Showing papers in "Journal of Microencapsulation in 2011"
TL;DR: In this review, a detailed description of the theoretical and practical aspects behind the production of different types of alginate-based microcapsules, for application in biotechnological and medical processes, using vibrating technology is given.
Abstract: For over a half a century now, microencapsulation has played a very important role in many industries and in the recent decades, this versatile technology has been applied to numerous biotechnology and medical processes. However, successful application in these areas requires a methodology which has the capability to produce mono-dispersed, homogenous-shaped capsules, with a narrow size distribution, using a short production time. The manufacture of capsules using vibrating technology has gained significant interest mainly due to its simplistic approach to produce homogenous microcapsules with the desired characteristics for biotechnological and medical processes. However, certain limitations still exist for this methodology, which include the inability to manufacture microcapsules at large quantities and/or using highly viscous polymers. In this review, a detailed description of the theoretical and practical aspects behind the production of different types of alginate-based microcapsules, for application in biotechnological and medical processes, using vibrating technology, is given.
166 citations
TL;DR: In-vitro drug release study indicated that the rate of drug release from nanoparticles was decreased by increasing the amount of chitosan, and by adding leucine, the particle size of microparticles deceased and the process yield and fine particle fraction (FPF) increased significantly.
Abstract: The aim of this study was to prepare spray dried inhalable powders containing isoniazid-loaded chitosan/tripolyphosphate (TPP) nanoparticles for sustained delivery of the drug to the lung. Nanoparticles were prepared by ionic gelation method. In-vitro drug release study indicated that the rate of drug release from nanoparticles was decreased by increasing the amount of chitosan. Entrapment of isoniazid into chitosan/TPP nanoparticles decreased minimum inhibitory concentrations (MIC) of the drug against mycobacterium avium intracellulare. Nanoparticles were spray dried using excipients such as lactose, mannitol and maltodextrin alone or with leucine. Results showed that the obtained powders had different aerosolization property. It was observed that by adding leucine, the particle size of microparticles deceased and the process yield and fine particle fraction (FPF) increased significantly. The in-vitro deposition data indicated that spray drying of isoniazid-loaded nanoparticles with lactose in the presence of leucine resulted in the production of inhalable powders with the highest FPF (45%).
108 citations
TL;DR: This review covers an update on the state of art of the manufacturing of polymeric NPs from preformed polymers, and conventional methods for NP preparation, such as spontaneous formulation and emulsification-based methods, and new approaches in NP technology are presented.
Abstract: Over the past few decades, nanoparticle (NP) formulation has been the subject of extensive research. The choice of a suitable NP formulation technique is dependent on the physicochemical properties of the drug, such as solubility and chemical stability. Different NP manufacturing methods enable modification of the physicochemical characteristics such as size, structure, morphology and surface texture, but also affect the drug loading, drug entrapment efficiency and release kinetics. This review covers an update on the state of art of the manufacturing of polymeric NPs from preformed polymers. Both, conventional methods for NP preparation, such as spontaneous formulation and emulsification-based methods, and new approaches in NP technology are presented. A comparative analysis is given for polymer, drug and solvent nature, toxicity, purification, drug stability and scalability of the method. The information obtained allows establishing criteria for selecting a method for preparation of NPs according to its advantages and limitations.
93 citations
TL;DR: In simulated gastrointestinal conditions, the SFD and FD cells show up to 4 h better tolerance than SD samples and unencapsulated cells in acidic and pepsin condition, which in turn results in good rehydration behaviour of the powdered product.
Abstract: Spray-drying (SD) and freeze-drying (FD) are widely used methods for microencapsulation of heat-sensitive materials like probiotics for long-term preservation and transport. Spray-freeze-drying (SFD) is relatively a new technique that involves spraying a solution into a cold medium and removal of solvent (water) by conventional vacuum FD method. In this study, the SFD microencapsulated Lactobacillus plantarum powder (1:1 and 1:1.5 core-to-wall ratios of whey protein) is compared with the microencapsulated powders produced by FD and SD methods. The SFD and FD processed microencapsulated powder show 20% higher cell viability than the SD samples. In simulated gastrointestinal conditions, the SFD and FD cells show up to 4 h better tolerance than SD samples and unencapsulated cells in acidic and pepsin condition. The morphology of SFD samples shows particles almost in spherical shape with numerous fine pores, which in turn results in good rehydration behaviour of the powdered product.
