Cardiac infiltration of diffuse large B-cell lymphoma manifesting as sustained ventricular tachycardia:a case report

Cardiac tumors are rare.However,cardiac metastases can occur in up to 10%of patients with cancer.Among cardiac neoplasms,metastases are much more common than primary cardiac tumors.[1]Metastatic cardiac neoplasms most frequently metastasize from the respiratory system.

Preparation of multicore millimeter-sized spherical alginate capsules to specifically and sustainedly release fish oil

Specific and sustained release of nutrients from capsules to the gastrointestinal tract has attracted many attentions in the field of food and drug delivery.In this work,we reported a monoaxial dispersion electrospraying-ionotropic gelation technique to prepare multicore millimeter-sized spherical capsules for specific and sustained release of fish oil.The spherical capsules had diameters from 2.05 mm to 0.35 mm with the increased applied voltages.The capsules consisted of uniform(at applied voltages of≤10 k V)or nonuniform(at applied voltages of>10 k V)multicores.The obtained capsules had reasonable loading ratios(9.7%-6.3%)due to the multicore structure.In addition,the obtained capsules had specific and sustained release behaviors of fish oil into the small intestinal phase of in vitro gastrointestinal tract and small intestinal tract models.The simple monoaxial dispersion electrospraying-ionotropic gelatin technique does not involve complicated preparation formulations and polymer modification,which makes the technique has a potential application prospect for the fish oil preparations and the encapsulation of functional active substances in the field of food and drug industries.

Cavefish mount a rapid and sustained regenerative response following skeletal muscle injury

Dear Editor,Physical injury and tissue damage are prevalent throughout the animal kingdom,with the ability to regenerate quickly and efficiently providing a selective advantage.In most vertebrates,skeletal muscle possesses a remarkable ability to regenerate,making it a valuable model for investigating the cellular processes underpinning tissue regeneration.Following damage,skeletal muscle mounts a complex regenerative cascade centered around dedicated muscle stem cells,i.e.,satellite cells.These satellite cells are,in turn,regulated by both resident and infiltrating innate immune cells of myeloid lineage,which play a crucial role in activating and guiding the transition of satellite cells towards maturation(Chen et al.,2020;Tidball,2017;Tidball&Villalta,2010).While critical for muscle regeneration,the innate immune system is energetically costly,resulting in many species decreasing immune investment under nutrient-limited environments.Whether this reduced investment results in a decreased capacity to mount a regenerative response following tissue damage remains unclear.Here,we utilized an emerging evolutionary model,the Mexican tetra(Astyanax mexicanus),to investigate the consequences of shifts in immune system investment on skeletal muscle regeneration.

Reciprocal activation of antigen-presenting cells and CAR T cells triggers a widespread endogenous anti-tumor immune response through sustained high-level IFNγproduction

Adoptive cell transfer(ACT)using chimeric antigen receptor(CAR)modified T cells and T cell receptor(TCR)engineered T cells has shown therapeutic efficacy in cancer treatment1,2.CAR T cells are widely applicable to tumor patients because of their ability to directly identify tumor cells in an MHCindependent manner.

Study on Sustained-Release Pesticides Blended with Fosthiazate-Stearic Acid/Expanded Perlite

The low utilization rate of pesticides makes the migration of pesticides in water and soil,which brings great harm to the ecosystem.The development of pesticide carriers with good drug loading capacity and release control abil-ity is an effective method to realize effective utilization of pesticides and reduce pesticide losses.In this work,fosthiazate-stearic acid/expanded perlite sustained-release particles were successfully prepared by vacuum impregnation using expanded perlite(EP)as carrier,fosthiazate(FOS)as model pesticide and stearic acid(SA)as hydrophobic matrix.The structure and morphology of the samples were studied by BET,FT-IR,TGA,XRD,DSC and SEM.The effects of different mass ratios of FOS to SA on loading capacity and release rate at 24 h were investigated.The sustained release behavior of FOS-SA/EP at different temperatures and pH values was investigated by static dialysis bag method.The results showed that FOS and SA were adsorbed in EP pores by physical interaction.With the mass ratios of FOS to SA decreasing from 7:3 to 3:7,the 24 h release rate of FOS-SA/EP decreased from 18.77%to 8.05%,and the drug loading decreased from 461.32 to 130.99 mg/g.FOS-SA/EP showed obvious temperature response at 25℃,30℃ and 35℃,the cumulative release rate(CRR)of 200 h were 33.38%,41.50%and 51.17%,respectively.When pH=5,the CRR of FOS was higher than that of pH=7,and the CRR of FOS for 200 h were 49.01%and 30.12%,respectively.At different temperatures and pH=5,the release mechanism of FOS-SA/EP belongs to the Fickian diffusion mechanism;When pH=7,the diffusion mechanism is dominant,and the dissolution mechanism is complementary.

