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Results for “IONTOPHORESIS”

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At least 199 records · Page 11Linked to original sources

PubMed2000

Permeability of the root canal wall and occlusion of dentinal tubules by Ag(NH3)2F: a comparison of combined use with pulsed Nd:YAG laser or iontophoresis.

OBJECTIVE: We used SEM-EDX and the Vickers hardness test to compare the penetration and hardness of silver resulting from use of either (i) pulsed Nd:YAG laser or (ii) iontophoresis, after root canal wall shaping using the standard method of coating with 38% Ag(NH3)2F solution. SUMMARY BACKGROUND DATA: There have not been any reports of penetration and hardness following the application of Ag(NH3)2F solution together with laser or iontophoresis. METHODS: We used 21 extracted human single-rooted teeth randomly divided into three groups. Group 1 was coated with Ag(NH3)2F, Group 2 was irradiated with a Nd:YAG laser after coating with Ag(NH3)2F solution, and Group 3 was iontophoresised after coating. Then we observed the permeability of silver through the root canal wall using SEM-EDX. RESULTS: The results show that iontophoresis after coating with Ag(NH3)2F solution (Group 3) resulted in the greatest and deepest penetration of silver into the root canal wall. There was no significant difference between teeth in Groups 1 and 2. For the hardness test, the 21 teeth were tested using SEM-EDX test, 7 untreated teeth were used as a control. The results show that Group 2 (laser treatment) teeth were the hardest. CONCLUSION: We therefore propose that root canals should be treated using irradiation with an Nd:YAG laser that has been coated with Ag(NH3)2F solution and that this method provides better results than either iontophoresis after coating, or coating alone.

Combined Modality Therapy↗

PubMed1993

Iontophoresis of reactive black 5 for pulsed dye laser sclerostomy.

Ab interno pulsed dye laser sclerostomy uses a gonioscopic approach to form a limbal fistula for the treatment of glaucoma. This procedure requires a full thickness penetration of stain in sclera for adequate absorption of the visible light energy. Iontophoresis is a technique using an electrical current to noninvasively deliver Reactive Black 5 (RB5) stain into sclera. This project determined the stability of RB5 stain as well as the optimal parameters for iontophoresis (probe tip surface area, current, and duration) in a rabbit model. RB5 stain was stable over time (72 hr) as well as after exposure to extreme heat (120 degrees C), scleral constituents (namely collagen), high concentrations of oxidants (1.5% H2O2), and laser light energy. Ideal parameters for iontophoresis included a probe tip surface area between 0.1 and 0.7 mm2, a current of 0.5 mA, and a duration of 5 min. The maximum concentration of RB5 stain achieved in sclera was 0.15%. The threshold of ablation for RB5 using an energy of 250 mJ was 0.001%. Iontophoresis can effectively deliver RB5 stain into sclera and may be a viable adjunct to ab interno pulsed dye laser sclerostomy procedures in the eye.

Animals↗

PubMed1994

Intravitreal delivery of ganciclovir in rabbits by transscleral iontophoresis.

To avoid the side effects of systemic administration of ganciclovir (GCV) for the treatment of cytomegalovirus (CMV) retinitis, we studied transscleral iontophoresis of GCV into rabbit eyes. After a single application with 20% (w/w) aqueous solution of GCV at 1.0 mA for 15 min gave a vitreal/retinal level of GCV at 74 +/- 17 micrograms/ml at 2 hours as determined by HPLC. At 24 hours after iontophoresis the vitreal/retinal level was above therapeutic level at 4.2 +/- 0.6 micrograms/ml. At 72 hours, there was still detectable level in the vitreous/retina. Hence, transscleral iontophoresis is able to deliver effective dose of GCV into the vitreous. Multiple applications of iontophoresis should be examined as a possible means of CMV treatment.

Animals↗

PubMed1994

Comparison of iontophoresis of lidocaine with a eutectic mixture of lidocaine and prilocaine (EMLA) for topically administered local anesthesia.

