首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Abstract

Dr. Armstrong's expert knowledge and vast experience with amphotericin B have allowed him to speak previously with authority on its merits and demerits. According to his assessment, amphotericin B is a valuable drug, marred by severe toxicity. I shall attempt to explain, in this short presentation, why liposomes as vehicles in which to administer amphotericin B have the potential to redress this agent's principal deficiency.  相似文献   

2.
This study reports a physicochemical stability evaluation of a previously reported liposomal prilocaine (PLCLUV) formulation () before and after steam sterilization as well as its local toxicity evaluation. Prilocaine (PLC) was encapsulated into extruded unilamellar liposomes (LUVs) composed by egg phosphatidylcholine:cholesterol:alfa-tocopherol (4:3:0.07, mole?%). Laser light-scattering analysis (p?>?0.05) and thiobarbituric acid reaction (p?>?0.05) were used to evaluate the liposomes physical (size) and chemical (oxidation) stability, respectively. The prilocaine chemical stability was followed by 1H-nuclear magnetic resonance. These tests detected no differences on the physicochemical stability of PLC or PLCLUV, sterilized or not, up to 30 days after preparation (p?>?0.05). Finally, the paw edema test and histological analysis of rat oral mucosa were used to assess the possible inflammatory effects of PLCLUV. PLCLUV did not evoke rat paw edema (p?>?0.05), and no significant differences were found in histological analysis, when compared to the control groups (p?>?0.05). The present work shows that PLCLUV is stable for a 30-day period and did not induce significant inflammatory effects both in the paw edema test and in histological analysis, giving supporting evidence for its safety and possible clinical use in dentistry.  相似文献   

3.
The present study was aimed at synthesizing an imidazole-based ionic liquid 1-butyl-3-methylimidazolium bromide (BMIMBr) and subsequent development of a novel ionic liquid-in-oil (IL/o) microemulsion (ME) system for dermal delivery of a poorly permeating drug 5-fluorouracil (5-FU). A significant enhancement in the solubility of 5-FU was observed in BMIMBr. IL/o MEs of 5-FU were prepared using isopropyl myristate, Tween 80/Span 20, and BMIMBr. Results of ex vivo skin permeation studies through mice skin indicated that the selected IL/o ME exhibited 4-fold enhancement in percent drug permeation as compared to aqueous solution, 2.3-fold as compared to hydrophilic ointment, and 1.6-fold greater permeation than water in oil (w/o) ME. The results of in vivo studies against dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mice skin carcinogenesis demonstrated that the IL/o ME could effectively treat skin cancer in 4 weeks. In addition, the side effects such as erythema and irritation associated with the conventional formulations were not observed. Histopathological studies showed that the use of IL/o ME caused no anatomic and pathological changes in the skin structure of mice. These studies suggest that the use of IL-based ME system can efficiently enhance the solubility and permeability of 5-FU and hence its therapeutic efficacy.  相似文献   

4.
There is a critical need for development of novel delivery systems to facilitate the translation of nucleic acid-based macromolecules into clinically-viable therapies. The aim of this investigation was to develop and evaluate a novel nanoparticles-in-microsphere oral system (NiMOS) for gene delivery and transfection in specific regions of the gastrointestinal (GI) tract. Plasmid DNA, encoding for the enhanced green fluorescent protein (EGFP-N1), was encapsulated in type B gelatin nanoparticles. NiMOS were prepared by further protecting the DNA-loaded nanoparticles in a poly(epsilon-caprolactone) (PCL) matrix to form microspheres of less than 5.0 μm in diameter. In order to evaluate the biodistribution following oral administration, radiolabeled (111In-labeled) gelatin nanoparticles and NiMOS were administered orally to fasted Balb/C mice. The results of biodistribution studies showed that, while gelatin nanoparticles traversed through the GI tract fairly quickly with more than 54% of the administered dose per gram localizing in the large intestine at the end of 2 h, NiMOS resided in the stomach and small intestine for relatively longer duration. Following oral administration of EGFP-N1 plasmid DNA at 100 μg dose in the control and test formulations, the quantitative and qualitative results presented in this study provide the necessary evidence for transfection potential of NiMOS upon oral administration. After 5 days post-administration, transgene expression in the small and large intestine of mice was observed. Based on these results, NiMOS show significant potential as novel gene delivery vehicle for therapeutic and vaccination purposes.  相似文献   