Coating Process of Paeonol Sustained Release Pills

[Objectives] To study the coating process of paeonol sustained release pills by extrusion-spheronization method taking ethyl cellulose as the coating material. [Methods] Paeonol pills were made by Auari AW-95 Full Automatic Pill Making Machine. Coating of paeonol sustained release pills was prepared by Auari Mini Pill Polishing Machine. The prescription and process factors of paeonol sustained release pills coating were investigated by single factor experiment and orthogonal experiment. The release of paeonol sustained release pills was determined according to the cumulative release curve of paeonol. [Results] The prepared paeonol sustained release pills released slowly within 24 h, and the release rate reached 80% in 12 h. [Conclusions] The prepared paeonol sustained release pills basically meet the 24 h sustained release standard, and can be further developed and applied.

National Economy Sustained Good Momentum of Recovery in October

In October,the macro-control policies continued to show their effects,production and supply increased steadily,market demand witnessed continuous improvement,employment and prices were generally stable,transformation and upgrades were advanced solidly,and the national economy sustained the good momentum of recovery.

The preparation and the in-vitro pharmacodynamics study of the intracapsular sustained-release preparations for the prevention of posterior capsule opacification

Docetaxel-loaded sustained-release preparation based on 2-Hydroxyethyl methacrylate(HEMA)and Methyl methacrylate(MMA)cross-linked copolymer(P(HEMA-co-MMA))was prepared to examine the potential use for preventing posterior capsule opacification(PCO).The preparations were prepared by polymerizing the mixture of HEMA,MMA,cross-linking agent(EGDMA),initiator(AIBN)and docetaxel.The influence factors and mechanism of drug release were studied in the experiments.FT-IR,X-RD and SEM methods were used to characterize the polymer(P(HEMA-co-MMA))and docetaxel-loaded sustained-release preparations.Biocompatibility of P(HEMA-co-MMA)and in-vitro effect of docetaxel-loaded sustained-release preparations were also evaluated.The results showed that docetaxel could release sustainedly from these preparations prepared by cross-linking polymerization.And the release rate could be accelerated by increasing the MMA ratio or EGDMA ratio of the polymer.Release mechanism of docetaxel fitted the Higuchi model well.The results of IR and X-RD showed that only a hydrogen bond was formed between docetaxel and P(HEMA-co-MMA).Docetaxel dispersed in P(HEMA-co-MMA)in amorphous form.The elution test showed that P(HEMA-co-MMA)had good biocompatibility and the in-vitro pharmacodynamics study proved that docetaxel could release stably from the preparations and inhibit HLECs’proliferation.The docetaxel-loaded sustained-release preparations proved to be a promising therapy for preventing PCO.These results also lay a theoretical and experimental foundation for the future.

Effect of acupuncture combined with Xijing Tongmai decoction on the sustained expression of transient outward potassium channel related protein in rats with myocardial infarction

Objective:To observe the sustained expression of transient outward potassium channel related proteins at the end of the treatment and 30 days after the end of the treatment in rats,and to explore the sustained curative effect and mechanism of acupuncture combined with Xijingtongmai decoction in rats with myocardial infarction.Methods:Twenty of 130 male SD rats were random extracted as the control group,and the rest were used to establish myocardial infarction by fed with high-fat diet and then injected with isoproterenol.According to ECG,80 rats were successfully established.Then they were randomly divided into model group,acupuncture combined with Chinese medicine group,acupuncture group and Western medicine group.The content of bFGF protein was measured by ELISA.The protein contents of Kv1.4,Kv4.2,Kv4.3 and KChIP2 were measured by Western blot.Results:At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).Compared with the treatment group at the end of treatment,the expression of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF protein in each treatment group 30 days after the end of treatment decreased slightly(P<0.05),but still higher than that of the model group at this time(P<0.05).The combination of acupuncture and Chinese medicine group decreased the least of them(P<0.05).Conclusion:The results showed that acupuncture combined with xijingtongmai decoction had a sustained good effect.Its sustained action mechanism may be achieved by continuously increasing the protein content of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF through transient outward potassium channel.

