Absorption of iontophoresis-driven 2% lidocaine with epinephrine in the tissues at 5 mm below the surface of the skin

Investigating iontophoresis as a therapeutic approach for Peyronie's disease: a systematic review

INTRODUCTION

Iontophoresis therapy (IPT) is a noninvasive technique that uses electrical impulses to deliver charged molecules into the skin for controlled and targeted drug delivery. IPT has been explored as a noninvasive treatment option for Peyronie's disease (PD), but the current literature in this regard is still scarce.

OBJECTIVE

We aimed to systematically review the current literature on the application of IPT in the management of PD to provide a comprehensive evaluation and holistic outlook on the subject.

METHOD

A comprehensive search strategy was implemented in the following databases to retrieve research articles: PubMed (MEDLINE), Scopus, and Web of Science. Google Scholar was also manually searched. The search results were imported into Rayyan reference management for assessment based on the predefined inclusion criteria. The quality of the articles was evaluated by the proper JBI checklist (ie, per the study design), and the JBI grades of recommendation were used for grading the evidence.

RESULTS

A systematic search yielded 451 publications, 11 of which met the criteria to be included in this systematic review. The results demonstrated that IPT, usually with verapamil and dexamethasone, has shown promising results in treating PD. These methods can reduce pain, plaque size, and penile curvature while improving sexual function and quality of life with no serious adverse events. However, most studies had moderate to low quality, indicating a weak recommendation for a certain health management strategy.

CONCLUSION

Based on the extant literature, there is currently insufficient evidence to support the use of IPT for the management of PD. Placing it in the forefront of research can facilitate the management choices for PD even further, given its therapeutic potential.

Epinephrine iontophoresis attenuates changes in skin blood flow and abolishes cutaneous contamination of near-infrared diffuse correlation spectroscopy estimations of muscle perfusion

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an optical imaging technique for measuring relative changes in skeletal muscle microvascular perfusion (i.e., fold change above baseline) during reactive hyperemia testing and exercise and is reported as a blood flow index (BFI). Although it is generally accepted that changes in BFI are primarily driven by changes in muscle perfusion, it is well known that large, hyperthermia-induced changes in cutaneous blood flow can uncouple this relationship. What remains unknown, is how much of an impact that changes in cutaneous perfusion have on NIR-DCS BFI and estimates of skeletal muscle perfusion under thermoneutral conditions, where changes in cutaneous blood flow are assumed to be relatively low. We therefore used epinephrine iontophoresis to pharmacologically block changes in cutaneous perfusion throughout a battery of experimental procedures. The data show that 1) epinephrine iontophoresis attenuates changes in cutaneous perfusion for up to 4-h posttreatment, even in the face of significant neural and local stimuli, 2) under thermoneutral conditions, cutaneous perfusion does not significantly impact NIR-DCS BFI during reactive hyperemia testing or moderate-intensity exercise, and 3) during passive whole body heat stress, when cutaneous vasodilation is pronounced, epinephrine iontophoresis preserves NIR-DCS measures of skeletal muscle BFI during moderate-intensity exercise. Collectively, these data suggest that cutaneous perfusion is unlikely to have a major impact on NIR-DCS estimates of skeletal muscle BFI under thermoneutral conditions, but that epinephrine iontophoresis can be used to abolish cutaneous contamination of the NIR-DCS BFI signal during studies where skin blood flow may be elevated but skeletal muscle perfusion is of specific interest.

Epinephrine penetrates through gingival sulcus unlike keratinized gingiva and evokes remote vasoconstriction in human

Background

It has been demonstrated in non-oral tissues that the locally evoked vasoconstriction could elicit remote vasoconstriction. This study aimed to investigate the spreading vasoconstrictor effects of epinephrine in the gingiva.

Methods

Gingival blood flow (GBF) was measured by laser speckle contrast imager in 21 healthy volunteers. In group A, two wells were fabricated from orthodontic elastic ligature and placed 2 mm apically to the free gingival margin at the mid buccal line of 12 (test side) and 21 (control side) teeth. The GBF was measured in the wells and tightly apical, coronal, distal and mesial to the wells. In group B, the wells were made on the buccal surface of the same teeth, including the gingival sulcus. Four regions were selected for measurement from the gingival margin reaching the mucogingival line (coronal, midway1, midway2 and apical). After the baseline recording, 3 µg epinephrine was applied into the test, and physiological saline into the control well. The GBF was recorded for 14 min. The gingival thickness was measured with a PIROP Ultrasonic Biometer.

