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1.
Calcium pectinate gel (CPG) beads entrapping catechin-loaded liposomes were prepared with or without hydroxypropylmethylcellulose (HPMC) (denoted as CPG-LH and CPG-L beads, respectively) and characterized in comparison with the CPG beads prepared without liposome and HPMC (denoted as CPG-C beads). For all types of beads, the catechin entrapment efficiency decreased by about 40-50% as the concentration of CaCl2 in gelling media increased from 2 to 6%. At a constant CaCl2 level, the entrapment efficiency was higher in the order of CPG-LH, CPG-L, and CPG-C beads. The in vitro release test showed that in simulated intestinal fluid the rate of catechin release was higher in the order of CPG-C, CPG-L, and CPG-LH beads, indicating that the catechin release was slowed by liposome and further retarded when HPMC was used simultaneously, whereas not in simulated gastric fluid. The addition of cholesterol in liposome could not retard but accelerated the catechin release. The results suggest that the CPG beads reinforced with liposome and HPMC could be employed for a sustained oral delivery of catechins, although further improvements are necessary. 相似文献
2.
The purpose of this research was to develop liposomal dry powder aerosols for protein delivery. The delivery of stable protein
formulations is essential for protein subunit vaccine delivery, which requires local delivery to macrophages in the lungs.
β-Glucuronidase (GUS) was used as a model protein to evaluate dry powder liposomes as inhaled delivery vehicles. Dimyristoyl
phosphatylcholine:cholesterol (7∶3) was selected as the liposome composition. The lyophilization of liposomes, micronization
of the powders, aerosolization using a dry powder inhaler (DPI), and in vitro aerodynamic fine particle fraction upon collection
in a twinstage liquid impinger were evaluated. After lyophilization and jet-milling, the total amount of GUS and its activity,
representing encapsulation efficiency and stability, were evaluated. The GUS amount and activity were measured and compared
with freshly-prepared liposomes in the presence of mannitol, 43% of initial GUS amount, 29% of GUS activity after lyophilization
and 36% of GUS amount, 22% of activity after micronization were obtained. Emitted doses from dry powder inhaler were 53%,
58%, 66%, and 73% for liposome powder:mannitol carrier ratios of 1∶0, 1∶4, 1∶9, and 1∶19. Fifteen percent of the liposome
particles were less than 6.4 μm in aerodynamic diameter. The results demonstrate that milled liposome powders containing protein
molecules can be aerosolized effectively at a fixed flow rate. Influences of different cryoprotectants on lyophilization of
protein liposome formulations are reported. The feasibility of using liposomal dry powder aerosols for protein delivery has
been demonstrated but further optimization is required in the context of specific therapeutic proteins.
Published: December 21, 2005 相似文献
3.
The aim of the present study was to design a depot delivery system of acyclovir sodium using multivesicular liposomes (MVLs)
to overcome the limitations of conventional therapies and to investigate its in vivo effectiveness for sustained delivery.
MVLs of acyclovir were prepared by the reverse phase evaporation method. The loading efficiency of the MVLs (45%–82%) was
found to be 3 to 6 times higher than conventional multilamellar vesicles (MLVs). The in vitro release of acyclovir from MVL
formulations was found to be in a sustained manner and only 70% of drug was released in 96 hours, whereas conventional MLVs
released 80% of drug in 16 hours. Following intradermal administration to Wistar rats, the MVL formulations showed effective
plasma concentration for 48 hours compared with MLVs and free drug solution (12–16 hours). C max values of MVL formulations were significantly less (8.6–11.4 μg/mL) than MLV and free drug solution (12.5 μg/mL). The AUC 0–48 of the MVL formulations was 1.5- and 3-fold higher compared with conventional liposomes and free drug solution, respectively.
Overall, formulations containing phosphatidyl glycerol as negatively charged lipid showed better results. The MVL delivery
system as an intradermal depot offers the advantage of a very high loading and controlled release of acyclovir for an extended
period of time. The increase in AUC and decrease in C max reflects that the MVL formulations could reduce the toxic complications and limitations of conventional IV and oral therapies.