Vitamin D supplementation improves sustained virologic response in chronic hepatitis C (genotype 1)-nave patients

AIM: To determine whether adding vitamin D, a potent immunomodulator, improves the hepatitis C virus (HCV) response to antiviral therapy. METHODS: Seventy-two consecutive patients with chronic HCV genotype 1 were randomized into two groups: the treatment group (n = 36, 50% male, mean age 47 ± 11 years) received Peg-α-2b interferon (1.5 μg/kg per week) plus ribavirin (1000-1200 mg/d) together with vitamin D3 (2000 IU/d, target serum level > 32 ng/mL), and the control group (n = 36, 60% male, mean age 49 ± 7 years) received identical therapy without vitamin D. HCV-RNA was assessed by realtime polymerase chain reaction (sensitivity, 10 IU/mL). The sustained virologic response (SVR) was defined as undetectable HCV-RNA at 24 wk post-treatment. RESULTS: Clinical characteristics were similar in both groups. The treatment group had a higher mean bodymass index (27 ± 4 kg/m2 vs 24 ± 3 kg/m2, P < 0.01), viral load (50% vs 42%, P < 0.01), and fibrosis score (> F2: 42% vs 19%, P < 0.001) than the controls. At week 4, 16 (44%) treated patients and 6 (17%) controls were HCV-RNA negative (P < 0.001). At week 12, 34 (94%) treated patients and 17 (48%) controls were HCV-RNA negative (P < 0.001). At 24 wk post-treatment (SVR), 31 (86%) treated patients and 15 (42%) controls were HCV-RNA negative (P < 0.001). Viral load, advanced fibrosis and vitamin D supplementation were strongly and independently associated with SVR (multivariate analysis). Adverse events were mild and typical of Peg-α-2b/ribavirin. CONCLUSION: Adding vitamin D to conventional Peg-α-2b/ribavirin therapy for treatment-na■ve patients with chronic HCV genotype 1 infection significantly improves the viral response.

Fatty liver in hepatitis C patients post-sustained virological response with direct-acting antivirals

AIM To determine steatosis and fibrosis prevalence in hepatitis C patients after a sustained virological response achieved with direct-acting antivirals.METHODS Transient elastography with controlled attenuation parameter(CAP) was used to assess hepatic steatosis post-sustained virological response(SVR);the CAP technology was not available in the United States at study initiation.Liver stiffness/fibrosis was measured before and 47 wk after treatment completion.Patients with genotype 3 and patients with cirrhosis were excluded.RESULTS One hundred and one patients were included in the study.Post-SVR there were decreases from baseline in alanine aminotransferase(ALT)(63.1 to 17.8 U/L),aspartate aminotransferase(51.8 to 21.5 U/L) and fibrosis score(7.4 to 6.1 k Pa)(P < 0.05).Post-SVR,48 patients(47.5%) had steatosis on CAP;of these,6.25% had advanced fibrosis.Patients with steatosis had higher body mass index(29.0 vs 26.1 kg/m2),glucose(107.8 vs 96.6 mg/d L),ALT(20.4 vs 15.3 mg/d L),CAP score(296.3 vs 212.4 d B/m) and fibrosis score(7.0 vs 5.3 k Pa);P < 0.05.Interestingly,compared to baseline,both patients with and without steatosis had change in fibrosis score post-SVR(7.7 k Pa vs 7.0 k Pa and 7.0 k Pa vs 5.3 k Pa);alternatively,(P < 0.05) and therefore patients with steatosis continued to have clinically significant stiffness(≥ 7 k Pa).CONCLUSION Fatty liver is very common in hepatitis C virus(HCV) patients post-SVR.These patients continue to have elevated mean fibrosis score(≥ 7 k Pa) compared to those without fatty liver;some have advanced fibrosis.Long term follow up is needed to assess steatosis and fibrosis in HCV patients post-SVR.

