Oral Presentations (LDD, LPES, LNM, LPAT, LNT, LPPT, LPM)

Probiotic microorganisms have been shown to provide specific health benefits when consumed as food supplements or as food components. The main problem of such products is the poor survival of the probiotic bacteria in the low pH of gastric fluid. However the use of synthetic excipients for enteric coating to prevent the exposure of microorganisms to gastric fluid is limited in food supplementary industry. Therefore the aim of this study was to develop an enteric coating formulation containing shellac as a natural polymer. Shellac possesses good resistance to gastric juice; the major disadvantage of this polymer is its low solubility in the intestinal fluid [1, 2]. Thus films containing different ratios of shellac and water-soluble polymers (sodium alginate, hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidon (PVP)) or plasticizers (glycerol and glyceryl triacetate (GTA)) were prepared in order to analyse the films’ melting temperatures (T_m), the changes in enthalpy (ΔH), their capability of taking up water, and their solubility in different media. The release characteristics of the films were studied by loading pellets with Enterococcus faecium M74 and coating them with formulations containing different amounts of shellac and polymer or plasticized shellac. Using dissolution tests, performed according to USP XXXI paddle method, the resistance of the coatings to simulated gastric fluid (SGF, pH 1.2) and the release of cells in simulated intestinal fluid (SIF, pH 6.8) was investigated.The trials showed that an increasing amount of plasticizer results in a decrease of T_m and ΔH of the films whereat glycerol had a superior plasticization effect to GTA. The compatibility of films made of water-soluble polymers and shellac was also concentration dependent. HPMC and PVP showed superior compatibility with shellac compared to sodium alginate, since films containing shellac and more than 10% [w/w] sodium alginate tended to separate into two phases. In the end five formulations containing shellac and either 5% [w/w] glycerol, 10% [w/w] PVP, 20% [w/w] PVP, 10% [w/w] HPMC, or 5% [w/w] sodium alginate emerged as feasible for enteric coating purposes.     

Development and characterization of chitosan succinate microspheres for the improved oral bioavailability of insulin

The present study describes the fabrication of insulin loaded chitosan succinate microspheres to improve the efficacy of orally administered insulin. Chitosan succinate polymer was synthesized and its microspheres were prepared by emulsion phase separation technique. The microspheres were characterized by FT-IR spectroscopy, scanning electron microscopy, particle size, X-ray diffraction, and swelling index. Insulin was loaded into the microspheres by passive absorption technique. The ability of microspheres to protect insulin from gastric enzymatic degradation was investigated. Stability of insulin in the microspheres was determined by gel electrophoresis and circular dichroism (CD). In vitro release studies were performed under simulated gastric and intestinal pH conditions (pH 2.0 and pH 7.4). The pharmacokinetic parameters were monitored after oral administration of insulin loaded chitosan succinate microspheres, chitosan succinate-insulin solution, as well as after subcutaneous injection of insulin to diabetic rats. The degree of succinate substitution in the synthesized polymer was 16%. The prepared microspheres were spherical with an average diameter of 49 +/- 2 microm. The insulin-loading capacity was 62%. Chitosan succinate microspheres were found to protect the degradation of insulin from gastric enzymes. The encapsulated insulin was quickly released in simulated intestinal fluid (SIF, pH 7.4), whereas a small fraction of insulin was released in simulated gastric fluid (pH 2.0). The relative pharmacological efficacy for chitosan succinate microspheres (16 +/- 4%) was almost fourfold higher than the efficacy of the chitosan succinate-insulin solution administration (4 +/- 1.5%). The results suggest that chitosan succinate microspheres could be used as a potential carrier for oral insulin delivery.     

