进行上药、包衣改进到流化床中进行，提高生产效率，节约人工及能耗，同时产品各项指标达到质量标准要求。方法 不改变原有处方组成，通过2种生产工艺的上药率、体外释放度指标和生产效率的比较，采用正交试验优化生产工艺参数。结果 该产品的流化床工艺可行，各项指标达到原工艺的水平，且提高生产效率，节约人工及能耗。结论 流化床生产工艺优于离心包衣锅，适合格列吡嗪缓释微丸的生产。     

布洛芬缓释微丸的制备

目的制备布洛芬缓释微丸。方法以药用糖丸为母核，欧巴代为粘合剂和包衣材料，采用包衣造粒机撒粉上药及流化床包衣的工艺制备布洛芬缓释微丸。结果制得的微丸均匀圆整，体外释放度测定结果表明，该微丸符合2005年版《中国药典（二部）》布洛芬缓释胶囊的质量要求。结论采用药用糖丸撒粉上药及流化床包衣的工艺可制备布洛芬缓释微丸。     

布洛芬膜控型和骨架型缓释微丸的制备和对比

目的 制备布洛芬膜控型和骨架型两种缓释微丸,并对体外释放进行分析,研究两者的释药机理.方法 两种缓释微丸均采用离心制丸机粉末层积法上药,流化床底喷包衣进行制备,采用Eudragit RLPO作为骨架材料和Eudragit RLPO与E100作为膜控缓释材料.结果 微丸光滑圆整,硬度适中,适合包衣,两种微丸均具有明显缓释效果,释药机制为扩散和溶蚀协同作用.结论 膜控型缓释微丸释放优于骨架型缓释微丸,制备工艺稳定可行.     

盐酸坦索罗辛缓释微丸胶囊的制备及处方工艺考察

目的:制备盐酸坦索罗辛缓释微丸胶囊。方法:采用苏丽丝、雅克宜、欧巴代II作为包衣材料,用流化床底喷溶液上药法制备载药微丸,并进行缓释包衣。结果:以释放度为指标,通过对包衣工艺及处方影响因素的考察,确定了包衣处方工艺。结论:本研究处方工艺简便,重现性良好,可能适合工业化生产。     

盐酸吡格列酮缓释微丸胶囊制备及体外释放特性

目的：制备盐酸吡格列酮缓释微丸胶囊并考察其体外释放特性。方法：底喷式流化床包衣制备盐酸吡格列酮缓释微丸,通过正交设计优化处方。结果：该方法简单易操作,所选处方工艺重复性良好,所制备微丸具有明显缓释作用。结论：该包衣处方及制备工艺简便可控,缓释微丸稳定性良好。     

琥珀酸去甲文拉法辛缓释微丸的制备及释放特性的研究

目的 采用乙基纤维素水分散体(Surelease(R))为包衣材料制备琥珀酸去甲文拉法辛(DVS)缓释微丸,并评价其体外释药性能.方法 采用溶液上药法,在蔗糖空白丸芯的基础上旋转锅包衣法上药,通过正交筛选优化上药工艺,再以Surelease(R)为缓释材料进行包衣,以原研缓释片为参比对微丸的体外释放进行评价,并将释放数据用常用模型拟合,探讨其释放机制.结果 所得缓释微丸的载药量和上药率均较高,含量均匀,当聚合物包衣增重32.4％时可达到与原研缓释片一致的释放特性,在piH1.2、pH4.5、水、pH6.8的释放介质中两者的相似因子分别为86.65、69.94、67.47、67.97,体外释放曲线符合一级方程.结论 制备的DVS缓释微丸具有较理想的缓释效果.     

洛索洛芬钠缓释微丸的制备

目的:本文拟制备洛索洛芬钠缓释微丸,以期达到降低毒副作用,维持平稳的血药浓度,提高病人顺应性之目的.方法:采用Eudragit(r)NE 30D水分散体作为包衣材料,用流化床悬浮包衣法对洛索洛芬钠微丸进行缓释包衣.结果:以释放度为指标,通过对包衣工艺及处方影响因素的考察,确定了包衣工艺.     

