Effect of variation in compaction force on properties of six direct compression tablet formulations.

The effect of variation in compaction force on six direct compression tablet matrixes was investigated. An instrumented tablet press allowed direct measurement of applied and ejection forces. Hardness, apparent tablet density, and disintegration times also were determined. The disintegration time of spray-dried lactose tablets was essentially independent of compaction force. However, in the other systems investigated, the properties studied showed varying types of dependence on compaction pressure. A direct compression formula was developed and exhibits a decrease in disintegration time as compaction force is increased.     

Food effects on tablet disintegration.

The aims of the present study was to investigate if food components, as represented by a multi-component nutritional drink for tube feeding, could affect tablet disintegration of standard tablets in vitro as well as in vivo and propose a mechanism for potential food effects on tablet disintegration. The tablet disintegration was delayed between 5 min and more than 1h in the simulated gastric fed medium compared to a simple buffer. This effect was dependent on the tablet composition. A similar delay in tablet disintegration was also found in vivo after administration of the nutritional drink to three Labradors as observed by removing the tablet from the stomach at different times through a gastric fistula. The delay in tablet disintegration appeared to be caused by precipitation of a film, mainly consisting of protein, on the tablet surface as indicated by disintegration studies with pure nutrients, identification by IR spectroscopy of contents of precipitates obtained in a model study were the nutrients were incubated with different tablet excipients and visual observations of tablets exposed to the simulated fed medium. The drug dissolution of a soluble compound, metoprolol tartrate, from a standard tablet was also strongly delayed in the simulated fed medium. In conclusion, food, could significantly delay tablet disintegration and drug dissolution in the stomach by formation of a film around the tablets. This effect could be monitored by a simple in vitro disintegration test using a test medium based on a nutritional drink. More studies are needed to investigate the significance of the slow tablet disintegrations on bioavailability and for which types of food the present effect occurs.     

Absorption of acetylsalicylic acid from enteric-coated tablets in relation to gastric emptying and in-vivo disintegration

The absorption of acetylsalicylic (ASA) acid from enteric coated tablets was studied in relation to gastric emptying and in-vivo disintegration. ASA tablets labelled with 51Cr were given to six healthy subjects under fasting and non-fasting conditions. The position and disintegration of the 51Cr-labelled tablets was followed by external radiation measurement and the amount of salicylic acid in blood and urine was analysed. The absorption of ASA from the studied enteric coated tablets was usually correlated with gastric emptying and in-vivo disintegration. However in some cases the absorption can be delayed between 10-20 h even if gastric emptying and disintegration of the tablet have occurred.     

大蒜辣素前体包芯片的制备

目的:制备大蒜辣素前体包芯片,使其口服后在短时间内促发酶促反应,生成大蒜辣素。方法:以蒜氨酸和蒜酶双层片为片芯,控酸颗粒为外层压制得到包芯片。并以人工胃液为介质小杯法考察包芯片大蒜辣素产率。结果:大蒜辣素前体包芯片在人工胃液中10 min内大蒜辣素产率>70%。结论:以蒜氨酸、蒜酶及控酸盐组合制备包芯片能够有效避免蒜酶在胃酸条件下失活,达到在体内获得较高产率大蒜辣素目的。     

胸腺肽α1结肠释放片的制备及其体外释药研究

目的:制备胸腺肽α1结肠释放片(Tα1片),评价其体外释药性能。方法:将Tα1制成片芯,2次包衣,内层为壳聚糖盐酸盐,外层为尤特奇L100-55。高效液相色谱(HPLC)法进行含量及含量均匀度测定,扫描电镜法评价壳聚糖盐酸盐包衣膜在模拟大肠液中的降解作用。以荧光剂FD-4为模型化合物,同法制备模拟结肠片,荧光分光光度法检测其在pH 1.2盐酸溶液,pH 6.8磷酸盐缓冲液及模拟大肠液中的体外释放性能。结果:Tα1片的含量及含量均匀度符合《中国药典》相关规定;电镜扫描结果表明,壳聚糖盐酸盐包衣膜在模拟大肠液中具有显著降解作用;模拟结肠片在pH 1.2盐酸溶液和pH 6.8磷酸盐缓冲液中的累积释药量6 h内小于23％,而在模拟大肠液中4 h基本释药完全。结论:本研究所制备的Tα1结肠释放片具有潜在的结肠靶向释药效果。     

Food-dependent disintegration of immediate release fosamprenavir tablets: In vitro evaluation using magnetic resonance imaging and a dynamic gastrointestinal system

