乳化溶剂挥发法制备重组人血管内皮抑制素缓释微球

目的:制备重组人血管内皮抑制素(恩度)缓释微球,并对微球理化性质及体外释放行为进行初步考察。方法:采用乳化溶剂挥发法(W/O/O)制备恩度载药微球;对微球载药量、粒径、突释、体外释放速率及降解行为进行考察,同时利用凝胶电泳初步评价体外释放过程中恩度的完整性。结果:增加聚乳酸-羟基乙酸嵌段共聚物(PLGA)中羟基乙酸的比例、提高PLGA浓度、降低内水相体积、提高理论载药量均增加微球载药能力;降低内水相体积、提高分散速度均减小突释。增加PLGA中羟基乙酸的比例,30 d时累积释放可增加到65%。降解实验说明释放初期微球主要以扩散方式释放恩度,释放后期主要表现为微球的降解。凝胶电泳结果表明微球制备过程对蛋白质聚集性的影响不大。结论:用PLGA作为载体材料制备微球,可以延缓恩度的释放。     

Small-molecule release from poly(D,L-lactide)/poly(D,L-lactide-co-glycolide) composite microparticles

Addition of biodegradable polymer shells surrounding polymeric, drug-loaded microparticles offers the opportunity to control drug release rates. A novel fabrication method was used to produce microparticles with precise control of particle diameter and the thickness of the polymer shell. The effect of shell thickness on release of a model drug, piroxicam, has been clearly shown for 2- to 15-microm thick shells of poly(D,L-lactide) (PDLL) surrounding a poly(D,L-lactide-co-glycolide) (PLG) core and compared to pure PLG microspheres loaded with piroxicam. Furthermore, the core-shell microparticles are compared to microspheres containing blended polymers in the same mass ratios to demonstrate the importance of the core-shell morphology. Combining PDLL(PLG) microcapsules of different shell thicknesses allows nearly constant release rates to be attained for a period of 6 weeks.     

The release behavior and kinetic evaluation of tramadol HCl from chemically cross linked Ter polymeric hydrogels

Background and the purpose of the study

Hydrogels, being stimuli responsive are considered to be effective for targeted and sustained drug delivery. The main purpose for this work was to study the release behavior and kinetic evaluation of Tramadol HCl from chemically cross linked ter polymeric hydrogels.

Methods

Ter-polymers of methacrylate, vinyl acetate and acrylic acid cross linked with ethylene glycol dimethacrylate (EGDMA) were prepared by free radical polymerization. The drug release rates, dynamic swelling behavior and pH sensitivity of hydrogels ranging in composition from 1-10 mol% EGDMA were studied. Tramadol HCl was used as model drug substance. The release behavior was investigated at pH 8 where all formulations exhibited non-Fickian diffusion mechanism.

Results and major conclusion

Absorbency was found to be more than 99% indicating good drug loading capability of these hydrogels towards the selected drug substance. Formulations designed with increasing amounts of EGDMA had a decreased equilibrium media content as well as media penetrating velocity and thus exhibited a slower drug release rate. Fitting of release data to different kinetic models indicate that the kinetic order shifts from the first to zero order as the concentration of drug was increased in the medium, showing gradual independency of drug release towards its concentration. Formulations with low drug content showed best fitness with Higuchi model whereas those with higher concentration of drug followed Hixson-Crowell model with better correlation values indicating that the drug release from these formulations depends more on change in surface area and diameter of tablets than that on concentration of the drug. Release exponent (n) derived from Korse-Meyer Peppas equation implied that the release of Tramadol HCl from these formulations was generally non-Fickian (n > 0.5 > 1) showing swelling controlled mechanism. The mechanical strength and controlled release capability of the systems indicate that these co-polymeric hydrogels have a great potential to be used as colon drug delivery device through oral administration.     