BACKGROUND: Almost all dermatologic surgery is accomplished using local anesthesia. To make our patients more comfortable, there is a constant search for less painful methods of administering anesthetic agents. Topical EMLA as well as iontophoresis are both useful in this regard. OBJECTIVE: In this study we compared topical EMLA with lidocaine delivered by iontophoresis in a double-blind placebo-controlled trial. Our goal was to assess the degree of anesthesia obtained as well as the relative rapidity of onset. METHODS: A double-blind controlled study was performed on 10 healthy volunteers between 26 and 37 years of age. Three test sites were placed on each forearm. EMLA or a moisturizer control was placed on two of the three test sites on each arm. Each site was wiped free of cream and tested for sensitivity to pinprick 30 and 60 minutes after cream placement. One iontophoretic unit was placed on each forearm. Both units were saturated with anesthesia with the control unit being turned off. Sensitivity to pinprick was evaluated at the iontophoretic sites and one of the EMLA sites 30 minutes after site placement on the subject. The additional EMLA-treated site was tested in the same manner 60 minutes after placement. RESULTS: Both EMLA cream and the iontophoretic unit delivered topical anesthesia greater than the control. Significantly more anesthesia was acquired 1 hour after application of EMLA than was seen 30 minutes earlier. The iontophoretic patch-treated area provided greater anesthesia than the EMLA-treated sites evaluated 30 and 60 minutes after placement. Both modalities provided significant anesthesia when left in place for 60 minutes. CONCLUSION: Both iontophoresis of lidocaine and topical EMLA delivered significant, and sometimes complete, local anesthesia. A greater degree of anesthesia is delivered via iontophoresis after 30 minutes as compared with EMLA left on the skin for 30 or 60 minutes. Both modalities have important and unique advantages and disadvantages. Topical EMLA and iontophoretically delivered lidocaine are both valuable tools for the dermatologic surgeon.

Administration, Cutaneous↗

PubMedDate not supplied

Iontophoresis for anesthesia during pulsed dye laser treatment of port-wine stains.

Port-wine stains (PWS) are benign, congenital vascular malformations found in approximately 0.3% of newborns. PWS may be effectively treated with the flashlamp pulsed dye laser (FPDL) at 585 nm. However, laser therapy of vascular lesions often produces pain. We performed a prospective double-blind, placebo-controlled evaluation of the iontophoresis of lidocaine 5% with epinephrine 1:50,000 and mepivacaine 2% with epinephrine 1:50,000. Thirty-six patients with facial PWS were included in the study; 13 of them were treated with lidocaine 5% with epinephrine, another 13 were treated with mepivacaine 2% with epinephrine, and the other 13 were treated with preservative-free 0.9% NaCl. The pain was graded by the patient on a visual analog scale from 0 to 10, comparing the iontophoretically treated area with an adjacent area treated without anesthesia. Pain evaluation by patients demonstrated a significant decrease in the pain of pulsed dye laser impulses using the iontophoresis of lidocaine 5% with epinephrine. No change in the efficacy of pulsed dye laser treatment of PWS or important side effects were observed in our patients. Iontophoresis of lidocaine 5% with epinephrine is a safe and effective method of local anesthesia for pulsed dye laser and it is more effective than the iontophoresis of mepivacaine 2% with epinephrine.

Adolescent↗

PubMed1997

Antiflammin 1 peptide delivered non-invasively by iontophoresis reduces irritant-induced inflammation in vivo.

The potential of an anti-inflammatory peptide (antiflammin 1) to reduce irritation when delivered transdermally by iontophoresis was examined. A model drug irritant, chlorpromazine, was co-delivered with and without antiflammin 1 by iontophoresis to hairless guinea pigs transdermally. Quantitative skin irritation measurements were obtained by monitoring erythema by skin color reflectance with the Minolta Chromameter. Antiflammin 1 delivered by iontophoresis significantly decreased, but did not eliminate, the erythema associated with co-delivery of an irritating drug compound. Lesion formation was also reduced in the presence of antiflammin 1. In vitro flux across hairless guinea pig skin demonstrated no significant differences in flux of the irritant compound in the presence or absence of antiflammin 1. In vivo generation and efflux of the inflammation mediator Prostaglandin E2 increased during 24-h application of irritant and was unchanged in the presence of antiflammin 1. This result is discussed with respect to recent evidence that antiflammins may act on the lipo-oxygenase pathway. In summary, antiflammin 1, an anti-inflammatory peptide, can be delivered transdermally by iontophoresis with retention of its biological activity in vivo.

