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At least 271 records · Page 15Linked to original sources

PubMed1999

A randomized clinical trial of dermal anesthesia by iontophoresis for peripheral intravenous catheter placement in children.

STUDY OBJECTIVE: To assess the efficacy of dermal anesthesia by lidocaine iontophoresis in children undergoing peripheral intravenous (PIV) catheter placement in the emergency department. METHODS: A double-blind, randomized, clinical trial was conducted at a tertiary children's hospital ED. Alert children 7 years or older requiring nonemergency PIV were eligible. Patients in the lidocaine group received 1 mL of 2% lidocaine with 1:100,000 epinephrine over a potential PIV site by iontophoresis. The control group received 1 mL of.9% saline solution with 1:100,000 epinephrine. After PIV placement, patients ranked the procedural pain using a visual analog scale. Complications were noted by visual inspection or telephone follow-up. RESULTS: During a 6-month period, 22 patients were assigned to the lidocaine group and 25 to the control group. There was no significant difference in age, sex, or ethnic background between the 2 study groups, and mean application time was 12.0 minutes. The median pain score was.5 in the lidocaine group compared with 4 in the control group (P =.0002; 95% confidence interval [CI] 1 to 5). No significant immediate or delayed complications were observed. CONCLUSION: Lidocaine iontophoresis provides effective dermal anesthesia for children older than 7 years of undergoing nonemergency PIV placement in the ED.

Anesthesia, Local↗

PubMedDate not supplied

[Transdermal iontophoresis with dexamethasone and verapamil for Peyronie's disease].

OBJECTIVES: To evaluate the effects of transdermal iontophoresis with verapamil and dexamethasone in patients with Peyronie's disease of less than one year of evolution. MATERIAL AND METHODS: We have treated ten patients twice a week during six consecutive weeks using iontophoresis with a Miniphysionizer dispositive. This device generates a 2mA electric current during 20 min which triggers the transdermal penetration of medication. In every session dexamethasone 8 mg and verapamil 5mg were administered inside a small self-adhesive receptacle on the penile skin overlying the fibrosis plaque. To evaluate the efficacy, penile curvature was measured by Kelami's test, while the plaque size was assessed by penile ultrasound. Other parameters like pain, erectile function and ability for vaginal intercourse were recorded using questionnaires. Safety parameters were also assessed during treatment. RESULTS: No improvement or progression in penile curvature was evidenced in any of the patients. The hardness of the plaque was reduced in 5 patients, becoming impalpable in 2 of them. Decrease in plaque volume was observed by penile ultrasound in 6. Pain improved in 8 patients, disappearing in 6 of them. One patient recovered his erectile function at the end of the treatment; whereas 3 referred that their ability for intercourse enhanced while 2 reported that treatment improved their sexual life in general. We didn't record any significantly side effects, except for a transitory and slight dermal redness on the site of electrode placement. CONCLUSIONS: Transdermal iontophoresis is an effective treatment for pain control in early stages of Peyronie's disease. Efficacy in reducing penile curvature seems to be limited. Controlled clinical trials are needed, and perhaps reviewing indications in order to obtain more relevant clinical effects.

Adult↗

PubMed2000

An in vivo investigation of the rabbit skin responses to transdermal iontophoresis.

To optimize the benefits of transdermal iontophoresis, it is necessary to develop a suitable animal model that would allow for extensive assessments of the biological effects associated with electro-transport. Rabbit skin responses to iontophoresis treatments were evaluated by visual scoring and by non-invasive bioengineering parameters and compared with available human data. In the current density range 0.1-1.0 mA/cm(2) applied for 1 h using 0.9% w/v NaCl and 0.5 mA/cm(2) for up to 4 h, no significant irritation was observed. 2 mA/cm(2) applied through an area of 1 cm(2) for 1 h resulted in slight erythema at both active electrode sites but without significant changes in transepidermal water loss (TEWL) and laser Doppler velocimetry (LDV). A value of 4 mA/cm(2) under similar conditions caused moderate erythema at the anode and cathode with TEWL and LDV being significantly elevated at both sites; 1 mA/cm(2) current applied for 4 h, caused moderate erythema at both anode and cathode; and 1 mA/cm(2) applied for 1 h caused no irritation when the area of exposure was increased from 1 to 4.5 cm(2). When significant irritation and barrier impairment occurred, the erythema was resolved within 24 h with barrier recovery complete 3-5 days post-treatment. Rabbit skin thus shows promise as an acceptable model for iontophoresis experiments.

Administration, Cutaneous↗

PubMed1999

Iontophoresis and electroporation: comparisons and contrasts.