85 citations
TL;DR: It was demonstrated that lecithin/chitosan NPs can be applied to skin cells at concentrations up to 200 µg/mL without inducing plasma membrane damage or cell viability decrease.
Abstract: In this study, the potential of lecithin/chitosan nanoparticles (NPs) as colloidal nanosystem for transdermal melatonin delivery was investigated Mean diameter and zeta-potential of NPs differing in lecithin type (Lipoid S45 and S100) and chitosan content ranged between 1137 and 3315 nm and 46 and 312 mV, respectively Melatonin loadings were up to 72% The potential of lecithin/chitosan NPs to enhance transdermal melatonin delivery was investigated by determining the drug flux across dermatomed porcine skin and its skin deposition Lecithin/chitosan NPs provided 13–23-fold higher flux compared to melatonin solution The highest flux, 90 � 021mg/cm 2 /h, was observed for S45 lecithin/chitosan NPs with lecithin/ chitosan weight ratio of 20:1 NP possible cytotoxicity in vitro was evaluated using human skin keratinocytes and fibroblasts It was demonstrated that lecithin/chitosan NPs can be applied to skin cells at concentrations up to 200mg/mL without inducing plasma membrane damage or cell viability decrease
84 citations
TL;DR: PH-sensitive copolymeric hydrogels prepared from N-vinylcaprolactam and methacrylic acid monomers by free radical polymerization offered 52% encapsulation efficiency and evaluated for oral delivery of human insulin were evaluated.
Abstract: pH-sensitive copolymeric hydrogels prepared from N-vinylcaprolactam and methacrylic acid monomers by free radical polymerization offered 52% encapsulation efficiency and evaluated for oral delivery of human insulin. The in vitro experiments performed on insulin-loaded microparticles in pH 1.2 media (stomach condition) demonstrated no release of insulin in the first 2 h, but almost 100% insulin was released in pH 7.4 media (intestinal condition) in 6 h. The carrier was characterized by Fourier transform infrared, differential scanning calorimeter, thermogravimetry and nuclear magnetic resonance techniques to confirm the formation of copolymer, while scanning electron microscopy was used to assess the morphology of hydrogel microparticles. The in vivo experiments on alloxan-induced diabetic rats showed the biological inhibition up to 50% and glucose tolerance tests exhibited 44% inhibition. The formulations of this study are the promising carriers for oral delivery of insulin.
74 citations
TL;DR: A preliminary study on HCT-116 colon cancer cells was developed to evaluate the influence of CU-loaded FA SLNs on cell viability and chitosan hydrochloride was added to FA SLN formulations to produce bioadhesive, positively charged nanoparticles.
Abstract: Curcumin (CU) loaded solid lipid nanoparticles (SLNs) of fatty acids (FA) were prepared with a coacervation technique based on FA precipitation from their sodium salt micelles in the presence of polymeric non-ionic surfactants. Myristic, palmitic, stearic, and behenic acids, and different polymers with various molecular weights and hydrolysis grades were employed as lipid matrixes and stabilisers, respectively. Generally, spherical-shaped nanoparticles with mean diameters below 500 nm were obtained, and using only middle-high hydrolysis, grade-polymer SLNs with diameters lower than 300 nm were produced. CU encapsulation efficiency was in the range 28–81% and highly influenced by both FA and polymer type. Chitosan hydrochloride was added to FA SLN formulations to produce bioadhesive, positively charged nanoparticles. A CU-chitosan complex formation could be hypothesised by DSC analysis, UV–vis spectra and chitosan surface tension determination. A preliminary study on HCT-116 colon cancer cells was developed to evaluate the influence of CU-loaded FA SLNs on cell viability.
71 citations
TL;DR: The results demonstrate the potential of ANNs in modelling and identification of critical parameters effective on final particle size and show that polymer concentration is the most affecting parameter on nanoparticle size distribution.
