Research progress of dental self-healing microcapsule materials / 口腔医学

@#The self-healing microcapsule material is one of the smart materials that can self-identify and self-heal microcracks. Adding microcapsules to dental resin composites can resist generation of microcracks and prolong service life of resin restorations. In this literature, the overview of self-healing microcapsule materials, the combined application of self-healing microcapsule materials and other modified materials, the silanization treatment of dental self-healing microcapsules, the dynamic mechanics, fatigue and aging studies on self-healing dental resins were comprehensively presented and reviewed. In addition, prospects of dental self-healing microcapsule materials were also discussed.

Development of novel self-adhesive resin cement with antibacterial and self-healing properties / 华西口腔医学杂志

OBJECTIVE@#This study aimed to develop novel self-adhesive resin cement with antibacterial and self-healing properties. Furthermore, the dentin bonding strength, mechanical properties, self-healing efficiency, and antibacterial property of the developed cement were measured.@*METHODS@#Novel nano-antibacterial inorganic fillers that contain quaternary ammonium salts with long-chain alkyls were synthesized. These fillers were added into self-adhesive resin cement containing self-healing microcapsules at mass fractions of 0, 2.5%, 5.0%, 7.5%, or 10.0%. The dentin shear bonding test was used to test the bonding strength, whereas the flexural test was used to measure the flexural strength and elastic modulus of the cement. The single-edge V-notched beam method was used to measure self-healing efficiency, and human dental plaque microcosm biofilms were chosen to calculate the antibacterial property.@*RESULTS@#The dentin shear bond strength significantly decreased when the mass fraction of the nano-antibacterial inorganic fillers in the novel cement reached 7.5% (P0.1). Resin cement containing 2.5% mass fraction or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilms, indicating strong antibacterial potency (P<0.05).@*CONCLUSIONS@#The novel self-adhesive resin cement exhibited promising antibacterial and self-healing properties, which enable the cement to be used for dental applications.

Encapsulation of Ginseng inside Poly(lactic-co-glycolic acid)/ Polyaniline Microcaspsules

@#Introduction: : Ginseng is a type of traditional medicine that has been used for thousand years to treat various diseases and has been proven effective in treating cardiovascular diseases. Incorporation of polyaniline (PANI) which is a type of conductive polymer together with ginseng into poly(lactic-co-glycolic acid) (PLGA) microcapsules is necessary for the treatment of cardiovascular diseases as the polymer will control drug release and the electroconductivity of PANI is beneficial on myocardium cells. Methods: Therefore, this project involved the encapsulation of ginseng inside PLGA/PANI microcapsules. The encapsulation of ginseng inside the microcapsules was verified through the identification of chemical composition of ginseng, PLGA and PANI using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Results: The results of scanning electron microscope (SEM) showed the formation of microspheres where the microcapsule size was decreased from 3.14±1.87 μm to 1.98±1.30 μm as the concentration of PANI increased. The distribution of microcapsules size was more homogeneous in the high concentration of PANI as been determined through the histogram analysis. In addition, the fluorescence analysis demonstrated the efficiency of ginseng encapsulation inside PLGA/PANI microcapsules through the appearance of stained ginseng inside the microcapsules. Conclusion: As a conclusion, the ginseng was successfully encapsulated within PLGA/PANI microcapsules that will be beneficial in drug delivery application, specifically in the cardiovascular area.

Preparation and Quality Evaluation of Zingiber officinale Oil Microcapsules / 中国药房

OBJECTIVE： To prepare Zingiber officinale oil microcapsules and to evaluate its quality. METHODS： Z. officinale oil microcapsules were prepared by spray drying method with sodium starch octenyl succinate as capsule material. The preparation technology was optimized by orthogonal test with mixing temperature of capsule material and capsule core， mass ratio of capsule material and capsule core， stirring speed as factors， using encapsulation efficiency as index. The drug loading， encapsulation efficiency， appearance， particle size distribution and stability of light， heat and humidity （using iodine value and peroxide value as indexes） were evaluated. RESULTS： The optimal preparation technology of Z. officinale oil microcapsules was that the mixing temperature of capsule material and core was 60 ℃； mass ratio of capsule material and capsule core was 10 ∶ 1； stirring speed was 12 000 r/min. Average drug-loading amount and encapsulation efficiency of Z. officinale oil microcapsules prepared by optimal technology were 17.97％ and 73.57％ （n＝3）. The morphology of Z. officinale oil microcapsules was round， smooth， non-sticky and uniform in size distribution. The average diameter of microcapsules was （6.30±0.27） μm. Under light， heat and humidity conditions， the iodine value and peroxide value of Z. officinale oil microcapsules changed slightly. CONCLUSIONS： The optimal preparation technology of Z. officinale oil microcapsules is simple and reproducible. The prepared microcapsules have good encapsulation efficiency， high drug loading amount and good stability.

