多索茶碱脉冲控释微丸的研制

目的 研究多索茶碱脉冲控释微丸的制备工艺,并考察其释药性能。方法 以微晶纤维素为骨架材料采用挤出滚圆法制备载药丸芯,通过流化床包衣法分别覆上交联羧甲基纤维素钠作为溶胀层、乙基纤维素和羟丙甲纤维素作为控释层制备多索茶碱脉冲微丸,通过单因素考察筛选丸芯、溶胀层、控释层的处方组成对体外释药性能的影响。结果 以微晶纤维素、羧甲基淀粉钠和乳糖为添加剂可制得性能良好的高载药微丸。随着溶胀层厚度的增加,药物释放时滞变短,速率显著增加;随着控释层包衣厚度的增加,时滞延长,释药减慢;控释层中羟丙甲纤维素用量或分子量增加,时滞缩短;控释层中增塑剂用量增加,时滞延长。结论 所得包衣微丸具有良好的脉冲释药性能,有广阔的应用前景。     

Development of pulsatile multiparticulate drug delivery system coated with aqueous dispersion Aquacoat ECD

The objective of this study was to develop and evaluate a pulsatile multiparticulate drug delivery system (DDS), coated with aqueous dispersion Aquacoat ECD. A rupturable pulsatile drug delivery system consists of (i) a drug core; (ii) a swelling layer, comprising a superdisintegrant and a binder; and (iii) an insoluble, water-permeable polymeric coating. Upon water ingress, the swellable layer expands, resulting in the rupturing of outer membrane with subsequent rapid drug release. Regarding the cores, the lag time was shorter, when 10% (w/w) theophylline was layered on sugar cores compared with cores consisting of 100% theophylline. Regarding swelling layer, the release after lag time was fast and complete, when cross-linked carboxymethyl cellulose (AcDiSol) was used as a swelling agent. In contrast, a sustained release was achieved after the lag time, when low-substituted hydroxypropyl cellulose (L-HPC) and sodium starch glycolate (Explotab) were used as swelling agents. The optimal level of AcDiSol to achieve a fast and complete release after the lag time was 26% (w/w) (based on the weight of the coated pellets) for poorly soluble theophylline and 48% (w/w) for highly soluble propranolol HCl. The lag time can be controlled by the coating level of an outer membrane and increased with increasing coating level of the outer membrane. Outer membrane, formed using aqueous dispersion Aquacoat ECD was brittle and ruptured sufficiently to ensure fast drug release, compared to ethylcellulose membrane formed using organic solution. The addition of talc led to increase brittleness of membrane and was very advantageous because of (i) reduced sensitivity of lag time on variations in the coating level and (ii) fast and complete drug release. Drug release starts only after rupturing of outer membrane, which was illustrated by microscopical observation of pellet during release.     

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。     

尼莫地平柱塞型脉冲释药胶囊的制备

目的:制备尼莫地平柱塞型脉冲释药胶囊。方法:采用灌注法制备非渗透性囊体,以HPMC K15M为缓释骨架材料制备柱塞片,以PEG 6000和PEG 4000为基质制备尼莫地平滴丸,用柱塞片将滴丸密封于非渗透性囊体内制备尼莫地平柱塞型脉冲释药胶囊。结果:溶剂为丙酮/二氯甲烷/乙酸乙酯(2:0.7:0.3),醋酸纤维素溶液浓度为10.5%,柱塞片缓释骨架材料HPMC K15M和乳糖比例为1:10,制得的尼莫地平柱塞型脉冲释药胶囊体外呈明显的脉冲释放,释药时滞为4~5 h。结论:通过调节柱塞片中HPMC K15M和乳糖比例可调节脉冲胶囊的释药时滞,将尼莫地平制成滴丸可满足脉冲胶囊时滞后快速释药的要求。     