The techniques of iontophoresis and electroporation can be used to enhance topical and transdermal drug delivery. Iontophoresis applies a small low voltage (typically 10 V or less) continuous constant current (typically 0.5 mA/cm2 or less) to push a charged drug into skin or other tissue. In contrast, electroporation applies a high voltage (typically, ?100 V) pulse for a very short (micros-ms) duration to permeabilize the skin. This electric assistance of drug delivery across skin will expand the scope of transdermal delivery to hydrophilic macromolecules such as the drugs of biotechnology. These two techniques differ in several aspects such as the mode of application and pathways of transport but can be used together for effective drug delivery. Iontophoresis is already used clinically in physical therapy clinics and is close to commercialization for development of a systemic delivery patch with miniaturized circuits and similar in overall size to a passive patch. The use of electroporation for drug delivery is relatively new and is being actively researched.

Administration, Cutaneous↗

PubMed1991

Study of the mechanisms of flux enhancement through hairless mouse skin by pulsed DC iontophoresis.

Enhanced iontophoretic transport using pulsed DC is usually explained by citing the observed decrease in skin resistance caused by an increase in AC pulse frequency at very small currents. Alternately, it has been suggested that the "on-to-off" nature of pulsed DC imparts an "impact energy" to the fluid, thereby increasing transport. This report provides a test of these mechanisms for enhanced delivery via pulsed iontophoresis. The DC resistance of hairless mouse skin during continuous and pulsed DC iontophoresis is measured as a function of time for selected pulse frequencies and duty cycles using current densities ranging from 0.1 to 1.0 mA/cm2. As a test of the impact energy mechanism, the iontophoretic transport of 14C-glucose measured with pulsed DC is compared with similar data obtained previously using continuous DC. It is suggested that pulsed current can yield lower resistance and enhanced drug delivery provided that (a) the "steady-state" current during the "on" phase of the pulse is very small and (b) the frequency is low enough to allow depolarization of the skin during the "off" phase of the pulse. The glucose transport results suggest that the "impact energy" concept does not apply to iontophoresis.

Animals↗

PubMed1990

Enhancement of the in vitro skin permeability of azidothymidine (AZT) via iontophoresis and chemical enhancer.

Azidothymidine (AZT) was used as a model drug to study the effect of iontophoresis on the skin permeation of a neutral compound. The rate of in vitro permeation across hairless rat skin was low and highly variable. With iontophoresis treatment the permeation rate was two- to threefold greater than by passive diffusion. The addition of varying amounts of sodium chloride to the donor enhanced the iontophoretic permeation rate an additional two- to threefold possibly due to convective forces. The addition of N-decylmethyl sulfoxide (C10MSO) to the donor increased the permeation rate by several hundred-fold over passive diffusion for hairless rat skin and approximately 75-fold for human skin. No additional enhancement was observed with the combination of C10MSO and iontophoresis treatment at constant current or constant voltage. It may be that the presence of C10MSO lowers the zeta potential of the skin, thus enhancement due to convective flow is minimized.

Animals↗

PubMed1994

Studies on the effects of applied voltage and duration on human epidermal membrane alteration/recovery and the resultant effects upon iontophoresis.

The effects of applied voltage and the duration of application upon human epidermal membrane (HEM) alterations and recovery were investigated. All experiments were conducted using a two-chamber diffusion cell with constant DC voltage (250-4000 mV) applied over a predetermined period, and HEM changes were monitored by measuring the electrical resistance before and after voltage termination. The key findings were that the rate of decrease in resistance was strongly dependent upon the applied voltage, the reversible recovery times were dependent upon both the magnitude and the duration of the applied field (frequently were several orders of magnitude greater than times for attaining significant resistance reduction), and reversible recovery times were much longer when lower voltages were applied for longer times to attain the same decrease in electrical resistance than for higher voltages at short times. These findings closely parallel those obtained on electrical breakdown/recovery of bilayer membranes (electroporation). The second part of this work examined the hypothesis that decreases in HEM electrical resistance induced by the applied voltage are accompanied by proportional increases in HEM permeability. A study was designed to test this hypothesis involving a four-stage protocol with HEM: passive transport, 250-mV iontophoresis, 2000-mV iontophoresis for 10 min, then back to 250-mV iontophoresis. The data obtained strongly support the view that the HEM alterations induced by the electric field result in pore formation and in the expected changes in HEM permeability.

Diffusion↗

PubMed2003

Transdermal reverse iontophoresis of valproate: a noninvasive method for therapeutic drug monitoring.