Optimizing preparation of microcapsules of eucalyptus citriodora oil by bex-behnken design and response surface method / 中国药学杂志

OBJECTIVE: To optimize the preparation process of microcapsules of eucalyptus citriodora oil, and to investigate its thermal stability. METHODS: Using gelatin as the capsule materials, the microcapsules were prepared by simple coacervation. Base on single factor experiments, three factors including the concentration of gelatin, the core-wall ratio and the reaction temperature were selected to study the preparation conditions by Box-Behnken design and response surface method with its encapsulation efficiency as index. The test results were analyzed by Design-Expert 8.0.6 software. RESULTS: The optimal preparation process was as follows: gelatin solution concentration 3.27%, core-wall ratio 2.5∶1, preparation temperature 50 ℃. Under the optimized preparation process, the encapsulation rate was 67.50%, which was different from the model prediction value (65.68%) by 2.77%. The particle size was about 75 μm and relatively uniform, and the surface was relatively smooth. Moreover, thermal analysis showed that microencapsulation of eucalyptus citriodora oil could significantly increase its thermal stability. CONCLUSION: Using Box-Behnken design and response surface method to optimize the preparation process of eucalyptus citriodora oil microcapsule is accurate, effective and feasible. Microencapsulation can improve the thermal stability of eucalyptus citriodora oil.

Curative effect of mesenchymal stem cells induced by microencapsuled chondrocytes on the intervertebral disc degeneration in rabbits / 西安交通大学学报(医学版)

Objective: To investigate the curative effect of mesenchymal stem cells (MSCs) induced by microencapsuled chondrocytes on the intervertebral disc degeneration (IDD) in rabbits. Methods: MSCs were induced by co-culture with microencapsuled chondrocytes. The surface antigens, proliferation rate, synthesis of proteoglycan and type Ⅱ collagen of MSCs were tested. Induced MSCs were transplanted into the rabbits to establish IDD models and evaluate the repairing effects. Results: After induction by microencapsuled chondrocytes for 7 d, the MSCs possessed certain surface characteristics of chondrocytes and could produce more proteoglycan and type Ⅱ collagen than Transwell system, while the proliferation of MSCs was not affected. After transplanting the MSCs induced by microencapsuled chondrocytes, the form, structure, and mechanical properties were maintained 16 weeks after operations. Conclusion: Compared with the Transwell system, the induction efficiency of microcapsule system is higher. Transplanting MSCs induced by microencapsuled chondrocytes into rabbit IDD models can repair degenerated discs effectively.

Effect of water immersion on a dental self-healing and antibacterial resin composite / 华西口腔医学杂志

OBJECTIVE@#This investigation aimed to develop a novel self-healing and antibacterial dental resin composite. The effects of water immersion on its properties were also evaluated.@*METHODS@#Microcapsules filled with healing agent of triethylene glycol dimethacrylate were synthesized on the basis of previous studies. Antibacterial resin composite contained nano-antibacterial inorganic fillers that were modified by quaternary ammonium salt with long-chain alkyl. Microcapsules were incorporated into antibacterial resin composite at mass fraction of 7.5%. A commercial resin composite named Tetric N-Ceram was used as control. The resin samples were immersed in 37 °C distilled water for different periods. A flexural test was used to measure the mechanical properties of the novel resin composite. A single-edge V-notched beam method was used to measure fracture toughness and self-healing efficiency. A dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming units (CFU) and lactic acid production of biofilm on the novel resin composite were calculated to test the antibacterial property.@*RESULTS@#Mechanical properties and fracture toughness decreased significantly after the composite was immersed in water for 30 days (P0.05). Water immersion did not weaken the self-healing capability of the composite (P>0.05), and self-healing efficiency of 64% could still be obtained even after 270 days. The antibacterial resin composite showed a strong inhibition effect on the biofilm metabolic activity versus water immersion time from 1 day to 270 days. Therefore, the composite could still have a promising antibacterial property even after being immersed in water (P<0.05).@*CONCLUSIONS@#Water immersion could weaken the mechanical properties of the novel self-healing and antibacterial resin composite, but it insignificantly affected the self-healing and antibacterial properties of the composite.