Sustained virologic response to direct-acting antiviral agents predicts better outcomes in hepatitis C virus-infected patients: A retrospective study

BACKGROUND Direct-acting antiviral agents(DAAs)are extremely effective in eradicating hepatitis C virus(HCV)in chronically infected patients.However,the protective role of the sustained virologic response(SVR)achieved by second-and thirdgeneration DAAs against the onset of hepatocellular carcinoma(HCC)and mortality is less well established.AIM To examine the occurrence of HCC or death from any cause in a retrospectiveprospective study of patients treated with DAAs.METHODS Patients were enrolled from a tertiary academic hospital center for liver disease management that collects subject data mainly from northeastern Italy.The study was conducted in 380 patients(age:60±13 years,224 males,32%with cirrhosis)treated with DAAs with or without SVR(95/5%),with a median follow up of 58 wk(interquartile range:38-117).The baseline anthropometric features,HCV viral load,severity of liver disease,presence of extra-hepatic complications,coinfection with HIV and/or HBV,alcohol consumption,previous interferon use,alphafetoprotein levels,and renal function were considered to be confounders.RESULTS The incidence rate of HCC in patients with and without SVR was 1.3 and 59 per 100 person-years,respectively(incidence rate ratio:44,95%CI:15-136,P<0.001).Considering the combined endpoint of HCC or death from any cause,the hazard ratio(HR)for the SVR patients was 0.070(95%CI:0.025-0.194,P<0.001).Other independent predictors of HCC or death were low HCV viremia(HR:0.808,P=0.030),low platelet count(HR:0.910,P=0.041),and presence of mixed cryoglobulinemia(HR:3.460,P=0.044).Considering SVR in a multi-state model,the independent predictors of SVR achievement were absence of cirrhosis(HR:0.521,P<0.001)and high platelet count(HR:1.019,P=0.026).Mixed cryoglobulinemia predicted the combined endpoint in patients with and without SVR(HR:5.982,P=0.028 and HR:5.633,P=0.047,respectively).CONCLUSION DAA treatment is effective in inducing SVR and protecting against HCC or death.A residual risk of HCC persists in patients with advanced liver disease or with complications,such as mixed cryoglobulinemia or renal failure.

Calculation analysis of sustained casing pressure in gas wells

Sustained casing pressure （SCP） in gas wells brings a serious threat to worker safety and environmental protection. According to geological conditions, wellbore structure and cement data of gas wells in the Sichuan-Chongqing region, China, the position, time, environmental condition and the value of SCP have been analyzed. On this basis, the shape of the pressure bleed-down plot and pressure buildup plot were diagnosed and the mechanism of SCP has been clarified. Based on generalized annular Darcy percolation theory and gas-liquid two-phase fluid dynamics theory, a coupled mathematical model of gas migration in a cemented annulus with a mud column above the cement has been developed. The volume of gas migrated in the annulus and the value of SCP changing with time in a gas well in Sichuan have been calculated by this model. Calculation results coincided well with the actual field data, which provide some reference for the following security evaluation and solution measures of SCP.

Development of composite PLGA microspheres containing exenatide-encapsulated lecithin nanoparticles for sustained drug release

This study aimed to prepare poly(D, L-lactic-co-glycolic acid) microspheres(PLGA-Ms)by a modified solid-in-oil-in-water(S/O/W) multi-emulsion technique in order to achieve sustained release with reduced initial burst and maintain efficient drug concentration for a prolonged period of time. Composite PLGA microspheres containing exenatideencapsulated lecithin nanoparticles(Ex-NPs-PLGA-Ms) were obtained by initial fabrication of exenatide-loaded lecithin nanoparticles(Ex-NPs) via the alcohol injection method,followed by encapsulation of Ex-NPs into PLGA microspheres. Compared to Ms prepared by the conventional water-in-oil-in-water(W/O/W) technique(Ex-PLGA-Ms), Ex-NPs-PLGAMs showed a more uniform particle size distribution, reduced initial burst release, and sustained release for over 60 d in vitro. Cytotoxicity studies showed that Ms prepared by both techniques had superior biocompatibility without causing any detectable cytotoxicity.In pharmacokinetic studies, the effective drug concentration was maintained for over 30 d following a single subcutaneous injection of two types of Ms formulation in rats, potentially prolonging the therapeutic action of Ex. In addition, administration of Ex-NPs-PLGA-Ms resulted in a more smooth plasma concentration-time profile with a higher area under the curve(AUC) compared to that of Ex-PLGA-Ms. Overall, Ex-NPs-PLGA-Ms prepared by the novel S/O/W method could be a promising sustained drug release system with reduced initial burst release and prolonged therapeutic efficacy.