PURPOSE: The objectives of this work were (a) to explore the potential of transdermal reverse iontophoresis for therapeutic drug monitoring and (b) to develop an "internal standard" calibration procedure so as to render the technique completely noninvasive. METHODS: A series of in vitro iontophoresis experiments was performed in which the subdermal concentration of sodium valproate was varied from 21 microM to 1 mM. Glutamic acid was also introduced into the subdermal donor at a fixed concentration to act as an "internal standard" for the calibration method. RESULTS: Both valproate and glutamate anions were recovered, as expected, at the anodal receptor chamber. The iontophoretic extraction flux of valproate was linearly correlated with the subdermal concentration. Glutamate flux was constant. It follows that the ratio of extracted fluxes (valproate/glutamate) was directly dependent upon (a) the subdermal valproate concentration and (b) the subdermal concentration ratio (valproate/glutamate), offering a means, thereby, to a completely noninvasive methodology. CONCLUSIONS: This work demonstrates the potential of reverse iontophoresis for noninvasive therapeutic monitoring. The simultaneous quantification of the analyte of interest and of an "internal standard" renders the withdrawal of a blood sample unnecessary.

Administration, Cutaneous↗

PubMed2004

Transdermal iontophoresis of rotigotine across human stratum corneum in vitro: influence of pH and NaCl concentration.

PURPOSE: The aim of this study was to characterize the influence of pH and NaCl concentration on the transdermal iontophoretic transport of the dopamine receptor agonist rotigotine across human stratum corneum (HSC). METHODS: Rotigotine transport was studied in vitro in side by side diffusion cells according to the following protocol: 6 h of passive diffusion, 9 h of iontophoresis, and 5 h of passive diffusion. A current density of 0.5 mA cm(-2) was used. The influence of donor phase pH (4, 5, and 6) and different concentrations of NaCl (0.07 and 0.14 M) on rotigotine iontophoretic flux were examined. The acceptor phase was phosphate-buffered saline (PBS) at pH 7.4 except in one series of experiments aimed to study the effects of rotigotine solubility on its iontophoretic transport. In this study, PBS at pH 6.2 was used. In separate studies. 14C-mannitol was used as a marker to determine the role of electro-osmosis during iontophoresis. RESULTS: The estimated iontophoretic steady-state flux (Flux(ss)) of rotigotine was influenced by the pH of the donor solution. At a drug donor concentration of 0.5 mg ml(-1), the iontophoretic flux was 30.0 +/- 4.2 nmol cm(-2) h(-1) at pH 6 vs. 22.7 +/- 5.5 nmol cm(-2) h(-1) at pH 5. However, when the donor concentration was increased to 1.4 mg ml(-1), no significant difference in iontophoretic rotigotine transport was observed between pH 5 and 6. Increase of NaCl concentration from 0.07 M to 0.14 M resulted in a decrease of the rotigotine Flux(ss) from 22.7 +/- 5.5 nmol cm(-2) h(-1) to 14.1 +/- 4.9 nmol cm(-2) h(-1). The contribution of electro-osmosis was estimated less than 17%. Probably due to the lipophilic character of the drug, impeding the partitioning of rotigotine from HSC to the acceptor compartment, steady-state transport was not achieved during 9 h of iontophoresis. CONCLUSIONS: Both pH and NaCl concentration of the donor phase are crucial on the iontophoretic transport of rotigotine. Electro-repulsion is the main mechanism of the iontophoretic transport of rotigotine.

Administration, Cutaneous↗

PubMed2003

Analgesia during radial artery cannulation: comparison of the effects of lidocaine applied by local injection or iontophoresis.

We compared the effect of lidocaine injection with lidocaine iontophoresis for pain relief during radial artery cannulation prior to induction of anaesthesia. Patients were allocated randomly to one of two groups. Group 1 (n = 15) received iontophoresis for 10 min prior to cannulation, using 4% lidocaine 4 ml. Group 2 (n = 15) received local infiltration of 1% lidocaine 1 ml using a 25G needle. Pain scores were recorded immediately after cannulation using a 10-cm visual analogue scale (VAS). There was no difference in mean (SD) pain scores [group 1: 2.2 (1.5) cm; group 2: 2.3 (2.7) cm; 95% CI of difference -1.8 to 1.5 cm]. Lidocaine delivered by iontophoresis is an effective and painless method of providing analgesia for radial artery cannulation.

Adolescent↗

PubMed1999

Tretinoin-iontophoresis in atrophic acne scars.