Alginate/chitosan microparticles for tamoxifen delivery to the lymphatic system

The efficacy of drug candidates is frequently limited by their inability to reach the target site of action, especially when they are administered through conventional dosage forms or drug delivery systems. Targeted drug delivery systems have increased the amount of drug reaching the site and simultaneously decrease the amount being distributed to other parts of the body. Microspheres have emerged as a remedial measure to improve site-specific drug delivery to a considerable extent. As an application, lung-targeting albumin loaded ofloxacin microspheres (ALOME) were prepared by water in oil emulsion method. The appearance and size distribution were examined by scanning electron microscopy, and the aspects such as in vitro release characteristics, stability, drug loading, loading efficiency, pharmacokinetics and tissue distribution in albino mice were studied. The experimental results showed that the microspheres have an average particle size of 11.32 μm. The drug loading and loading efficiency were (66.95 and 94.8%) respectively. The in vitro release profile of the microspheres matched the Korsmeyer's Peppas release pattern, and the release after 1 h was 42%, while for the original drug, ofloxacin, under the same conditions, 90.02% released in the first half an hour. After intravenous administration (15 min), the drug concentration of microspheres group in lung of albino mice was 432 μg g⁻¹ while that of controlled group was 1.32 μg g⁻¹ ALOME found to release the drug to a maximum extent in the target tissue, lung. Histopathological studies proved the tissue compatibility of ALOME to be safe.     

Controllable release of pirfenidone by polyvinyl alcohol film embedded soft contact lenses in vitro and in vivo

To increase the amount of pirfenidone (PFD) loaded in polyvinyl alcohol (PVA) film embedded soft contact lens (SCL), and evaluate its function of sustaining delivery of drug in vitro and in vivo. Drug loading efficiency within PVA film and SCLs, drug release from SCLs in vitro, and the effects of parameters of SCLs and external environment on drug release in vitro were evaluated by ultraviolet–visible spectrophotometer at 312 nm. Safety of SCLs was evaluated in vitro by transformed human corneal epithelial cell. Safety in vivo was determined by optical coherence tomography and histology of anterior segment of rabbits. Drug release study in tear fluid and aqueous humor were measured by ultra-performance liquid chromatography. SCLs had smooth surface and were fit for experimental rabbits. Amount of PFD in PVA film and SCLs were 153.515 μg ± 12.508 and 127.438 μg ± 19.674, respectively, PFD in PVA film was significantly higher than SCLs (p=.006) and closed to 150 μg (targeting amount of PFD to be loaded). Thickness of SCLs, molecular weight of PVA, and amount of PVA used in SCLs affected drug release in vitro significantly. Thickness of PVA film and amount of drug in SCLs had no effect on drug release rate in vitro. SCLs were safe in vitro and in vivo, PFD released from SCLs could be detected around 12 hours in tears and aqueous humor, and the concentration of drug was higher than eye drop at all detected time points while amount of PFD in SCLs was lower than eye drop. Drug loaded PVA film embedded SCLs may be a promising ocular drug delivery system.     

Facile synthesis of pH sensitive polymer-coated mesoporous silica nanoparticles and their application in drug delivery

pH-responsive polymer shell chitosan/poly (methacrylic acid) (CS-PMAA) was coated on mesoporous silica nanoparticles (MSN) through the facile in situ polymerization method. The resultant composite microspheres showed a flexible control over shell thickness, surface charges and hydrodynamic size by adjusting the feeding amount of MSN and the molar ratio of [-NH(2)]/MAA. The MSN/CS-PMAA composite microspheres were stable in the pH range of 5-8 as well as in the physiological saline (0.15M NaCl). Doxorubicin hydrochloride (DOX) was applied as a model drug to investigate the drug storage and release behavior. The results demonstrated that DOX could be effectively loaded into the composite microspheres. The cumulative release of DOX-loaded composite microspheres was pH dependent and the release rate was much faster at low pH (5.5) than that of pH 7.4. The cytotoxicity test by MTT assay showed that the blank carrier MSN/CS-PMAA microspheres were suitable as drug carriers. The cellular uptake of composite microspheres was investigated by confocal laser scanning microscopy (CLSM), which indicated that MSN/CS-PMAA could deliver the drugs into HeLa cell. The above results imply that the composite microspheres are a promising drug delivery system for cancer therapy.     