甲硝唑缓释微丸的研制

目的制备甲硝唑缓释微丸,并对其体外释药行为进行研究。方法采用离心造粒技术制备甲硝唑丸;并在此基础上,在流化床内采用丙烯酸树脂水分散体对其进行包衣,制备甲硝唑缓释微丸。分别考察包衣材料的比例及用量对甲硝唑缓释微丸体外释药行为的影响。结果包衣材料EudragitNE30D与EudragitL30D-55质量比为1∶1、增重8%时,甲硝唑缓释微丸在模拟人体胃肠道的pH溶液中释放较理想。结论采用离心造粒技术和丙烯酸树脂流化床包衣,成功地制备了甲硝唑缓释微丸,它具有良好的缓释效果。     

盐酸二甲双胍缓释微丸的制备及体外释放度考察

目的:制备盐酸二甲双胍(metformin hydrochloride,MH)缓释微丸,并考察其体外释药行为。方法:通过离心造粒法制得MH微丸,以乙基纤维素水分散体(Surelease),丙烯酸树脂水分散体(EudragitNE30D,RS30D)作为膜控释包衣材料,通过流化床包衣制备MH缓释微丸,并考察不同包衣材料、包衣增重、固化时间、释放介质对释放度的影响。结果:离心造粒制得微丸圆整度好,有一定强度,适合包衣,Surelease包衣增重11%时所得的缓释微丸在12 h具有明显的缓释效果,不受释放介质的影响,为零级释放,且12 h释放可以达到85%以上。释放机制主要是通过无孔膜扩散作用。结论:通过离心造粒并用Surelease包衣的MH缓释微丸缓释效果明显,且为零级释放。     

伊拉地平缓释胶囊的制备工艺及体外释药研究

目的:研究伊拉地平缓释胶囊制备工艺,并对其体外释药进行考察。方法:采用醇溶上药法(流化床底喷装置)制备伊拉地平微丸,并进行伊拉地平微丸质量评价及粉体学性质研究。用乙基纤维素(EC)和羟丙甲基纤维素(HPMC)为包衣材料,采用流化床进行包衣制备伊拉地平缓释微丸,对缓释微丸体外释放进行评价并考察不同热处理时间以及人工胃液对缓释微丸药物释放的影响,同时对批内和批间释药情况进行比较。结果:制备得到的伊拉地平微丸质量良好,不同热处理时间(1~12 h)对于伊拉地平缓释微丸的释药特性影响不大,在制备过程中可不进行热处理,干燥即可。人工胃液会显著地降低伊拉地平缓释微丸的释药速率,宜将其置于肠溶胶囊中。伊拉地平缓释微丸批间及批内重复性较好,在0.1%十二烷基二甲基氧化胺溶液12 h释放符合零级释药模型动力学过程。结论:制备得到的伊拉地平缓释胶囊缓释效果好,达到了释药要求。     

Effect of common excipients on Caco-2 transport of low-permeability drugs.

The Biopharmaceutics Classification System (BCS) allows waivers of in vivo bioequivalence for rapidly dissolving immediate-release (IR) formulations of drugs with high solubility and high permeability. One potential issue in possibly extending BCS biowaivers to low-permeability drugs is the potential for excipients to modulate the intestinal permeability of the drug. The objective of this work was to evaluate the effect of nine individual excipients on the Caco-2 permeability of seven low-permeable compounds that differ in their physiochemical properties. Generally, most excipients had no influence on drug permeability. With the exception of sodium lauryl sulfate, no excipient affected Caco-2 monolayer integrity. Sodium lauryl sulfate moderately increased the permeability of almost all the drugs. Tween 80 significantly increased the apical-to-basolateral direction permeability of furosemide, cimetidine, and hydrochlorothiazide, presumably by inhibiting their active efflux, without affecting mannitol permeability. Additionally, docusate sodium moderately increased cimetidine permeability. Other excipients did not have significant effect on the permeability of these three drugs. Further work is needed to interpret the in vivo consequences of these observations from cell culture.     

制剂技术在提高BCSIV类药物生物利用度中的应用及此类药物体内外相关性研究现状

随着组合化学和高通量筛选在药物发现中的广泛应用．别暌选药物不断涌现,其中不乏各种BCSIV类药物,而该类药物凸显的低溶解性／低渗透性极大地阻碍了其进一步的临床开发与应用。因此,如何有效提高该类药物生物利用度,已成为药剂学研究者长期以来广泛关注并致力于解决的课题。分类综述制剂技术在改善BCSIV类药物溶解性／渗透性方面的应用研究,并简介该类药物的体内外相关性研究进展。     

In vitro permeation of several drugs through the human nail plate: relationship between physicochemical properties and nail permeability of drugs.