BACKGROUND: Atrophic acne scars are a frequent problem after acne. Hitherto, mainly invasive treatment measures were possible. In a recent paper, we demonstrated the positive effects of iontophoresis with 0.025% tretinoin gel vs. estriol 0.03%. OBJECTIVE: In this further study, the recording of the clinical effects of iontophoresis with 0.025% tretinoin gel in atrophic acne scars was supplemented by immunohistochemistry investigations of collagen I and III, proliferation markers, and the estimation of epidermal thickness. METHODS: The treatment was performed twice weekly in 32 volunteer patients for a period of 3 months by application of the substance under a constant direct current of 3 mA for 20 min. Skin biopsies prior to and at the end of treatment were performed in 32 voluntary patients in order to investigate collagen I/III and proliferation markers by immunohistochemistry methods. RESULTS: Clinically, at the end of treatment, in 94% of patients a significant decrease in the scar depth was observed. Neither epidermal thickness nor proliferation markers revealed a significant increase at the end of treatment. Furthermore, collagen I and collagen III showed no common trend, as expressed statistically by a lack of significance. In some cases, increases in collagen III became evident at the end of treatment. CONCLUSIONS: Tretinoin-iontophoresis is an effective, noninvasive treatment of atrophic acne scars without causing disturbing side-effects.

Acne Vulgaris↗

PubMedDate not supplied

Lidocaine iontophoresis for topical anesthesia before dermatologic procedures in children: a randomized controlled trial.

Local anesthesia by injection in pediatric patients undergoing dermatologic procedures is not well received because of the pain of injection and the fear of needles. Lidocaine iontophoresis is a method of topical anesthesia where lidocaine is driven into the skin under the influence of electric current. We performed a prospective double-blind, placebo-controlled evaluation of iontophoresis of 2% lidocaine with 1:100,000 epinephrine. Sixty children requiring dermatologic procedures were enrolled (50 shave biopsy, 7 curettage, 2 injection, 1 punch biopsy). Twenty-nine of 31 patients in the lidocaine group versus 2 of 29 placebo patients required no supplemental anesthesia (p < 0.001). The pain reported by the patients on the Oucher pain scale subsequent to the procedure was significantly lower in the lidocaine group (p < 0.001). Investigators and parents also rated pain lower in the lidocaine group (p < 0.001). Blanching and/or erythema occurred in 58 of 60 patients, but resolved within 1 hour in all patients. There were no other adverse events. Lidocaine iontophoresis is a safe and effective method of topical anesthesia prior to dermatologic procedures in children.

Adolescent↗

PubMed2005

Effect of chemical penetration enhancer and iontophoresis on the in vitro percutaneous absorption enhancement of insulin through porcine epidermis.

The purpose of this study was to investigate the effect of chemical enhancers (fatty acids and limonene) and iontophoresis on the in vitro permeability enhancement of insulin through porcine epidermis. The following fatty acids were used: palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3). Franz diffusion cells and the Scepter iontophoretic power source were used for the percutaneous absorption studies. Cathodal iontophoresis was performed at 0.2 mA/cm2 current density. Iontophoresis in combination with chemical enhancers synergistically increased (p<0.05) the in vitro permeability of insulin. Linolenic acid (C18:3) produced greater permeability of insulin through epidermis than did other fatty acids during passive (44.45 x 10(-4) cm/h) and iontophoretic (78.03 x 10(-4) cm/h) transport. Lispro insulin flux was significantly (p<0.05) greater through linolenic acid and limonene pretreated epidermis compared to untreated controls during both passive and iontophoretic transports. Using limonene as a penetration enhancer, a linear increase in the passive and iontophoretic flux of lispro insulin was observed with donor concentrations increasing from 100 IU/mL to 300 IU/mL. Iontophoretic flux through limonene-treated epidermis using 0.5 mA/cm2 current density and 300 IU/mL insulin donor solution was 45.63 IU/cm2/day. Using an iontophoretic patch size of 10 cm2, we would be able to deliver 50 IU of insulin within 3 h.

Administration, Cutaneous↗

PubMed2004

Reverse iontophoresis for non-invasive transdermal monitoring.

Iontophoresis is the application of a small electric current to enhance the transport of both charged and polar, neutral compounds across the skin. Manipulation of either the total charge delivered and/or certain electrode formulation parameters allows control of electromigration and electroosmosis, the two principal mechanisms of transdermal iontophoresis. While the approach has been mainly used for transdermal drug delivery, 'reverse iontophoresis', by which substances are extracted to the skin surface, has recently been the subject of considerable effort. Glucose monitoring has been extensively studied and other applications, including therapeutic drug monitoring, are contributing to the development of the technique. An internal standard calibration procedure may ultimately render this novel monitoring technique completely non-invasive.

Blood Glucose↗

PubMed1992

Treatment of traumatic myositis ossificans with acetic acid iontophoresis.