Drug delivery of amoxicillin molecule as a suggested treatment for covid-19 implementing functionalized mesoporous SBA-15 with aminopropyl groups

SARS-CoV-2 is a novel coronavirus that was isolated and identified for the first time in Wuhan, China in 2019. Nowadays, it is a worldwide danger and the WHO named it a pandemic. In this investigation, a functionalization post-synthesis method was used to assess the ability of an adapted SBA-15 surface as a sorbent to load the drug from an aqueous medium. Different characterization approaches were used to determine the characterization of the substance before and after functionalization such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), nitrogen adsorption–desorption porosimetry (Brunauer–Emmett–Teller) BET surface area analysis, and thermal gravimetric analysis (TGA). Batch adsorption testing was carried out in a single adsorption device to find the impact of multiple variables on the drug amoxicillin charge output. The following parameters were studied: 0–72 hr. contact time, 20–120 mg/l initial concentration, and 20–250 mg of NH₂-SBA-15 dose. The outcomes from such experiments revealed the strong influence and behavior of the amino-functional group to increase the drug''s load. Drug delivery outcomes studies found that amoxicillin loading was directly related to NH₂-SBA-15 contact time and dose, but indirectly related to primary concentration. It was observed that 80% of amoxicillin was loaded while the best release test results were 1 hour and 51%.     

Preparation and characterization of Mitomycin-C loaded chitosan-coated alginate microspheres for chemoembolization

Mitomycin-C loaded and chitosan-coated alginate microspheres were prepared for use in chemoembolization studies. In this respect, first alginate microspheres were prepared by using a spraying method using an extrusion device with a small orifice and following suspension cross-linking in an oil phase. Chitosan-coating onto the alginate microspheres was achieved by polyionic complex formation between alginate and chitosan. CaCl₂ was used as a cross-linker for alginate microspheres. The obtained chitosan-coated alginate microspheres were spherical shaped and ～100–400?µm average size. The microspheres were evaluated based on their swellability and the swelling ratio was changed between 50–280%. CaCl₂ concentration, stirring rate, chitosan molecular weight, chitosan concentration and time for coating with chitosan were selected as the effective parameters on microsphere size and swelling ratio. Equilibrium swellings were achieved in ～30?min. On the other hand, chitosan molecular weight, chitosan concentration and time for coating with chitosan were found as the most effective parameters on both drug loading ratio and release studies. Maximum drug loading ratio of 65% was achieved with high molecular weight (HMW) chitosan, highest chitosan concentration (i.e. 1.0% v/v) and shortest time for coating with chitosan (i.e. 1?h) values.     

Wettability and contact angle affect precorneal retention and pharmacodynamic behavior of microspheres

In the present study, we describe the development of betaxolol hydrochloride and montmorillonite with ion exchange in a single formulation to create a novel micro-interactive dual-functioning sustained-release delivery system (MIDFDS) for the treatment of glaucoma. Betaxolol hydrochloride molecule was loaded onto the montmorillonite by ion exchange and MIDFDS formation was confirmed by XPS data. MIDFDS showed similar physicochemical properties to those of Betoptic, such as particle size, pH, osmotic pressure, and rheological properties. Nevertheless, the microdialysis and intraocular pressure test revealed better in vivo performance of MIDFDS, such as pharmacokinetics and pharmacodynamics. With regards to wettability, MIDFDS had a larger contact angle (54.66 ± 5.35°) than Betoptic (36.68 ± 1.77°), enabling the MIDFDS (2.93 s) to spread slower on the cornea than Betoptic (2.50 s). Moderate spreading behavior and oppositely charged electrostatic micro-interactions had a comprehensive influence on micro-interactions with the tear film residue, resulting in a longer precorneal retention time. Furthermore, MIDFDS had a significant sustained-release effect, with complete release near the cornea. The dual-functioning sustained-release carrier together with prolonged pre-corneal retention time (80 min) provided sufficiently high drug concentrations in the aqueous humor to achieve a more stable and long-term IOP reduction for 10 h. In addition, cytotoxicity and hemolysis tests showed that MIDFDS had better biocompatibility than Betoptic. The dual-functioning microspheres presented in this study provide the possibility for improved compliance due to low cytotoxicity and hemolysis, which suggests promising clinical implications.     