Results

In group A, the GBF did not increase or decrease after the application of epinephrine. In group B, the GBF significantly decreased in all regions of the test side and remained low for the observation period. The vasoconstriction appeared with delays in more apical regions (at min 1 in the coronal and the midway1, at min 2 in the midway2, at min 4 in the apical region). Similarly, the amount of the decrease at 14 min was the largest close to sulcus (− 53 ± 2.9%), followed by the midway1 (− 51 ± 2.8%) and midway2 (− 42 ± 4.2%) and was the lowest in the apical region (− 32 ± 5.8%). No correlation was found between GBF and gingival thickness.

Conclusion

Epinephrine could evoke intense vasoconstriction propagating to the mucogingival junction, indicating the presence of spreading vasoconstriction in the human gingiva. The attached gingiva is impermeable to epinephrine, unlike the gingival sulcus.

This trial was registered in ClinicalTrials.gov titled as Evidence of Spreading Vasoconstriction in Human Gingiva with the reference number of NCT04131283 on 16 October 2019. https://clinicaltrials.gov/show/NCT04131283

Iontophoretic skin delivery systems: Success and failures

Iontophoretic transdermal delivery uses a small electric current to push charged molecules into the skin under an electrode of same polarity and offers an attractive option to facilitate the delivery of macromolecules or hydrophilic molecules and to improve patient compliance. This technique has been used in physical therapy clinics for several decades, though the science was not always there to support claims of clinical effectiveness. Recently, this modality of treatment has undergone more systematic and rigorous investigations to withstand the scrutiny of regulatory authorities. In recent years various drugs have gained FDA approval for iontophoretic patches. This technique is gaining recognition due to better compliance rates, non-invasive drug delivery leading to fewer side effects, and sustained release of the drug. Furthermore, programmed delivery and bolus delivery systems have helped with customizing the drug dosage and frequency of dosage based on the patient's need.

Targeted drug delivery therapies inspired by natural taxes

A taxis is the movement responding to a stimulus of an organism. This behavior helps organisms to migrate, to find food or to avoid dangers. By mimicking and using natural taxes, many bio-inspired and bio-hybrid drug delivery systems have been synthesized. Under the guidance of physical and chemical stimuli, drug-loaded carriers are led to a target, for example tumors, then locally release the drug, inducing a therapeutic effect without influencing other parts of the body. On the other hand, for moving targets, for example metastasis cancer cells or bacteria, taking advantage of their taxes behavior is a solution to capture and to eliminate them. For instance, several traps and ecological niches have been fabricated to attract cancer cells by releasing chemokines. Cancer cells are then eliminated by drug loaded inside the trap, by radiotherapy focusing on the trap location or by simply removing the trap. Further research is needed to deeply understand the taxis behavior of organisms, which is essential to ameliorate the performance of taxes-inspired drug delivery application.

The short-term effectiveness of low-level laser, phonophoresis, and iontophoresis in patients with lateral epicondylosis

STUDY DESIGN

Randomized parallel group trial.

INTRODUCTION

Various treatment options for lateral epicondylosis have been reported in the literature.

PURPOSE OF STUDY

We aimed to compare the effectiveness of low-level laser therapy (LLLT), phonophoresis, and iontophoresis in terms of pain, function, and grip strength.

METHODS

This study that comprised 37 patients with lateral epicondylosis was planned as a prospective randomized parallel group trial. Twelve participants were randomized to the LLLT group, 12 to the phonophoresis group, and 13 to the iontophoresis group. The Visual Analog Scale (VAS), pressure algometer, the Patient-Rated Tennis Elbow Evaluation, and grip strength dynamometer were used to measure outcomes. The measurements were performed at baseline and at the end of 15 sessions.