Inhibitory effect of phospholipid complex nanocapsules modified triptolide on glioma cells / 国际生物医学工程杂志

Objective To investigate the anti-glioma treatment effect of triptolide modified by phospholipid complex nanocapsule encapsulation technology in vitro.Methods Human glioma U87 ceils were used to investigate the uptake efficiency of tumor cells to nano-microcapsules TPL and TPL.MTT method was used to detect the proliferation inhibition rate of U87 cells by nano-microcapsule TPL.The levels of ATP and ROS in U87 cells were measured to reflect cell proliferation and apoptosis effect of nano-microcapsules TPL.Results Glioma cells are sensitive to TPL and nano-microcapsule TPL.Compared with single TPL,nano-microcapsule TPL has better glioma cell inhibitory effect and anti-tumor activity (P＜0.05),and has significantly reduced ATP level (P＜0.05) and increased ROS level (P＜0.05) in U87 cells.Conclusions After being encapsulated by nanocapsule technology,TPL has good glioma cell targeting and can significantly enhance the inhibitory effect of drug-loaded liposomes on glioma cell proliferation.

Preparation of zedoary turmeric oil microcapsule by spray drying method / 中草药

Objective: To establish the optimal prescription and technique for preparing zedoary turmeric oil (ZTO) microcapsule. Methods: Using the diameter of microcapsule, microcapsule form, and embedding rate as indexes, the ratio of capsule materials, ratio of core material and capsule material, content of dry matter, content of additive, speed of emulsifying, time of emulsifying, temperature of wind and the power of feed were studied. Results: The optimal conditions for preparation of spray drying of ZTO microcapsule were as follows: gum Arabic-gelatin (1.0∶1.0), core material-capsule material (0.30∶1.0), PEG6000 content of 2%, dry matter content of 20%; The optimal technique was as follows: The emulsion speed was 10 600 r/min, emulsifying time was 9 min, temperature of inlet air was 160 ℃, and feed power was 6%. According to the optimum experimental conditions, the microcapsule was round relatively, the surface density was well, the particle size of microcapsule appeared uniform distribution, most concentrates in 1.0—2.5 μm, and showed good normal distribution, the average particle size was 1.913 μm, the embedding rate could reach 75.4%. Conclusion: This experiment can increase the stability of ZTO, cover up its bad smell, and raise the utilization ratio of drugs, the repeatability is also good.

Study on Bioequivalence of Levodopa Micro-capsule Floating Tablets in Beagle Dogs after Multi-dose Ad-ministration / 中国药房

OBJECTIVE:To study the bioequivalence of Levodopa micro-capsule floating tablets in Beagle dogs after multi-dose administration. METHODS:6 dogs were collected and divided into Levodopa micro-capsule floating tablets group and Com-pound levodopa preparation group (Benserazide tablet,reference preparation). They were given levodopa 200 mg intragastrically, every 8 h,for consecutive 4 day. In two-period crossover test,HPLC method was established to determine the concentration of le-vodopa in dog. The pharmacokinetic parameter,bioequivalence and plasma concentration fluctuation of steady state were calculated. RESULTS:The main pharmacokinetic parameters of Levodopa micro-capsule floating tablets and reference preparation were as that cmax were(4.23±0.75)and(8.47±1.18)μg/ml;AUC0-∞ were(12.18±1.16)and(13.81±2.12)μg·h/ml;tmax were(1.83±0.26) and(0.67±0.13)h,respectively. 90% confidence intervals for the geometric mean ratio of AUC0-∞ for test and reference prepara-tion were 80.61%-97.90%,and that for cmax were 42.75%-57.63%,respectively. There was statistical significance in tmax between test and reference preparation. Degree of fluctuation of test and reference preparation at steady state were(283.914±43.217)% and (506.489±78.965)%,and fluctuation coefficient were(177.463±7.873)% and(187.405±1.650)%,respectively. The degree of fluctuation of test preparation was significantly less than that of reference preparation. CONCLUSIONS:Levodopa micro-capsule floating tablets show good sustained-release property,and are bioequivalent with reference preparation in absorption after multiple dose administration. It also has lesser fluctuation of blood concentration.