Published: September 20, 2005 相似文献
4.
The purpose of this study was to establish a new experimental approach to determine the maximum amount of campothecin (CPT)
that can be incorporated in liposomes, and to use this method to compare the CPT-incorporation capacity of various liposome
formulations. Small, CPT-saturated liposomes were prepared by dispersing freeze-dried blends of lipids and drug in phosphate
buffer, and subsequent probe-sonication. Excess precipitated CPT could be separated from the liposomes by ultra-centrifugation.
The small and homogeneous liposome size obtained gave a good and reproducible recovery of liposomes in the supernatant (>80%),
whereas the acidic pH (pH 6.0) kept CPT in its hydrophobic lactone form, which is poorly soluble in the buffer. The maximum
CPT-incorporation capacity of 12 different liposome formulations was investigated, using the described method, and was found
to vary widely. With liposomes made of neutral and anionic phospholipids, the solubili ty of CPT in the buffer was improved
by approximately a factor of 10 (from ∼2.7 to 15–50 μg/mL) as compared with buffer. With cationic liposomes containing 1,2-dioleoyl-3-trimethylammonium-propane
(DOTAP), a maximum CPT-solubilization of ∼100-fold, the buffer solubility was reached, probably owing to an electrostatic
interaction between the cationic lipids and the carboxylate-CPT isomer. Increasing DOTAP fractions within egg-phosphatidylcholine
(EPC)/DOTAP liposomes reached a CPT-incorporation plateau at ∼20 mol% DOTAP. The presented approach appears suitable to study
the incorporation capacity of any drug component within small vesicles as long as the liposome incorporation is high relative
to the intrisic water solubility of the drug. 相似文献
5.
An objective of the present investigation was to prepare and evaluate Eudragit-coated pectin microspheres for colon targeting
of 5-fluorouracil (FU). Pectin microspheres were prepared by emulsion dehydration method using different ratios of FU and
pectin (1:3 to 1:6), stirring speeds (500–2000 rpm) and emulsifier concentrations (0.75%–1.5% wt/vol). The yield of preparation
and the encapsulation efficiencies were high for all pectin microspheres. Microspheres prepared by using drug:polymer ratio
1:4, stirring speed 1000 rpm, and 1.25% wt/vol concentration of emulsifying agent were selected as an optimized formulation.
Eudragit-coating of pectin microspheres was performed by oil-in-oil solvent evaporation method using coat: core ratio (5:1).
Pectin microspheres and Eudragit-coated pectin microspheres were evaluated for surface morphology, particle size and size
distribution, swellability, percentage drug entrapment, and in vitro drug release in simulated gastrointestinal fluids (SGF).
The in vitro drug release study of optimized formulation was also performed in simulated colonic fluid in the presence of
2% rat cecal content. Organ distribution study in albino rats was performed to establish the targeting potential of optimized
formulation in the colon. The release profile of FU from Eudragit-coated pectin microspheres was pH dependent. In acidic medium,
the release rate was much slower; however, the drug was released quickly at pH 7.4. It is concluded from the present investigation
that Eudragit-coated pectin microspheres are promising controlled release carriers for colon-targeted delivery of FU.
Published: February 16, 2007 相似文献
6.
In this study, the use of biodegradable polymers for microencapsulation of naltrexone using solvent evaporation technique
is investigated. The use of naltrexone microspheres for the preparation of matrix devices is also studied. For this purpose,
poly(L-lactide) (PLA) microspheres containing naltrexone prepared by solvent evaporation technique were compressed at temperatures
above the Tg of the polymer. The effect of different process parameters, such as drug/polymer ratio and stirring rate during
preparation of microspheres, on the morphology, size distribution, and in vitro drug release of microspheres was studied.