RESULTS

Investigation of the pain scores revealed that all VAS scores were improved in both the laser and iontophoresis groups (VAS at rest: P = .015, effect size (ES) = 1.49 and P = .016, ES = 0.58, respectively; VAS during activity: P = .008, ES = 1.05 and P = .008, ES = 1.16, respectively; VAS at night: P = .013, ES = 1.01 and P = .016, ES = 0.72, respectively). Only advance in function and grip strength was associated with the iontophoresis group (Patient-Rated Tennis Elbow Evaluation P = .006, ES = 0.78; grip strength with elbow extension P = .011, ES = 1.03; with elbow flexion P = .003, ES = 0.52).

DISCUSSION

The most effective approach could not be highlighted among the existing studies in the literature as they were applied in combination with other therapies.

CONCLUSION

In our study, we observed that LLLT provides a benefit only for pain, whereas iontophoresis is beneficial for both pain and function. If the effect size is evaluated, LLLT is more influential than iontophoresis for decreasing pain. However, when we compared phonophoresis and iontophoresis in terms of effectiveness, we found that iontophoresis has better effects for pain, function, and grip strength.

Iontophoretic Dexamethasone Phosphate Compared to Topical Prednisolone Acetate 1% for Noninfectious Anterior Segment Uveitis

PURPOSE

To evaluate the safety and efficacy of dexamethasone phosphate ophthalmic solution (EGP-437) delivered by a transscleral iontophoresis delivery system (EyeGate II) compared to that of topical prednisolone acetate 1% (PA 1%) in subjects with noninfectious anterior uveitis.

DESIGN

Prospective, randomized, double-masked, parallel group, noninferiority clinical trial.

METHODS

A total of 193 subjects with active noninfectious anterior uveitis (anterior chamber [AC] cell count ≥11 cells) were randomized to EGP-437 delivered by iontophoresis (days 0 and 7) or self-administered PA 1% daily (tapered schedule, days 0-28). Masking was maintained with placebo iontophoresis or eye drops. The primary efficacy endpoint was the proportion of subjects with an AC cell count of zero on day 14. Noninferiority of EGP-437 was defined if the lower limit of the confidence interval (CI) for the difference (EGP-437 minus PA 1%) was less than -10%.

RESULTS

At day 14, 32 of 96 EGP-437 subjects (33.3%) and 32 of 97 PA 1% subjects (33.0%) had an AC cell count of zero (difference, 0.34; 95% CI, -12.94 to 13.63; P = 0.064). Efficacy trended better with EGP-437 among patients with more severe baseline uveitis (AC cell count >25). Safety and tolerability were good with both treatments. EGP-437 subjects experienced fewer IOP elevations ≥6 mm Hg versus PA 1% subjects (13 vs 24 incidents, respectively, through day 28).

CONCLUSIONS

Despite clinically similar response rates, statistical noninferiority of EGP-437 versus a tapered regimen of PA 1% was not achieved. Numerical trends suggesting fewer IOP elevations with EGP-437, similar efficacy overall, and possibly better efficacy in more severe disease warrant further study.

Ophthalmic Drug Delivery Using Iontophoresis: Recent Clinical Applications

Background: Iontophoresis is a noninvasive delivery system designed to overcome barriers to ocular penetration of topical ophthalmic medications by employing a low-amplitude electrical current to promote the migration of a charged drug substance across biological membranes. Trans-scleral iontophoresis of dexamethasone phosphate has demonstrated dramatically increased intraocular concentrations of dexamethasone in rabbit ocular tissues compared with topical instillation, including 50- to 100-fold greater aqueous humor concentrations. Methods: This article reviews available data on recent clinical applications of iontophoretic ophthalmic drug delivery. Results: The EyeGate II delivery system (EGDS) is a trans-scleral iontophoresis system that has been used in conjunction with EGP-437, a proprietary-charged formulation of dexamethasone phosphate for iontophoretic delivery. In patients with noninfectious anterior uveitis, EGP-437, delivered through 2 iontophoretic treatments using the EGDS, demonstrated similar efficacy to topical prednisolone acetate 1% eye drops instilled 8 times daily over 28 days, suggesting the potential to decrease or eliminate the need for daily dosing of topical steroids in this patient population. Other applications for EGP-437 delivered through the EGDS that have been explored in clinical trials include treatment of dry eye, postsurgical inflammation and pain, and scleritis. In addition, transcorneal iontophoresis has been used outside of the United States to enhance riboflavin penetration in patients undergoing corneal cross-linking as therapy for progressive keratoconus. Conclusions: The reviewed studies demonstrate the feasibility of using iontophoresis to enhance drug delivery to ocular tissues and support the potential of this noninvasive technique across a range of ophthalmic indications.