Sustained virological response: A milestone in the treatment of chronic hepatitis C

AIM: To evaluate the long-term eradication of hepatitis C virus (HCV) infection and liver-related complications in chronically infected patients that have achieved sustained virological response. METHODS: One hundred and fifty subjects with chronic hepatitis C (CHC) or cirrhosis and sustained virological response (SVR) between the years of 1989 and 2008 were enrolled in a long-term clinical follow-up study at the Gastrointestinal and Liver Unit of the University Hospital of Naples "Federico Ⅱ". At the beginning of the study, the diagnosis of HCV infection was made on the basis of serum positivity for antibodies to HCV and detection of HCV RNA transcripts, while a diagnosis of chronic hepatitis was formulated using imaging techniques and/or a liver biopsy. SVR was achieved by interferon-based therapy, both conventional and pegylated, with and without ribavirin treatment. The patients were evaluated for follow-up at a median length of 8.6 years, but ranged from 2-19.9 years. Among them, 137 patients had pre-treatment CHC and 13 had cirrhosis. The patients were followed with clinical, biochemical, virological, and ultrasound assessments on a given schedule. Finally, a group of 27 patients underwent a liver biopsy at the beginning of the study and transient elastography at their final visit to evaluate changes in liver fibrosis. RESULTS: The median follow-up was 8.6 years (range 2-19.9 years). HCV RNA remained undetectable in all patients, even in patients who eventually developed liver-related complications, indicating no risk of HCV recurrence. Three liver-related complications were observed: two cases of hepatocellular carcinoma and one case of bleeding from esophageal varices resulting in an incidence rate of 0.23%/person per year. Further, all three complications took place in patients diagnosed with cirrhosis before treatment began. Only one death due to liver-related causes occurred, resulting in a mortality rate of 0.077% person per year. This amounts to a 99.33% survival rate in our cohort of patients after therapy for HCV infection. Finally, of the 27 patients who underwent a liver biopsy at the beginning of the study, a reduction in liver fibrosis was observed in 70.3% of the cases; only three cases registering values of liver stiffness indicative of significant fibrosis. CONCLUSION: Patients with CHC and SVR show an excellent prognosis with no risk of recurrence and a very low rate of mortality. Our data indicate that viruseradication following interferon treatment can last up to 20 years.

Sustained release of exosomes loaded into polydopamine-modified chitin conduits promotes peripheral nerve regeneration in rats

Exosomes derived from mesenchymal stem cells are of therapeutic interest because of their important role in intracellular communication and biological regulation.On the basis of previously studied nerve conduits,we designed a polydopamine-modified chitin conduit loaded with mesenchymal stem cell-derived exosomes that release the exosomes in a sustained and stable manner.In vitro experiments revealed that rat mesenchymal stem cell-derived exosomes enhanced Schwann cell proliferation and secretion of neurotrophic and growth factors,increased the expression of Jun and Sox2 genes,decreased the expression of Mbp and Krox20 genes in Schwann cells,and reprogrammed Schwann cells to a repair phenotype.Furthermore,mesenchymal stem cell-derived exosomes promoted neurite growth of dorsal root ganglia.The polydopamine-modified chitin conduits loaded with mesenchymal stem cell-derived exosomes were used to bridge 2 mm rat sciatic nerve defects.Sustained release of exosomes greatly accelerated nerve healing and improved nerve function.These findings confirm that sustained release of mesenchymal stem cell-derived exosomes loaded into polydopamine-modified chitin conduits promotes the functional recovery of injured peripheral nerves.

Application of sustained delivery microsphere of cyclosporine A for preventing posterior capsular opacification in rabbits

AIM:To explore the inhibitory effect of a sustained cyclosporin A (CsA) delivery microsphere (CsA-MS) on posterior capsular opacification (PCO) in rabbit eyes after cataract extraction. ·METHODS:Twenty New Zealand white rabbits accepted cataract extraction plus intraocular lens implantation and their left eyes were intraoperatively injected CsA-MS prepared using polymer polylactioglycolic acid (PLGA) as a carrier and their right eyes were injected with empty MS. The changes in cornea, anterior chamber reaction, intraocular pressure, PCO and CsA concentration in aqueous humor were examined postoperatively and all the eyes were enucleated 3 months after surgery for histopathological and morphological examination with light microscopy and electron microscopy. · RESULTS:Conjunctival hyperemia, corneal edema, intraocular pressure and anterior chamber response of experimental and control eyes were similar, while PCO in CsA MS injected eyes was greatly improved compared with that in control eyes. Posterior capsules in CsA-MS injected eyes were smooth and lens epithelial cells (LEC) did not proliferate significantly (P 】0.05), while LEC in posterior capsule of control eyes had different degrees of proliferation and cortical regeneration. LEC in CsA-MS injected eyes were not functionally active and underwent apoptosis, whereas LEC in control eyes were functionally active (F-test, P =0.025). In addition, the cornealultrastructure showed no differences between CsA-MS and MS injected eyes. CONCLUSION:CsA-MS has high bioavailability in rabbit eyes and could inhibit postoperative PCO occurrence and development during the study period, suggesting that CsA-MS may be a promising, effective and safe administration route to prevent PCO in clinic.