Administration, Cutaneous↗

PubMedDate not supplied

Facilitated diffusion by iontophoresis of vasoactive agents to the rat incisor pulp.

The use of iontophoresis for facilitated diffusion of vasoactive agents into the dental pulp was investigated in lower incisor teeth of anaesthetized rats. Acetylcholine, carbachol and noradrenaline were iontophoresed with anodal and sodium nitroprusside with cathodal direct current through a superficial dentin exposure. Pulpal blood flow was measured with laser Doppler flowmetry. Current intensities below 100 microA of both polarities, using sodium chloride as a medium, caused no or minor afferent nerve-induced vasodilation, but excited sympathetic fibres of the pulp in a current-dependent manner. The current threshold for facilitated diffusion of acetylcholine was about 20 microA. The vascular responses to the cholinergic and noradrenergic drugs appeared within a minute after the onset of current and they were abolished by systemic administration of atropine and phenoxy benzamine, respectively. Iontophoresis of acetylcholine (40-100 microA for 20-120 s) caused a 3-fold increase of pulpal blood flow which was not dose-dependent; carbachol provoked a high-magnitude, long-lasting vasodilation and so did sodium nitroprusside. Noradrenaline caused a long-lasting vasoconstriction. In denervated rats iontophoresis of carbachol had effects similar to those seen in intact animals. None of the drugs used locally had any effect on systemic blood pressure. The results of this study indicate that iontophoresis can be used for delivery of vasoactive agents from an exposed dentin surface into the pulp in sufficient quantity to elicit drug-specific local vascular responses without causing systemic vascular effects.

Acetylcholine↗

PubMed1994

Quantification, qualification, and microbial killing efficiencies of antimicrobial chlorine-based substances produced by iontophoresis.

The dependence of microbial killing on chloride ions present in solutions undergoing iontophoresis is addressed. A 400-microA current was applied to vials containing synthetic urine or saline, and the production of chlorine-based substances (CBSs) was detected by the N,N-diethyl-p-phenylene diamine colorimetric method. It was found that as the time of current application increased, the total concentration of CBSs also increased. The iontophoretic current converted (through oxidation) chloride ions present in the solutions into CBSs such as free chlorine, chlorine dioxide, chlorite, monochloramine, and dichloramine (the last two were produced by iontophoresis only when nitrogenous substances were present in the solution). Two of the CBSs (free Cl and ClO2), when they were separately added back to microbial suspensions (approximately 3 x 10(5) CFU/ml) at the same concentrations at which they were detected in either 0.46% (wt/vol) NaCl solution or synthetic urine iontophoresed for 4 h at 400 microA, reduced or eliminated bacterial genera and a fungus. However, when free Cl and ClO2 were jointly added back to microbial suspensions, bacterial and fungal killing was synergistic and more rapid and complete than when these chlorine-based biocides were added separately. Therefore, iontophoresis of solutions containing chloride ions produces chlorine-based biocides that are responsible for the antimicrobial effect of iontophoresis.

Bacteria↗

PubMed2005

Iodide iontophoresis as a treatment for dry eye syndrome.

BACKGROUND/AIMS: Among the causes related to the development or perpetuation and aggravation of dry eye disease, oxidative reactions may have a role in the pathogenesis of this disorder. Antioxidants, such as iodide, have shown a strong effect in preventing the oxidative damage to constituents of the anterior part of the eye. In this clinical trial the effectiveness of iodide iontophoresis and iodide application without current in moderate to severe dry eye patients was compared. METHODS: 16 patients were treated with iodide iontophoresis and 12 patients with iodide application without current for 10 days. Subjective improvement, frequency of artificial tear application, tear function parameters (break up time, Schirmer test without local anaesthesia), vital staining (fluorescein and rose bengal staining) as well as impression cytology of the bulbar conjunctiva were evaluated before treatment, 1 week, 1 month, and 3 months after treatment. RESULTS: A reduction in subjective symptoms, frequency of artificial tear substitute application, and an improvement in certain tear film and ocular surface factors could be observed in both groups. A stronger positive influence was seen after application of iodide with current (iontophoresis), as observed in a distinct improvement in break up time, fluorescein and rose bengal staining, and in a longer duration of this effect compared with the non-current group. No significant change in Schirmer test results and impression cytology were observed in both groups. CONCLUSIONS: Iodide iontophoresis has been demonstrated to be a safe and well tolerated method of improving subjective and objective dry eye factors in patients with ocular surface disease.