Abstract: The purpose of this study was to prepare nanoparticles made of tri-block poly(lactide)–poly(ethylene glycol)–poly (lactide) (PLA–PEG–PLA) with controlled size as drug carrier. Artificial neural networks (ANNs) were used to identify factors which influence particle size. In this way, PLA–PEG–PLA was synthesized and was made into nanoparticles by nanoprecipitation under different conditions. The copolymer and the resulting nanoparticles were characterized by various techniques such as proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, photon correlation spectroscopy and scanning electron microscopy. The developed model was assessed and found to be of high quality. The model was then used to survey the effects of processing factors including polymer concentration, amount of drug, solvent ratio and mixing rate on particle size of polymeric nanoparticles. It was observed that polymer concentration is the most affecting parameter on nanoparticle size distribution. The results demonstrate the potential of ANNs in modelling and identification of critical parameters effective on final particle size.
71 citations
TL;DR: Formulation of MTA–SLNs would be a potential delivery carrier for ocular delivery, with the advantages of a more intensive treatment for glaucoma, lower in doses and better patient compliance compared to the conventional eye drops.
Abstract: Methazolamide (MTA) is an antiglaucoma drug; however, there are many side effects of its systemic administration with insufficient ocular therapeutic concentrations. The aim of this study was to formulate MTA-loaded solid lipid nanoparticles (SLNs) and evaluate the potential of SLNs as a new therapeutic system for glaucoma. SLNs were prepared by a modified emulsion-solvent evaporation method and their physicochemical characteristics were evaluated. The pharmacodynamics was investigated by determining the percentage decrease in intraocular pressure. The ocular irritation was studied by Draize test. Despite a burst release of SLNs, the pharmacodynamic experiment indicated that MTA-SLNs had higher therapeutic efficacy, later occurrence of maximum action, and more prolonged effect than drug solution and commercial product. Formulation of MTA-SLNs would be a potential delivery carrier for ocular delivery, with the advantages of a more intensive treatment for glaucoma, lower in doses and better patient compliance compared to the conventional eye drops.
69 citations
TL;DR: Biodegradable Poly(lactic-co-glycolic acid; PLGA), microspheres encapsulating the angiogenic protein recombinant human vascular endothelial growth factor (rhVEGF) were formed to achieve VEGF release in a sustained manner and showed promising delivery system which can be used for therapeutic angiogenesis.
Abstract: Biodegradable Poly(lactic-co-glycolic acid; PLGA), microspheres encapsulating the angiogenic protein recombinant human vascular endothelial growth factor (rhVEGF) were formed to achieve VEGF release in a sustained manner. These microspheres are a promising delivery system which can be used for therapeutic angiogenesis. The PLGA microspheres incorporating two different initial loading amounts of rhVEGF have been prepared by a modified water-in-oil-in-water (w/o/w) double emulsion/solvent evaporation technique. The microspheres have been characterized by particle size distribution, environmental scanning electron microscopy (ESEM), light microscopy, encapsulation efficiency and their degradation was studied in vitro. The rhVEGF released from microspheres was quantified by the competitive enzyme-linked immunosorbent assay (ELISA) and human umbilical vein endothelial cell (HUVEC) proliferation assay was used to assess biological activity of the released VEGF. The microspheres were spherical with diameters of ...
67 citations
TL;DR: The results suggest that the developed novel lecithinized microemulsion systems have a promising potential for the improved topical delivery of dithranol.
Abstract: The objective of this study was to develop and characterize a novel dithranol-containing phospholipid microemulsion systems for enhanced skin permeation and retention. Based on the solubility of dithranol, the selected oils were isopropyl myristate (IPM) and tocopherol acetate (TA), and the surfactants were Tween 80 (T80) and Tween 20 (T20). The ratios of cosurfactants comprising of phospholipids and ethanol (1 : 10) and surfactant to co-surfactant (1 : 1 and 2.75 : 1) were fixed for the phase diagram construction. Selected microemulsions were evaluated for globule size, zeta potential, viscosity, refractive index, per cent transmittance, stability (freeze thaw and centrifugation), ex vivo skin permeation and retention. The microemulsion systems composed of IPM and T80 with mean particle diameter of 72.8 nm showed maximum skin permeation (82.23%), skin permeation flux (0.281 mg/cm2/h) along with skin retention (8.31%) vis-a-vis systems containing TA and T20. The results suggest that the developed novel le...