Development and in-vivo evaluation of insulin-loaded chitosan phthalate microspheres for oral delivery

Novel chitosan phthalate microspheres containing insulin were prepared by emulsion cross-linking technique. The feasibility of these microspheres as oral insulin delivery carriers was evaluated. The pH-responsive release behaviour of insulin from microspheres was analysed. The ability of chitosan phthalate-insulin microspheres to enhance intestinal absorption and improve the relative pharmacological availability of insulin was investigated by monitoring the plasma glucose and insulin level of streptozotocin-induced diabetic rats after oral administration of microspheres at insulin dose of 20 IU kg(-1). In simulated gastric fluid (pH 2.0), insulin release from the microspheres was very slow. However, as the pH of the medium was changed to simulated intestinal fluid (pH 7.4), a rapid release of insulin occurred. The relative pharmacological efficacy for chitosan phthalate microspheres (18.66 +/- 3.84%) was almost four-fold higher than the efficacy of the chitosan phthalate-insulin solution administration (4.08 +/- 1.52%). Chitosan phthalate microspheres sustained the plasma glucose at pre-diabetic level for at least 16 h. These findings suggest that the microsphere is a promising carrier as oral insulin delivery system.     

Enhanced absorption of insulin and (Asu(1,7))eel-calcitonin using novel azopolymer-coated pellets for colon-specific drug delivery

The objective of this study was to estimate colon-specific delivery of insulin and (Asu(1,7))eel-calcitonin using novel azopolymer-coated pellets. In vitro drug-release experiments from the azopolymer-coated pellets containing fluorescein isothiocyanate dextran (MW 4400; FD-4) were carried out by the Japanese Pharmacopoeia (J.P.) XIII rotating basket method with some slight modifications. Little release of FD-4 from the pellets was observed in phosphate buffered saline. However, the release of FD-4 was markedly increased in the presence of rat cecal contents. The intestinal absorption of insulin and (Asu(1,7))eel-calcitonin after oral administration of the azopolymer-coated pellets containing these peptides with camostat mesilate was evaluated by measuring the hypoglycemic and hypocalcemic effects, respectively. A slight decrease in plasma glucose levels was observed following the oral administration of these pellets containing 12.5 IU of insulin compared with the same dose of insulin solution. Camostat mesilate, a protease inhibitor that is incorporated with insulin in these pellets, further decreased the plasma glucose levels in a dose-dependent manner. Similar results were also obtained with the oral administration of pellets containing (Asu(1,7))eel-calcitonin. These findings suggest that azopolymer-coated pellets may be useful carriers for the colon-specific delivery of peptides including insulin and (Asu(1,7))eel-calcitonin.     

Proteolytic enzymes as a limitation for pulmonary absorption of insulin: in vitro and in vivo investigations

In vitro biodegradation of insulin in lung cytosol and subcellular pellets of normal and diabetic rats was investigated. Rat lung was homogenized and subcellular fractions were isolated by ultracentrifugation. Degradations of [125I]-insulin after incubation with lung cytosol or subcellular pellets was determined using the trichloroacetic acid method. The results show that insulin is highly degraded in cytosol and subcellular pellets. Cytosolic insulin degradation was strongly inhibited by bacitracin or sodium cholate. The degradation of insulin in the lung cytosol from diabetic rats was significantly less than from normal rat. The lung protease activity reached a maximum at pH 7.4. Enzyme inhibitors like bacitracin and sodium cholate noticeably enhanced the relative pharmacological bioavailability of insulin when given intratracheally with insulin to normal rats. Acidic insulin solutions (pH 3.0) had more pronounced hypoglycaemic effects than neutrol solution (pH 7.0). These in vitro and in vivo results suggest that the proteolytic enzymes in the lung limit pulmonary delivery of insulin. The coadministration of protease inhibitors would be a useful approach for improving the pulmonary absorption of insulin.     

Effects of Various Protease Inhibitors on the Intestinal Absorption and Degradation of Insulin in Rats