Adult↗

PubMed2006

Treatment of plantar fasciitis by LowDye taping and iontophoresis: short term results of a double blinded, randomised, placebo controlled clinical trial of dexamethasone and acetic acid.

OBJECTIVES: To determine if, in the short term, acetic acid and dexamethasone iontophoresis combined with LowDye (low-Dye) taping are effective in treating the symptoms of plantar fasciitis. METHODS: A double blinded, randomised, placebo controlled trial of 31 patients with medial calcaneal origin plantar fasciitis recruited from three sports medicine clinics. All subjects received six treatments of iontophoresis to the site of maximum tenderness on the plantar aspect of the foot over a period of two weeks, continuous LowDye taping during this time, and instructions on stretching exercises for the gastrocnemius/soleus. They received 0.4% dexamethasone, placebo (0.9% NaCl), or 5% acetic acid. Stiffness and pain were recorded at the initial session, the end of six treatments, and the follow up at four weeks. RESULTS: Data for 42 feet from 31 subjects were used in the study. After the treatment phase, all groups showed significant improvements in morning pain, average pain, and morning stiffness. However for morning pain, the acetic acid/taping group showed a significantly greater improvement than the dexamethasone/taping intervention. At the follow up, the treatment effect of acetic acid/taping and dexamethasone/taping remained significant for symptoms of pain. In contrast, only acetic acid maintained treatment effect for stiffness symptoms compared with placebo (p = 0.031) and dexamethasone. CONCLUSIONS: Six treatments of acetic acid iontophoresis combined with taping gave greater relief from stiffness symptoms than, and equivalent relief from pain symptoms to, treatment with dexamethasone/taping. For the best clinical results at four weeks, taping combined with acetic acid is the preferred treatment option compared with taping combined with dexamethasone or saline iontophoresis.

Acetic Acid↗

PubMed2002

Transtympanic iontophoresis with a biocompatible paramagnetic solution at MR imaging: experimental feasibility study in rabbits.

PURPOSE: To determine the feasibility of transtympanic iontophoresis in experimental animals with a paramagnetic contrast agent at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Optimal MR sequence parameters and appropriate paramagnetic ion concentrations of a water and gadopentetate dimeglumine solution were initially assessed with phantoms. Iontophoresis was performed in left ears of five rabbits after the external auditory canals were filled with a solution of water and gadopentetate dimeglumine of optimal concentration, and right ears were used as controls. Signal-to-structural noise ratio (SSNR) and contrast-to-structural noise ratio (CSNR) were measured by using regions of interest, and the overall image quality was assessed subjectively. RESULTS: Spin-echo (SE) MR sequences were superior to gradient-echo (GRE) MR sequences in terms of SSNR, CSNR, and overall image quality. Highest SSNR and CSNR values were achieved with 2 mmol/L (2 mM) of gadopentetate dimeglumine solution with both SE (repetition time msec/echo time msec, 500/12; flip angle, 90 degrees ) and GRE (300/10; flip angle, 90 degrees ) sequences in both phantoms and animals. The high signal intensity of gadopentetate dimeglumine solution was recognized in middle ears, vestibules, and semicircular canals of all rabbit ears that had undergone iontophoresis and in none of the control ears. CONCLUSION: With the solution of water and gadopentetate dimeglumine, the maximum SSNR and CSNR with both SE and GRE MR imaging sequences were achieved. The solution can be transferred to the middle and inner ear cavities across an intact tympanic membrane by using transtympanic iontophoresis.