As expected, stirring rate influenced particle size distribution of microspheres and hence drug release profiles. By increasing
the stirring speed from 400 to 1200 rpm, the mean diameter of microspheres decreased from 251 μm to 104 μm. The drug release
rate from smaller microspheres was faster than from larger microspheres. However, drug release from microspheres with low
drug content (20% wt/wt) was not affected by the particle size of microspheres. Increasing the drug content of microspheres
from 20% to 50% wt/wt led to significantly faster drug release from microspheres. It was also shown that drug release from
matrix devices prepared by compression of naltrexone microspheres is much slower than that of microspheres. No burst release
was observed with matrix devices. Applying higher compression force, when compressing microspheres to produce tablets, resulted
in lower drug release from matrix devices. The results suggest that by regulating different variables, desired release profiles
of naltrexone can be achieved using a PLA microparticulate system or matrix devices. 相似文献
7.
The objective of this study was to develop an efficient tumor vasculature targeted liposome delivery system for combretastatin
A4, a novel antivascular agent. Liposomes composed of hydrogenated soybean phosphatidylcholine (HSPC), cholesterol, distearoyl
phosphoethanolamine-polyethylene-glycol-2000 conjugate (DSPE-PEG), and DSPE-PEG-maleimide were prepared by the lipid film
hydration and extrusion process. Cyclic RGD (Arg-Gly-Asp) peptides with affinity for αvβ3-integrins expressed on tumor vascular
endothelial cells were coupled to the distal end of PEG on the liposomes sterically stabilized with PEG (long circulating
liposomes, LCL). The liposome delivery system was characterized in terms of size, lamellarity, ligand density, drug loading,
and leakage properties. Targeting nature of the delivery system was evaluated in vitro using cultured human umbilical vein
endothelial cells (HUVEC). Electron microscopic observations of the formulations revealed presence of small unilamellar liposomes
of ∼120 nm in diameter. High performance liquid chromatography determination of ligand coupling to the liposome surface indicated
that more than 99% of the RGD peptides were reacted with maleimide groups on the liposome surface. Up to 3 mg/mL of stable
liposomal combretastatin A4 loading was achieved with ∼80% of this being entrapped within the liposomes. In the in vitro cell
culture studies, targeted liposomes showed significantly higher binding to their target cells than non-targeted liposomes,
presumably through specific interaction of the RGD with its receptors on the cell surface. It was concluded that the targeting
properties of the prepared delivery system would potentially improve the therapeutic benefits of combretastatin A4 compared
with nontargeted liposomes or solution dosage forms. 相似文献
8.
The purpose of this research was to investigate whether Eudragit S100 microspheres have the potential to serve as an oral
carrier for peptide drugs like insulin. Microspheres were prepared using water-in oil-in water emulsion solvent evaporation
technique with polysorbate 20 as a dispersing agent in the internal aqueous phase and polyvinyl alcohol (PVA)/polyvinyl pyrrolidone
as a stabilizer in the external aqueous phase. The use of smaller internal aqueous-phase volume (50 μL) and external aqueous-phase
volume (25 mL) containing PVA in the manufacturing process resulted in maximum encapsulation efficiency (81.8%±0.9%). PVA-stabilized
microspheres having maximum drug encapsulation released 2.5% insulin at pH 1.0 in 2 hours. In phosphate buffer (pH 7.4), microspheres
showed an initial burst release of 22% in 1 hour with an additional 28% release in the next 5 hours. The smaller the volumes
of internal and external aqueous phase, the lower the initial burst release. The release of drug from microspheres followed
Higuchi kinetics. Scanning electron microscopy of PVA-stabilized microspheres demonstrated spherical particles with smooth
surface, and laser diffractometry revealed a mena particle size of 32.51±20 μm. Oral administration of PVA stabilized microspheres
in normal albino rabbits (equivalent to 6.6 IU insulin/kg of animal weight) demonstrated a 24% reduction in blood glucose
level, with maximum plasma glucose reduction of 76±3.0% in 2 hours and effect continuing up to 6 hours. The area under the
percentage glucose reduction-time curve was 93.75%. Thus, our results indicate that Eudragit S100 microspheres on oral administration
can protect insulin from proteolytic degradation in the gastrointestinal tract and produce hypoglycemic effect. 相似文献
9.