The effects of protease inhibitors on the intestinal absorption of insulin were investigated in situ in closed small and large intestinal loops in rats, and the stability of insulin was examined in homoge-nates of the small and large intestine. The intestinal absorption of insulin was evaluated by its hypoglycemic effect. When insulin alone was administered into small or large intestinal loops, no marked hypoglycemic response was observed in either region. Of the coadministered protease inhibitors, soybean trypsin inhibitor (1.5, 10 mg/ml) marginally promoted insulin absorption from the large intestine, whereas aprotinin (10 mg/ml) did to a moderate degree. However, a significant hypoglycemic effect was obtained following large intestinal administration of insulin with 20 mM of Na-glycocholate, camostat mesilate and bacitracin, when compared with the controls. In contrast, we found little hypoglycemic effect following small intestinal coadministration of insulin with these protease inhibitors. In the stability experiment, bacitracin, camostat mesilate and Na-glycocholate were effective in reducing insulin degradation in both small and large intestinal homogenates. It was found that the reduction in the proteolytic rate of insulin was related to the decrease in plasma glucose concentration by these protease inhibitors in the large intestine. These findings suggest that coadministration of protease inhibitors would be useful for improving the large intestinal absorption of insulin.     

Interactions between ciprofloxacin and antacids--dissolution and adsorption studies

Ciprofloxacin is a fluorinated quinolone antibacterial agent extensively used against both Gram-positive and Gram-negative microorganisms. In certain polytherapy programs, ciprofloxacin can be administered with some antacids that could modify its dissolution rate and reduce its absorption leading to therapeutic failure. The aim of this study was to evaluate the influence of some antacids on the availability of ciprofloxacin. The release of ciprofloxacin from tablets in the presence of antacids, such as sodium bicarbonate, calcium hydroxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, magnesium trisilicate and magaldrate was studied on BP 2002 dissolution test apparatus. These studies were carried out in simulated gastric and intestinal juices for 3 hours at 37 degrees C. The results confirmed that the dissolution rate of tablets was markedly retarded in the presence of all the antacids studied. Magaldrate and calcium carbonate in simulated gastric juice exhibited relatively higher adsorption capacities, as did magnesium trisilicate and calcium hydroxide in simulated intestinal juice.     

Pharmacokinetic study of niosome-loaded insulin in diabetic rats

Background and the purpose of the study

Encapsulation of human insulin in lipid vesicular systems such as niosomes was sought as a route to protect this protein against proteolytic enzymes and to improve its oral bioavailability. The purpose of this study was to assess the effect of insulin encapsulation in niosomes on oral bioavailability in diabetic rats.

Methods

Recombinant human insulin was entrapped in multilamellar niosomes composed of polyoxyethylene alkyl ether surfactants (Brij 52 and Brij 92) or sorbitan monostearate (Span 60) and cholesterol. The amount of insulin released in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF) were measured at 37°C. The protection of entrapped insulin against pepsin, α-chymotrypsin and trypsin were evaluated in comparison with free insulin solution. Diabetes was induced by IP injection of streptozotocin (65 mg/kg) in male wistar rats and effects of orally administered niosomes and subcutaneously injected insulin on hypoglycemia and elevation of insulin levels in serum were compared.

Results and conclusion

The extent and rate of insulin release from Brij 92 and Span 60 vesicles were lower than that of Brij 52 niosomes (P<0.05). Vesicles protected insulin in comparison with free insulin solution against proteolytic enzymes (P<0.05) significantly. Animals treated with oral niosome-encapsulated insulin (100 IU/kg) showed decreased levels of blood glucose and elevated serum insulin, which in the case of Brij 92 niosomes, hypoglycemic effect was significant (P<0.05).Niosomes were also stable in solubilizing bile salt solutions and could effectively prolong the release of insulin in both SGF and SIF. Results of this study showed that niosomes may be utilized as oral carriers of insulin; however, to increase bioavailability of insulin, further studies on the protease inhibitor co-encapsulation in niosomal formulations might be helpful.     

Grapefruit juice decreases the systemic availability of itraconazole capsules in healthy volunteers.

The systemic availability of itraconazole capsules may be reduced secondary to elevated gastric pH and possibly by presystemic intestinal metabolism via CYP3A4. Grapefruit juice is acidic and an inhibitor of intestinal CYP3A4. To determine the effect of grapefruit juice on the systemic availability of itraconazole capsules, serum itraconazole and hydroxy-itraconazole concentrations were determined in eleven healthy volunteers studied in a randomized, two-way crossover design. Concurrent grapefruit juice resulted in a 43% decrease in the mean itraconazole AUC0-48 (2507 ng x hr/mL versus 1434 ng x hr/mL, p = 0.046) and a 47% decrease in the mean hydroxy-itraconazole AUC0-72 (7264 ng x hr/mL versus 3880 ng x hr/mL, p = 0.025). Grapefruit juice also significantly increased the mean itraconazole Tmax (5.5 versus 4 hours). We conclude that concomitant grapefruit juice does not enhance the systemic availability of itraconazole capsules, but rather appears to impair itraconazole absorption. Therefore, concomitant grapefruit juice will not likely be useful in improving the oral availability of itraconazole capsules.     

