盐酸多西环素注射用缓释凝胶的体内释药研究

目的考察盐酸多西环素注射用缓释凝胶的体内释放特性及体内外相关性。方法将含药凝胶注射到家兔牙龈内 ,用HPLC法测定不同时间凝胶中的残余药量 ,从而计算药物的释放量。结果 7d盐酸多西环素的释放度达 99 7%。结论药物可缓释 7d ,体内外相关。     

不同PLGA型号对奥曲肽微球的包封率和体外释放行为的影响

考察了不同型号聚乳酸-羟基乙酸共聚物(PLGA)作为水溶性药物奥曲肽微球载体对载药量、包封率和体外释放行为的影响.结果表明,PLGA中丙交酯含量降低,载药量和包封率降低,而突释量增大.PLGA型号相同时,黏度较大的PLGA微球载药量和包封率较高,突释量较小.采用PLGA与聚乳酸(PLA)混合材料制备的微球比单用PLGA材料微球的突释量小、载药量和包封率高、缓释效果好.     

处方和工艺参数对盐酸昂丹司琼微球体外释放度的影响

目的：考察处方工艺参数对微球体外释放度的影响.方法：采用O/O型乳化溶剂挥发法,以乳酸-羟基乙酸共聚物为载体,制备盐酸昂丹司琼（Ondansetron hydrochloride,OND）微球.采用紫外分光光度法测定微球的体外释放度.结果：选择对OND具有较好溶解能力的混合溶剂为内油相溶剂,可以降低突释;增加理论载药量,延缓正己烷加入的时间和减小粒径可以增加OND微球的释药速度.结论：通过对处方和工艺的调节可使OND微球的体外释药曲线符合Higuchi方程,2周的累积释放量在80%左右.     

制备工艺对石杉碱甲微球体外释药机制的影响

目的考察制备工艺对石杉碱甲(Hup)乳酸-羟基乙酸共聚物(PLGA)微球体外释药机制的影响。方法 采用两种O/O型乳化溶剂挥发法工艺(A法和B法)制备Hup微球。考察微球的体外释药曲线，结合微球在释放介质中的降解速度和溶胀速度曲线以及微球的形态和微球中药物的分布情况阐述微球的释药机制。结果采用A法制备的微球包封率为47.60%，体外无明显突释现象，可缓释35 d，符合零级动力学方程，通过扩散和降解两种机制释药。采用B法制备的微球包封率为83.50%，体外可缓释21 d，整体释药曲线符合Higuchi方程，主要以扩散机制释药。结论采用A法制备的微球具有更理想的缓释效果。     

可生物降解盐酸多西环素缓释凝胶的含量测定

目的：建立可生物降解盐酸多西环素缓释注射凝胶的含量测定方法。方法：采用紫外分光光度法，测定波长276nm。结果：线性范围4．1－24．6ug.mL^-1，标准曲线A＝0．03019C＋0．003648，相关系数r=0\9997，回收率99．89％，RSD％＝0．81％，结论：方法准确可靠，可用于该制剂的含量测定。     

Physicochemical characterization and release mechanism of a novel prednisone biodegradable microsphere formulation

The aim of this work was the characterization of a new formulation of prednisone long-term controlled release biodegradable microspheres. Poly(DL-lactide-co-glycolide) (PLGA) polymers were used for MS preparation. A S/O/W solvent evaporation method was employed for prednisone entrapment. The system was characterized by using UV spectrophotometry, particle sizing, scanning electron microscopy, differential scanning calorimetry, X rays diffractometry, and microRaman spectroscopy. The release mechanism was studied by fitting Weibull, Peppas, Higuchi, and zero order kinetic models. The microspheres (MS) showed a good encapsulation efficiency and morphology, a suitable size and long-term release profile. Burst release was seen to depend on crystalline prednisone distributing close to the MS surface, and no particular prednisone-polymer interaction occurred. Weibull and Peppas were the best fitting models. Prednisone was released from PLGA MS following a Fickian diffusion and case II transport for higher molecular weight (MW) polymers, and a more complex mechanism involving solubilization, diffusion, and erosion, for low MW PLGA. Fully characterized PLGA MS may represent a good tool for a long-term delivery of prednisone in low-dose regimen treatments.     

一阶导数光谱法测定奥硝唑凝胶剂的含量

目的建立奥硝唑凝胶剂中奥硝唑的含量测定方法.方法采用一阶导数光谱法,样品不经分离直接测定奥硝唑凝胶剂中奥硝唑的含量,以波长296nm与262nm间的振幅值(D)作为定量依据.结果线性范围为8.0～80.0μg.mL-1,r=-0.9999,平均回收率为100.71%,RSD为0.89%.结论本法简便、快速、准确,可作为该制剂的质量控制方法.     