5.
Development of palatable formulations for pediatric and geriatric patients involves various challenges. However, an innovative development with beneficial characteristics of marketed formulations in a single formulation platform was attempted. The goal of this research was to develop solid oral flexible tablets (OFTs) as a platform for pediatrics and geriatrics as oral delivery is the most convenient and widely used mode of drug administration. For this purpose, a flexible tablet formulation using cetirizine hydrochloride as model stability labile class 1 and 3 drug as per the Biopharmaceutical Classification System was developed. Betadex, Eudragit E100, and polacrilex resin were evaluated as taste masking agents. Development work focused on excipient selection, formulation processing, characterization methods, stability, and palatability testing. Formulation with a cetirizine-to-polacrilex ratio of 1:2 to 1:3 showed robust physical strength with friability of 0.1% (w/w), rapid in vitro dispersion within 30 s in 2–6 ml of water, and 0.2% of total organic and elemental impurities. Polacrilex resin formulation shows immediate drug release within 30 min in gastric media, better taste masking, and acceptable stability. Hence, it is concluded that ion exchange resins can be appropriately used to develop taste-masked, rapidly dispersible, and stable tablet formulations with tailored drug release suitable for pediatrics and geriatrics. Flexible formulations can be consumed as swallowable, orally disintegrating, chewable, and as dispersible tablets. Flexibility in dose administration would improve compliance in pediatrics and geriatrics. This drug development approach using ion exchange resins can be a platform for formulating solid oral flexible drug products with low to medium doses.  相似文献   

6.
Abstract

We have been interested for several years in the development of carrier-dependent antitumor agents. these agents should have the following properties: enhanced antitumor activity compared with the parent compound, decreased toxicity, lack of cross-resistance, and compatibility with the drug carrier.  相似文献   

7.
In anti-cancer therapy mediated by a nanoparticle-based drug delivery system (DDS), overall efficacy depends on the release efficiency of cargos from the nanoparticles in the cancer cells as well as the specificity of delivery to tumor tissue. However, conventional liposome-based DDS have no mechanism for specifically releasing the encapsulated cargos inside the cancer cells. To overcome this barrier, we developed nanoparticles containing a novel liposomal membrane destabilization peptide (LMDP) that can destabilize membranes by cleavage with intramembranous proteases on/in cancer cells. Calcein encapsulated in liposomes modified with LMDP (LMDP-lipo) was effectively released in the presence of a membrane fraction containing an LMDP-cleavable protease. The release was inhibited by a protease inhibitor, suggesting that LMDP-lipo could effectively release its cargo into cells in response to a cancer-specific protease. Moreover, when LMDP-lipo contained fusogenic lipids, the release of cargo was accelerated, suggesting that the fusion of LMDP-lipo with cellular membranes was the initial step in the intracellular delivery. Time-lapse microscopic observations showed that the release of cargo from LMDP-lipo occurred immediately after association of LMDP-lipo with target cells. Consequently, LMDP-lipo could be a useful nanoparticle capable of effective release of cargos specifically into targeted cancer cells.  相似文献   

