壳聚糖-阿拉伯胶布洛芬缓释微囊制备工艺初探

本文以壳聚糖和阿拉伯胶为囊材,采用复凝法将非甾族抗炎药布洛芬微囊化。探索了不同pH值、不同壳聚糖浓度、不同搅拌转速、不同成囊温度、不同浓度戊二醛固化交联剂对微囊制备工艺的影响:研究表明在PH值=4.0,壳聚糖浓度为0.3%,搅拌转速为200r·min-1,成囊温度为45℃,戊二醛用量为25%,1.0mL时制备的缓释微囊;具有囊型好、粒径分布均匀,包封率高且制备工艺稳定。     

Targeted cancer chemotherapy with arterial microcapsule chemoembolization: review of 1013 patients

 To evaluate the feasibility of intraarterial infusion of microencapsulated anticancer drugs (chemoembolization), collective data on 1013 cancer patients were reviewed. Ethylcellulose microcapsules containing mitomycin C (median total dose 20 mg), cisplatin (60 mg) or peplomycin (40 mg) were given to tumor-feeding arteries by bolus infusion in 79% of the patients and by fractionated infusion in the others, as a palliative (71%) or preoperative measure (29%). The target sites were the liver (42%), kidney (24%), intrapelvic organs (18%), lung (4%), head and neck (3%), bone (1%) and others (9%), excluding the central nervous system and gastrointestinal tract. The incidence of overall adverse effects ranged from 0.2 to 54.9%, but grade 2–3 hematological, renal and hepatic toxicities, local pain, abdominal discomfort, cutaneous reaction, remote embolization and infection were < 10%. Nine patients (0.9%) in the early stages of trials suffered serious complications including treatment-related death in two with critical underlying diseases of the target organs. The remaining patients recovered from the adverse effects, except for grade 2 cutaneous reactions, within 2 months by routine palliative measures. A ≥ 50% tumor reduction was seen in 28% of 427 evaluable tumors (42% for < 25-cm² tumors and 20% for ≥ 25-cm² tumors) with a median treatment number of one. The response rate depended on both the tumor size and the treatment number (P< 0.05), but it was not affected by prior therapies. Mitomycin C microcapsules produced a higher response rate. Complete or partial remission of intractable pain and genitourinary gross hemorrhage was found in two-thirds of eligible patients. The results indicate that this treatment modality, though restricted by catheter technique, can be applied to various tumor lesions with an acceptable morbidity and prospective trials are justified to evaluate the potential role of such a targeted chemotherapy. Received: 30 December 1994/Accepted: 14 May 1995     

Effect of Drug-Polymer Interaction on the Release Characteristics of Methacrylic Acid Copolymer Microcapsules Containing Theophylline

Theophylline anhydrate microcapsules with different amounts of MA/MMA copolymer (Eudragit L) were prepared by the solvent evaporation method. Qualitative as well as quantitative investigation of the drug-polymer interaction by Fourier transform infrared (FTIR) spectroscopy with a curve fitting program was undertaken. The release mechanisms of theophylline in pH 1.2 and pH 6.8 media were also studied to elucidate the effect of drug-polymer interaction on the release characteristics of microcapsules. Direct evidence for a hydrogen bonding interaction between theophylline and Eudragit L in microcapsules was obtained. Moreover, the fraction of hydrogen bonded theophylline increased with the increase of Eudragit L. The dissolution of theophylline from microcapsules exhibited an enteric-coated release property. The drug release mechanism was found to fit the Higuchi matrix model in the simulated gastric acid condition, but drug release was much more rapid in the pH 6.8 buffer solution. The drug release rate decreased as the composition of theophylline increased, and it was proportional to the fraction of hydrogen bonded theophylline. These results suggest that the increased fraction of hydrogen bonded theophylline in microencapsulation might improve the mixing and dispersibility of theophylline in the Eudragit L matrix, thus resulting in the increase of the release rate of theophylline from microcapsules.     

微囊包膜纯化初生猪胰岛移植治疗糖尿病大鼠研究

在链脲佐菌素所致的８只糖尿病Ｗｉｓｔａｒ大鼠腹腔内移值免疫隔离膜包囊纯化初生猪胰岛，观察效果。移值后有效率为８８％，完全援解率为５０％，且缓解持续时间最长一只达１８０天以上。对照组无效。这证实我们所研制的免疫隔离包囊初生猪胰岛在异种移植过程中起到预期的抗排异反应，故可进入临床以治疗糖尿病患者。     

辅料因素对双黄连微囊吸湿量与分散性的影响

目的:研究辅料因素对双黄连微囊吸湿时吸湿量与分散性的影响。方法:单因素考察,检测不同囊材、抗粘剂以及原辅料配比制成双黄连微囊吸湿后的吸湿量与分散性。结果:样品吸湿导致分散性降低,但常常吸湿量大的样品分散性仍较好。结论:在防潮技术研究中,不仅要检测样品的吸湿量,也需要考察样品吸湿后的分散性。     

Evaluation of modified alginate-chitosan-polyethylene glycol microcapsules for cell encapsulation

A bioartificial pancreas, a medical device entrapping islets of Langerhans (islets) in an immunoisolative membrane, has been regarded as one of the most promising approaches to treat insulin-dependent diabetic patients. In this study, various modifications of alginate-chitosan microcapsules were made such as the inclusion of polyethylene glycol (PEG) and the use of crosslinkers such as carbodiimide (EDC) and glutaraldehyde (GA) in the core and onto the microcapsule membrane surface. A characterization of the modified microcapsules in terms of mechanical stability and albumin diffusion as well as their surface properties using SEM was performed. A mild GA treatment greatly enhanced the mechanical stability of the microcapsules, and this treatment did not affect the coating process of chitosan or PEG. The biological response to such microcapsules was evaluated by microencapsulation of red blood cells (RBC) and subsequent observation of their hemoglobin release. The encapsulated RBC in the PEG-GA coated microcapsules were found to be less hemolytic and had improved stability and biocompatibility. The results suggest the possibility of developing biological assist organs by microencapsulation of mammalian cells such as islets or liver cells in immunoisolative microcapsules in the near future.