TL;DR: Encapsulation of ethyl hexanoate in whey protein nanoparticles reduced the mass transfer of aroma at the surface of the matrix and improved its retention.
Abstract: Aroma-loaded nanoparticles (d < 300 nm) were prepared by cross-linking denatured whey protein through pH-cycling. The effect of nanoparticulation conditions and aroma concentration on the physicochemical characteristics of nanoparticles and aroma release profile was studied. Better retention of aroma was observed when ethyl hexanoate was added before nanoparticle formation. The highest aroma retention was obtained for nanoparticles produced at pH 5.0 and 5.5 without calcium addition. These nanoparticles are characterized by a less compact and more porous internal structure allowing a higher loading of aroma. Increasing aroma concentration increased the diameter and the voluminosity of the aroma-loaded nanoparticles. The percentage of aroma retention showed an increase from 7% to 24% over the tested concentration range while the value averaged 2% for native or denatured whey protein. Encapsulation of ethyl hexanoate in whey protein nanoparticles reduced the mass transfer of aroma at the surface of the matr...
TL;DR: In this study, the surface-engineered long-circulating PLGA nanoparticles were assessed for brain-specific delivery and the specific role of Tf ligand on PEGylated NPs for brain delivery was confirmed.
Abstract: Polymer-based nanotechnologies are proposed to be an alternative for drug administration, delivery and targeting to those of conventional formulations. The blood brain barrier is frequently a rate-limiting factor in determining permeation of a drug into brain. In this study, the surface-engineered long-circulating PLGA nanoparticles (NPs) were assessed for brain-specific delivery. Long circulating NPs of PLGA- and PEG-synthesised copolymer were prepared by emulsification solvent evaporation method. Further, the surface of PEGylated NPs was modified by anchoring transferrin (Tf) ligand for receptor-mediated targeting to brain. NPs were characterised for shape and size, zeta potential, entrapment efficiency and in vitro drug release. In vitro cytotoxicity studies were performed on human cancer cell lines. Confocal Laser Scanning Microscopy studies show the enhanced uptake of Tf-appended PEGylated NPs and their localisation in the brain tissues. Hence, the specific role of Tf ligand on PEGylated NPs for brain delivery was confirmed.
TL;DR: Chitosan microparticles loaded with minoxidil sulphate were able to sustain about three times the release rate of MXS and were characterised by yield, encapsulation efficiency, size and morphology, giving them the potential to target and improve topical therapy of alopecia with minxidil.
Abstract: Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (� 82%), a mean diameter of 3.0mm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil.
TL;DR: The presence of PFO when transplanted into a large animal model such as baboon and its absence in small animal models such as rodents suggest that the host immune response towards alginate microcapsules is species rather thanAlginate specific.
Abstract: Pericapsular fibrotic overgrowth (PFO) may be attributed to an immune response against microcapsules themselves or to antigen shedding through microcapsule pores from encapsulated islet tissue. Modification of microcapsules aimed at reducing pore size should prevent PFO and improve graft survival. This study investigated the effect of increased gelling time (20 vs. 2 min) in barium chloride on intrinsic properties of alginate microcapsules and tested their biocompatibility in vivo. Prolonged gelling time affected neither permeability nor size of the microcapsules. However, prolonged gelling time for 20 min produced brittle microcapsules compared to 2 min during compression test. Encapsulation of human islets in both types of microcapsules affected neither islet viability nor function. The presence of PFO when transplanted into a large animal model such as baboon and its absence in small animal models such as rodents suggest that the host immune response towards alginate microcapsules is species rather than alginate specific.
TL;DR: Flow focusing permitted the preparation of insulin-loaded microcarriers with better geometry and physicochemical properties for the oral route, along with greater insulin loading capabilities and sustained insulin release kinetics.