The purpose of this research was to assess the physicochemical properties of a controlled release formulation of recombinant
human growth hormone (rHGH) encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) composite microspheres. rHGH was loaded
in poly(acryloyl hydroxyethyl) starch (acHES) microparticles, and then the protein-containing microparticles were encapsulated
in the PLGA matrix by a solvent extraction/evaporation method. rHGH-loaded PLGA microspheres were also prepared using mannitol
without the starch hydrogel microparticle microspheres for comparison. The detection of secondary structure changes in protein
was investigated by using a Fourier Transfer Infrared (FTIR) technique. The composite microspheres were spherical in shape
(44.6±2.47 μm), and the PLGA-mannitol microspheres were 39.7±2.50 μm. Drug-loading efficiency varied from 93.2% to 104%. The
composite microspheres showed higher overall drug release than the PLGA/mannitol microspheres. FTIR analyses indicated good
stability and structural integrity of HGH localized in the microspheres. The PLGA-acHES composite microsphere system could
be useful for the controlled delivery of protein drugs. 相似文献
10.
The purpose of this research was to investigate the effects of different concentrations of polymer and sucrose stearate, aluminum
tristearate as dispersing agents on microsphere properties and performance. The yield values of microspheres were over the
78%, and the encapsulation efficiencies were found to be ∼735. Particle sizes of microspheres prepared with aluminum tristearate
were between 76 and 448 μm, while that of the microspheres containing sucrose stearate were between 521 and 2000 μm. Morphological
and physicochemical properties of microspheres were investigated by scanning electron micrography and differential scanning
calorimetry (DSC). DSC analysis indicated that verapamil hydrochloride formed a solid solution with acrylic polymers. In vitro
release studies were performed using the flow-through cell method. While ∼80% of drug was released from the microspheres containing
aluminum tristearate in 480 minutes, the same amount of drug was released from microspheres containing sucrose stearate in
only 60 minutes. Chemical structures and concentrations of the dispersing agents were clearly effective on the physical properties
of microspheres and their drug-release characteristics.
Published: February 24, 2006 相似文献
11.
Orntide acetate, a novel luteinizing hormone-releasing hormone (LHRH) antagonist, was prepared and evaluated in vivo in 30-day
and 120-day sustained delivery formulations using a rat animal model. Orntide poly(d,l- lactide-co-glycolide) (PLGA) and poly(d,l-
lactide) (PLA) microspheres were prepared by a dispersion method and administered subcutaneously in a liquid vehicle to rats
at 2.2 mg Orntide/kg of body weight (30-day forms) or 8.8 mg Orntide/kg (120-day forms). Serum levels of Orntide and testosterone
were monitored by radioimmunoassays, and a dose-response study at 4 closes (3, 2.25, 1.5, and 1.75 mg Orntide/kg) was conducted
to determine the effective dose of Orntide. Microspheres with diameters between 3.9 and 14 μ were prepared. The onset and
duration of testosterone suppression varied for different microsphere formulations and were influenced both by polymer properties
and by microsphere characteristics. Microspheres prepared with 50∶50 and 75∶25 copolymers effectively sustained peptide release
for 14 to 28 days, whereas an 85∶15 copolymer and the PLA microspheres extended the pharmacological response for more than
120 days. Increase in drug load generally accelerated peptide release from the microspheres, resulting in higher initial serum
levels of Orntide and shorter duration of the release: In general, apparent release was faster in vivo than under in vitro
conditions. Orntide microspheres effectively suppressed testosterone in rats, providing rapid onset of release and extended
periods of chemical castration. Testosterone suppression occurred immediately after microsphere administration without the
initial elevation seen with LHRH superagonists. 相似文献
12.