In the present study, we demonstrated the value of two advanced tools, the TNO gastric and small Intestinal Model (TIM-1) and magnetic resonance imaging (MRI), for the in vitro evaluation of food-dependent disintegration of immediate release fosamprenavir tablets. Upon introduction of a tablet with the nutritional drink Scandishake Mix® in the stomach compartment of TIM-1, simulating the fed state, disintegration and fosamprenavir dissolution were significantly postponed compared to the fasted state (lag time 80 ± 23 min). This resulted in a lag in the appearance of bioaccessible fosamprenavir (<5% during the first 2 h), even though the nutritional state did not significantly alter the cumulative bioaccessibility after 5 h. These results were in agreement with the previously observed postprandial delay in gastric fosamprenavir tablet disintegration and subsequent amprenavir absorption in healthy volunteers. Therefore, TIM-1 can be used in tablet development to identify food-induced disintegration issues causing unexpected clinical behavior. From a mechanistic perspective, we applied MRI to illustrate impaired water ingress in fosamprenavir tablets immersed in the nutritional drink compared to simulated gastric fluid. This effect may be attributed to both competition between nutritional components and the tablet for the available water (indicated by reduced rotational and translational diffusion) as well as the possible formation of a food-dependent precipitation layer on the HPMC-coated tablet.     

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.     

烟酸缓释片在体外释放和体内吸收的相关性研究

目的：研究烟酸缓释片在体内外的相关性。方法：通过烟酸缓释片体外释放试验和体内动力学研究，考察其在体内外的相关性。结果：烟酸缓释片在人工胃液及人工肠液中均能缓慢释药，体内血药浓度维持时间长，体外释放百分率与体内吸收分数呈良好相关性。结论：烟酸缓释片在体外释放和体内吸收之间有明显的相关性。     

盐酸吗啡普通片及硫酸吗啡控释片在不同溶剂中溶释过程的对照研究

本文采用紫外分光光度法对国产盐酸吗啡普通片及合资厂产硫酸吗啡控释片于蒸馏水、人工胃液、人工肠液中进行体外溶出度和释放度测定。结果表明，两种片剂的溶释均符合中国药典９５版标准，控释片在人工肠液中溶释参数Ｔ５０、Ｔｄ、ｍ与在蒸馏水及人工胃液中的溶释参数差异具显著性（Ｐ＜０．０１），在人工肠液中的释放过程明显缓慢。     

Effect of magnesium stearate or calcium stearate as additives on dissolution profiles of diltiazem hydrochloride from press-coated tablets with hydroxypropylmethylcellulose acetate succinate in the outer shell

Effect of magnesium stearate (MgSt) or calcium stearate (CaSt) on the dissolution profiles of diltiazem hydrochloride in the core of press-coated (PC) tablets with an outer shell composed of hydroxypropylmethylcellulose acetate succinate (HPMCAS) was evaluated by porosity and changes in IR spectra of tablets. In JP first fluid (pH 1.2), the lag time increased with decreasing porosity and was greatest by the addition of MgSt to HPMCAS. While, in JP second fluid (pH 6.8), it increased with decreasing porosity by the addition of CaSt, but hardly changed by the addition of MgSt. Thus, using tablets prepared with the same composition as the outer shell, the changes in IR spectra and uptake amount of the dissolution media after immersion in first fluid and second fluid were determined. The results suggested that some physicochemical interaction occur between MgSt and HPMCAS in tablets with HPMCAS and MgSt and the uptake increased markedly in each dissolution medium. These phenomena seem to cause a prolongation of lag time in first fluid but a shortening of it in second fluid in PC tablets with HPMCAS and MgSt. In contrast, CaSt and HPMCAS did not show such interactions and increased the hydrophobic properties of the outer shell. Consequently, the lag time was only slightly prolonged in first fluid, however, markedly prolonged in second fluid due to suppression of second fluid penetration into micro pores in the outer shell and HPMCAS gel formation on the surface in PC tablets with HPMCAS and CaSt.     

Drug delivery to the colon using novel one-step, dry-coated tablets (OSDrC)

One-step dry-coated tablets (OSDrC), which are useful as colon-targeting drugs, were prepared using Eudragit L 100-55 (Eud-L) and chitosan (Chit) as an outer layer. The lag time of OSDrC with an outer layer of Eud-L : Chit at a ratio of 3 : 1 in each test medium was greater than the gastric emptying time in the first fluid simulating the stomach and was greater than the small intestine transit time in phosphate buffer (pH 7.4) simulating the small intestine. Drug-release profiles of OSDrC were evaluated under test conditions considering the amount of gastric acid and bile acid, as well as the amount of fluid in the colon. The lag time of OSDrC was greater than the gastric emptying time in test medium simulating the stomach and greater than the small intestine transit time in test medium simulating the small intestine, although it was affected by the amount of gastric acid and bile acid. Drug release from OSDrC was completed within the colonic transit time in the test medium simulating the colon, although it was affected by the amount of fluid in the colon. Therefore the prepared OSDrC were found to permit drug delivery to the colon.     