Abstract: Context: Oral administration of insulin is severely limited by very low bioavailability. Biocompatible polymeric nanocarriers have been investigated to overcome this problem. Flow focusing (FF) has revolutionized current engineering of poly(D,L-lactide-co-glycolide) (PLGA) based micromedicines. This technique has never been used to formulate insulin-loaded PLGA microparticles.Objective: Investigation of the benefits rising from the synthesis of insulin-loaded PLGA microplatforms by FF, compared to double emulsion/solvent evaporation method.Materials and methods: Both synthesis methodologies were compared in terms of geometry, surface physicochemical properties and insulin vehiculization capabilities. The stability of the peptide during the formulation procedure was further analysed.Results: FF permitted the preparation of insulin-loaded microcarriers with better geometry and physicochemical properties for the oral route, along with greater insulin loading capabilities and sustained insulin release kinetic...
TL;DR: A microparticulate melanoma cancer vaccine via the transdermal route is formulated using microneedle-based Dermaroller® which is available for cosmetic purposes and shows immunogenicity and protection against live tumour cells.
Abstract: In this study, we formulated a microparticulate melanoma cancer vaccine via the transdermal route. The vaccine was delivered using microneedle-based Dermaroller® which is available for cosmetic purposes. Unlike subcutaneous injections, administration using microneedles is painless and in general can increase the permeability of many compounds ranging in size from small molecules to proteins and microparticles that do not normally penetrate the skin. The vaccine microparticles were taken up by the antigen presenting cells which demonstrated a strong IgG titre level of 930 ug/mL in serum samples. The formulation increased the immunogenicity of the vaccine by incorporating the antigen into an albumin matrix having a size range of around 0.63–1.4 µm which acted as a synthetic adjuvant. The animals were vaccinated with 1 prime and 4 booster doses administered every 14 days over 8 weeks duration, followed by challenge with live tumour cells which showed protection after transdermal vaccination.
TL;DR: The potential of chitosan microparticles as a carrier of doxorubicin for the treatment of visceral leishmaniasis was evaluated by macrophage-mediated drug targeting approach and substantial reduction in leish manial parasite load was displayed.
Abstract: The potential of chitosan microparticles as a carrier of doxorubicin for the treatment of visceral leishmaniasis was evaluated by macrophage-mediated drug targeting approach. Cationic charge of doxorubicin was masked by complexing it with dextran sulphate (a poly anion) in order to facilitate its incorporation into cationic chitosan microparticles. Prior to in vitro and in vivo studies, characterization studies were carried out systematically: particle size (∼1.049 µm), surface morphology (fluorescence microscopy – spherical structured microparticles), Fourier transform infrared spectroscopy (to characterize effective cross-linking) and differential scanning calorimetry. In vitro studies were carried out in J774.1 in order to check the effective endocytotic uptake of microparticles by macrophages. In vivo studies were conducted in Syrian golden hamsters as per well-established protocols and the results drawn from in vivo studies displayed substantial reduction in leishmanial parasite load for doxorubicin-...
TL;DR: Compared with the solution containing the same level of PTX and SRF, PTX–SRF-BSA-NPs demonstrated significantly lower haemolysis and myelosuppression effect.
Abstract: Paclitaxel and sorafenib loaded albumin nanoparticles (PTX–SRF-BSA-NPs) were prepared and studied here to avoid the toxicities from the excipients in the Taxol® and explore the effect of such combination on the antitumour efficacy and toxicity. PTX-BSA-NPs and so on were used as controls. The particle size, zeta potential, encapsulation efficiency and morphology were evaluated. Less than 70% of each drug released within 24 h. PTX and SRF existed as molecular or amorphous form in the PTX–SRF-BSA-NPs. The particle size did not change much after 2-month storage in freeze-dried form or 24 h in suspension. The treatment with PTX–SRF-BSA-NPs (7.5 mg kg−1 PTX + 7.5 mg kg−1 SRF) exhibited lower myelosuppression than PTX-BSA-NPs (15 mg kg−1 PTX) while it remained or increased the antitumour effect in mice tumour models. Compared with the solution containing the same level of PTX and SRF, PTX–SRF-BSA-NPs demonstrated significantly lower haemolysis and myelosuppression effect.
TL;DR: Electrostatic deposition method was used to form primary, secondary and tertiary emulsions containing lipid droplets coated by nanolaminated biopolymer coatings, suggesting the formation of a calcium alginate gel that restricted lipases access to emulsified lipids.
