硫酸特布他林脉冲控释片的制备与释放机理研究硫酸特布他林脉冲控释片的制备与释放机理研究

目的制备硫酸特布他林双层包衣脉冲片，考察处方及释放条件对体外释药行为的影响，解析其释放机理。方法粉末直接压片法制备含渗透活性物质的片芯，滚转包衣锅法分别包溶胀层和控释衣层。通过测定释放度研究脉冲片的制剂学特征，并研究脉冲片的吸水动力学和膨胀行为。结果双层包衣片以脉冲形式释放，释药时滞随控释衣层厚度增加而延长，释药速度减小；渗透活性物质和溶胀层可提高快速释放期的释药速率。溶出介质pH值和搅拌速度对释药行为无影响。释药机理包括扩散、溶胀和渗透泵原理。结论调整控释衣膜厚度和组成可获得理想的脉冲释药行为，满足时辰治疗的要求。     

特布他林脉冲控释微丸体外释放度影响因素的研究

目的:考察硫酸特布他林脉冲控释微丸释放度的影响因素.方法:采用滚制法制备载药丸芯,使用水溶胀性材料为内包衣溶胀层,乙基纤维素水分散体为外包衣控释层制备脉冲控释微丸,并考察十二烷基硫酸钠(SDS)含量、溶胀层和控释层包衣增重量对药物释放的影响.结果:药物通过控释层衣膜破裂而释放,内包衣层中SDS的加入与否、溶胀层和控释层厚度对脉冲控释微丸的释药时滞和释药速率均具有显著性影响.结论:制备的脉冲控释微丸,在模拟人体内胃肠道pH值变化条件下达到了时滞为4.5 h,时滞后1.5 h累积释药80%以上的脉冲释药效果.     

盐酸普萘洛尔脉冲释放片的制备及其体外释药研究

目的 制备盐酸普萘洛尔双层包衣脉冲释放片,并研究其体外释药行为。方法 采用粉末直接压片法制备盐酸普萘洛尔片芯,滚转包衣锅法分别包羟丙甲纤维素溶胀层和丙烯酸树脂控释层。采用体外溶出试验考察处方及溶出条件对本品释药行为的影响。结果 本品经过一定时滞后以脉冲形式释药,渗透活性物质氯化钠、溶胀层及控释层厚度、丙烯酸树脂RS/RL的配比均影响本品时滞。溶出方法及不同pH溶出介质对本产品的时滞无影响。结论 盐酸普萘洛尔脉冲释放片具有脉冲释放特性,体外时滞约为4 h。     

硫酸沙丁胺醇脉冲控释微丸的制备

目的制备硫酸沙丁胺醇脉冲控释微丸。方法采用挤出滚圆法制备载药丸芯 ,使用水溶胀性材料为内包衣溶胀层 ,乙基纤维素水分散体为外包衣控释层制备脉冲控释微丸 ,并考察溶胀层材料类型、十二烷基硫酸钠 (SDS)含量、溶胀层和控释层包衣增重量对药物释放的影响。结果药物通过控释层衣膜破裂而释放 ,溶胀层材料类型、内包衣层中SDS的加入与否、溶胀层和控释层厚度对脉冲控释微丸的释药时滞和释药速率均具有显著性影响。结论采用低取代羟丙基纤维素为溶胀性材料 ,并加入 0 0 5 2mol LSDS ,共同作为内包衣层 ,制备的脉冲控释微丸 ,当内包衣层和外包衣层增重均为 1 8%时 ,在模拟人体内胃肠道pH值变化条件下达到了时滞为 4 5h ,时滞后 1 5h累积释药 80 %以上的脉冲释药效果     

硫酸沙丁胺醇脉冲控释微丸的制备

为制备硫酸沙丁胺醇脉冲控释微丸，采用挤出滚圆法制备载药丸芯，使用水溶胀性材料为内包衣溶胀层，乙基纤维素水分散体为外包衣控释层制备脉冲控释微丸，并考察溶胀层材料类型、十二烷基硫酸钠(SDS)含量、溶胀层和控释层包衣增重对药物释放的影响。结果表明．药物通过控释层衣膜破裂而释放，溶胀层材料类型、内包衣层中SDS的加入与否、溶胀层和控释层厚度对脉冲控释微丸的释药时滞和释药速率均具有显性影响。结论：采用低取代羟丙基纤维素为溶胀性材料．并加入1．5％SDS，共同作为内包衣层．制备的脉冲控释微丸，当内包衣层和外包衣层增重均为18％时。在模拟人体内胃肠道pH值变化条件下达到了时滞为4．5h，时滞后1．5h累积释药80％以上的脉冲释药效果。     

