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Transdermal drug delivery has become one of the research focuses in pharmaceutical formulations due to its potential advantages. In order to overcome the natural barrier function of the skin, several physical, chemical and pharmaceutical enhancement strategies have been developed to promote the transdermal permeation and adsorption of drugs. Electret is a kind of functional dielectric material with permanent electric polarization state. The electrostatic filed and microcurrent produced by electret can be used as physical permeation enhancer to improve the transdermal drug delivery. In this article, we reviewed the mechanism, influencing factors and current research progress of electret as one of the physical enhancing permeation strategies.
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Objective To study the effect of electret electrostatic-field on the preparation and characteristics of nanopaticles carrying quaternary ammonium chitosan and epidermal growth factor (EGF), so as to explore the percutaneous transport mechanism of drug-loading nanoparticles. Methods Under different electret electrostatic-fields, ionic crossing method was used to prepare EGF-loading chitosan nanoparticles using EGF as model drug, chitosan as material, and sodium tripolyphosphate (TPP) as crosslinking agent. Transmission electron microscope was employed to observe the surface morphology of nanoparticles * the particle size and the zeta potential of the EGFToading nanoparticles were also examined. Results (1) The EGF-loading chitosan nanoparticles prepared in this study had uniform distribution, good dispersibility and stability. (2) The size of the EGF-loading nanoparticles increased with the increase of chitosan concentration, indicating that chitosan concentrationmight be the main reason for the nanoparticle size. (3) The particle size of the EGF-loading chitosan nanoparticles decreased with the increase of electrostatic field; and the change of the zeta potential was closely related to the polarity of the applied electric field. (4) The particle size of EGFloading nanoparticles decreased with the increase of storage time. Conclusion The morphology, particle size and zeta potential of chitosan nanoparticles are closely related to the intensity and polarity of the applied electric field; proper electric field parameters shouldbe chosen to prepare high quality chitosan nanoparticles with appropriate particle size and stability.
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Objective To compare the effects of chemical penetration enhancers and negative electret in promoting percutaneous penetrationof 5-fluorouracil (5-FU) through rat scar and dorsal skin in vitro, so as to lay a foundation for preparing delayed-release 5-FU electret transdermal patch. Methods The in vitro transdermal behaviors of 5-FU through rat scar and dorsal skin under the actions of 1 % azone, 10% ethyl oleate, —1 000 V electret, —1 500 V electret and —2 000 V electret were studied using improved Franze diffusion cell and high performance liquid chromatography (HPLC). Results (1) Both 1% azone and 10% ethyl oleate promoted the penetration of 5-FU through rat scar and dorsal skin, with the promoting effect of 10% ethyl oleate being better than that of 1% azone. (2) Although the transdermal behaviors of 5-FU were similar through scar skin and dorsal skin at the presence of chemical enhancers, the cumulative penetration amount through the scar skinwas less than that through the dorsal skin. (3) The negative electrets used in this study had satisfactory penetration promoting effect, with the promoting effect from strong to weak being —2 000 V electret > — 1 500 V electret > — 1 000 V electret Moreover, the scar skin also had less cumulative penetration amount of 5-FU than that of the dorsal skin under the action of electrets. Conclusion Both the chemical enhancers and electrets can enhance the transdermal delivery of 5-FU. 10% ethyl oleate and — 2 000 V electret have the best enhancing effect on 5-FU transdermal delivery and can be considered for preparation of 5-FU electret transdermal patch.
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Objective To study and optimize the preparation process and abserve the related properties of electret flu-orouracil gel patch .Methods the adhesives and moistening agents were screened by preliminary experiment .The optimal matrix proportion in the blank gel patch was obtained with orthogonal design .The charge storage stability of the patch was studied by compensation method .The transdermal behaviors of the patch were evaluated by modified diffusion cell method and HPLC .Results The optimal matrix proportions of PAAS ∶ gelatin ∶ PVA ∶ Kaolin ∶ CMC-Na ∶ moistening agents were 0 .2∶0 .7∶0 .5∶0 .7∶0 .2∶12 .The patch had a good charge storage stability .All the electrets and 3% azone could enhance the cumulative penetration amount of drug and they had synergistic enhancing effect .Conclusion The qualified electret fluorouracil gel patch was prepared under the optimal process ,which had no skin irritation and the behavior of transdermal de-livery was better than that of the traditional gel patch .