Abstract: The influence of nanolaminated biopolymer coatings around lipid droplets on their physical stability and in vitro digestibility by pancreatic lipase was studied. An electrostatic deposition method was used to form primary, secondary and tertiary emulsions containing lipid droplets coated by: 1°, β-lactoglobulin (β-Lg); 2°, β-Lg-alginate; 3°, β-Lg-alginate-chitosan. The influence of pH (3–7), calcium concentration (5 or 20 mM) and oil type (long vs. medium chain triglycerides) on their physical stability and lipid digestibility was examined. Biopolymer layers had little impact on lipid digestion at 5 mM calcium suggesting that they became detached from the droplet surfaces, but they slowed down digestion considerably at 20 mM calcium, suggesting the formation of a calcium alginate gel that restricted lipases access to emulsified lipids. This study has important implications for design of delivery systems to control lipid digestion and release.
TL;DR: The results indicated that the release of curcumin was significantly increased in the presence of 1% (w/v) rat caecal contents, and it could be concluded that Eudragit® S100 coated calcium pectinate microsphere was a potential carrier for colon delivery ofCurcumin.
Abstract: Currently, colon-specific drug delivery systems have been investigated for drugs that can exert their bioactivities in the colon. In this study, Eudragit® S100 coated calcium pectinate microsphere, a pH-dependent and enzyme-dependent system, as colon-specific delivery carrier for curcumin was investigated. Curcumin-loaded calcium pectinate microspheres were prepared by emulsification-linkage method, and the preparation technology was optimised by uniform experimental design. The morphology of microspheres was observed under scanning electron microscopy. Interactions between drug and polymers were investigated with differential scanning calorimetry (DSC) and X-ray diffraction. In vitro drug release studies were performed in simulated colonic fluid in the presence of Pectinex Ultra SP-L or 1% (w/v) rat caecal content, and the results indicated that the release of curcumin was significantly increased in the presence of 1% (w/v) rat caecal contents. It could be concluded that Eudragit® S100 coated calcium pec...
TL;DR: This review examines the different types of non-deformable nanoparticles (NP) which have been developed for pharmaceutical applications and particular emphasis is given to the disposition and transfer of NP in the skin.
Abstract: In recent years, nanotechnology and nanoengineering have stimulated much research in the field of drug delivery. This review examines the different types of non-deformable nanoparticles (NP) which have been developed for pharmaceutical applications. Metal, metallic oxide, polymeric, starch, quantum dot, fullerene and carbon nanotube NP are discussed. Only those studies which have focused on particle interaction with human and porcine skin models in vitro and in vivo are considered. Particular emphasis is given to the disposition and transfer of NP in the skin. As the methodology and experimental design of published studies should have an impact on the results obtained, these are also critically examined.
TL;DR: Differential scanning calorimetry and X-ray diffraction were implemented to characterize the IBU state of freeze-dried SLNs and IBU was found to be in both amorphous and crystalline form within the lipid matrix.
Abstract: Solid lipid nanoparticles (SLNs) loaded with ibuprofen (IBU) were prepared by solvent-free high-pressure homogenization (HPH). The produced SLNs consisted of stearic acid, triluarin or tripalmitin as lipid matrixes and various stabilizers. The produced empty and IBU-loaded SLNs were characterized for particle size stability over 8 months. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were implemented to characterize the IBU state of freeze-dried SLNs. IBU was found to be in both amorphous and crystalline form within the lipid matrix. The lyophilized powders showed increased dissolution rates for IBU depending on the lipid nature. SLNs were incubated in Caco-2 cells for 24 h showing negligible cell cytotoxicity up to 15 mg/mL.
TL;DR: The enhanced skin permeation and bioavailability of LMWH can be achieved with flexosomes in comparison with ethosomes, which has the potential to replace the parenteral dosage forms for the treatment of venous thromboembolism, pulmonary embolism and cardiovascular events.