Animals↗

PubMed1998

Comparison of the effects of cetirizine and ebastine on the skin response to histamine iontophoresis monitored with laser Doppler flowmetry.

BACKGROUND: The administration of histamine with iontophoresis is an alternative method to skin prick tests or intradermal injections. Skin reactions obtained with this method can be recorded with laser Doppler flowmetry (LDF) and previous studies with this method have shown histamine-induced laser Doppler changes in the wheal area. OBJECTIVE: In order to compare the influence of two H1 receptor antagonists (cetirizine 10 mg vs. ebastine 10 mg) on the skin vascular responses to histamine introduced by iontophoresis, we designed a double-blind, randomized, two-period crossover trial in which 18 volunteers were randomized. METHODS: Before and 2, 5 and 7 h after drug administration, iontophoresis (30 s, 1.4 mA/cm2) of histamine 10% was performed and followed by (1) monitoring of skin vascular responses with LDF at the administration site and at 1 cm from it, and (2) wheal and flare area measurements. RESULTS: 2, 5 and 7 h after intake of the antihistaminic drug, there were significant differences between both drugs. Concerning LDF recordings, we noted at the histamine administration site an increase in perfusion unit (PU) values which is an effect known to be in proportion to the degree of inhibition of wheal reaction, and at 1 cm distal to the histamine administration site, there was a decrease in PU values. These changes were more marked under cetirizine. A greater suppressive effect of cetirizine on the wheal and flare reaction was consistently observed at all time points during the study, demonstrating its superior efficacy. CONCLUSION: We conclude that (1) cetirizine demonstrated a stronger antihistaminic effect compared to ebastine at all time points; (2) iontophoresis appears to be an appropriate method to study specific microvascular changes at the delivery site of histamine and hence to detect the earliest changes occurring at the site of agonist-antagonist competition in the skin.

Adult↗

PubMed1995

Noninvasive investigation of human skin after in vivo iontophoresis.

The main objective of our study was to investigate skin function and structure in human volunteers after electrical current application in order to demonstrate the safety of iontophoresis in vivo. The direct current was applied for 30 min at a density of 0.1 and 0.2 mA/cm2. Iontophoresis increased cutaneous blood flow as measured by laser Doppler flowmetry (LDF). This increase was reversible within 1 h and was more pronounced at higher current density. Measurements of transepidermal water loss (TEWL) and LDF were the same at the cathode and the anode sites. Except for 5 min at 0.2 mA/cm2 density, TEWL values were not enhanced as compared to control values (no iontophoresis). Attenuated total reflectance-Fourier transform infrared spectroscopy of the stratum corneum structure showed a transient increase (30 min) in hydration after electrode application for 30 min. No alteration in lipid structure could be shown. These results augur the safety of drug delivery by iontophoresis.

Adult↗

PubMed2004

Hydrogel probe for iontophoresis drug delivery to the eye.

The aim of this study was to evaluate the use of a solid hydrogel loaded with a drug solution as a probe for ejecting drugs to the eye upon application of low current iontophoresis. Hydroxyethyl methacrylate (HEMA), cross-linked with ethylene glycol dimethacrylate (EGDMA), and cross-linked arabinogalactan or dextran were prepared to form solid hydrogels. The hydrogels were examined for their mechanical suitability, absorption of drug solution and in vitro release properties when applying an iontophoretic current through the drug-loaded hydrogel into a solid-agar surface. Transconjunctival and transscleral iontophoresis of gentamicin sulfate was studied in healthy rabbits using drug-loaded disposable HEMA hydrogel disc probes. Gentamicin concentrations in different eye segments were assayed using a fluorescence polarization immunoassay. Preliminary corneal toxicity was examined in rabbits using a current intensity of 2.5 and 5.1 mA/cm2 for 60 and 120 s. The most appropriate hydrogel is composed of HEMA, 2% EGDMA and 75% water. lontophoresis onto agar gel was found indicative for the evaluation of iontophoretic activity of a hydrogel. Transscleral iontophoretic treatment resulted in high concentrations of drugs in the posterior segments of the eye. Application of iontophoresis onto the rabbit eye caused a reversible swelling of the cornea which lasted a few hours after application. Low current iontophoresis using drug-loaded hydrogel has a potential clinical value in obtaining high drug concentration at posterior segments of the eye.