一阶导数光谱法测定奥硝唑凝胶剂的含量

OBJECTIVETo establish a determine the content of ornidazole in ornidazole gel. METHODSThe first order derivative spectrophotometry was used to determine the ornidazole in ornidazole suppository without separation. The quantitative calculations was based     

Release profile of lidocaine HCl from topical liposomal gel formulation

Liposomal hydrogel formulations of lidocaine HCl, suitable for topical application, have been prepared and drug release properties in vitro have been evaluated. Liposomes composed of Soya lechitin and cholesterol, with lidocaine HCl, entrapped in the inner water compartment, were prepared by simple hydration method. Topical liposomal gel formulations were prepared by incorporation of liposomes into a structured vehicle (hydrogels of Carbopol 940 in concentration of 1.5, 1.75 and 2%). High percentage of encapsulated drug in liposomes has been obtained (over 70%). Liposomal gel formulations provided prolonged drug release rate. The concentration of gelling agent in a range 1.5-2.0% affected the release rate slightly. In vitro release data showed that release kinetic can be described as diffusion-controlled, while liposomes act as reservoir systems for continuous delivery of drug. Proposed formulations provided stable percentage of entrapped drug and drug release within an examination period of 3 weeks.     

葛根素眼用凝胶的体外释放研究

目的:研制葛根素眼用凝胶剂。方法:建立UV法测定制剂的含量及体外释药量,采用桨法进行处方的体外释药实验,建立HPLC法测定离体角膜渗透量,应用离体角膜进行体外渗透实验。结果:亲水凝胶材料用量越小,葛根素从凝胶基质中释放越快,凝胶体外释放符合Higuchi方程;离体角膜渗透行为符合零级释放规律。结论:葛根素眼用凝胶达到了延迟释放的目的。     

Zero-order release profile of metoclopramide hydrochloride sublingual tablet formulation

This report describes zero-order approximation for metoclopramide hydrochloride sublingual tablet formulation. Effects of type and concentration of excipients on release were investigated. Study revealed that highest rate of dissolution was attained with crosspovidone and decreased in the order crosspovidone > sodium starch glycolate > ac-di-sol. All formulations demonstrated flush release, except the one containing 10% crosspovidone where a lag time of 0.5?min. was depicted. Increasing the concentration of crosspovidone from 5 to 10% gave the same half-life, whereas kinetics of release changed to zero order. Differential scanning colorimetry and infrared spectroscopy did not reveal any sign of physical or chemical interaction between drug and crosspovidone. In order to study the alignment of polymeric network inside tablet matrix, scanning electron microscopy was performed on the tablet and its cross-section. Matrix with 10% crosspovidone showed higher density of interconnections extending to the interior of core enabling fast and constant release. Hence physicochemical characteristics of crosspovidone could be tailored by varying its concentration, in a way that provided a porous matrix with tight arrangement of polymeric chains, resembling to an assemblage of cylinders with constant apertures, from which zero-order release was approached.     

beta-Estradiol biodegradable microspheres: effect of formulation parameters on encapsulation efficiency and in vitro release

The purpose of this work was to study the effect of organic solvent and surfactant type on the in vitro release behavior in general and on the burst release in particular of beta-estradiol from PLA/PLGA microspheres. Also the effect of these variables on the encapsulation efficiency was investigated. The microspheres were prepared by solvent evaporation technique using dichloromethane (DCM), ethyl acetate (EtAc), tetrahydrofuran (THF), chloroform (CHCl3) or acetone (AC) as organic solvent and polyvinyl alcohol (PVA), Tween 80, sodium lauryl sulfate (SLS) or benzalkonium chloride (BKCI) as surfactant. The obtained microspheres were tested for encapsulation efficiency and in vitro drug release using 50% methanol/buffer pH 7.4 as dissolution medium. EtAC and PVA formulations showed the highest encapsulation efficiency and the lowest burst release. These microspheres were further characterized for particle size distribution, SEM and zeta potential. The results suggested that these materials could be starting materials to prepare a beta-estradiol biodegradable controlled delivery system.     

Huperzine A-phospholipid complex-loaded biodegradable thermosensitive polymer gel for controlled drug release

The huperzine A-phospholipid complex loaded biodegradable thermosensitive PLGA-PEG-PLGA polymer gel was studied as injectable implant system for controlled release of huperzine-A (HA). First, HA molecules were successfully incorporated into the soybean phosphatidylcholine (SP) molecules to form the huperzine-A-soybean phosphatidylcholine complexes (HA-SPC), which was proved by FT-IR, DSC, XRD, solubility study, TEM, etc. The results indicated that hydrogen bonds and electrostatic interaction between HA and SP molecules play an important role in the formation of HA-SPC. Secondly, the HA-SPC was loaded into biodegradable PLGA-PEG-PLGA thermosensitive gel as injectable implant material to control the release of HA. The in vitro and in vivo drug release behaviors of the prepared products were studied. The in vitro release studies demonstrated that the HA-SPC-loaded gel significantly reduced the initial burst of drug release and extended the release period to about 2 weeks. The in vivo pharmacokinetics study of HA-SPC-loaded gel in rabbits showed that plasma concentration of HA (2.54-0.15ng/mL) was detected for nearly 2 weeks from delivery systems upon single subcutaneous injection. What's more, the in vitro release pattern correlated well with the in vivo pharmacokinetics profile. The present study indicates that HA-SPC loaded PLGA-PEG-PLGA thermal gel may be an attractive candidate vehicle for controlled HA release.