The objectives of the present study are to clarify the relationship between the physicochemical properties and the nail permeability of drugs through human nail plates. Homologous p-hydroxybenzoic acid esters were used to investigate the relationship between the octanol/water partition coefficient and the permeability coefficient of several drugs. The nail permeability was found to be independent of the lipophilicity of a penetrating drug. However, the nail permeability of several model drugs was found to markedly decrease as their molecular weights increased. The nail permeability of an ionic drug was found to be significantly lower than that of a non-ionic drug, and the nail permeability of these drugs markedly decreased as their molecular weights increased. The permeation of a model drug, 5-fluorouracil (5-FU), through healthy nail plates was also determined and compared with that through nail plates with fungal infections. The drug permeation through a nail plate decreased with an increase in nail plate thickness. Nail plates with fungal infections exhibited approximately the same 5-FU permeation as healthy nail plates. We suggest that the permeability of a drug is mainly influenced by its molecular weight and permeability through nails with fungal infection can be estimated from data on healthy nail permeability.     

Evaluation of insulin permeability and effects of absorption enhancers on its permeability by an in vitro pulmonary epithelial system using Xenopus pulmonary membrane

The permeability of insulin across Xenopus pulmonary membrane and the effects of various absorption enhancers on insulin permeability were examined using an in vitro Ussing chamber technique. Absorption enhancers used in this study were sodium caprate (NaCap), sodium glycocholate (NaGC), sodium salicylate (NaSal) and ethylenediaminetetraacetic acid disodium salt (EDTA). The permeability of insulin across Xenopus pulmonary membrane significantly increased in the presence of NaCap and NaGC, while EDTA and NaSal did not enhance the permeability. In addition, the enhancing effect of NaGC increased as the concentrations of these enhancers increased. Transmembrane resistance (Rm) of Xenopus lung was markedly decreased in the presence of these enhancers, and NaCap showed a greater effect on Rm than NaGC. Furthermore, the amount of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) released from the apical side of the Xenopus pulmonary membrane increased in the presence of these enhancers. These results indicate that NaCap and NaGC improve the pulmonary absorption of insulin, but they are toxic to the pulmonary membrane. These findings suggest that this method is useful for estimating the permeability characteristics of peptides across the pulmonary membrane and for evaluating the effects of various additives on their permeability and their membrane toxicity.     

In-vitro Permeability of the Human Nail and of a Keratin Membrane from Bovine Hooves: Prediction of the Penetration Rate of Antimycotics through the Nail Plate and their Efficacy

In contrast to the partition coefficient octanol/water the molecular size of penetrating drugs has a noticeable influence on the permeability of the human nail plate and a keratin membrane from bovine hooves. The relationship between permeability and molecular weight is founded on well-established theories. The correlation between the permeability of the nail plate and that of the hoof membrane allows a prediction of the nail permeability after determination of the drug penetration through the hoof membrane. The maximum flux of ten antimycotics (amorolfine, bifonazole, ciclopirox, clotrimazole, econazole, griseofulvin, ketoconazole, naftifine, nystatin and tolnaftate) through the nail plate was predicted on the basis of their penetration rates through the hoof membrane and their water solubilities. An efficacy coefficient against onychomycoses was calculated from the maximum flux and the minimum inhibitory concentration. Accordingly, amorolfine, ciclopirox, econazole and naftifine are expected to be especially effective against dermatophytes, whereas in the case of an infection with yeasts only, amorolfine and ciclopirox are promising.     

Analysis of the receptors mediating vascular actions of bradykinin

Summary A range of bradykinin (BK) analogues was assessed for their ability to antagonise the action of BK on rabbit jugular vein, a B₂-receptor containing tissue, and compared with their action against BK-induced increases in skin vascular permeability in the rabbit and rat. The results demonstrate that modification of the BK (nonapeptide) structure by the insertion of certain d-amino acids in positions 5, 7 and 8 in addition to elongation of the amino terminal resulted in compounds with potent antagonistic action against BK on rabbit jugular vein and rabbit skin vascular permeability. The same BK analogues did not antagonise the action of BK on rat skin vascular permeability. It is concluded that the kinin receptor mediating an increase in vascular permeability in the rabbit is the same as that mediating contraction of the rabbit jugular vein in vitro, that is the B₂-type. The kinin receptor mediating an increase in skin vascular permeability in the rat is difficult to classify but does not appear to be of the B₂ type. Send offprint requests to E. T. Whalley     

The bacterial outer-membrane permeability of beta-lactam antibiotics.

Two penicillins and 5 cephalosporins were evaluated for their ability to pass through the outer-membranes of Proteus morganii, Citrobacter freundii and Escherichia coli. Cefazolin, ceftezole and cephaloridine showed high permeability through the outer-membranes of these Gram-negative bacteria. Benzylpenicillin and cephalothin, on the contrary, showed low permeability. The outer-membrane permeability of ampicillin and cephalexin varied from species to species. C. freundii was found to have the highest barrier against both the penicillins and the cephalosporins, and E. coli appeared to have a low barrier against the cephalosporins. The hydrophobic character of the beta-lactam antibiotics, which was estimated by a reversed-phase thin-layer chromatography was closely related to the outer-membrane permeability. In general, the more hydrophilic antibiotic showed the higher outer-membrane permeability. However, cephaloridine, the most lipophilic compound among the antibiotics tested, showed good permeability.     