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.     

In vitro and in vivo evaluation of insulin microspheres containing protease inhibitor

The aim of this study was to investigate the applicability of microspheres containing protease inhibitor for oral delivery of insulin (CAS 9004-10-8). Microspheres of insulin were prepared by water-in-oil-in-oil (w/o1/o2) double emulsion solvent evaporation method. Formulations with different drug/polymer ratios were prepared and characterized by drug loading, loading efficiency, yield, particle size, scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR). The in vitro release studies were performed in pH 1.2 and 7.4. In vivo studies on rats were conducted in order to investigate the bioavailability and performance of oral microspheres. The best polymer to drug ratio in microspheres was 15.6:1 (F2 formulation). The loading efficiency was 77.36%, production yield was 54.55% and mean particle size was 222.4 microm. SEM studies showed that the microspheres were spherical and porous in nature. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the first order model. The results of enzymatic degradation indicated that insulin could be protected from trypsinic degradation in the microspheres. Our results indicate that the microspheres containing aprotinin (CAS 9087-70-1) have the advantage of high loading efficiency, pH responsive and prolonged release carrying insulin to the optimum site of absorption as well as the enhanced insulin absorption and biological response.     

Solubility and stability of dalcetrapib in vehicles and biological media

Dalcetrapib solubility was determined in aqueous and in non-aqueous vehicles and in biorelevant media. In a pure aqueous environment the solubility was low but could be increased by addition of surfactants or complexing agents. This was also reflected in the solubility seen in simulated gastrointestinal (GI) fluids, with almost no solubility in simulated gastric fluid, but reasonable solubilisation in simulated intestinal fluids containing lecithin and bile salt. Additionally, the stability of dalcetrapib was determined in simulated GI fluids with and without pancreatic lipase. In solutions without lipase, dalcetrapib was slowly hydrolysed, but in the presence of lipase the hydrolysis rate was significantly faster depending on pH and enzyme activity. In biological fluids, dissolved dalcetrapib appeared to behave similarly being rapidly hydrolysed in human intestinal fluids with a half-life below 20s with no degradation observed in human gastric fluids at low pH. The results provide supportive evidence that absorption is higher under fed conditions and indicate lipase inhibitors might interfere with oral absorption of dalcetrapib.     

The effect of pharmacologically altered gastric pH on cadmium absorption from the diet and its accumulation in murine tissues.

Solubility of Cd in Cd-amended mouse chow in water was reduced by increased pH; even less Cd was solubilized by simulated digestion in vitro, where increased gastric phase pH decreased solubility, an effect that persisted following intestinal digestion at pH 5.5. These data suggested that increasing gastric pH in vivo pharmacologically would reduce Cd accumulation in target organs of mice treated with omeprazole (a proton-pump inhibitor) or cimetidine (a H2-receptor antagonist). This expectation was mostly not realized. Gastric pH in animals receiving Cd-amended diet was increased by omeprazole, but not cimetidine, relative to animals receiving no drugs, and Cd-amended diet. Tissue concentrations of Cd were similar among the three groups receiving Cd-amended diet, for liver, kidney and testes. Small intestine Cd concentration was lower for omeprazole-treated animals than for those receiving neither drug and Cd-amended diet, suggesting that omeprazole decreased Cd absorption by this organ. This effect may have been compensated for by increased uptake of complexed Cd by the large intestine, as accumulation in the liver, kidney and testes was not reduced. In vitro determinations of bioaccessible Cd in food may not predict in vivo bioaccumulation in all target organs.     