5-氨基水杨酸结肠定位给药时控微丸的制备与体外释放

目的　用水分散体包衣技术制备5-氨基水杨酸结肠定位微丸给药系统。方法　以低粘度HPMC为内层溶胀材料,乙基纤维素水分散体Aquacoat为外层控释包衣材料,柠檬酸三乙酯为增塑剂,使用流化床包衣设备,制备时间控制的微丸,用释放度测定法研究微丸在不同pH介质中的释放度。结果　溶胀层的加入对制备时控微丸是必要的,药物是通过外膜破裂释放的,溶胀层厚度增加,释药时滞有一定程度的缩短,外层厚度增加以及增塑剂用量增加,可显著延长释药时滞。微丸释药随介质pH增加而加快,在模拟胃肠道pH情况下延迟5 h释药,之后10 h内释药完全。结论　通过调整内外层的包衣厚度可制备5-氨基水杨酸结肠定位给药微丸。     

Modulation of a pulsatile release drug delivery system using different swellable/rupturable materials

Diclofenac sodium tablets consisting of core coated with two layers of swelling and rupturable coatings were prepared and evaluated as a pulsatile drug delivery system. Cores containing the drug were prepared by direct compression using microcrystalline cellulose and Ludipress as hydrophilic excipients with the ratio of 1:1. Cores were then coated sequentially with an inner swelling layer of different swellable materials; either Explotab, Croscarmellose sodium, or Starch RX 1500, and an outer rupturable layer of different levels of ethylcellulose. The effect of the nature of the swelling layer and the level of the rupturable coating on the lag time and the water uptake were investigated. Drug release rate studies were performed using USP paddle method. Results showed the dependence of the lag time and water uptake prior to tablet rupture on the nature of the swelling layer and the coating levels. Explotab showed a significant decrease in the lag time, followed by Croscarmellose sodium and finally by Starch RX 1500. Increasing the level of ethylcellulose coating retarded the diffusion of the release medium to the swelling layer and the rupture of the coat, thus prolonging the lag time.     

A novel system for three-pulse drug release based on "tablets in capsule" device

The objective of the present study was to obtain programmed drug delivery from a novel system, which contains a water-soluble cap, impermeable capsule body, and two multi-layered tablets. Types of materials for the modulating barrier and its weight can significantly affect the lag time (defined as the time when drug released 8% of the single pulse dosage). We chose sodium alginate and hydroxy-propyl methyl cellulose (HPMC E5) as the candidate modulating barrier material. Through adjusting ratio of sodium alginate and lactose, lag time was controllable between the first two pulsatile release. Linear relationship was observed between the ratio and the lag time. Through adjusting the ratio of HPMC E5/lactose, lag time between the second and the third pulse can be successfully modulated. In further studies, drug release rate of the second pulsatile dose can be improved by adding a separating layer between the third and the modulating barrier layer in the three-layered tablet. To evaluate contribution of bulking agent to drug release rate, lactose, sodium chloride, and effervescent blend were investigated. No superiority was found using sodium chloride and effervescent blend. However, lactose favored it. The results reveal that programmed drug delivery to achieve pulsatile drug release for three times daily can be obtained from these tablets in capsule system by systemic formulation approach.     

Different HPMC viscosity grades as coating agents for an oral time and/or site-controlled delivery system: an investigation into the mechanisms governing drug release

When used as release-controlling coating agents for tableted core-based pulsatile delivery systems, three different hydroxypropyl methylcellulose (HPMC) grades, Methocel E5, E50, and K4M, provided lag phases of varying duration (Methocel K4M > E50 > E5) and a prompt and quantitative model drug release. Dissolution/mechanical erosion, permeability increase and disruption of the hydrated polymeric layer were assumed to participate in the definition of the overall release pattern. Based on these premises, we investigated what process(es) might prevail in the release-controlling mechanism for each HPMC grade. The polymers were evaluated for dissolution and swelling, while the finished systems were concomitantly evaluated for drug release and polymer dissolution. The obtained results indicated likely similarities between Methocel E5 and E50 performances, which we hypothesized to be mainly dissolution/erosion-controlled, and a clearly different behavior for Methocel K4M. This polymer indeed proved to yield higher viscosity and slower dissolving gel layer, which was able to withstand extensive dissolution/erosion for periods that exceeded the observed lag phases. The particular characteristics of swollen Methocel K4M were shown to be associated with possible drug diffusion phenomena, which might impair the prompt and quantitative release phase that is typical of pulsatile delivery.     

pH-independent pulsatile drug delivery system based on hard gelatin capsules and coated with aqueous dispersion Aquacoat ECD.