The purpose of this case report is to document the treatment of a patient who had traumatic myositis ossificans with acetic acid iontophoresis. A 16-year-old boy developed quadriceps femoris muscle myositis ossificans as a result of a springboard diving accident. A 2% acetic acid solution was administered via iontophoresis into the myositis ossificans, followed by 8 minutes of pulsed ultrasound at 1.5 W/cm2. The treatment was performed three times per week for 3 weeks. At the conclusion of the treatments, radiographic findings indicated a 98.9% decrease in the size of the ossified mass. The patient regained full range of motion and was able to return to pain-free activity. This case report demonstrates the potential for a therapeutic program of acetic acid iontophoresis and ultrasound in eliminating myositis ossificans.

Acetates↗

PubMed1995

Iontophoresis: applications in transdermal medication delivery.

This article presents a review of the literature relating to iontophoresis. This technique has been used in physical therapy to introduce ionic medications through the skin, primarily for a local effect. Recently, there has been increased interest in using this technique for the transdermal delivery of medications, both ionic and nonionic. This article includes an overview of the history of iontophoresis and a discussion of the physico-chemical and biological factors affecting iontophoretic drug transfer for both local and systemic effects. Factors affecting skin injury and techniques for optimizing iontophoretic drug delivery through the use of current modulation, electrode construction, and skin permeation enhancers are also discussed. Clinical applications of iontophoresis in physical therapy and the pharmacology of selected medications are presented. Thoughts for future potential uses of this technique and needs for further research are also discussed.

Adrenal Cortex Hormones↗

PubMed2004

Digital iontophoresis of vasoactive substances as measured by laser Doppler imaging--a non-invasive technique by which to measure microvascular dysfunction in Raynaud's phenomenon.

OBJECTIVE: To test the hypothesis that microvascular vasodilation is impaired in patients with systemic sclerosis (SSc) compared with patients with primary Raynaud's phenomenon (PRP) and healthy controls, using the technique of laser Doppler imaging to quantify blood flow responses to iontophoresis of vasoactive agents. METHODS: Microvascular blood flow was measured by laser Doppler imaging before, during and after 120 s iontophoresis (30 microA) of 1% acetylcholine chloride (ACh, endothelium-dependent) and 1% sodium nitroprusside (NaNP, endothelium-independent). Two adjacent fingers of the left hand were studied, and the procedure then repeated on the right. Ten patients with limited cutaneous SSc (LCSSc), 10 patients with PRP and 11 healthy control subjects were studied. RESULTS: Vasodilation in response to both ACh and NaNP iontophoresis, as measured by 'area under the blood flow.time curve' (AUC), normalized for baseline flux, was similar in the control and PRP groups, but was diminished in the LCSSc group compared with both control and PRP groups (ACh results: control vs LCSSc P = 0.028, PRP vs LCSSc P = 0.005; NaNP results: control vs LCSSc P = 0.004, PRP vs LCSSc P = 0.005). There were no differences between groups in baseline flux values nor in voltages required to drive the 30 microA current. CONCLUSIONS: Both endothelium-dependent and endothelium-independent vasodilation are impaired in patients with LCSSc. Vasodilatory responses in patients with PRP are similar to those in controls. If reproducibility is confirmed to be satisfactory, then these techniques could be used to examine disease progression over time and responsiveness to vasoactive treatment, thus facilitating clinical trials.

Acetylcholine↗

PubMed2005

A pilot study of acetic acid iontophoresis and ultrasound in the treatment of systemic sclerosis-related calcinosis.

OBJECTIVES: Our aim was to perform a pilot study to investigate whether iontophoresis of acetic acid, followed by ultrasound, might be a safe and effective treatment for systemic sclerosis (SSc)-related calcinosis. This combination treatment has been used in other calcifying disorders. METHODS: Three female patients (ages 51, 62 and 59 yr) were studied. Each underwent treatment nine times over a 3-week period. Iontophoresis was with 2-5% acetic acid at 100 microA for 20 min, followed by ultrasound at 1.5 W/cm(2) for 8 min at each visit. The primary endpoint was the degree of radiographic calcinosis as quantified by image analysis after adjusting for soft tissue change. RESULTS: There were no side-effects from treatment. Mean radiographic intensity fell in all patients (by 18.0, 8.9 and 8.5%), although the maximum density and the area of calcinosis fell in only one patient. However, none of the patients reported any benefits from the treatment. CONCLUSIONS: In this small pilot study none of the patients experienced clinical improvement, despite an intensive treatment schedule over 3 weeks. However, there may have been some radiographic improvement. Given that there is currently no effective treatment for SSc-related calcinosis a larger study incorporating higher 'doses' of iontophoresis is indicated.

Acetic Acid↗