8.
Cetirizine is a piperazine-derived second-generation antihistaminic drug recommended for treatment of pruritus associated with atopic dermatitis. The present investigation encompasses development of a nanosized novel elastic vesicle-based topical formulation of cetirizine dihydrochloride using combination of Phospholipon® 90G and edge activators with an aim to have targeted peripheral H1 antihistaminic activity. The formulation was optimized with respect to phospholipid/drug/charge inducer ratio along with type and concentration of edge activator. The optimized formulation was found to be satisfactory with respect to stability, drug content, entrapment efficiency, pH, viscosity, vesicular size, spreadability, and morphological characteristics. The ex vivo permeation studies through mice skin were performed using Franz diffusion cell assembly. It was found that the mean cumulative percentage amount permeated in 8 h was almost twice (60.001 ± 0.332) as compared to conventional cream (33.268 ± 0.795) and aqueous solution of drug (32.616 ± 0.969), suggesting better penetration and permeation of cetirizine from the novel vesicular delivery system. Further, therapeutic efficacy of optimized formulation was assessed against oxazolone-induced atopic dermatitis in mice. It was observed that the developed formulation was highly efficacious in reducing the itching score (4.75 itches per 20 min) compared to conventional cream (9.75 itches per 20 min) with profound reduction in dermal eosinophil count and erythema score. To conclude, a novel vesicular, dermally safe, and nontoxic topical formulation of cetirizine was successfully developed and may be used to treat atopic dermatitis after clinical investigation.KEY WORDS: atopic dermatitis, cetirizine, elastic vesicles, oxazolone, topical  相似文献   

9.
Abstract

AmBisome is a lyophilized formulation of amphotericin B incorporated into small unilamellar liposomes composed of hydrogenated soy phosphatidylcholine, distearoyl phosphatidylglycerol, and cholesterol. In aqueous solution AmBisome is quite stable; less than 5% of the drug dissociates from the liposomes during a 72 hour incubation period in human plasma. This stability to loss of drug is a key factor, accounting for the ability of AmBisome to markedly reduce the well known acute and chronic toxicities associated with administration of amphotericin B. Numerous animal and clinical studies have documented therapeutic efficacy of AmBisome for a wide range of fungal infections. Mechanism of action studies indicate that AmBisome liposomes specifically bind to the fungal cell surface, dam the cell membrane, and kill the fungus. In some cases, AmBisome had a slightly lower potency than amphotericin B itself, but much higher doses of AmBisome could be administered safely resulting in an improved therapeutic profile.  相似文献   

10.
A Novel Nanoparticle Formulation for Sustained Paclitaxel Delivery   总被引:1,自引:0,他引:1  
Purpose  To develop a novel nanoparticle drug delivery system consisting of chitosan and glyceryl monooleate (GMO) for the delivery of a wide variety of therapeutics including paclitaxel. Methods  Chitosan/GMO nanoparticles were prepared by multiple emulsion (o/w/o) solvent evaporation methods. Particle size and surface charge were determined. The morphological characteristics and cellular adhesion were evaluated with surface or transmission electron microscopy methods. The drug loading, encapsulation efficiency, in vitro release and cellular uptake were determined using HPLC methods. The safety and efficacy were evaluated by MTT cytotoxicity assay in human breast cancer cells (MDA-MB-231). Results  These studies provide conceptual proof that chitosan/GMO can form polycationic nano-sized particles (400 to 700 nm). The formulation demonstrates high yields (98 to 100%) and similar entrapment efficiencies. The lyophilized powder can be stored and easily be resuspended in an aqueous matrix. The nanoparticles have a hydrophobic inner-core with a hydrophilic coating that exhibits a significant positive charge and sustained release characteristics. This novel nanoparticle formulation shows evidence of mucoadhesive properties; a fourfold increased cellular uptake and a 1000-fold reduction in the IC50 of PTX. Conclusion  These advantages allow lower doses of PTX to achieve a therapeutic effect, thus presumably minimizing the adverse side effects.  相似文献   

11.
The Dtxd (Diphtheria toxoid) was the first antigen encapsulated within liposomes, their adjuvant properties were discovered (their capacity to enhance the vaccine immunogenicity). The point here is not to propose a new method to prepare this lipossomal vaccine. The central idea is to give new dresses for old vaccines by using classical and well-established liposome preparation method changing only the encapsulation pH and the immunization protocol.

The most appropriate method of Dtxd encapsulation within liposome was based on lipid film hydration in 100 mM citrate buffer, pH 4.0. This was accompanied by changes on protein hydrophobicity, observed by CD and fluorescence spectroscopies. Whenever the Dtxd exposed its hydrophobic residues at pH 4.0, it interacted better with the lipossomal (observed by electrophoretic mobility) film than when its hydrophobic residues were buried (pH 9.0). The Dtxd partition coefficient in Triton-X114 and the acrylamide fluorescence quenching were also pH dependent. Both were bigger at pH 4.0 than at pH 9.0. The relationship protein structure and lipid interaction was pH dependent and now it can be easily maximized to enhance encapsulation of antigens in vaccine development.