Animals↗

PubMed1989

Antibiotic iontophoresis in the treatment of burn perichondritis of the rabbit ear.

Perichondritis of the pinna is a serious late infection of burns involving the ear. The avascular nature of this injury renders systemic antibiotic therapy ineffective in delivering adequate levels of drug to the area to provide antimicrobial activity. Treatment has traditionally been surgery in some form, resulting in further disfigurement of the damaged cartilagenous framework. Iontophoresis, a method of dispersing charged particles through a relatively impermeable membrane by a light electrical field, appears to be a feasible method of antibiotic delivery. This initial pilot study investigated the development of perichondritic-like burns in ten rabbit ears, and techniques for gentamicin iontophoresis and assay in devitalized cartilage. Five rabbits, with ear burns simulating perichondritis, were treated with gentamicin iontophoresis on one ear and gentamicin-soaked gauze on the other. Resulting assays of the ear cartilages, after four treatments over a 2-day period, demonstrated a nearly twenty-fold increase in gentamicin levels in the iontophoresis-treated ears, compared to low levels in the soaked ears. Systemic absorption was negligible in all rabbits.

Animals↗

PubMed1989

[Enhanced percutaneous absorption of formoterol furmarate via pulsed iontophoresis. I. Effect of constant current and constant voltage].

The effect of iontophoresis on percutaneous absorption of formoterol fumarate (FF) was investigated in vitro with abdominal skin excised from guinea pig. By passive diffusion, the flux at steady state for stripped skin was about 230 times greater than that for intact skin. Therefore, it is suggested that stratum corneum is a barrier for the percutaneous absorption of FF. Penetrated amount of FF increased significantly with an increase in donor concentration from 0.035% to 0.07%. Under the constant current iontophoresis the large flux accompanied with the high applied voltage was shown at the beginning of iontophoresis. Thereafter the flux decreased with a decrease in applied voltage. Under the constant voltage iontophoresis a linear relationship between penetrated amount of FF and time was observed.

Animals↗

PubMed1989

[Enhanced percutaneous absorption of formoterol fumarate via pulsed iontophoresis. II. Effect of polarity, pulse frequency and duty].

To clarify the effect of polarity, pulse frequency and duty on the iontophoretic transport of formoterol fumarate (FF), in vitro and in vivo studies were performed with guinea pigs. In the in vitro studies, the flux at steady state was enhanced by the factor 7.61 with anodal iontophoresis in comparison with control, whereas, with cathodal iontophoresis it was restrained by the factor 0.79. When pulse frequency was varied from 0 to 40 kHz, the flux at steady state was enhanced with an increase in pulse frequency. In the in vivo studies with varying the duty of pulse potential from 10 to 100%, the maximum plasma concentration of FF was obtained at a 30% duty. In contrast, the plasma concentration of FF achieved at 100% duty was not high. With stripped skin, no significant difference in the plasma concentration of FF was shown between iontophoresis and control. Consequently, it is suggested that iontophoresis contributes to FF penetration across stratum corneum.

Animals↗

PubMed1980

Inner ear lidocaine concentrations following iontophoresis.

This study has established the feasibility of measuring perilymph lidocaine levels after iontophoresis for local tympanic anesthesia in the rabbit model. A subsequent study may now be performed to produce a valid, dose-response curve correlating perilymph lidocaine levels and cochlear responses. In this manner the effects of and safety of lidocaine iontophoresis for tympanic anesthesia can be determined with certainty. After intravenous sedation, eight rabbits underwent iontophoresis followed by diagnostic vestibulotomies. Perilymph samples were taken and analyzed for lidocaine levels. Significant amounts of perilymph lidocaine were found in both the intact and perforated tympanic membrane groups. In the perforated tympanic membrane group, the perilymph lidocaine level was eight times that of the intact tympanic membrane group. Future studies to determine the dose-response relationship of perilymph lidocaine to cochlear responses are now possible. Thus, the safety of lidocaine iontophoresis and the degree of inner ear toxicity of lidocaine can be established quantitatively.

Animals↗