氢溴酸高乌甲素脉冲释放片的研究*

目的以氢溴酸高乌甲素为模型药物研究脉冲释放片剂并同时考察用包衣的方法制备脉冲给药系统的可行性.方法以氢溴酸高乌甲素为模型药物,制备适宜的片芯;以乙基纤维素和丙烯酸树脂Ⅱ号的乙醇溶液包衣,采用滚转包衣法,制备氢溴酸高乌甲素脉冲释放片剂.通过体外释放度实验,考察片芯和衣层对片剂释药行为的影响.结果片芯处方、包衣层厚度及包衣处方对氢溴酸高乌甲素脉冲释放片的释药行为均有影响.结论通过调整片芯中崩解剂的用量、包衣层的厚度和组成,可以得到具有不同释药时滞的氢溴酸高乌甲素片剂.     

阿莫西林脉冲释药微丸的研制

目的:制备阿莫西林脉冲释药微丸。方法:取空白丸芯分别以含药层、溶胀层(羧甲基淀粉钠)和控释层(乙基纤维素水分散体)顺序依次进行包衣制备阿莫西林脉冲释药微丸。采用紫外法和篮法考察溶胀层(12%、16%、20%)和控释层包衣增重(24%、28%、32%)及不同介质(水、盐酸、pH6.8磷酸盐缓冲液)对药物释放的影响。结果:溶胀层和控释层包衣增重对脉冲控释微丸的释药时滞和释放速率具有显著影响,药物释放情况不受介质pH值的影响;溶胀层和控释层包衣增重分别为16%、28%时制备的微丸时滞时间约为4h,时滞后4h累积释药率达到80%。结论:所制备的阿莫西林脉冲释药微丸具有体外脉冲释放作用。     

5-氨基水杨酸时控结肠定位控释微丸及其制剂的研制

目的制备5-氨基水杨酸微丸及其时控结肠定位控释释药系统的研究。方法首先采用挤出滚圆机制备了含药微丸,然后使用流化床包衣设备将微丸包衣,以羟丙甲纤维素和微粉硅胶的混合物包衣作为溶胀控释层,以乙基纤维素水分散体Surelease包衣作为时滞包衣层,并将包衣微丸装入肠溶胶囊。用释放度测定法研究微丸的释放行为。结果药物通过时滞层破裂开始释放,该层厚度增加可显著延长释药时滞。调节羟丙甲纤维素的型号、包衣增重及羟丙甲纤维素与微粉硅胶两者比例,可以控制药物释放速度。在模拟胃肠道pH情况下延迟5 h释药,之后的10 h内释药完全。结论可通过调整溶胀控释层包衣混合物的比例、型号、包衣厚度及时滞层的包衣厚度,制备5-氨基水杨酸时控结肠定位控释释药系统。     

复方丹参脉冲控释滴丸的制备及其体外释放度考察

目的 制备复方丹参脉冲控释滴丸,并考察其体外释放度.方法 以复方丹参滴丸为载药丸芯,对包衣材料配比及包衣材料用量进行选择,对控释滴丸体外释药情况进行考察.结果 溶胀层的种类与包衣增重、控释层的包衣增重对药物的释放影响显著,采用交联羧甲基纤维素钠（CMC-Na）作为溶胀层材料,乙基纤维素水分散体作为控释层材料,溶胀层包衣增重12％,控释层包衣增重20％,所制备的微丸时滞时间为4h左右,时滞后3h内累积释药达到80％.结论 制备的复方丹参脉冲控释滴丸体外释放可达到脉冲控释效果.     

双氯灭痛控释微丸的制备与释药的研究

目的 :制备双氯灭痛控释微丸并研究其释放机理。方法 :用单因素实验方法考察了包衣液中溶媒系统的组成、膜材的浓度、致孔剂和增塑剂对药物释放的影响。结果 :膜材浓度增加、水比例增大 ,释药速度加快 ;PVPK30 浓度增加 ,释药速度有所加快。这些因素与包衣厚度共同决定衣膜的控释能力。结论 :本制剂属于包衣骨架控释微丸 ,随着包衣厚度的改变 ,释放机理有所不同。     

Release characteristics and in vitro-in vivo correlation of pulsatile pattern for a pulsatile drug delivery system activated by membrane rupture via osmotic pressure and swelling.