Mice were primed with formulations containing 5 μg of Dtxd within liposomes prepared in pH 4.0 or 7.0 or 9.0. The boosters were done 38 or 138 days after the first immunization. The IgM produced by immediate response of all lipossomal formulations were higher than the control (free protein). The response patterns and the immune maturity were measured by IgG1 and IgG2a titrations. The IgG1 titers produced by both formulations at pH 4.0 and 7.0 were at least 22 higher than those produced by mice injected lipossomal formulation at pH 9.0. When the boosters were done, 138 days after priming the mice produced a IgG2a titer of 29 and the group that received the booster 30 days after priming produced a titer of 25. The strongest antibody production was the neutralizing antibody (245 higher than the control) produced by those mice injected with lipossomal formulation at pH 4.0 with the booster done 138 days after priming. The simple change on lipossomal pH formulation and timing of the booster enhanced both antibody production and selectivity.  相似文献   

12.
Abstract

The dye, Sulphorhodamine B, was entrapped within liposomes prepared by the reverse evaporation technique. Marked differences in absorption spectra were found when free and entrapped dyes were compared, with a shift in the wavelength of maximum absorption. When entrapped dye was released by lysis of the liposomes, for example by detergent, the absorption spectrum reverted to that of free dye. This absorption change was employed in a novel marker system for complement-mediated immunoassay. As a model assay, human serum albumin was measured using this approach. Liposomes which had been coated with albumin were incubated with anti-albumin antibody and complement and the resulting absorption change measured using an automated spectrophotometric analyser. The decrease in absorption change on the addition of albumin formed the basis of a competitive homogeneous immunoassay for human serum albumin. Using purified albumin as a standard, a correlation of 0.96 was obtained when the albumin in human serum was measured in the liposomal assay and the results compared to measurements using a bromocresol green method.  相似文献   

13.
The objective was to prepare a novel nail lacquer formulation to improve the ungual and trans-ungual delivery of apremilast for the potential treatment of nail psoriasis. Nail lacquer formulation was prepared using Eudragit® S 100 as a film-forming polymer and the mixture of ethanol, ethyl acetate, and water as a solvent system. As a result of high-throughput screening studies, dexpanthenol and salicylic acid were found to be the potential penetration enhancers. After 7 days of in vitro studies, the cumulative amount of apremilast delivered by the nail lacquer formulation across the nail plate was found to be ~3-fold (0.52 ± 0.07 μg/cm2) more compared to control (nail lacquer formulation without enhancers) (0.19 ± 0.02 μg/cm2). The cumulative amount of apremilast retained in the nail plate in the case of nail lacquer formulation was 1.26 ± 0.18 μg/mg which was found to be ~2-fold more compared to control (0.57 ± 0.07 μg/mg). Human subject studies were performed on the nails of thumb and index finger of six volunteers for 15 days. As a result, the cumulative amount of apremilast retained in the free distal edge of the nail plate in the case of nail lacquer was found to be ~2-fold (0.93 ± 0.14 μg/mg) more related to control (0.41 ± 0.04 μg/mg). As a conclusion, nail lacquer formulation was found to be capable of delivering a substantial amount of apremilast into the nail apparatus; thus, it can be a potential option for the treatment of nail psoriasis.  相似文献   