The aim of this study was the development of a veterinary dosage form constituted by injectable biodegradable microspheres
designed for the subcutaneous release of carboplatin, a chemotherapeutic drug. Poly(D,L-lactide) (PDLLA) microspheres were
prepared by an emulsification/spray-drying method, using the drug-to-polymer weight ratios 1∶9 and 1∶5; blank microspheres
(1% w/v) were prepared as a comparison. Microparticles were characterized in terms of morphology, encapsulation efficiency,
and in vitro drug release behavior. In vivo tests were conducted on rats by subcutaneous injection of microsphere aqueous
suspensions. Levels of carboplatin were evaluated both in the skin and in serum. The microparticles obtained had a spherical
shape; particle size ranged from 5 to 7 μm, dependent on drug loading. Microspheres were able to control the in vitro release
of the drug: approximately 90% to 100% of the carboplatin was released over 30 days. In vivo results showed that the microspheres
were able to release high drug amounts locally, and sustained serum levels of drug were also achieved. Based on these results,
carboplatin-loaded PDLLA microspheres may be useful for local delivery of the antineoplastic drug to the tumor, avoiding tumor
recurrence in small animals, and may decrease the formation of distant metastases.
Published: September 20, 2005 相似文献
13.
The purpose of this research was to prepare spray-dried mucoadhesive microspheres for nasal delivery. Microspheres composed
of hydroxypropyl methylcellulose (H), chitosan (CS), carbopol 934P (CP) and various combinations of these mucoadhesive polymers,
and maltodextrin (M), colloidal silicon dioxide (A), and propylene glycol (P) as filler and shaper, were prepared by spray-drying
technique. Using propranolol HCl as a model drug, microspheres were prepared at loadings exceedings 80% and yields between
24% and 74%. Bulky, free flowing microspheres that had median particle size between 15 and 23 μm were obtained. Their zeta
potential was according to the charge of polymer. Adhesion time of mucoadhesive microspheres on isolated pig intestine was
ranked, CS>CP: H>CP>H, while the rank order of swelling was CP>CS>H. Increasing the amount of CP in CP∶H formulations increased
the percentage of swelling. Infrared (IR) spectra showed no interaction between excipients used except CS with acetic acid.
The release of drug from CP and CP∶H microspheres was slower than the release from H and CS microspheres, correlated to their
viscosity and swelling. Long lag time from the CP microspheres could be shortened when combined with H. The permeation of
drug through nasal cell monolayer corresponded to their release profiles. These microspheres affected the integrity of tight
junctions, relative to their swelling and charge of polymer. Cell viability was not affected except from CS microspheres,
but recovery could be obtained. In conclusion, spray-dried microspheres of H, CS, CP, and CP∶H could be prepared to deliver
drug through nasal cell monolayer via the opening of tight junction without cell damaging.
Published: February 10, 2006 相似文献
14.
Psoriasis is a chronic, autoimmune skin disease affecting approximately 2% of the world's population. Clobetasol propionate
which is a superpotent topical corticosteroid is widely used for topical treatment of psoriasis. Conventional dosage forms
like creams and ointments are commonly prefered for the therapy. The purpose of this study was to develop a new topical delivery
system in order to provide the prolonged release of clobetasol propionate and to reduce systemic absorption and side effects
of the drug. Clobetasol propionate loaded-poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by oil-in-water
emulsion–solvent evaporation technique. Particle size analysis, morphological characterization, DSC and XRD analyses and in vitro drug release studies were performed on the microparticle formulations. Emulgel formulations were prepared as an alternative
for topical delivery of clobetasol propionate. In vitro drug release studies were carried out from the emulgel formulations containing pure drug and drug-loaded microspheres. In
addition, the same studies were performed to determine the drug release from the commercial cream product of clobetasol propionate.