The objective of this study was to develop a rupturable, capsule-based pulsatile drug delivery system with pH-independent properties prepared using aqueous coating. The drug release is induced by rupturing of the top-coating, resulting by expanding of swellable layer upon water penetration through the top-coating. Croscarmellose sodium (AcDiSol) is a preferable superdisintegrant compared to low substituted hydroxypropylcellulose (L-HPC) and sodium starch glycolate (Explotab), because of controlled lag time, followed by a quick and complete drug release. However, due to its anionic character, AcDiSol showed pH-dependent swelling characteristics (pH 7.4 > 0.1N HCl) resulting in a pH-dependent lag time. The pH dependency could be eliminated by the addition of fumaric acid to the swelling layer, which allowed to keep an acidic micro-environment. Formation of the rupturable top-coating was successfully performed using an aqueous dispersion of ethylcellulose (Aquacoat) ECD), whereby sufficient drying during the coating was needed to avoid swelling of the AcDiSol layer. A higher coating level was required, when aqueous dispersion was used, compared to organic coatings. However, an advantageous aspect of the aqueous coating was the lower sensitivity of the lag time to a deviation in the coating level.     

Design and evaluation of a dry coated drug delivery system with an impermeable cup, swellable top layer and pulsatile release

In this investigation a novel oral pulsatile drug delivery system based on a core-in-cup dry coated tablet, where the core tablet surrounded on the bottom and circumference wall with inactive material, is proposed. The system consists of three different parts, a core tablet, containing the active ingredient, an impermeable outer shell and a top cover layer-barrier of a soluble polymer. The core contained either diclofenac sodium or ketoprofen as model drugs. The impermeable coating cup consisted of cellulose acetate propionate and the top cover layer of hydrophilic swellable materials, such as polyethylene oxide, sodium alginate or sodium carboxymethyl cellulose. The effect of the core, the polymer characteristics and quantity at the top cover layer, on the lag time and drug release was investigated. The results show that the system release of the drug after a certain lag time generally due to the erosion of the top cover layer. The quantity of the material, its characteristics (viscosity, swelling, gel layer thickness) and the drug solubility was found to modify lag time and drug release. The lag time increased when the quantity of top layer increased, whereas drug release decreased. The use of sodium carboxymethyl cellulose resulted in the greatest swelling, gel thickness and lag time, but the lowest drug release from the system. Polyethylene oxide showed an intermediate behaviour while, the sodium alginate exhibited the smallest swelling, gel thickness and the shortest lag time, but the fastest release. These findings suggest that drug delivery can be controlled by manipulation of these formulations.     

Pulsatile systems for colon targeting of budesonide: in vitro and in vivo evaluation

The purpose of this study is to increase the lag time and prevent release of budesonide, a corticosteroid drug used in Crohn's disease for the first 5?h and efficiently deliver it to the colon. Eudragit S100 spray-coated capsules and pulsatile systems using tablet plugs of cellulose acetate butyrate (CAB), HPMC K4M, guar gum, and pectin were prepared. Eudragit S100-coated capsules released 80.62% after 5 h. In pulsatile systems, decreasing the ratio of the polymer significantly increased the rate and extent of drug release. Spray-coating with EUD S100 decreased the extent of drug release to 48.41%, 69.94%, 80.58%, and 45.23% in CAB, HPMC K4M, pectin, and guar gum, respectively; however, the entire amount was released in the target area. In the presence of bacterial enzymes, selected formulas showed nearly 100% release. X-ray imaging performed to monitor the capsules throughout the GIT in human volunteers of the capsules and spray-coated pulsatile systems with 25% guar gum in the plug showed bursting in the transverse and ascending colon, respectively. Both formulations showed marked reduction in induced rabbit colitis model.     