Evaluation of an enteric coated naproxen tablet using gamma scintigraphy and pH monitoring

Enteric coated naproxen tablets and pH-sensitive radiotelemetry capsules were both radiolabelled and administered to 6 healthy volunteers following breakfast. The median gastric emptying times for the tablets and capsules were 3.3 h and 4.2 h, respectively. In general, the intragastric pH remained below 2 with only transient increases following food consumption. Five of the naproxen tablets disintegrated in the small intestine and one in the stomach. In the ileum the pH was greater than 6 resulting in a mean time for tablet disintegration of 1.2 h after gastric emptying. There was a close correlation between tablet disintegration and the first detection of naproxen in the blood. Peak plasma concentrations of the drug occurred 4 h after tablet disintegration. This study has demonstrated that gastric emptying is the main factor influencing the onset of drug release from enteric coated tablets.     

Prüfung von synthetischen magensaftresistenten und darmsaftlöslichen Überzügen

The dependance of the gastric juice resistance and intestinal juice solubility on the thickness of the coating was investigated on three synthetic varnishes. The varnish was sprayed onto spherical tablets having the same size. The cellulose-acetatephthalate coating must have a minimum thickness of 35 μ, Eudragit varnish 45 μ for a gastric juice resistance of at least 6 hours, allowing it to disintegrate in the intestinal juice within 30 minutes. „Universal varnish”︁ Gebeka protects the tablets in the gastric juice with a coating of 20 μ, but the disintegration time in the intestinal juice varies from 11/2 to 3 hours.     

Preparation and in vitro evaluation of enteric-coated tablets of rosiglitazone sodium

The aim of this study was to prepare the rosiglitazone sodium enteric-coated tablets and investigate its release rate. The rosiglitazone sodium enteric-coated tablet was prepared by single punch tablet press using substituted hydroxypropyl cellulose and polyvinylpyrrolidone (PVP). The release rate from the enteric-coated tablet of rosiglitazone sodium was evaluated. The release rate study showed that few rosiglitazone sodium was released from enteric coated formulation within 2 h in simulated gastric juice, while it released more than 80% of the labeled amount in 30 min in simulated intestinal juice. The preparing method of rosiglitazone sodium enteric-coated tablets was simple and had a good reproducibility. The release condition and determined methods could be used for the routine determinations of rosiglitazone sodium enteric-coated tablets.     

Roller compaction and tabletting of St. John's wort plant dry extract using a gap width and force controlled roller compactor. II. Study of roller compaction variables on granule and tablet properties by a 3(3) factorial design

The purpose of this study was to investigate the influence of roller compaction parameters and the amount of magnesium stearate used in dry granulation on granule and tablet properties of a dry herbal extract from St. John's wort (Hypericum perforatum L.). Two different extract batches were blended with magnesium stearate and compacted using a gap width and force controlled roller compactor. A 3(3) factorial design was used to evaluate the influence of the three independent variables, the amount of magnesium stearate, the roller compaction force, and the granulating sieve size on the mean particle size of granulated extracts and on the disintegration time of tablets containing these granulated extracts. The evaluation was done by multilinear stepwise regression analysis. The mean particle size d50 (R2 > 0.9) of both compacted extracts increased with increasing compaction force and with granulating sieve size. The disintegration time of the tablets was mostly in the range 5-15 min and increased slightly with increasing magnesium stearate concentration in the compacted extract and with decreasing compaction force of the roller compaction. The incorporation of magnesium stearate into the granulated extract reduced its potential negative influence on the disintegration time, while maintaining its functionality as a lubricant.     

蛇床子素及其β-环糊精包合物在不同溶出介质中的溶出速率研究

目的:考察蛇床子素及其β-环糊精包合物在不同溶出介质中的溶出行为.方法:用紫外分光光度法测定蛇床子素和包合物分别在人工胃液、人工肠液、15%乙醇、30%乙醇、0.2%十二烷基硫酸钠的人工胃液、0.5%十二烷基硫酸钠的人工胃液中的溶出速率.结果:蛇床子素和包合物在人工胃液、人工肠液中溶出太少,不能满足测定条件,在0.5%十二烷基硫酸钠的人工胃液中,溶出很快,不能完全区分二者的溶出度差异,用含0.2%十二烷基硫酸钠的人工胃液作溶出介质,效果较好.结论:介质对蛇床子素及包合物的溶出有很大影响,但在所有溶出介质中包合物的溶出速率均快于蛇床子素,且具有显著性差异(P＜0.05).     