Role of P-glycoprotein-mediated secretion in absorptive drug permeability: An approach using passive membrane permeability and affinity to P-glycoprotein.

It has been shown in vivo and in vitro that P-glycoprotein (P-gp) may be able to influence the permeability of its substrates across biological membranes. However, the quantitative contribution of the secretion process mediated by P-gp on the overall permeability of membranes has not been determined yet. In particular, observations need to be clarified in which substrates showing high affinity to P-glycoprotein, e.g., verapamil, apparently do not seem to be greatly influenced by P-gp in their permeability and consequently also with respect to their extent of GI-absorption after oral administration, whereas weaker substrates of P-gp, e.g., talinolol, have clearly shown P-gp-related absorption phenomena such as nonlinear intestinal permeability and bioavailability. Experiments with Caco-2 cell monolayers and mathematical simulations based on a mechanistic permeation model should aid in clarifying the underlying mechanism for these observations and quantifying the influence of passive membrane permeability and affinity to P-gp to the overall transmembrane drug flux. In addition, the concentration range of drug at which P-glycoprotein-mediated transport across the biological membrane is relevant should be examined. The permeability of various drugs in Caco-2 monolayers was determined experimentally and modeled using a combination of passive absorptive membrane permeability and a Michaelis-Menten-type transport process in the secretory direction. The passive permeabilities were experimentally obtained for the apical and basolateral membrane by efflux experiments using Caco-2 monolayers in the presence of a P-gp inhibitor. The Michaelis-Menten parameters were determined by a newly developed radioligand-binding assay for the quantification of drug affinity to P-gp. The model was able to accurately simulate the permeability of P-glycoprotein substrates, with differing passive membrane permeabilities and P-glycoprotein affinities. Using the outlined approach, permeability vs donor-concentration profiles were calculated, and the relative contribution of passive and active transport processes to the overall membrane permeability was evaluated. A model is presented to quantitatively describe and predict direction-dependent drug fluxes in Caco-2 monolayers by knowing the affinity of a compound to the exsorptive transporter P-gp and its passive membrane permeability. It was shown that a combination of high P-gp affinity with good passive membrane permeability, e.g., in the case of verapamil, will readily compensate for the P-gp-mediated reduction of intestinal permeability, resulting in a narrow range in which the permeability depends on the apical drug concentration. On the other hand, the permeability of compounds with low passive membrane permeability (e. g., talinolol) might be affected over a wide concentration range despite low affinity to P-gp.     

Enhanced transdermal delivery of phenylalanyl-glycine by chemical modification with various fatty acids

We synthesized three novel lipophilic derivatives of phenylalanyl-glycine (Phe-Gly), C4-Phe-Gly, C6-Phe-Gly and C8-Phe-Gly by chemical modification with butyric acid (C4), caproic acid (C6) and octanoic acid (C8). The effect of the acylation on the stability, permeability and accumulation of Phe-Gly in the skin was investigated by in vitro studies. The stability of Phe-Gly in skin homogenates was low, but was significantly improved by the acylation. In the transport studies, a Franz-type diffusion cell was used for the permeability experiments with Phe-Gly and its acyl derivatives. The permeability of acyl-Phe-Gly derivatives across the intact skin was higher than that of native Phe-Gly. Of all the acyl-Phe-Gly derivatives, C6-Phe-Gly was the most permeable compounds across the intact skin. On the other hand, the permeability of acyl-Phe-Gly derivatives across stripped skin was less than that of native Phe-Gly in the initial time period of transport studies, but their permeability was higher than that of native Phe-Gly at the end of the transport studies. When the skin was pretreated with ethanol, which could inactivate the peptidases responsible for the degradation of Phe-Gly, the permeability of native Phe-Gly was higher than that of acyl derivatives. These findings indicated the involvement of peptidases on the permeability of Phe-Gly across the skin. The relationship between the lipophilic indexes of Phe-Gly derivatives and the permeability coefficients indicated that there is an optimal carbon number of fatty acid for improving the transdermal permeability of Phe-Gly by the acylation. A good correlation was found between the accumulation of these acyl-Phe-Gly derivatives in the intact skin and their lipophilicity. These results suggest that the stability and permeability of Phe-Gly were improved by chemical modification with fatty acids and this enhanced permeability of Phe-Gly by the acylation may be attributed to the protection of Phe-Gly from the enzymatic degradation in the skin and the increase in the partition of Phe-Gly to the stratum corneum.