Pulsatile systems for colon targeting of budesonide: In vitro and in vivo evaluation

The purpose of this study is to increase the lag time and prevent release of budesonide, a corticosteroid drug used in Crohn’s disease for the first 5?h and efficiently deliver it to the colon. Eudragit S100 spray-coated capsules and pulsatile systems using tablet plugs of cellulose acetate butyrate (CAB), HPMC K4M, guar gum, and pectin were prepared. Eudragit S100-coated capsules released 80.62% after 5?h. In pulsatile systems, decreasing the ratio of the polymer significantly increased the rate and extent of drug release. Spray-coating with EUD S100 decreased the extent of drug release to 48.41%, 69.94%, 80.58%, and 45.23% in CAB, HPMC K4M, pectin, and guar gum, respectively; however, the entire amount was released in the target area. In the presence of bacterial enzymes, selected formulas showed nearly 100% release. X-ray imaging performed to monitor the capsules throughout the GIT in human volunteers of the capsules and spray-coated pulsatile systems with 25% guar gum in the plug showed bursting in the transverse and ascending colon, respectively. Both formulations showed marked reduction in induced rabbit colitis model.     

Modified release from hydroxypropyl methylcellulose compression-coated tablets

The goal of this study was to obtain flexible extended drug release profiles (e.g., sigmoidal, pulsatile, increasing/decreasing release rates with time) with hydroxypropyl methylcellulose (HPMC) compression-coated tablets. Drugs of varying solubility (carbamazepine, acetaminophen, propranolol HCl and chlorpheniramine maleate) were incorporated into the tablet core in order to evaluate the flexibility/limitations of the compression-coated system. The HPMC-compression-coating resulted in release profiles with a distinct lag time followed by different release phases primarily determined by the drug solubility. Carbamazepine, a water-insoluble drug, was released in a pulsatile fashion after a lag time only after erosion of the HPMC compression-coat, while the more soluble drugs were released in a sigmoidal fashion by diffusion through the gel prior to erosion. With carbamazepine, increasing the molecular weight of HPMC significantly increased the lag time because of the erosion-based release mechanism, while, in contrast, molecular weight did not affect the release of the more soluble drugs. The lag-time and the release rate could also be well controlled by varying the HPMC amount in and the thickness of the compression-coating. A pulsatile release could also be achieved for water-soluble drugs by introducing an enteric polymer coating between the drug core and the HPMC compression-coating. This novel concept of introducing an enteric subcoating eliminated drug diffusion through the gelled HPMC layer prior to its erosion. Incorporating drug in the compression-coating in addition to the tablet core in varying ratios resulted in release profiles with increasing, decreasing or constant release rates. In conclusion, a versatile single-unit delivery system for a wide range of drugs with great flexibility in release profiles was presented.     

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     

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。     

伊贝沙坦脉冲微丸的制备方法

目的：考察伊贝沙坦脉冲控释微丸的制备工艺。方法：采用流化床工艺,将伊贝沙坦原料黏附在空白丸芯上,制成含药微丸;以低取代羟丙基纤维素为包溶胀层材料,乙基纤维素水分散体为包控释层材料,采用同样的工艺包溶胀层和控释层,并通过正交试验优选最佳工艺条件。按最佳包衣工艺操作,以低取代羟丙基纤维素、吐温-80、乙基纤维素水分散体和葵二酸二丁酯为包衣材料,以释药时滞及时滞后的突释药量为指标,优选最佳处方。结果：最佳工艺条件为：上药、包溶胀层、包控释层工艺中使用的风量分别为20、30、40 m3.h-1;进风温度分别为45、50、50℃;喷雾压力均为0.2 MPa;喷液速度分别为8、9、9.gs-1。4种包衣材料在微丸中所占的最佳质量百分比分别为25%、1%、25%和0.5%,制得的脉冲控释微丸的平均时滞约为7小时,时滞后2小时突释量均大于70%。结论：在该工艺条件下制备的伊贝沙坦脉冲控释微丸的体外释放能够达到脉冲控释效果,制备工艺简单、可控。     

Effect of Fill Weight,Capsule Shell,and Sinker Design on the Dissolution Behavior of Capsule Formulations of a Weak Acid Drug Candidate BMS‐309403