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Objective To study the effects of positive polarity electret combined with different concentrations of azone in promoting the transdermal delivery of cyclosporin A, so as to explore the feasibility and the rule of electret combined with chemical enhancers in promoting transdermal delivery. Methods Cyclosporin A was used as the model drug in the present study. Positive polarity electret was prepared using corona charge technique. Franz diffusion cell system and HPLC techniques were applied to investigate the roles of positive polar electret, azone of different concentrations and their combination in promoting penetration of cyclosporin A in vitro. Results Satisfactory penetration promoting effects for cyclosporin A was observed in excised skin 24 h after exposure to +500 V, +1 000 V and +2 000 V electret. Compared to the control group, 1%, 3%, and 5% azone promoted the steady-state penetration rates of cyclosporin A by 6. 72, 2. 11, and 1. 43 folds after 24 h exposure. Combination of +1 000V electret plus 1% azone showed better penetration promoting effect than other combinations, but electret with different positive charges and different concentrations of azone showed no synergistic effect in promoting cyclosporin A penetration. Conclusion Positive polarity electret has a penetration promoting effect for transdermal delivery of cyclosporin A. Positive polarity electret and azone show no synergistic effect on promoting penetration of cyclosporin A.
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Objective: To compare the effects of electret and chemical enhancers in enhancing the transdermal delivery of meloxicam. Methods: The study was divided into 4 groups, including meloxicam patch group (control), chemical enhancer + meloxicam patch group, electret meloxicam patch, and electret + chemical enhancer + meloxicam patch group. The in vitro skin permeation of meloxicam from patches was examined by using a modified Franz diffusion cell. Ultraviolet spectrophotometry (362 nm) was used to analyze the drug concentration in the receptor. The 10 h-cumulated permeation amount of meloxicam from patchs was calculated in 3 experimental groups and were compared with that the control group. The enhancing abilities of electret and chemical enhancers were compared and the synergistic effect of them was assessed. Results: (1) 1%, 3% and 5% azones showed 1.20, 1.33, and 1.26 fold-increases in the 10 h-cumulated permeation of meloxiam respectively as compared with control group(P<0.05). (2) Most of the chemical enhancers used in this study(1%, 3% and 5% azones, 10% ethyl oleate, 1% menthnol,and 30% sulphoxiade),except for 20% propylene glycol,had enhancing effect on transdermal delivery of melocicam. Ethyl oleate(10%) was proven to be the most potent enhancer,showing a 1.86-fold cumulated permeation that of the control group(P<0.05); (3) Electret was more potent than the chemical enhancers in promoting meloxicam transdermal delivery, showing a 2.16-fold cumulated permeation that of control group (P<0.05); (4) Electret improved the enhancing effect of chemical enhancers in this study. The cumulated permeation of meloxicam in electret + chemical enhancer + meloxicam patch group was 1.14-2.82 folds that of the chemical enhancer + meloxicam patch group(P<0.05). Conclusion: Electret has a good promoting effect for transdermal drug delivery and can be used as a novel enhancer in transdermal delivery of drugs.
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Objective: Currently most researches concerning electret transdermal patches are performed by one-factor experimental design with relatively poor efficiency. To analyze the influencing factors in a more systematical and effective manner, we put forward an optimized design for in vitro experiment with electret transdermal patches. Methods: Due to the great number and various levels of factors impacting the charge storage stability of electrets, we combined uniform design and orthogonal design to optimize the screening for the stable transdermal patch. In the following in vitro study, we optimized the design of percutaneous experiments to screen for charge polarity and penetration enhancers using a two-factor experimental design. And using an orthogonal experimental design, we further studied the influence of different levels of main drug, surface potential and penetration enhancer on transdermal absorption. Conclusion: The present design, taking into consideration of various factors and using multi-factor experimental design, can more effectively analyze data, reduce workload, and is feasible.