Abstract: Low molecular weight heparin (LMWH)-loaded flexible liposomes (flexosomes) were formulated for transdermal delivery, and their physicochemical and pharmacokinetic parameters were compared with LMWH-loaded ethosomes. Flexosomes had similar particle size compared with ethosomes, but their deformability was higher than that of ethosomes (76.7% vs. 46.8%). In vitro, flexosomes demonstrated 2.6-fold higher permeability coefficient than ethosomes. In comparison to LMWH aqueous solution, skin deposition of flexosome increased 3.2-fold, while that of ethosome increased only 2.0-fold. In vivo, after the topical application of flexosome to hairless mouse, [anti-Xa]max was 1.11 IU/mL, while ethosomes showed only 0.32 IU/mL. Moreover, AUC0–24 h of flexosomes was 2.5-fold higher than ethosomes. In conclusion, the enhanced skin permeation and bioavailability of LMWH can be achieved with flexosomes in comparison with ethosomes. The LMWH transdermal delivery via flexosomes has the potential to replace the parenteral dosa...
TL;DR: The relative bioavailabilities for SNS and SQSLN were 37.39% and 66.53%, respectively, compared to 18.87% bioavailability obtained after administration of SMS, indicating suitability of nanoparticulate formulations for improving bioavailability.
Abstract: Solid lipid nanoparticles (SLNs) and nanosuspensions (NSs) have shown great promise for improving bioavailability of poorly water-soluble drugs. This study was aimed to develop SLNs and NS of Saquinavir (SQ) for improvement in bioavailability. These formulations were characterized and their pharmacokinetics and biodistribution in mice were evaluated. Saquinavir-loaded SLNs (SQSLNs) showed particle size 215 � 9n m and entrapment efficiency 79.24 � 1.53%, while solid-state studies (differential scanning calorimetry and X-ray diffraction) indicated entrapment of the drug in SLNs. Saquinavir NS (SNS) showed particle size 344 � 16 nm with fourfold increase in saturation solubility and its solid-state studies showed reduction in crystallinity. Pharmacokinetics and biodistribution studies of orally administered SQSLN and SNS in mice exhibited higher plasma level concentration compared to saquinavir microsuspension (SMS). The relative bioavailabilities for SNS and SQSLN were 37.39% and 66.53%, respectively, compared to 18.87% bioavailability obtained after administration of SMS, indicating suitability of nanoparticulate formulations for improving bioavailability.
TL;DR: The promising role of microencapsulation is summarized, exploring both floating and mucoadhesive microparticles and their application in the treatment of Helicobacter pylori, highlighting the clinical potential of eradication of this widespread infection.
Abstract: Many strategies have been proposed to explore the possibility of exploiting gastroretention for drug delivery. Such systems would be useful for local delivery, for drugs that are poorly soluble at higher pH or primarily absorbed from the proximal small intestine. Generally, the requirements of such strategies are that the vehicle maintains controlled drug release and exhibits prolonged residence time in the stomach. Despite widespread reporting of technologies, many have an inherent drawback of variability in transit times. Microparticulate systems, capable of distributing widely through the gastrointestinal tract, can potentially minimise this variation. While being retained in the stomach, the drug content is released slowly at a desired rate, resulting in reduced fluctuations in drug levels. This review summarises the promising role of microencapsulation in this field, exploring both floating and mucoadhesive microparticles and their application in the treatment of Helicobacter pylori, highlighting the clinical potential of eradication of this widespread infection.
TL;DR: Thermogravimetric analysis demonstrated that microcapsules containing red thyme oil showed a more consistent range of oil loading, from 50 to 80%, than microcapsule containing clove bud oil, which ranged from 30 to 80% (more deviated).
Abstract: The purpose of this study was to produce a safer microcapsule loaded with clove bud oil and red thyme oil to reduce the population of house dust mites (HDMs). Gelatin-based microcapsules 4–85 µm in size were created, with agitation speed and type of oil playing a critical role in governing their size. Microcapsules made up of single spherical units less than 30 µm in diameter remained separate on the fibre, whereas larger microcapsules of over 30 µm ruptured or aggregated. Thermogravimetric analysis (TGA) demonstrated that microcapsules containing red thyme oil showed a more consistent range of oil loading, from 50 to 80%, than microcapsules containing clove bud oil, which ranged from 30 to 80% (more deviated). Mortality tests on Dermatophagoides farinae conducted on fabric with attached microcapsules showed that clove bud oil, containing a more phenolic monoterpenoid (eugenol), was more effective at reducing the live HDMs (94% mortality).