吲哚美辛结肠定位凝胶微丸的研究

目的制备吲哚美辛凝胶微丸实现结肠定位给药。方法采用滴制法制备海藻酸钙微丸,以微球圆整度、包封率、载药量为质量指标,通过正交试验选出优化处方,并用丙烯酸树脂Eudragit S100进行包衣。结果凝胶微丸在人工胃液和人工肠液中6 h累积释放率小于15%,而在人工结肠液中2 h达80%以上。结论所制得的吲哚美辛凝胶微丸符合结肠定位的基本要求。     

Grapefruit juice enhances the bioavailability of the HIV protease inhibitor saquinavir in man

Aims Saquinavir is a potent HIV protease inhibitor whose effectiveness is limited in vivo by its low bioavailability. Since saquinavir is metabolized by CYP3A4, the effect of grapefruit juice, an inhibitor of CYP3A4, was investigated on its bioavailability.
Methods After an overnight fast, eight healthy volunteers were treated with either 400  ml grapefruit juice or water before intravenous (12  mg) or oral saquinavir (600  mg) was administered. Serial blood samples were obtained over the following 24  h and standardized meals were served 5 and 10  h after the administration of saquinavir. The plasma concentrations of saquinavir were determined by high-performance liquid chromatography and pharmacokinetic parameters were calculated by routine methods.
Results The AUC was not affected by grapefruit juice after intravenous administration, but it increased significantly from 76±96 (water, mean (s.d.) to 114±70 (μg  l⁻¹  h (grapefruit juice) after oral saquinavir. Similarly, the oral bioavailability of saquinavir increased by a factor of 2 with grapefruit juice (from 0.7% to 1.4%). In contrast, clearance, volume of distribution and elimination half-life of saquinavir were not affected by grapefruit juice. After oral, but not after intravenous administration, the plasma concentration-time curve showed a second peak after lunch irrespective of pretreatment, suggesting enhancement of absorption by food.
Conclusions The studies demonstrate that grapefruit juice increases the bioavailability of saquinavir without affecting its clearance, suggesting that inhibition of intestinal CYP3A4 may contribute. Since the antiretroviral effect of saquinavir is dose-dependent, inhibition of CYP3A4 may represent a way to enhance its effectiveness without increasing the dose.     

地龙湿法超微粉碎提取物在模拟胃肠环境中的降解研究

研究地龙湿法超微粉碎提取物在模拟胃肠环境中的降解情况。采用调整溶液pH及膜生物反应器原理两种方法终止酶解反应、Bradford法检测地龙蛋白浓度变化情况、SDS-PAGE凝胶电泳法检测地龙蛋白的降解情况、HPLC方法检测地龙小分子物质降解情况。结果表明, 地龙蛋白在人工胃液中发生完全降解; 在人工肠液中, 高分子量蛋白发生较大程度降解, 而低分子量蛋白未发现明显降解。地龙小分子物质在人工胃液中未发生明显降解; 在人工肠液中出现明显降解, 并且出现了新的小分子物质。地龙湿法超微粉碎提取物在体内发挥药效作用的物质可能是已降解后的多肽、氨基酸及可稳定存在于肠液环境的小分子物质。     

Leaky enteric coating on ranitidine hydrochloride beads: Dissolution and prediction of plasma data.

The present research is based on the hypothesis that leaky enteric-coated pellets formulations are able to provide sustained input for drugs that have an absorption window, such as ranitidine hydrochloride, without jeopardizing their bioavailability. Leaky enteric-coated pellets formulations are defined as enteric-coated pellets that allow some of the drug to be released from the formulation in gastric fluid. Different approaches to making leaky enteric-coated pellets were investigated using extrusion-spheronization followed by spray coating. Leaky enteric coats were formulated using a commonly used enteric polymer, Eudragit((R)) L 30 D-55, combined with soluble compounds including lactose, PEG 8000 and surfactants (Span 60 (hydrophobic) or Tween 80 (hydrophilic)). The rate of drug release from the formulations in simulated gastric fluid can be tailored by varying the additive's amount or type. All leaky enteric-coated formulations studied completely released the drugs within 30min after changing dissolution medium to phosphate buffer, pH 6. Predictions of plasma concentration-time profiles of the model drug ranitidine hydrochloride from leaky enteric-coated pellets in fasted conditions and from immediate-release formulations were performed using computer simulations. Simulation results are consistent with a hypothesis that leaky enteric-coated pellets formulations provide sustained input for drugs shown to have an absorption window without decreasing bioavailability. The sustained input results from the combined effects of the formulation and GI transit effects on pellets. The present research demonstrates a new application of knowledge about gastrointestinal transit effects on drug formulations. It also shows that enteric-coating polymers have new applications in areas other than the usual enteric-coated formulations. The hypothesis that a leaky enteric-coated pellets formulation may maintain or increase the bioavailability of drugs that have a window of absorption is still to be confirmed by further in vivo studies.     