Development of cisplatin-loaded hydrogels for trans-portal vein chemoembolization in an orthotopic liver cancer mouse model

Transarterial chemoembolization is a standard treatment for intermediate-stage hepatocellular carcinoma (HCC). This study evaluated the anti-tumor effect of the semi-interpenetrating network (IPN) hydrogel as a novel embolic material for trans-portal vein chemoembolization (TPVE) in vivo. A nude mice orthotopic HCC model was established, followed by TPVE using IPN hydrogel loaded with or without cisplatin. Portal vein blockade was visualized by MRI and the development of tumor was monitored by IVIS Spectrum Imaging. Tumor proliferation and angiogenesis were evaluated by Ki67 and CD34 staining respectively. Intra-tumor caspase 3, Akt, ERK1/2, and VEGF activation were detected by Western Blot. ¹⁸F-FMISO uptake was evaluated by microPET-MRI scanning. IPN hydrogel first embolized the left branch of portal vein within 24 hours and further integrated into the intra-tumor vessels during 2 weeks after the treatment. Mice treated with cisplatin-loaded hydrogels exhibited a significant decrease in tumor growth, along with lower plasma AFP levels as compared to hydrogel-treated and untreated tumor-bearing mice. By Ki67 and CD34 staining, the TPVE with IPN hydrogel suppressed tumor proliferation and angiogenesis. In addition, increased tumor apoptosis shown by up-regulation of caspase 3 with decreased expressions of tumor cell survival indicators Akt and ERK1/2 were observed in the treatment groups. Consistent with the decreased expression of VEGF after TPVE, hypoxia level in the tumor was also reduced as indicated by ¹⁸F-FMISO uptake level. IPN hydrogel-based TPVE significantly suppressed the tumor development by regulating intra-tumor angiogenesis and cell survival in an orthotopic HCC mouse model, suggesting a viable embolic agent for transarterial chemoembolization.     

Preparation and characterization of Mitomycin-C loaded chitosan-coated alginate microspheres for chemoembolization

Mitomycin-C loaded and chitosan-coated alginate microspheres were prepared for use in chemoembolization studies. In this respect, first alginate microspheres were prepared by using a spraying method using an extrusion device with a small orifice and following suspension cross-linking in an oil phase. Chitosan-coating onto the alginate microspheres was achieved by polyionic complex formation between alginate and chitosan. CaCl(2) was used as a cross-linker for alginate microspheres. The obtained chitosan-coated alginate microspheres were spherical shaped and approximately 100-400 microm average size. The microspheres were evaluated based on their swellability and the swelling ratio was changed between 50-280%. CaCl(2) concentration, stirring rate, chitosan molecular weight, chitosan concentration and time for coating with chitosan were selected as the effective parameters on microsphere size and swelling ratio. Equilibrium swellings were achieved in approximately 30 min. On the other hand, chitosan molecular weight, chitosan concentration and time for coating with chitosan were found as the most effective parameters on both drug loading ratio and release studies. Maximum drug loading ratio of 65% was achieved with high molecular weight (HMW) chitosan, highest chitosan concentration (i.e. 1.0% v/v) and shortest time for coating with chitosan (i.e. 1 h) values.     

胸腺肽α1缓释注射微球的研究

制备胸腺肽α₁(Tα₁)的长效注射微球，并对微球的体外释放特性、体外活性及药效学进行考察。采用复乳法(W/O/W)制备了载Tα₁聚乳酸-羟基乙酸嵌段共聚物(PLGA)的微球；考察微球的粒径大小、外观及包封率等理化特性；以HPLC法测定微球的体外释放速率；采用CCK-8法评价微球制备工艺和体外释放过程中Tα₁的生物学活性；体内药效学研究中采用流式细胞仪检测免疫抑制模型大鼠给予Tα₁微球后所产生的CD₄⁺，CD₈⁺因子的量，根据CD₄⁺/CD₈⁺的比值变化评价体内药效。微球球形圆整，分散性好，两个优选处方(外水相中加入5%氯化钠和10%葡萄糖)的微球包封率分别为87.8%和90.2%；Tα₁微球1个月的体外累积释放可达90%以上。使用含10%葡萄糖的PVA溶液作为外水相，较好地保持了制备工艺过程中的Tα₁生物学活性，在体外释放过程中Tα₁的生物学活性略有下降；Tα₁微球可显著提高免疫抑制模型小鼠的免疫力。用可生物降解的聚合物PLGA作为载体材料，可以将Tα₁制备成缓释1个月的注射微球。     

Electrosprayed minocycline hydrochloride-loaded microsphere/SAIB hybrid depot for periodontitis treatment

