Delivery of didanosine from enteric-coated,sustained-release bioadhesive formulation

The aim of our study is to assess the release characteristics, in vitro permeation, and stability of an enteric-coated, bioadhesive, sustained-release formulation of didanosine (ddI). Enteric-coated tablets of ddI, containing Polyox® WSRN-303 and Methocel K4M, were prepared using hydroxypropylmethylcellulose phthalate (HPMCP 5.5). The enteric-coated formulation was resistant to dissolution in 0.1 N HCl solution but dissolved within 10 min ( ±2 min) in pH 7.4 phosphate buffered saline. The release profiles were linear with square root time. Stability studies indicate that the formulations were stable at 4°C, room temperature, and 40°C upon storage for 6 months. Polyox® WSRN-303 tablets exhibited a higher ddI permeation ratio across live intestinal tissue compared with conventional tablets. Enteric-coated, sustained-release, bioadhesive tablets deliver ddI in small doses and at the same time prevent acid-induced degradation and hence hold a potential to improve ddI's oral bioavailability.     

国产司帕沙星片的含量测定及体外溶出度考察

采用紫外分光光度法测定司帕沙星片的含量及体外溶出度。以０．１ｍｏｌ／Ｌ盐酸液为溶剂,在２９８ｎｍ波长处测定。司帕沙星浓度在２～１２ｍｇ／Ｌ范围内与吸收度呈良好的线性关系（ｒ＝０．９９９８,ｎ＝６）,平均回收率为１００．２％,ＲＳＤ为０．２９％。     

HPLC法测定复方黄连素片中盐酸小檗碱的含量

建立了ＨＰＬＣ测定复方黄莲素片中盐酸小檗碱含量的方法。该法回收率大于９８％,相对标准差（ＲＳＤ）小于０．５％。     

Influence of the coating thickness and type of oral delivery system (tablets, pellets) on the stability towards degradation by neutron irradiation: Validation of neutron activation III

Enteric coated dexchlorpheniramine maleate (DCPA) tablets and pellets with varying coating thickness were subjected to several in vitro tests after irradiation by thermal neutrons in a flux of 1.1×10¹³ n cm⁻² s⁻¹ for 2, 4 or 15 min. The appearance of the tablet formulation changed extensively after exposure of the tablets to pile radiation. The irradiation caused the film to loosen from the surface of the core, indicating the generation of gases during the irradiation process. Already after irradiating the tablets for 2 min the disintegration and dissolution behaviour were significantly changed. The extent of tablet damage increased with increasing time of exposure and increasing thickness of the coating. Compared with the tablet formulation, the cores could resist a larger amount of irradiation since dissolution behaviour of the cores was only affected after 15 min of irradiation. This indicates that the irradiation procedure initially affects the coating of the formulation. Although the dissolution behaviour of the pellet formulations changed significantly after the irradiation procedure, the changes were too small to be attributed exclusively to radiation damage.     

法莫替丁缓释片的实验研究

用紫外分光光度法测定法莫替丁缓释片的体外释放。体外释放数据表明该缓释片在模拟人工胃液中缓慢释放药物,维持8小时以上。分别用单指数分布模型、威布尔分布模型和希古契方程进行拟合,得出t_0、t_(50)值及拟合方程的相关系数。结果表明3种模型都可以较好地反映该缓释片的释放过程,其中以单指数分布模型为最佳。     

臭梧桐薄膜包衣片中黄酮类成分的含量测定

采用ＵＶ法及ＨＰＬＣ法分别对臭梧桐薄膜包衣片中的总黄酮及海常素进行定量测定，平均回收率为９７．０％和９５．７％。前者简便易行，后者对有效成分控制准确可靠，两者结合可为控制该制剂的内在质量提供可靠的依据。     

薄层扫描法测定黄杨宁片环维黄杨星D的含量

目的：测定黄杨宁片中环维黄杨星D的含量。方法：采用薄层扫描法，以氯仿-丙酮-二乙胺（25：20：2）为展开剂，测定波长为410nm，参比波长为700nm。结果：环维黄杨星D在1．017-10．17μg范围内线性关系良好，r=0．99570，平均回收率为97．31％，RSD：1．0％（n=5）。结论：该方法比传统的分光光度法简便快速、重现性好，可用于测定黄杨宁片的含量。     

HPLC法测定复方化瘀片中灯盏乙素含量

目的测定复方化瘀片中灯盏乙素含量。方法采用HPLC法,流动相为0.4%冰醋酸溶液乙腈(76∶24);检测波长335nm;流速1.0mL/min。结果灯盏乙素在1.0～160.0μg/ml范围具有良好线性关系,加样回收率均大于98.0%,RSD<3%。结论方法简单,重现性好,可作为复方化瘀片中灯盏乙素的含量测定方法。     

HPLC同时测定银黄含化片中绿原酸和黄芩苷含量

目的　建立HPLC法测定银黄含化片中绿原酸和黄芩苷含量的方法。方法　采用ODS色普柱(25 0mm×4 . 6mm,5 μm),以乙腈- 1%磷酸溶液为流动相进行梯度洗脱,检测波长为316nm。结果　绿原酸、黄芩苷分别在0 . 0 2mg·ml-1～0 . 19mg·ml-1和0 . 1mg·ml-1～0 . 8mg·ml-1浓度范围内呈良好线性关系,平均回收率分别为97. 3%和98. 6 %。结论　方法准确、灵敏,回收率高,可用于该制剂的质量控制     

毛细管气相色谱法测定氯唑沙宗片含量

目的　测定氯唑沙宗片中氯唑沙宗含量。方法　采用毛细管气相色谱法,色谱柱:OV -I弹性石英毛细管柱(30m×0 . 2 5mm,0 . 1μm),汽化室温度:2 2 0℃,检测器温度:2 5 0℃;检测器:FID检测器;载气:氮气;流速:2 . 5ml·min-1,尾吹:2 0ml·min-1,分流比5∶1。结果　氯唑沙宗15～4 0 μg·ml-1(r =0 9998)范围内呈良好线性关系,平均回收率为10 0 . 2 %。结论　该方法测定氯唑沙宗含量准确、可靠,回收率高。