This study attempted to characterize the influence of core and coating formulations on the release profiles to establish in vitro/in vivo correlations of pulsatile pattern for a pulsatile drug delivery system activated by membrane rupture based on three core tablet formulations (A-core: HPMC 50+4000cps, B-core: E10M, and C-core: K100M) coated with various thicknesses of a semipermeable ethylcellulose membrane plasticized with HPMC 606 (Pharmacoat 606) at different ratios with/without adding various amounts of water to dissolve it in the coating solution. Drug release behaviors were investigated using apparatus II in four media of pH 1.2 solution, pH 6.8 buffer, deionized water, and a NaCl solution rotated at 75, 100, and 150rpm. Pilot studies of the in vivo pharmacokinetics were conducted as well for comparison with the in vitro results. Results demonstrated that drug release from the three kinds of core tablets in deionized water increased with an increasing stirring rate, and decreased with an increasing viscosity grade of HPMC used in the core formulations. A significant promotion of drug release from core tablets was observed for the three levels of NaCl media in comparison with that in deionized water. Results further demonstrated that a slightly slower release rate in pH 1.2 solution and a faster release rate in pH 6.8 buffer than that in deionized water were observed for the A-core and B-core tablets, with the former being slower than the latter. However, similar release rates in the three kinds of media were observed for C-core tablets, but they were slower than those for the A- and B-core tablets. Dissolution of coated tablets showed that the controlling membrane was ruptured by osmotic pressure and swelling which activated drug release with a lag time. The lag time was not influenced by the pH value of the release medium or by the rotation speeds. The lag time increased with a higher coating level, but decreased with the addition of the hydrophilic plasticizer, Pharmacoat 606, and of the water amount in the coating solution. The lag time also increased with a higher concentration of NaCl in the medium. The release rate after the lag time was determined by the extent of retardation of gelation of HPMC in the core tablet based on the ionic strength of the medium. Results of the three pilot crossover studies for the exemplified pulsatile systems indicated that the lag time for the in vivo plasma profile was well correlated with that determined from the in vitro release profile in pH 1.2 solution and the in vivo release rate was better reflected by that performed in pH 6.8 buffer.     

Microporous bilayer osmotic tablet for colon-specific delivery

Microporous bilayer osmotic tablet bearing dicyclomine hydrochloride and diclofenac potassium was developed using a new oral drug delivery system for colon targeting. The tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan-coating process. The developed microporous bilayer osmotic pump tablet (OPT) did not require laser drilling to form the drug delivery orifice. The colon-specific biodegradation of pectin could form in situ delivery pores for drug release. The effect of formulation variables like inclusion of osmogen, amount of HPMC and NaCMC in core, amount of pore former in semipermeable membrane was studied. Scanning electron microscopic photographs showed formation of in situ delivery pores after predetermined time of coming in contact with dissolution medium. The number of pores was dependent on the amount of the pore former in the semipermeable membrane. In vitro dissolution results indicated that system showed acid-resistant, timed release and was able to deliver drug at an approximate zero order up to 24 h. The developed tablets could be effectively used for colon-specific drug delivery to treat IBS.     

Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: screening of formulation variables and in vitro investigation

A microbially triggered colon-targeted osmotic pump (MTCT-OP) has been studied. The gelable property at acid condition and colon-specific biodegradation of chitosan were used to: (1) produce the osmotic pressure, (2) form the drug suspension and (3) form the in situ delivery pores for colon-specific drug release, respectively. The scanning electron microscopy (SEM) study and the calculation of membrane permeability were applied to elucidate the mechanism of MTCT-OP. The effects of different formulation variables, including the level of pH-regulating excipient (citric acid) and the amount of chitosan in the core, the weight gain of semipermeable membrane and enteric-coating membrane, and the level of pore former (chitosan) in the semipermeable membrane, have been studied. Results of SEM showed that the in situ delivery pores could be formed in predetermined time after coming into contact with dissolution medium, and the number of pore was dependent on the initial level of pore former in the membrane. The amount of budesonide release was directly proportional to the initial level of pore former, but inversely related to the weight of semipermeable membrane. The effects of variations in the level of citric acid and chitosan in the core formulation on drug release were studied. The different levels of enteric-coating membrane could prevent cellulose acetate membrane (containing chitosan as pore former) from forming pore or rupture before contact with simulated colonic fluid, but had no effect on the drug release. Budesonide release from the developed formulation was inversely proportional to the osmotic pressure of the release medium, confirming that osmotic pumping was the major mechanism of drug release. These results showed that MTCT-OP based on osmotic technology and microbially triggered mechanism had a high potential for colon-specific drug delivery.     