Alternating Current Iontophoresis for Control of Postoperative Pain

Control of early postoperative pain entails the use of various medications including acetaminophen, nonsteroidal anti-inflammatory drugs, selective cyclooxygenase-2 inhibitors, tramadol, and opioids. However, these medications should be carefully administered in patients with aspirin-exacerbated respiratory disease because some medications may trigger adverse reactions after maxillofacial surgeries. The goal of postoperative pain control in patients with aspirin-exacerbated respiratory disease is to eliminate pain without complications. Local anesthesia is an efficient tool for the control of postoperative pain after maxillofacial surgeries. We utilized a transdermal drug delivery system, iontophoresis by alternating current, in order to develop an alternative technique for administering local anesthetic to control postoperative pain in 2 patients with aspirin-exacerbated respiratory disease. A visual analogue scale was used to objectively measure the severity of pain. A 55-year-old woman who underwent mandibular wisdom tooth extraction and an 18-year-old woman who underwent sagittal split ramus osteotomy of the mandible both complained of pain multiple times. After application of iontophoresis, the visual analogue scale score was reduced to zero and postoperative pain could be controlled. There were no adverse events such as bronchospasm or skin irritation after the application of iontophoresis by alternating current.

Selected Medicines Used in Iontophoresis

Iontophoresis is a non-invasive method of systemic and local drug delivery using an electric field. Iontophoresis enables diffusion of the selected drug via skin, mucosa, enamel, dentin, and other tissues. The amount of delivered therapeutic molecules is about 10⁻2000 times greater than conventional forms of delivery. Among other fields, this method is used in dentistry, ophthalmology, otorhinolaryngology, and dermatology. According to related literature, the most important drugs studied or administered by iontophoresis are: Local anesthetics, opioids, steroids, non-steroidal anti-inflammatory drugs, antibacterial drugs, antifungal drugs, antiviral drugs, anticancer drugs, fluorides, and vitamins. The present review covers current available data regarding the selected medicines used in iontophoresis. Furthermore, indications and conditions of iontophoresis application are reviewed.

The time course of dexamethasone delivery using iontophoresis through human skin, measured via microdialysis

STUDY DESIGN

Controlled laboratory study.

OBJECTIVE

To determine the time course of dexamethasone sodium phosphate (Dex-P) during iontophoresis to underlying tissues using microdialysis.

BACKGROUND

In human participants, real-time information of Dex-P transdermal delivery during iontophoresis is unknown.

METHODS

Sixty-four healthy male participants (mean ± SD age, 24.2 ± 3.3 years; height, 181.8 ± 26.1 cm; mass, 82.4 ± 11.8 kg; subcutaneous fat thickness, 0.61 ± 0.19 cm) were randomly assigned into 1 of 6 groups: (1) 1-mA current, 1-mm probe depth; (2) 1-mA current, 4-mm probe depth; (3) 2-mA current, 1-mm probe depth; (4) 2-mA current, 4-mm probe depth; (5) in vivo retrodialysis; and (6) skin perfusion flowmetry. Microdialysis probes were used to assess the combined recovery (Dex-total) of Dex-P, dexamethasone, and its metabolite.

RESULTS

There was no difference in Dex-total between current intensities (P = .99), but a greater amount of Dex-total was recovered superficially at 1 mm compared to the 4-mm depth (P<.0001). Peak concentration mean ± SD values for the 1- and 2-mA currents at 1 mm were 10.8 ± 8.1 and 7.7 ± 5.5 µg/mL, and at 4 mm were 2.0 ± 0.8 and 1.3 ± 0.9 µg/mL, respectively. Peak skin perfusion was 741.4% ± 408.7% and 711.6% ± 260.8% at baseline for 1- and 2-mA intensities, respectively. Skin perfusion returned to baseline levels earlier during 1-mA intensity at a 110 mA · min dose within the treatment, compared to 2 mA at 60 minutes posttreatment.