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Objective: To study charge storage stability of electret film made of polypropylene (PP)/porous polytetrafiuoroethylene(PTFE)/polypropylene composite. Methods: The PP/porous PTFE/PP composite electret film was prepared with porous PTFE, polyethylene(PE) and PP by heat melting technique. The charge storage stability of the electret film and transportation were evaluated by using the methods of isothermal surface potential attenuation and open-circuit thermally stimulated discharge (TSD) current spectra. Results: (1) The charge storage stability of PP/porous PTFE/PP composite electret was superior to that of PP electret made under ordinary temperature, because the space charge of PP/porous PTFE/PP electret was transferred from deep trap to flat trap during the heat melting process. (2) Satisfactory charge storage stability was observed in PP/porous PTFE/PP electret when under the condition of high humidity. Conclusion: PP/porous PTFE/PP electret film has satisfactory charge storage stability and can be used as a novel enhancer in transdermal delivery of drugs.
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Objective: To study the enhancing effects of electret on transdermal delivery of lidocaine patches in vitro. Methods: In vitro rat skin permeation experiment was carried out with lidocaine patches, lidocaine paches with azone, positive/negative electret lidocaine patches, and positive/negative electret lidocaine patches with azone by using Franz diffusion cells. The accumulated lidocaine concentrations in rat skin treated with each kind of patches were examined by HPLC to investigate the influence of electret on transdermal delivery of lidocaine. Results: (1) The enhancement rates of 1%, 3% and 5% azone lidocaine patches 10 h after application were 1. 06, 1. 10 and 1. 66 folds (P<0. 05, 5% azone to lidocaine patch group) that of the lidocaine patch, respectively. (2) Lidocaine patches with negative electret containing 1%, 3% and 5% azone showed similar transdermal behavior to the corresponding chemical enhancer patches. (3) Lidocaine patches with positive electret containing 1%, 3% and 5% azone showed much better enhancing effect than the corresponding chemical enhancer lidocaine patches (P<0. 05). Besides, 5% azone together with positive electret showed a cooperative enhancing effect. Conclusion: Positive electret patch has better effect in enhancing transdermal delivery of lidocaine. Besides, the cooperative enhancing effect of azone with positive electret on transdermal delivery of lidocaine is in a concentration-dependent manner with azone.
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Objective: To determine meloxicam concentrations in both plasma and extract solution of tested-skin in SD rats and the fluorescence intensity, location of fluorescein sodium salt (NaFI) in striped rat skin within 4 h after transdermal administration, so as to investigate the enhancing effect of negative electret on percutaneous absorption of meloxicam and percutaneous absorption route of NaFI. Methods: Pharmaceutical method and grid-controlled constant corona charge technique were used to prepare electret meloxicam patch. High performance liquid chromatography (HPLC) method was employed to determine meloxicam concentration after transdermal administration. NaFI was used as probe to determine the localization and percutaneous absorption route of NaFI by using laser scanning confocal microscopy (LSCM). Results: (DNegative electret and its polypropylene(PP) electret meloxicam patch exhibited a good charge storage stability. (2)The results of HPLC demonstrated that electret had a remarkable enhancing effect on percutaneous absorption of meloxicam after application for 1-4 h. (3) LSCM further proved the enhancing effect of negative electret on percutaneous absorption of small molecules. We also found that the stratum corneum and the hair follicle areas were the two main pathways for the enhancing effect of the electret. Conclusion: Negative electret can be used as an enhancer for transdermal permeation of meloxicam.
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Electret filtration material is a kind of promising new air filtration material due to the advantages of high filtration efficiency,low flow resistance,power saving and anti-bacteria.In the paper the concept of electret,primary raw material of electret filtration material,the characteristics of electret filter material,charging method to make electret and the influence of charging technology on the charge storage characteristic of electret filter material were introduced,the application of electret filtration material on air purification was described also.