In vitro and in vivo evaluation of novel osmotic pump tablets of isosorbide-5-mononitrate containing polyvinyl pyrrolidone (PVP) for controlled release

A novel osmotic pump tablet with ethyl cellulose (EC) and polyvinyl pyrrolidone (PVP) as the semipermeable membrane and isosorbide-5-mononitrate (5-ISMN) as the model drug was formulated in this study. Zero order release kinetics were attained by avoiding aging during storage. Drug release increased with an increase in the percentage of PVP K30 in the semipermeable membrane. However, drug release decreased with increased coating weight. Drug release rates decreased continuously for tablets coated with EC/PEG4000 and cellulose acetate (CA)/PEG4000. This tendency was more marked with longer storage time. However, there was little change in drug release rates for tablets with a semipermeable membrane of EC/PVP K30 at 6, 12 or 24 months. The weight loss test also validated the results mentioned above. The relative bioavailability of the osmotic-pump tablets against the reference formulation in single and multiple dose regimens was 116.7 and 106.5, respectively. This means that the bioavailability of osmotic pump tablets using PVP as the plasticiser was equal to that of the reference formulation. In general, 5-ISMN osmotic pump tablets with a semipermeable membrane composed of EC/PVP K30 may be useful in providing constant drug delivery with minimum fluctuations during longer storage time.     

布地奈德固体分散体增溶型渗透泵片的研制及其释药机制

制备布地奈德固体分散体增溶型单层渗透泵片（以下简称布地奈德渗透泵片）,并进行其释药机制研究。方法：用超临界流体技术制备的布地奈德-聚氧乙烯N750固体分散体作为含药片芯,以提高难溶性药物的溶解度;通过单因素实验优化片芯处方和包衣膜处方,制备布地奈德渗透泵片;设计实验考察包衣膜内外渗透压差对制剂稳态释药速率的影响,阐述其释药机制。结果：药物溶解度、促渗透剂种类和用量、增塑剂用量均对布地奈德渗透泵片的体外释药行为有影响,优化处方的体外释药方程为：Q=7.6077t＋0.7764,r=0.9997;其释药行为主要受包衣膜内外溶液渗透压控制,扩散释药仅占整个药物释放的30.39％。结论：渗透泵机制在布地奈德渗透泵片释药过程中占主导地位,体外释药符合零级动力学过程。     

Factors Affecting the Release of Nifedipine from a Swellable Elementary Osmotic Pump

Oral osmotic devices including an elementary osmotic pump (EOP) are efficient systems for the delivery of drugs with high/moderately water-solublility. In this study we designed a new type of EOP for the efficient delivery of poorly water-soluble and practically insoluble drugs. In this system, called swellable elementary osmotic pump (SEOP), drug is released from the delivery orifice in the form of a very fine dispersion of drug in gel which is ready for dissolution and absorption. Factors affecting the release of drug from the SEOP containing a poorly water-soluble drug, nifedipine, were explored extensively. To this end, effect of swelling and wetting agents, orifice size, concentration of osmotic agent, and hydrophobic plasticizer were investigated. Interestingly, in the absence or low concentration of a hydrophobic plasticizer (caster oil), the osmotic devices did not retain their integrity in dissolution media. Caster oil in concentration of > 1% was necessary for tablets to retain their integrity during dissolution process. A zero-order release kinetics for nifedipine was achieved following the effective optimization of the concentrations of swelling agent, osmotic agent, wetting agent, and also size of orifice and membrane thickness in SEOP. The zero-order release lasted for 10 hr at pH 6.8 dissolution medium. The designed SEOP is suggested as an efficient controlled delivery system for oral delivery of a poorly water soluble drug such as nifedipine.     

Factors affecting the release of nifedipine from a swellable elementary osmotic pump

Oral osmotic devices including an elementary osmotic pump (EOP) are efficient systems for the delivery of drugs with high/moderately water-solubility. In this study we designed a new type of EOP for the efficient delivery of poorly water-soluble and practically insoluble drugs. In this system, called swellable elementary osmotic pump (SEOP), drug is released from the delivery orifice in the form of a very fine dispersion of drug in gel which is ready for dissolution and absorption. Factors affecting the release of drug from the SEOP containing a poorly water-soluble drug, nifedipine, were explored extensively. To this end, effect of swelling and wetting agents, orifice size, concentration of osmotic agent, and hydrophobic plasticizer were investigated. Interestingly, in the absence or low concentration of a hydrophobic plasticizer (caster oil), the osmotic devices did not retain their integrity in dissolution media. Caster oil in concentration of > 1% was necessary for tablets to retain their integrity during dissolution process. A zero-order release kinetics for nifedipine was achieved following the effective optimization of the concentrations of swelling agent, osmotic agent, wetting agent, and also size of orifice and membrane thickness in SEOP. The zero-order release lasted for 10 hr at pH 6.8 dissolution medium. The designed SEOP is suggested as an efficient controlled delivery system for oral delivery of a poorly water soluble drug such as nifedipine.