14.
15.
Simvastatin (SV), a drug of the statin class currently used orally as an anti-cholesterolemic via the inhibition of the 3-hydroxy-3-methyl-glutaryl-Coenzyme A (HMG-CoA) reductase, has been found not only to reduce cholesterol but also to have several other pharmacological actions that might be beneficial in airway inflammatory diseases. Currently, there is no inhalable formulation that could deliver SV to the lungs. In this study, a pressurised metered-dose inhaler (pMDI) solution formulation of SV was manufactured, with ethanol as a co-solvent, and its aerosol performance and physico-chemical properties investigated. A pMDI solution formulation containing SV and 6% w/w ethanol was prepared. This formulation was assessed visually and quantitatively for SV solubility. Furthermore, the aerosol performance (using Andersen Cascade impactor at 28.3 L/min) and active ingredient chemical stability up to 6 months at different storage temperatures, 4 and 25°C, were also evaluated. The physico-chemical properties of the SV solution pMDI were also characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and laser diffraction. The aerosol particles, determined using scanning electron microscopy (SEM), presented a smooth surface morphology and were spherical in shape. The aerosol produced had a fine particle fraction of 30.77 ± 2.44% and a particle size distribution suitable for inhalation drug delivery. Furthermore, the short-term chemical stability showed the formulation to be stable at 4°C for up to 6 months, whilst at 25°C, the formulation was stable up to 3 months. In this study, a respirable and stable SV solution pMDI formulation for inhalation has been presented that could potentially be used clinically as an anti-inflammatory therapy for the treatment of several lung diseases.Key Words: lung inflammation, pMDI, pressurised metered dose inhaler, simvastatin  相似文献   

16.
Alcohol-induced dose dumping is a serious concern for the orally administered prolonged release dosage forms. The study was designed to optimize the independent variables, propylene glycol alginate (PGA), Eudragit RS PO (ERS) and coating in mucoadhesive quetiapine prolonged release tablets 200 mg required for preventing the alcohol-induced dose dumping. Optimal design based on response surface methodology was employed for the optimization of the composition. The formulations are evaluated for in vitro drug release in hydrochloric acid alone and with 40% v/v ethanol. The responses, dissolution at 120 min without alcohol (R1) and dissolution at 120 min with alcohol (R2), were statistically evaluated and regression equations are generated. PGA as a hydrophilic polymeric matrix was dumping the dose when dissolutions are carried in 0.1 N hydrochloric acid containing 40% v/v ethanol. ERS addition was giving structural support to the swelling and gelling property of PGA, and thus, was reducing the PGA erosion in dissolution media containing ethanol. Among the formulations, four formulations with diverse composition were meeting the target dissolution (30–40%) in both the conditions. The statistical validity of the mathematical equations was established, and the optimum concentration of the factors was established. Validation of the study with six confirmatory runs indicated high degree of prognostic ability of response surface methodology. Further coating with ReadiLycoat was providing an additional resistance to the alcohol-induced dose dumping. Optimized compositions showed resistance to dose dumping in the presence of alcohol.  相似文献   

17.
Abstract

When considering the use of combination therapies with liposomal anticancer agents several approaches can be defined. One approach could rely on administration of one liposomal formulation with more than one entrapped cytotoxic drug. This study focuses on an assessment of a liposomal formulation containing vincristine and mitoxantrone. Distearoyl phosphatidylcholine (DSPC)/Cholesterol (Choi) (55:45 molar ratio) liposomes were loaded with vincristine using transmembrane pH gradients. These systems were subsequently incubated with mitoxantrone to effect uptake of the second drug. Retention of both drugs was determined in vitro and in vivo. In vitro drug release indicated >95% retention of mitoxantrone and approximately 75% retention of vincristine when liposomes were prepared with an initial interior pH of 2.0. In vivo results however, demonstrated that greater than 80% of the encapsulated vincristine was released within 1 hour following i.v. administration. The instability of a liposomal formulation containing two anticancer drugs following i.v. administration may be a consequence of a combination of factors including drug-loading induced collapse of the transmembrane pH gradient, loss due to osmotic effects and an associated insertion of serum proteins into the bilayer, as well as the presence of a large biological “sink” which can alter the transbilayer drug gradient in favor of drug release.  相似文献   