Two strengths of BMS‐309403 capsules were developed from a common stock granulation. Dissolution testing of the capsules was conducted utilizing the USP apparatus 2 (paddle) with a neutral pH dissolution medium. Unexpectedly, the lower‐strength capsules exhibited slower dissolution than the higher‐strength capsules filled with the same stock granulation. Higher variability was also observed for the lower‐strength capsules. This was found to be mainly caused by a low fill weight in a relatively large size hard gelatin capsule shell. Instead of bursting open, some gelatin capsule shells softened and collapsed onto the granulation, which delayed the release of the active drug. The problem was aggravated by the use of coil sinkers which hindered the medium flow around the capsules. Switching from the gelatin capsule shells to the HPMC (hydroxypropyl methylcellulose) shells reversed the dissolution rate ranking between the two capsule strengths. However, both dissolved at a slower rate initially than the gelatin capsules due to the inherent dissolution rate of the HPMC shells at pH 6.8. Notably, the HPMC shells did not occlude the granulation as observed with the gelatin shells. The study demonstrated that the dissolution of capsule formulations in neutral pH media was significantly affected by the fill weight, sinker design, and capsule shell type. Careful selection of these parameters is essential to objectively evaluate the in vitro drug release.     

Release behavior and photo-image of nifedipine tablet coated with high viscosity grade hydroxypropylmethylcellulose: effect of coating conditions

An orally applicable nifedipine-loaded core tablets was coated using high viscosity grade HPMC (100,000 cps) in ethanol/water cosolvent. The release of coated tablet was evaluated using USP paddle method in 900 ml of simulated gastric fluid (pH 1.2) for 2 h followed by intestinal fluid (pH 6.8) for 10 h. The surface morphologies using scanning electron microscope and photo-images using digital camera of coated tablet during the release test were also visualized, respectively. The viscosity of hydro-alcoholic HPMC solution largely decreased as the amount of ethanol increased. There was no significant difference in viscosity among plasticizers used. The distinct and continuous coated layer was observed using scanning electron microscope. However, the surface morphologies were highly dependent on HPMC concentration and ratio of coating solvents. The higher ratio of ethanol/water gave a longer lag time prior to drug release. Lag time also increased as a function of the coating levels based on weight gains due to increased thickness of coated layer. Lag time is inversely correlated with HPMC concentration in ethanol/water (5:1) cosolvent. As the HPMC concentration slightly decreased from 3.8 to 3.2% in hydroalcoholic coating solution, a large increase of lag time was observed. As the swelling (mixing) time of high viscosity grade HPMC in ethanol/water cosolvent increased from 1 to 5 h, the release rate was decreased due to enough plasticization of polymer. Based on photo-imaging analysis, the coated tablet was initially swelled and gelled without erosion and disintegration over 5 h. The disintegration of the coated tablet was occurred approximately 7 h after dissolution, resulting in pulsed release of drug. The high viscosity grade HPMC can be applicable for polymeric coating after careful selection of solvent systems. The release behavior and lag time could be controlled by coating conditions such as HPMC concentration, ethanol/water ratio as a coating solvent, coating level and swelling (mixing) time of coating solution. The current time-controlled release tablet coated with high viscosity grade HPMC with a designated lag time followed by a rapid release may provide an alternative to site specific or colonic delivery of drugs. In addition, the release behavior can be matched with body's circadian rhythm pattern in chronotherapy.     

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。     

Effect of fill weight, capsule shell, and sinker design on the dissolution behavior of capsule formulations of a weak acid drug candidate BMS-309403

Two strengths of BMS-309403 capsules were developed from a common stock granulation. Dissolution testing of the capsules was conducted utilizing the USP apparatus 2 (paddle) with a neutral pH dissolution medium. Unexpectedly, the lower-strength capsules exhibited slower dissolution than the higher-strength capsules filled with the same stock granulation. Higher variability was also observed for the lower-strength capsules. This was found to be mainly caused by a low fill weight in a relatively large size hard gelatin capsule shell. Instead of bursting open, some gelatin capsule shells softened and collapsed onto the granulation, which delayed the release of the active drug. The problem was aggravated by the use of coil sinkers which hindered the medium flow around the capsules. Switching from the gelatin capsule shells to the HPMC (hydroxypropyl methylcellulose) shells reversed the dissolution rate ranking between the two capsule strengths. However, both dissolved at a slower rate initially than the gelatin capsules due to the inherent dissolution rate of the HPMC shells at pH 6.8. Notably, the HPMC shells did not occlude the granulation as observed with the gelatin shells. The study demonstrated that the dissolution of capsule formulations in neutral pH media was significantly affected by the fill weight, sinker design, and capsule shell type. Careful selection of these parameters is essential to objectively evaluate the in vitro drug release.