CONCLUSION

Transdermal delivery of Dex-P during iontophoresis was successfully measured in vivo through human skin. Measurable concentrations of Dex-total were found regardless of current intensity. Although current-induced vasodilation occurred, it did not significantly affect the tissue accumulation of Dex-total.

Evaluation of common anesthetic and analgesic techniques for tail biopsy in mice

Tail biopsy in mice is a common procedure in genetically modified mouse colonies. We evaluated the anesthetic and analgesic effects of various agents commonly used to mitigate pain after tail biopsy. We used a hot-water immersion assay to evaluate the analgesic effects of isoflurane, ice-cold ethanol, ethyl chloride, buprenorphine, and 2-point local nerve blocks before studying their effects on mice receiving tail biopsies. Mice treated with ethyl chloride spray, isoflurane and buprenorphine, and 2-point local nerve blocks demonstrated increased tail-flick latency compared with that of untreated mice. When we evaluated the behavior of adult and preweanling mice after tail biopsy, untreated mice demonstrated behavioral changes immediately after tail biopsy that lasted 30 to 60 min before returning to normal. The use of isoflurane, isoflurane and buprenorphine, buprenorphine, 2-point nerve block, or ethyl chloride spray in adult mice did not significantly improve their behavioral response to tail biopsy. Similarly, the use of buprenorphine and ethyl chloride spray in preweanling mice did not improve their behavioral response to tail biopsy compared with that of the untreated group. However, immersion in bupivacaine for 30 s after tail biopsy decreased tail grooming behavior during the first 30 min after tail biopsy. The anesthetic and analgesic regimens tested provide little benefit in adult and preweanling mice. Given that tail biopsy results in pain that lasts 30 to 60 min, investigators should carefully consider the appropriate anesthetic or analgesic regimen to incorporate into tail-biopsy procedures for mice.

New delivery systems for local anaesthetics-part 2

Part 2 of this paper deals with the techniques for drug delivery of topical and injectable local anaesthetics. The various routes of local anaesthetic delivery (epidural, peripheral, wound catheters, intra-nasal, intra-vesical, intra-articular, intra-osseous) are explored. To enhance transdermal local anaesthetic permeation, additional methods to the use of an eutectic mixture of local anaesthetics and the use of controlled heat can be used. These methods include iontophoresis, electroporation, sonophoresis, and magnetophoresis. The potential clinical uses of topical local anaesthetics are elucidated. Iontophoresis, the active transportation of a drug into the skin using a constant low-voltage direct current is discussed. It is desirable to prolong local anaesthetic blockade by extending its sensory component only. The optimal release and safety of the encapsulated local anaesthetic agents still need to be determined. The use of different delivery systems should provide the clinician with both an extended range and choice in the degree of prolongation of action of each agent.

Effect of duration and amplitude of direct current when lidocaine is delivered by iontophoresis

Dosage for the galvanic stimulation for iontophoresis varies. Clinicians manipulate the duration or the amplitude of the current, but it is not known which is more effective. We compared the anesthetic effect of lidocaine HCL (2%) by manipulating the current parameters on 21 healthy volunteers (age: 21.2 ± 4.2, height 170.7 ± 10.2 cm, mass 82.1 ± 19.2 kg). Three conditions were administered in a random order using a Phoresor II^® with 2 mL, 2% lidocaine HCL in an iontophoresis electrode. (1) HASD (40 mA_*min): High amplitude (4 mA), short duration (10 min); (2) LALD (40 mA.min): Low amplitude (2 mA), long duration (20 min); (3) Sham condition (0 mA, 20 min). Semmes-Weinstein monofilament (SWM) scores were taken pre and post intervention to measure sensation changes. Two-way ANOVA with repeated measures was used to compare sensation. Both iontophoresis treatments: LALD (4.2 ± 0.32 mm) and HASD (4.2 ± 0.52 mm) significantly increased SWM scores, indicating an increase in anesthesia, compared to the sham condition (3.6 ± 0.06 mm) p < 0.05. Neither LALD nor HASD was more effective and there was no difference in anesthesia with the sham. Lidocaine delivered via iontophoresis reduces cutaneous sensation. However, there was no benefit in either a HASD or LALD treatment.