复方低分子肝素口服结肠靶向给药胶囊的研制

目的:研制用于溃疡性结肠炎治疗的复方低分子肝素口服结肠靶向给药胶囊。方法:通过考察颗粒的流动性、吸湿性,筛选复方制剂的最佳处方。从外观性状、装量差异、含量测定、体外溶出试验4个方面对制得胶囊进行质量检查。结果:筛选出最佳处方为可溶性淀粉:糊精:低聚木糖质量比为2∶3∶3;建立了天青A法测定低分子肝素含量,并进行了方法学考察;所制得的胶囊在人工胃液及在pH 6.8的人工肠液中不崩解,在pH 7.8的人工肠液中快速崩解释放。结论:所研制的复方低分子肝素口服结肠靶向胶囊符合规定。     

Insulin‐loaded nanocapsules for oral administration: In vitro and in vivo investigation

The purpose of this work was to investigate the ability of poly(isobutylcyanoacrylate) nanocapsules to protect insulin from degradation by proteolytic enzymes providing biologically active insulin by the oral route. Insulin was labeled with Texas Red^® for release studies and microscopy observations. The fluorescent marker was mostly retained by the nanocapsules incubated in the reconstituted gastric medium but the release was 75% within 30 min when the nanocapsules were incubated in the reconstituted intestinal medium. Turbidimetric measurements and electron microscopy observations confirmed that the nanocapsules were degraded in the reconstituted intestinal medium, whereas nanocapsule integrity was preserved in the reconstituted gastric medium. In vivo studies of the gastrointestinal distribution of insulin‐loaded nanocapsules after oral feeding showed that nanocapsules were retained by the stomach for 30 min. One hour after oral administration, nanocapsules reached the lower part of the intestine (ileum). Fluorescence microscopy and confocal microscopy carried out on portions of the small intestine revealed the presence of concentrated fluorescent spots into the mucosa and even in the lamina propia, suggesting that insulin‐loaded nanocapsules could cross the intestinal epithelium. These data suggest that PIBCA nanocapsules can efficiently protect insulin when given orally. In addition, they seemed to be significantly involved in the absorption mechanism. Drug Dev. Res. 49:109–117, 2000. © 2000 Wiley‐Liss, Inc.     

重组水蛭素肠溶包衣微丸的制备及体外释放行为考察

目的研制重组水蛭素口服肠溶包衣微丸,并对其在不同pH释放介质中的释放行为进行考察,为重组水蛭素口服制剂的研究与开发提供实验依据。方法以羟丙甲基纤维素酞酸酯(HP55)为包衣材料,利用离心造粒机和流化床包衣设备制备重组水蛭素肠溶包衣微丸;采用二喹啉甲酸(BCA)法测定重组水蛭素肠溶包衣微丸的药物含量。结果所制备的重组水蛭素肠溶包衣微丸药物含量质量分数为3.513%。pH梯度释放实验结果表明,所研制的包衣微丸人工胃液中2 h药物仅释放4.98%;pH 5.8释放介质中继续释放,0.5 h释放82.13%,1 h释放95.47%;pH 7.2释放介质中继续释放,0.5 h释放97.53%,1 h释放98.33%。结论重组水蛭素肠溶包衣微丸在人工胃液中几乎不释药,可避免水蛭素被胃蛋白酶所降解;在人工肠液中药物释放快速而且完全,有利于水蛭素在肠道中的吸收。