Tensile Strength Characteristics of GFRP Bars in Concrete Beams with Work Cracks under Sustained Loading and Severe Environments

To investigate the effect of different environmental conditions of GFRP bars in concrete beams with work cracks subjected to sustained loads, the beams were exposed in indoor, freeze/thaw cycles and immersed in alkaline solution at elevated temperature. The bars were carefully extracted from the beams and tested in order to evaluate residual tensile properties. The results show that the tensile strength decreased significantly in the highly aggressive conditions but not in the natural conditions. The effect of GFRP bars casting in concrete beams demonstrated approximately 2.5% decrease of tensile strength caused by pore water environment in concrete beams on basis of those of the original bars. The effect of sustained loading plus work cracks demonstrated about 10.5% tensile strength decrease on basis of those of the bars only casted in concrete beams. The effect of environments under sustained loading plus work cracks demonstrated about 17% tensile strength decrease caused by a saturated solution of Ca（OH）2 and 60-2 ℃ tap water （pH=12-13） and about 8% tensile strength decrease caused by freezing and thawing cycle （F/T）, both on basis of those of the bars of the indoor beams only under sustained loading plus work cracks. The results demonstrate the effects of the tensile strengths under different environmental conditions of GFRP bars in concrete beams with work cracks subjected to sustained loads.

Sustained release donepezil loaded PLGA microspheres for injection:Preparation,in vitro and in vivo study

The purpose of this study was to develop a PLGA microspheres-based donepezil(DP)formulation which was expected to sustain release of DP for one week with high encapsulation efficiency(EE).DP derived from donepezil hydrochloride was encapsulated in PLGA microspheres by the O/W emulsion-solvent evaporation method.The optimized formulation which avoided the crushing of microspheres during the preparation process was characterized in terms of particle size,morphology,drug loading and EE,physical state of DP in the matrix and in vitro and in vivo release behavior.DP microspheres were prepared successfully with average diameter of 30m,drug loading of 15.92±0.31%and EE up to 78.79±2.56%.Scanning electron microscope image showed it has integrated spherical shape with no drug crystal and porous on its surface.Differential scanning calorimetry and X-ray diffraction results suggested DP was in amorphous state or molecularly dispersed in microspheres.The Tg of PLGA was increased with the addition of DP.The release profile in vitro was characterized with slow but continuous release that lasted for about one week and fitted well with first-order model,which suggested the diffusion governing release mechanism.After single-dose administration of DP microspheres via subcutaneous injection in rats,the plasma concentration of DP reached peak concentration at 0.50 d,and then declined gradually,but was still detectable at 15 d.A good correlation between in vitro and in vivo data was obtained.The results suggest the potential use of DP microspheres for treatment of Alzheimer’s disease over long periods.

Evaluation of gum mastic(Pistacia lentiscus) as a microencapsulating and matrix forming material for sustained drug release

In this study, a natural gum mastic was evaluated as a microencapsulating and matrixforming material for sustained drug release. Mastic was characterized for its physicochemical properties. Microparticles were prepared by oil-in-oil solvent evaporation method. Matrix tablets were prepared by wet and melt granulation techniques. Diclofenac sodium(DFS) and diltiazem hydrochloride(DLTZ) were used as model drugs. Mastic produced discrete and spherical microspheres with DLTZ and microcapsules with DFS. Particle size and drug loading of microparticles was in the range of 22–62 μm and 50–87%, respectively. Increase in mastic:drug ratio increased microparticle size, improved drug loading and decreased the drug release rate. Microparticles with gum: drug ratio of 2:1 could sustain DLTZ release up to 12 h and released 57% DFS in 12 h. Mastic produced tablets with acceptable pharmacotechnical properties. A 30% w/w of mastic in tablet could sustain DLTZ release for 5 h from wet granulation,and DFS release for 8 h and 11 h from wet and melt granulation, respectively. Results revealed that a natural gum mastic can be used successfully to formulate matrix tablets and microparticles for sustained drug release.