Minocycline hydrochloride (MINO) has been one of the most frequently used antibiotics in the treatment of periodontitis due to its antibacterial activity and osteogenesis effects; however, high levels of MINO administered during the treatment halt the formation of new bone. Therefore, the purpose of the present study was to prepare a MINO-microsphere/sucrose acetate isobutyrate (SAIB) hybrid depot to reduce the burst release of MINO and ensure antibacterial and osteogenesis effects of MINO in the treatment of periodontitis. Uniform microspheres, approximately 5 µm size, with a slightly rough surface and different MINO loading (10, 12, and 14%) were prepared, and the microspheres were added into SAIB, after which the burst release significantly decreased from 66.18 to 2.92%, from 71.82 to 3.82%, and from 73.35 to 4.45%, respectively, and the release from all the MINO-microspheres/SAIB hybrid depots lasted for 77 days. In addition, cytotoxicity test showed that the MINO-microsphere with 12% drug loading promoted the proliferation of osteoblasts the most and was subsequently used in vivo experiments. Moreover, in the model of ligatured-induced periodontitis in SD rats, the MINO-microsphere/SAIB hybrid depot not only significantly increased the alveolar bone height and bone volume but also reduced the inflammation of the periodontal tissue. Additionally, it also inhibited the expression of the receptor activator of nuclear factor-kappa B ligand (RANKL) and promoted the expression of osteoprotegerin (OPG).. These results indicated that the MINO-microsphere/SAIB hybrid depot might be promising in the treatment of periodontitis.     

胰高血糖素样肽-1长效注射微球的研究

目的制备载胰高血糖素样肽-1(GLP-1)的长效注射微球，并对其体外释放特性及药效学进行考察。方法采用复乳法(W/O/W)制备载GLP-1聚乳酸-羟基乙酸嵌段共聚物(PLGA)的微球；考察微球的粒径大小、外观及包封率等理化特性；以HPLC法测定微球的体外释放速率；在体动物法评价微球制备工艺和体外释放过程中GLP-1的生物学活性。在糖尿病模型小鼠体内考察了微球的降血糖作用。结果微球球形圆整，分散性好，包封率在80%以上；GLP-1微球1个月的体外累积释放可达85%，其释放行为符合近似零级释放模式；使用明胶溶液作为内水相，较好地保持了制备工艺过程中的GLP-1生物学活性，在体外释放过程中GLP-1的生物学活性略有下降；GLP-1微球可显著降低糖尿病模型小鼠的血糖水平，降糖作用可维持1个月。结论用可生物降解的聚合物PLGA作为载体材料，可以将GLP-1制备成缓释1个月的注射微球。     

Bupivacaine-loaded biodegradable poly(lactic-co-glycolic) acid microspheres I. Optimization of the drug incorporation into the polymer matrix and modelling of drug release

Bupivacaine has been encapsulated by solvent evaporation method based on O/W emulsion, using poly(DL-lactic-co-glycolic) acid (PLGA) 50:50. The particle size can be controlled by changing stirring rate and polymer concentration. The encapsulation efficiency was affected by polymer concentration and burst effect of bupivacaine released from particles was affected by drug/polymer mass ratio. Orthogonal design was used to optimize the formulation according to drug content, encapsulation efficiency and burst effect. The dissolution profile and release model were evaluated with two different bupivacaine microspheres (bupi-MS) groups including low drug loading (6.41%) and high drug loading (28.92%). It was observed that drug release was affected by drug loading especially the amount of drug crystal attached on surface of bupi-MS. The drug release profile of low drug loaded bupi-MS agreed with Higuchi equation and that of high drug loaded bupi-MS agreed with first order equation.     

生物可降解型石杉碱甲微球的研究

目的制备能够在一个月甚至更长时间内缓释石杉碱甲的注射型生物可降解微球。方法选用端基不封口的PLA或PLGA、采用简单的O/W乳化溶剂挥发法制备微球;详细考察了微球的形态、粒径及分布、载药量和包封率;用透析法测定微球的体外药物释放曲线。结果成功地将石杉碱甲包裹入聚合物中;制得的微球表面光滑,但不同材料制得的微球内部结构不同,粒径全部小于250μm,粒径分布较窄,载药量的质量分数在4%~6.5%内,包封率的质量分数在45%-65%内,比用端基封口的聚合物制备的微球包封率高15倍以上;体外释药试验表明,载有石杉碱甲的3种微球能够在5-7周内缓释药物。结论利用生物可降解型微球缓释石杉碱甲是可行的。     