Preparation Technology Screening of Activated Carbon N-acetylcysteine Microcapsule / 中国药房

OBJECTIVE:To prepare Activated carbon N-acetylcysteine microcapsule (ACNAC),and to optimize preparation technology. METHODS:ACNAC was prepared by emulsion cross-linked method using biodegradable material gelatin as capsule wall material. Using comprehensive evaluation index of drug-loading amount,entrapment rate and particle size distribution percent-age(the percentage of 80-140 μm particle)as index,drug-loading ratio,amount of gelatin,mixing speed and the amount of emul-sifier as factors,single factor test and orthogonal test were used to optimize formulation technology. The technology was validated and distribution of particle size of ACNAC was determined. RESULTS:The optimal formulation technology was as follows as drug-loading ratio 1∶1,gelatin 15%,emulsifier 2.0%,mixing speed 1 000 r/min. Average drug-loading amount of 6 batches of ACNAC was 15.9%(RSD=1.21%),average encapsulation efficiency was 78.1%(RSD=1.11%)and average particle size distri-bution percentage was 81.9%. CONCLUSIONS:ACNAC is prepared successfully,and formulation technology is reasonable and feasible.

Properties and controlled release of chitosan microencapsulated limonene oil

Chitosan microcapsules containing limonene essential oil as active ingredient were prepared by coacervation using three different concentrations of NaOH (0.50, 1.00, 1.45 wt%) and fixed concentrations of chitosan and surfactant of 0.50 wt%. The produced microcapsules were fully characterized in their morphology and chemical composition, and the kinetic release analysis of the active ingredient was evaluated after deposition in a non-woven cellulose fabric. The concentration of 1.00 and 1.45 wt% clearly show the best results in terms of dimension and shape of the microcapsules as well as in the volatility results. However, at the concentration of 1 wt% a higher number of microcapsules were produced as confirmed by FTIR and EDS analysis. Free microcapsules are spherical in size with disperse diameters between 2 and 12 μm. Immobilized microcapsules showed sizes from 4 to 7 μm, a rough surface and loss of spherical shape with pore formation in the chitosan walls. SEM analysis confirms that at higher NaOH concentrations, the larger the size of the microcapsules. This technique shows that by tuning NaOH concentration it is possible to efficiently control the release rate of encapsulated active agents demonstrating great potential as insect repellent for textiles.

Preparation of paeoniflorin microcapsule and its in vitro release behavior / 中草药

Objective: To optimize the preparation technology of paeoniflorin microcapsule (PM), and to study its behavior of in vitro release. Methods: Using encapsulation efficiency and drug loading as indicators, the PM were prepared by complex agglutination method, the preparation technology of PM was optimized by Doehlert design. The dissolution volume of PM within 20 h and the release curve were measured by HPLC, afterwards its morphology and particle size were studied by electron microscopy. Results: The encapsulation efficiency and drug loading were significantly related to the ratio of coating material, stirring speed, and pH value. The optimal conditions were as follows: the ratio of coating material to paeoniflorin was 4.3:1, the stirring speed was 305 r/min, and the pH value was 4.0. The obtained microcapsules were smooth round capsule-shaped, with non-adhesions and uniform particle size, the encapsulation efficiency was up to 83.81%, the drug loading was 24.24%, and the microcapsule diameter was below 200 μm, with sustained-release effect. Conclusion: The complex agglutination method is simple and reliable to prepare PM, and the product is stable. As a new formulation, microcapsule has a broad prospect for development.

Dissipative particle dynamics method for numerical simulation of distributing state of lutein molecules in modified starch microcapsules / 中国药学杂志

OBJECTIVE: To simulate the distribution state of lutein molecules in modified starch by dissipative particle dynamics method. METHODS: Materials Studio 4.0 Software was used with Visualizer Module to build 3D models of lutein and modified starch. The Discover and Amorphous Cell modules were used to calculate the solubility parameter. Dissipative particle dynamics module was used to simulate lutein distribution in the microcapsules. SEM was used to investigate the structure of the microcapsules. RESULTS: Dissipative particle dynamics simulations showed the aggregation morphology of modified starch inclusion of lutein molecules and the bead movement ability. Dissipative particle dynamics numerical simulation was verified by in vitro experiments, and the results were satisfactory. The feeding ratio of modified starch and lutein was 100;40. The microcapsules production rate was 47.63%, and the microcapsulation efficiency was 85.79%. The particle size of the microcapsules was 70 μm. CONCLUSION: Dissipative particle Dynamics simulation can show the distribution of drugs in microcapsules very well and can be used to predict the feeding ratio.