Effect of Anions on Adsorption of Bile Salts by Colestipol Hydrochloride

The Langmuir affinity constant and adsorptive capacity for the adsorption of citrate anion or cholate anion by colestipol hydrochloride at pH 7.5, 37°C, were similar. Prior exposure of colestipol hydrochloride to citrate anion caused the adsorption of cholate anion to decrease slightly in comparison to a control utilizing only cholate anion. The concentration of citrate anion was found to be directly related to the decrease in cholate anion adsorption. Simultaneous exposure of colestipol hydrochloride to citrate and cholate anions at pH 7.5, 37°C, resulted in the same adsorption of cholate anion as sequential exposure to citrate anion followed by cholate anion. Sequential exposure of colestipol hydrochloride to simulated gastric fluid and simulated intestinal fluid containing cholate anion resulted in a small decrease in cholate adsorption which was attributed to competition with phosphate anion in simulated intestinal fluid. Pepsin in the simulated gastric fluid did not affect adsorption of cholate anion from simulated intestinal fluid. Preexposure to components of tomato juice and orange juice also slightly reduced the adsorption of cholate anion by colestipol hydrochloride.     

盐酸黄连素微囊溶出度的研究

本文报道采用微囊技术掩盖黄连素的苦味，通过对溶出度的研究表明，该品在人工胃液、肠液中的溶出度与片剂无显著差异，对治疗作用亦无影响，解决了儿童服药不便的难题。     

丹酚酸B脂化乳的制备及其稳定性研究

目的制备丹酚酸B脂化乳,并考察其在人工胃肠液中的稳定性。方法制备丹酚酸B脂化乳粒、脂化乳。采用紫外分光光度法测定并比较脂化乳粒、脂化乳中丹酚酸B在人工胃液和人工肠液中的变化。结果不同制剂中丹酚酸B在人工胃液中的量均有所降低,但脂化乳和脂化乳粒均较水溶液中丹酚酸B的量高,3 h后丹酚酸B水溶液中药物的量分别较脂化乳、脂化乳粒少19.3%、6.4%。不同制剂中丹酚酸B在人工肠液中的量均有所降低,但脂化乳、脂化乳粒均较水溶液中丹酚酸B的量高,6 h后丹酚酸B水溶液中药物的量分别较脂化乳、脂化乳粒少32.7%、5.3%。结论丹酚酸B脂化乳、脂化乳粒均能提高人工胃、肠液中所包载药物的稳定性;且脂化乳效果优于脂化乳粒。     

Colonic release and reduced intestinal tissue damage of coated tablets containing naproxen inclusion complex

A colonic-release delivery system containing naproxen inclusion complex with 2-hydroxypropyl-β-cyclodextrin (2-HPβCD) was originally proposed. The core tablets consisting of the naproxen inclusion complex and disintegrants (Ac-Di-Sol^®, Primojel^®, Avicel^® or Polyplasdone^®) were formed by direct compression, and then coated with the polymers, either pH-dependent Eudragit^® S100 and/or pH-independent Eudragit^® RS100 with plasticizers like dibutyl sebacate (DBS) and aluminum tristearate (AT). The in vitro release characteristics were evaluated in simulated gastric fluid for 2 h and then subsequently in simulated intestinal fluid for 12 h. The potential histological changes were also evaluated after direct dosing of suspensions of naproxen alone and powdered mixtures of inclusion complex-loaded tablet into rat intestinal segments. No distinct colonic release was observed when disintegrants were excluded in the single-layered coated tablets regardless of coated structures, giving a zero-order fashion over 12 h. The coated tablet with double-layered structures of Eudragit^® S100 and Eudragit^® RS100 was not also applicable. In contrast, colonic release was achieved when the core tablet containing inclusion complex and disintegrant was coated with only Eudragit^® S100 in a single-layered structure. The colonic-release tablet was resistant in gastric fluid for 2 h and for 2–4 h in intestinal fluid, followed by rapid release of the drug after a total of 4–6 h of lag time depending on the type of disintegrants. The lag time was advanced in case of DBS while delayed in case of AT. On histological examination, the inclusion complex-loaded suspension caused less intestinal tissue damage than naproxen alone. Based on these findings, the colonic-release tablet with enteric coatings which contains inclusion complex and disintegrants could be useful to deliver drugs like naproxen to the lower small intestine and upper colon with increased dissolution and reduced intestinal tissue damage.