The release of clobetasol propionate from the emulgel formulations was significantly higher than the commercial product. In
addition, the encapsulation of clobetasol propionate in the PLGA microspheres significantly delayed the drug release from
the emulgel formulation. As a result, the decrease in the side effects of clobetasol propionate by the formulation containing
PLGA microspheres is expected. 相似文献
15.
Connexin‐43 (Cx43) containing giant liposomes (GL) were prepared by a baculovirus expression–liposome fusion method. Recombinant budded viruses expressing Cx43 were prepared and then fused with GLs containing DOPG/DOPC at pH 4.5. Connexon formation on the GL membrane was observed by transmission electron microscope. Hydrophilic fluorescent dye transfers were observed through a Cx43‐mediated pathway not only between Sf9 ( Spodoptera frugiperda) cells with Cx43 but also from giant Cx43 liposomes to Cx43‐expressing U2OS cells (human osteosarcoma cell). The functional connexin‐containing liposome is expected to be useful for cellular cytosolic delivery systems. The original orientation and function of Cx43 was maintained after integration into the liposomes. The liposome fusion method will create new opportunities as a tool for analysis of channel membrane proteins. Biotechnol. Bioeng. 2010;107: 836–843. © 2010 Wiley Periodicals, Inc. 相似文献
16.
The instability of liposomal delivery system during passaging through the gastrointestinal tract (GIT) stimulates a demand to find a stable liposome. This research studied the implications of different types of phospholipids (different fatty acid chain length and saturation, various head group) on liposomal physiochemical properties and stability in the human GIT. The micropolarity of liposomal membrane increased with the decrease of chain lengths of phospholipids, while the morphology observation revealed that the liposomes formed by different phospholipids showed similar in appearance and shapes. The liposomes formed by C20:0 deformed more severely in simulated gastric fluid, while others exhibited slight changes in the membrane structure. In simulated intestinal fluid, pancreatic lipase and phospholipase A2, synergized with bile salts, damaged the bilayers structure of all liposomes, with the entrapped lactoferrin release and hydrolysis. Although the various phospholipid structures lead to some difference on the physicochemical properties (size and micropolarity), the enzymic influence displayed more significance during in vitro digestion compared to the types of wall materials. Current results could provide valuable information for the development of more stable and reliable food-grade liposomes in the GIT. 相似文献
17.
In order to develop a novel transdermal drug delivery system that facilitates the skin permeation of finasteride encapsulated
in novel lipid-based vesicular carriers (ethosomes)finasteride ethosomes were constructed and the morphological characteristics
were studied by transmission electron microscopy. The particle size, zeta potential and the entrapment capacity of ethosome
were also determined. In contrast to liposomes ethosomes were of more condensed vesicular structure and they were found to
be oppositely charged. Ethosomes were found to be more efficient delivery carriers with high encapsulation capacities. In vitro percutaneous permeation experiments demonstrated that the permeation of finasteride through human cadaver skin was significantly
increased when ethosomes were used. The finasteride transdermal fluxes from ethosomes containing formulation (1.34 ± 0.11 μg/cm 2/h) were 7.4, 3.2 and 2.6 times higher than that of finasteride from aqueous solution, conventional liposomes and hydroethanolic
solution respectively ( P < 0.01).Furthermore, ethosomes produced a significant ( P < 0.01) finasteride accumulation in the skin, especially in deeper layers, for instance in dermis it reached to 18.2 ± 1.8 μg/cm 2. In contrast, the accumulation of finasteride in the dermis was only 2.8 ± 1.3 μg/cm 2 with liposome formulation. The study demonstrated that ethosomes are promising vesicular carriers for enhancing percutaneous
absorption of finasteride. 相似文献
18.