Preparation of compound vitamin microcapsules using cross-linked gelatin as wall material / 中国药学杂志

OBJECTIVE: To study the preparation and in vitro release profile of compound vitamin microencapsules using cross-linked gelatin as wall material. METHODS: At the presence of hydrogen peroxide, the cross-linked gelatin was prepared with ferulic acid as the cross-linking agent. During this reaction, horseradish peroxidase was used as the catalyst. Influences of reaction conditions on the cross-linking degree were investigated. Compound vitamin microcapsules were prepared by spray-drying technique using the obtained cross-linked gelatin as wall material. The core material was the mixture of thiamine hydrochloride (vitamin B1), riboflavin (vitamin B2), pyridoxine hydrochloride (vitamin B6), folic acid and nicotinamide. The effect of the ratio of wall material to core material on the encapsulation efficiency and loading of the vitamins were investigated. The size and surface morphology of the compound vitamin microcapsules were characterized. The encapsulation efficiency, loading and in vitro release property of the core material were determined by fluorospectrophotometry. RESULTS: A comparatively high cross-linking degree (ca. 10%) of cross-linked gelatin was obtained under the following reaction conditions:temperature of 40°C, pH value of 8.0, gelatin concentration of 9% (W/V), ferulic acid concentration of 40 mmol·L-1 and reaction time of 24 h. The vitamins were embedded by the cross-linked gelatin and the encapsulation efficiency was more than 85%. Scanning electron microscopy (SEM) study showed that the compound vitamin microcapsules had a regular spherical shape but the majority presented rough surfaces or dents. Particle size analysis indicated that the microcapsules had a mean diameter of 15.27 μm. At the ratio of coating material to core material was 10/1 (W/W), the vitamins encapsulated with the cross-linked gelatin released completely in 30 min in simulated gastric fluid, and they released completely in 16 min in simulated intestinal fluid. They released slower than the vitamins encapsulated with the gelatin accordingly. CONCLUSION: Compound vitamin microencapsules with high encapsulation efficiency and sustained release effect can be obtained by spray-drying using cross-linked gelatin as wall material.

Biocompatibility of phosphorylcholine modified alginate-chitosan microcapsules / 中华内分泌外科杂志

ObjectiveTo explore whether the biocompatibility of phosphorylcholine (PC) modified alginate-chitosan microcapsules could be improved. MethodsPC modified alginate-chitosan microcapsules were obtained by high-voltage electrostatic system.Bradford method was adopted to determine the adsorption amounts of bovine serum albumin by chitosan alone and PC modified chitosan.Alginate-chitosan-PC microcapsules (experimental group) and alginate-chitosan microcapsules ( control group) were respectively implanted into the peritoneal cavity of mice and retrieved 4 weeks after transplantation.Fibrosis of the capsules was evaluated by HE staining.Glucose stimulated insulin secretion (GSIS) assay was used to assess the insulin secretion response of encapsulated and nonencapsulated rat islets. Results The adsorption amount of protein was 189.4 μg/mg and 90.5 μg/mg respectively by chitosan alone and PC modified chitosan.The difference had statistical significance ( t =5.549, P ＜ 0.05 ).In contrast to the control group, the cellular reaction on the surface of the modified microcapsules was weaker, with no obvious fibrosis found.The insulin secreted by encapsulated islets and nonencapsulated islets was( 3.298 ± 1.680 ) μIU/ml VS (4.299 ± 1.159 ) μIU/ml ( t =1.096, P ＞ 0.05 ) in response to low-glucose stimulus and( 11.783 ± 4.175 ) μIU/ml VS ( 12.875 ± 2.268 ) μIU/ml ( t =0.514, P ＞ 0.05 ) in response to high-glucose stimulus.Conclusions PC can improve the biocompatibility of alginate-chitosan microcapsules, with no effect on the biological function of encapsulated islets.It may be more appropriate to use modified microcapsules encapsulating islets for transplantation.