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The procedure that enhances osteogenesis and shortens the healing period is required for successful implant therapy. It has been introduced that osteogenesis is enhanced by the generation of electric field. Many researchers have demonstrated that application of electric and electromagnetic field promote bone formation. It also has been shown that electrical stimulation enhances peri-implant bone formation. Recently, several investigators have reported that noninvasive electrical stimulation using negatively charged electret such as polytetrafluoroethylene(PTFE) promotes osteogenesis. Therefore, we were interested in the effect of noninvasive electrical stimulation using negatively charged electret on the periimplant bone healing. After titanium implant were installed in the proximal tibial metaphysis of New Zealand white rabbit, negatively charged PTFE membrane fabricated by corana dischage was inserted into the inner hole of the experimental implant and noncharged membrane was applied into control implant. After 4 weeks of healing, histomorphometric analysis was performed to evaluate peri-implant bone response. The histomorphometric evaluations demonstrated experimental implant tended to have higher values in the total bone-to-implant contact ratio(experimental ; 49.9+/-13.52% vs control ; 37.5+/-19.44%) , the marrow bone contact ratio(experimental ; 34.94+/- 13.32% vs control ; 24.15+/-13.69%), amount of newly formed bone in the endosteal region(experimental ; 1.00+/-0.30mm vs control ; 0.61+/-0.24mm) and bone area in the medullary canal(experimental ; 13.55+/-4.98% vs control ; 9.03+/-3.05%). The mean values of the amount of newly formed bone(endosteal region) and bone area(medullary canal) of the experimental implant demonstrated a statistically significant difference as compared to the control implant(p<0.05). In conclusion, noninvasive electrical stimulation using negatively charged electret effectively promoted peri-implant new bone formation in this study. This method is expected to be used as one of the useful electrical stimulation for enhancing bone healing response in the implant therapy
Subject(s)
Rabbits , AnimalsABSTRACT
The procedure that enhances osteogenesis and shortens the healing period is required for successful implant therapy. It has been introduced that osteogenesis is enhanced by the generation of electric field. Many researchers have demonstrated that application of electric and electromagnetic field promote bone formation. It also has been shown that electrical stimulation enhances peri-implant bone formation. Recently, several investigators have reported that noninvasive electrical stimulation using negatively charged electret such as polytetrafluoroethylene(PTFE) promotes osteogenesis. Therefore, we were interested in the effect of noninvasive electrical stimulation using negatively charged electret on the periimplant bone healing. After titanium implant were installed in the proximal tibial metaphysis of New Zealand white rabbit, negatively charged PTFE membrane fabricated by corana dischage was inserted into the inner hole of the experimental implant and noncharged membrane was applied into control implant. After 4 weeks of healing, histomorphometric analysis was performed to evaluate peri-implant bone response. The histomorphometric evaluations demonstrated experimental implant tended to have higher values in the total bone-to-implant contact ratio(experimental ; 49.9+/-13.52% vs control ; 37.5+/-19.44%) , the marrow bone contact ratio(experimental ; 34.94+/- 13.32% vs control ; 24.15+/-13.69%), amount of newly formed bone in the endosteal region(experimental ; 1.00+/-0.30mm vs control ; 0.61+/-0.24mm) and bone area in the medullary canal(experimental ; 13.55+/-4.98% vs control ; 9.03+/-3.05%). The mean values of the amount of newly formed bone(endosteal region) and bone area(medullary canal) of the experimental implant demonstrated a statistically significant difference as compared to the control implant(p<0.05). In conclusion, noninvasive electrical stimulation using negatively charged electret effectively promoted peri-implant new bone formation in this study. This method is expected to be used as one of the useful electrical stimulation for enhancing bone healing response in the implant therapy
Subject(s)
Rabbits , AnimalsABSTRACT
Electret is a kind of functional material which can store charge for a long time. The external electrical field and microcurrent produced by electret can be applied to restore the electret state of the injured tissue, to improve the microcirculation and to accelerate the union of fracture, wound and nerve regeneration. Recently, the application study of electret in life science has been proceeding briskly. This paper briefly summarizes the application situation of electret in life science.
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This paper designs a heart sound processing analog circuit, in which the amplification circuit, the filter circuit and the lifting of electrical level circuit are involved. It also gives a safety design problem analysis using an electret capacitor microphone to pick-up the heart sound signals. It is proved that the circuit is reliable and effective.