TL;DR: The nanosuspension was found to provide a sustained in vitro release, following the Higuchi square-root release kinetics, and indicated that the nanos Suspension released the drug by combination of dissolution and diffusion.
Abstract: In this study, diclofenac-loaded Eudragit S100-based nanosuspension was prepared by nanoprecipitation method and characterised for particle size, morphology, in vitro release, and for its in vivo ocular anti-inflammatory activity. The diclofenac-loaded Eudragit S100 nanosuspension was found to have a particle size of 172 nm, polydispersibility index of 0.14 and zeta potential of −23.7 ± 6.07 mV, indicating that the nanosuspension is fairly stable. The nanosuspended particles were found to be spherical in shape. The nanosuspension was found to provide a sustained in vitro release, following the Higuchi square-root release kinetics. The results indicated that the nanosuspension released the drug by combination of dissolution and diffusion. The in vivo evaluation of nanosuspension in PGE2-induced ocular inflammation in rabbit model revealed a significantly (p < 0.05) higher inhibition of PGE2-induced polymorphonuclear leukocytes migration and lid-closure scores as compared with the aqueous solution of diclof...
TL;DR: Spray drying was proven as a suitable method for preparing structured microparticles which can control drug release even at exceptionally high drug loadings and preserved its antibacterial effectiveness.
Abstract: Spray dried microparticles containing mupirocin calcium were designed as acrylic matrix carriers with modulated drug release for efficient local drug delivery at minimum daily dose. Particle generation in spray drying and its effect on release performance were assessed by varying drug : polymer ratios with consequently altered initial saturations. Narrow-sized microparticles with mean diameters of 1.7–2.5 µm were obtained. Properties of the generated solid dispersions were examined by X-ray, thermal (thermogravimetric analysis, modulated differential scanning calorimetry) and spectroscopic (Fourier transformed infrared, Fourier transformed Raman) methods and correlated with drug loading and in vitro release. The best control over mupirocin release was achieved for 2 : 1 (w/w) drug : polymer ratio and found to be strongly process-dependent. For a particular ratio, increased feed concentration (>4%) boosted while increased inlet temperature (≥100°C) reduced drug release. Antimicrobial activity testing confi...
TL;DR: Fab′-conjugated liposomes served as a drug delivery system with dual functions: targeted delivery and solubilizing capacity and inhibited prostaglandin E2 production induced by TNF-α-pre-stimulation more efficiently than when loaded in conventional liposome.
Abstract: When an inflammatory stimulus is given, vascular endothelial cells express various cell adhesion molecules including the vascular cell adhesion molecule (VCAM)-1. In this study, the possibility of specifically delivering anti-inflammatory drugs to activated endothelial cells by utilizing VCAM-1 as a target receptor was explored by loading celecoxib, a selective cyclooxygenase-2 inhibitor, into liposomes coupled to the Fab' fragment against VCAM-1. Anti-VCAM-1-Fab'-conjugated liposomes were prepared by forming an amide linkage between amino groups of Fab' and the carboxylic group of glutaryl-N-phosphatidylethanolamine in liposomes using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linker in the presence of sulpho-N-hydroxysuccinimide. The coupling of Fab' to phospholipids constituting liposomes was confirmed by SDS-PAGE analysis. Under our optimized conjugation conditions, 130.0 µg Fab' was coupled to 1 µmol liposomes. Immunoblotting analysis showed that VCAM-1 protein expression could be induced by incubating human umbilical vein endothelial cells (HUVEC) with TNF-α. Confocal laser microsopy analysis revealed that Fab' conjugation to liposomes selectively increased liposomal uptake in TNF-α-pre-stimulated (VCAM-1-expressed) HUVECs, but not in cells without VCAM-1 expression. The concentration of celecoxib loaded in Fab'-conjugated liposomes was 281.1 ± 29 µg/mL, suggesting that liposomal loading also helped to overcome the limitations in celecoxib administration caused by its poor water solubility. Celecoxib loaded in Fab'-conjugated liposomes inhibited prostaglandin E₂ (PGE₂) production induced by TNF-α-pre-stimulation more efficiently than when loaded in conventional liposomes. Therefore, Fab'-conjugated liposomes served as a drug delivery system with dual functions: targeted delivery and solubilizing capacity.