Preparation and characterization of capsosome as a novel sandwich-type drug carrier / 中国药学杂志

OBJECTIVE: To fabricate a novel sandwich-type drug carrier called "capsosome" using natural polyelectrolytes such as chitosan and alginate, then characterize the structure, drug loading and release profile. METHODS: Chitosan and alginate and DMPG (Dimyristoyl Phosphatidylglycerole) liposomes were coated on the CaCO3 microparticles using layer-by-layer assembly technique. Upon removal of the CaCO3 template core, stable capsosomes, containing one layer of intact liposomes as cargo, were obtained; As a model drug, DOX with different concentrations was used to evaluate the drug loading ability of capsosome, the cumulative release a-mount was determined at different time points. RESULTS: Confocal laser scanning microscope images and transmission electron microscope images indicated that liposomes were embeded in the microcapsule shell successfully, drug loading amount of the obtained capsosomes increased with the DOX incubation concentration increasing (100-1000 μg · mL-1), the highest loading amount could reach to 30.47 × 10-3 ng/each capsosome, the cumulative release amount was about 46% in 48 h. CONCLUSION: The capsosome had favourable drug loading and release ability, it deserved to be studied as a novel drug carrier. Copyright 2012 by the Chinese Pharmaceutical Association.

Preparation and in vitro release evaluation of metoprolol succinate sustained-release microcapsules / 中国药学杂志

OBJECTIVE: To prepare sustained-release microcapsules of metoprolol succinate(MS) and to investigate the influencing factors. METHODS: The sustained-release microcapsules of metoprolol succinate were prepared with ethyl cellulose(EC) in one step by the emulsion-solvent diffusion method. Uniform design was used to optimize the formulation and preparation technique. Its release behavior in vitro was studied. RESULTS: All microcapsules prepared under the optimum condition were spherical and smooth with the mean particle size in the range of 80-90 μm. The entrapment efficiency was 83.16% and drug release from the MS microcapsules during 18 h reached 96.1% in vitro. CONCLUSION: The microcapsules have good morphological characteristics, high entrapment efficiency and sustained-release effect in vitro.

Novel multi-layer APPPA microcapsules for oral delivery: preparation condition, stability and permeability.

Oral therapy utilizing cell microencapsulation has shown promise in the treatment of many diseases. Current obtainable microcapsule membranes, however, show inadequate stability in the gastrointestinal (GI) environment, thus restricting the general application of live cells for oral therapy. To overcome this limitation, we have previously developed a novel multi-layer alginate/poly-L-lysine/pectin/poly-L-lysine/alginate microcapsule (APPPA) with demonstrated improvement on membrane stability over the frequently reported alginate/poly-L-lysine/alginate (APA) microcapsules. In this study, we further examined the effects of preparation conditions on microcapsule formation, and assessed the membrane strength and GI stability. Results showed that increased membrane strength of the APPPA microcapsules was attained by using pectin with low degree of esterification as the mid-layer material, saline as the solvent for the preparation solutions and washing medium, and 0.1 M CaCl2 as the gelling solution for alginate cores. Resistance of this membrane to the simulated GI fluids was also investigated. Permeability of and release profiles from the APPPA microcapsules were found comparable to the APA microcapsules. These findings suggested that the multi-layer APPPA microcapsule formulation may have potential in oral delivery of proteins, live bacterial cells and other biomedical applications.

Low Frequency Ultrasound Triggering Drug Release from Improved PLGA Microcapsules in Vitro / 中国康复理论与实践

@# Objective To study the effect of low frequency on drug release from improved PLGA microcapsules, and investigate the possibility of utilizing PLGA microcapsules as the carrier of ultrasound targeted drug delivery system to deliver drug into brain. Methods Doxorubicin loaded poly (D,L lactic-co-glycolic acid) (PLGA) microcapsules were prepared via double emulsion solvent evaporate method and coated with either chitosan or gelatin. In vitro drug release profile and the drug release rate under the exposure of low frequency pulsed ultrasound (25 kHz) and continuous wave ultrasound (35.1 kHz) were assayed. Results The coating with chitosan or gelatin can depress the burst of drug release. The drug release rate from uncoated and chitosan-coated microcapsules did not changed with the exposure of ultrasound, and the rate of gelatin-coated microcapsules did increased. The effect of pulsed ultrasound was stronger than that of continuous ultrasound. Conclusion The drug release from gelatin-coated PLGA microcapsules can be controlled and triggered by 25 kHz pulsed ultrasound, which may be a potent carrier of targeting drugs into brain.