18.
The aim was to develop a liposomal oxymatrine conjugating d-alpha tocopheryl polyethylene glycol 1000 succinate (OMT-LIP) for enhanced therapeutics of hepatic fibrosis. OMT-LIP was prepared using the remote loading method. The influences of formulation compositions on the encapsulation efficiency of OMT-LIP were investigated. Mean particle size, zeta potential, morphology, in vitro release, fibrotic liver targeting, and therapeutics of OMT-LIP were thoroughly assessed. The intraliposomal buffer composition and concentration, extraliposomal phase composition and pH, types of phospholipid, lipid molar ratio composition, and theoretical drug loading are crucial factors to entrap OMT into liposomes. The optimum OMT-LIP presented spherically unilamellar microstructures with entrapment efficiency of 79.7 ± 3.9%, mean particle size of 121.6 ± 52.9 nm, and zeta potential of −5.87 mV. OMT-LIP significantly increased the accumulation of OMT in the fibrotic liver with an 11.5-fold greater AUC than OMT solution in the dimethylnitrosamine (DMN)-induced hepatic fibrosis animals. OMT-LIP could be a potential strategy to improve treatment outcomes for hepatic fibrosis, showing the protective effects to mice given CCl4 and the enhanced therapeutics to mice with either DMN or CCl4-induced hepatic fibrosis.KEY WORDS: fibrotic liver targeting, hepatic fibrosis, liposomes, oxymatrine, therapeutics  相似文献   

19.
Abstract

Liposomes composed of egg-phosphatidylcholine and egg-phosphati-dylglycerol containing recombinant interleukin-2 (rIL-2) were prepared and characterised for use in locoregional anticancer immunotherapy. During the encapsulation studies it was observed that the protein precipitated. Therefore, the impact of the precipitation phenomenon on the characteristics and in vivo performance of rIL-2 liposomes was studied. Recombinant IL-2 was diluted in various aqueous media and the amount of precipitated protein determined. Also, the in vitro bioactivity, chemical stability, and in vivo antitumor efficacy of liposomes prepared with precipitated rIL-2 or non-precipitated rIL-2 were assessed.

Massive protein precipitation (60 up ± 95% of total protein) was observed upon dilution of rIL-2 in salt-containing media, but not upon dilution in 5% glucose or water. Liposomes prepared with precipitated rIL-2 were shown to release 50% of the entrapped rIL-2 over a three-day period at 37° in protein-containing media. Loss of rIL-2 bioactivity and chemical integrity was observed during storage at 4° over a 4-week period. Locoregional administration of precipitated rIL-2 in the guinea pig Line 10 tumor model resulted in significantly more tumor growth inhibition than administration of non-precipitated rIL-2. Liposomes containing non-precipitated rIL-2 were found to elicit similar antitumor effects as precipitated rIL-2. The results point to the importance of proper characterisation of new rIL-2 formulations as the physical properties of formulated rIL-2 may strongly influence its bioactivity.  相似文献   

20.
The present investigation was undertaken with the objective of formulating orodispersible film(s) of the antidepressant drug tianeptine sodium to enhance the convenience and compliance by the elderly and pediatric patients. The novel film former, lycoat NG73 (granular hydroxypropyl starch), along with different film-forming agents (hydroxypropyl methyl cellulose, hydroxyethyl cellulose, and polyvinyl alcohol), in addition to three film modifiers; namely, maltodextrin, polyvinyl pyrrolidone K90 and lycoat RS780 (pregelatinized hydroxypropyl starch) were evaluated. Eight formulae were prepared by the solvent-casting method; and were evaluated for their in vitro dissolution characteristics, in vitro disintegration time, and their physico-mechanical properties. The promising orodispersible film based on lycoat NG73 (F1); showing the greatest drug dissolution, satisfactory in vitro disintegration time and physico-mechanical properties that are suitable for orodispersible films, was evaluated for its bioavailability compared with a reference marketed product (Stablon® tablets) in rabbits. Statistical analysis revealed no significant difference between the bioavailability parameters (Cmax (ng/ml), tmax (h), AUC0–t (ng h ml−1), and AUC0–∞ (ng h ml−1)] of the test film (F1) and the reference product. The mean ratio values (test/reference) of Cmax (89.74%), AUC0–t (110.9%), and AUC0–∞ (109.21%) indicated that the two formulae exhibited comparable plasma level-time profiles. These findings suggest that the fast orodispersible film containing tianeptine is likely to become one of choices for acute treatment of depression.Key words: bioavailability from orodispersible films and tablets, fast-dissolving films, orodispersible films, solvent-casting method, tianeptine sodium  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号