Surface-immobilized liposome layers are of interest for various potential applications such as localized drug delivery, but their characterization is challenging. We have employed an AFM method and fluorescent dye release to analyze anchored liposomes. In addition, we studied whether the liposomes are surface-bound solely via specific interaction (NeutrAvidin/biotin) or whether physisorptive binding also plays a role. Liposomes containing PEG-biotin lipids were affinity bound to NeutrAvidin molecules which had been immobilized onto solid supports via three different hydrogel interlayers. After liposome docking, approaching the surface with a colloid probe mounted onto an AFM cantilever showed considerable compression behavior, consistent with expectation based on intact, deformable liposomes but not lipid bilayers, thus showing that disruption of liposomes did not occur upon immobilization onto these support surfaces. Plastic deformation suggestive of liposome disruption on compression was not observed. The kinetics of fluorescent dye release also demonstrated that intact liposomes had been successfully immobilized onto all three supports. Blocking surface-immobilized NeutrAvidin molecules with excess biotin in solution before exposure to liposomes showed that the docking of liposomes was dependent largely but not exclusively on biotin-NeutrAvidin affinity binding, with evidence for some nonspecific physisorption, as the extent of liposome binding onto blocked NeutrAvidin surfaces was appreciably lower than for unblocked surfaces but not zero. Finally, consecutive addition of further NeutrAvidin and liposome layers enabled fabrication of multilayers, and this was clearly seen in AFM compressibility and fluorescent dye release measurements. 相似文献
19.
Deformable propylene glycol-containing liposomes (DPGLs) incorporating metronidazole or clotrimazole were prepared and evaluated as an efficient drug delivery system to improve the treatment of vaginal microbial infections. The liposome formulations were optimized based on sufficient trapping efficiencies for both drugs and membrane elasticity as a prerequisite for successful permeability and therapy. An appropriate viscosity for vaginal administration was achieved by incorporating the liposomes into Carbopol hydrogel. DPGLs were able to penetrate through the hydrogel network more rapidly than conventional liposomes. In vitro studies of drug release from the liposomal hydrogel under conditions simulating human treatment confirmed sustained and diffusion-based drug release. Characterization of the rheological and textural properties of the DPGL-containing liposomal hydrogels demonstrated that the incorporation of DPGLs alone had no significant influence on mechanical properties of hydrogels compared to controls. These results support the great potential of DPGL-in-hydrogel as an efficient delivery system for the controlled and sustained release of antimicrobial drugs in the vagina. 相似文献
20.
Context: Pirfenidone (PFD) is an anti-fibrotic and anti-inflammatory agent indicated for the treatment of idiopathic pulmonary fibrosis (IPF). The current oral administration of PFD has several limitations including first pass metabolism and gastrointestinal irritation. Objective: The aim of this study is to investigate the feasibility of transdermal delivery of PFD using liposomal carrier system. Materials and methods: PFD-loaded liposomes were prepared using soy phosphatidylcholine (SPC) and sodium cholate (SC). Encapsulation efficiency (EE) of PFD in liposomes was optimized using different preparation techniques including thin film hydration (TFH) method, direct injection method (DIM) and drug encapsulation using freeze–thaw cycles. In vitro drug release study was performed using dialysis membrane method. The skin permeation studies were performed using excised porcine ear skin model in a Franz diffusion cell apparatus. Results and discussion: The average particle size and zeta-potential of liposomes were 191?±?4.1?nm and ?40.4?±?4.5?mV, respectively. The liposomes prepared by TFH followed by 10 freeze–thaw cycles showed the greatest EE of 22.7?±?0.63%. The optimized liposome formulation was incorporated in hydroxypropyl methyl cellulose (HPMC) hydrogel containing different permeation enhancers including oleic acid (OA), isopropyl myristate (IPM) and propylene glycol (PG). PFD-loaded liposomes incorporated in hydrogel containing OA and IPM showed the greatest flux of 10.9?±?1.04?μg/cm 2/h across skin, which was 5-fold greater compared with free PFD. The cumulative amount of PFD permeated was 344?±?28.8?μg/cm 2 with a lag time of 2.3?±?1.3?h. Conclusion: The hydrogel formulation containing PFD-loaded liposomes can be developed as a potential transdermal delivery system. 相似文献
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