SPG膜乳化法制备粒径均一可控的载蛋白缓释微球

目的：研究一种制备粒径均一可控的载蛋白缓释微球的新工艺,探究微球粒径、载体材料、形态结构与微球载药释药性能的关系。方法：以牛血清白蛋白（BSA）为模型药物,PLGA 和PEG-PLGA作为载体材料,采用SPG膜乳化法,通过调整不同孔径（3,5,7,12 μm）的SPG膜制备不同粒径的微球。考察微球粒径、包封率、释放行为、表面/内部形态等性质,并对微球微观结构相关的参数如孔径、平面孔隙率等进行定量分析。结果：微球的粒径与SPG膜孔径呈正相关关系,且相关系数>0.9。随着微球粒径的增大,载药量和包封率也呈现增大的趋势,突释减轻。PLGA和PEG-PLGA微球的内部结构随微球粒径增加的变化差异较大。结论：获得较为满意的制备载蛋白微球的新工艺,微球形态圆整,粒径均一可控。     

Synthesis of nanocapsules blended polymeric hydrogel loaded with bupivacaine drug delivery system for local anesthetics and pain management

Local anesthetics are used clinically for the control of postoperative pain management. This study aimed to develop chitosan (CS) with genipin (GP) hydrogels as the hydrophilic lipid shell loaded poly(ε-caprolactone) (PC) nanocapsules as the hydrophobic polymeric core composites (CS-GP/PC) to deliver bupivacaine (BPV) for the prolongation of anesthesia and pain relief. The swelling ratio, in vitro degradation, and rheological properties enhancement of CS-GP/PC polymeric hydrogel. The incorporation of PC nanocapsules into CS-GP hydrogels was confirmed by SEM, FTIR, and XRD analysis. Scanning electron microscopy results demonstrated that the CS-GP hydrogels and CS-GP/PC polymeric hydrogels have a porous structure, the pore dimensions being non-uniform with diameters between 25 and 300 μm. The in vitro drug release profile of CS-GP/PC polymeric hydrogel has been achieved 99.2 ± 1.12% of BPV drug release in 36 h. Cellular viability was evaluated using the CCK-8 test on 3T3 fibroblast cells revealed that the obtained CS-GP/PC polymeric hydrogel with BPV exhibited no obvious cytotoxicity. The CS-GP/PC polymeric hydrogel loaded with BPV showed significant improvement in pain response compared to the control group animals for at least 7 days. When compared with BPV solution, CS-GP hydrogel and CS-GP/PC polymeric hydrogel improved the skin permeation of BPV 3-fold and 5-fold in 24 h, respectively. In vitro and in vivo results pointed out PC nanocapsules loaded CS-GP hydrogel can act as effective drug carriers, thus prolonging and enhancing the anesthetic effect of BPV. Histopathological results demonstrated the excellent biodegradability and biocompatibility of the BPV-loaded CS-GP/PC polymeric hydrogel system on 7, 14, and 21 days without neurotoxicity.

HIGHLIGHTS

• Preparation and characterization of CS-GP/PC polymeric hydrogel system.
• BPV-loaded CS-GP/PC exhibited prolonged in vitro release in PBS solution.
• Cytotoxicity of BPV-loaded CS-GP/PC polymeric hydrogel against fibroblast (3T3) cells.
• Development of CS-GP/PC a promising skin drug-delivery system for local anesthetic BPV.

     

盐酸倍他洛尔蒙脱石微球的制备及其体外释放性能的研究

目的制备可满足缓释要求的镶嵌蒙脱石的离子交换缓释微球。方法采用S/O1/O2/O3复乳-溶剂挥发法制备微球,考察处方因素包括复乳相体积比例、药物质量浓度、膜材用量和乳化剂质量分数对微球制备的影响。以微球体外释放为考察指标,优化微球处方。结果研究所得到的微球最佳处方为大豆油∶药物=6∶1,药物∶膜材=1∶5,乳化剂质量分数为0.5%²%。除乳化剂外,其他因素对微球体外释放均有较大影响。所制备微球的体外释放可以达到10h,基本无突释现象。进行形态观察发现,微球较为圆整,粒径比较均匀。结论采用优化处方以复乳-溶剂挥发法所制备盐酸倍他洛尔蒙脱石微球体外具有缓释性能。