Iontophoresis for enhancing penetration of dermatologic and antiviral drugs

Transdermal delivery via medical device technologies

INTRODUCTION

Despite their effectiveness and indispensability, many drugs are poorly solvated in aqueous solutions. Over recent decades, the need for targeted drug delivery has led to the development of pharmaceutical formulations with enhanced lipid solubility to improve their delivery properties. Therefore, a dependable approach for administering lipid-soluble drugs needs to be developed.

AREAS COVERED

The advent of 3D printing or additive manufacturing (AM) has revolutionized the development of medical devices, which can effectively enable the delivery of lipophilic drugs to the targeted tissues. This review focuses on the use of microneedles and iontophoresis for transdermal drug delivery. Microneedle arrays, inkjet printing, and fused deposition modeling have emerged as valuable approaches for delivering several classes of drugs. In addition, iontophoresis has been successfully employed for the effective delivery of macromolecular drugs.

EXPERT OPINION

Microneedle arrays, inkjet printing, and fused deposition are potentially useful for many drug delivery applications; however, the clinical and commercial adoption rates of these technologies are relatively low. Additional efforts is needed to enable the pharmaceutical community to fully realize the benefits of these technologies.

Symptoms-modifying effects of electromotive administration of glucosamine sulphate among patients with knee osteoarthritis

Background:

Most trials on symptom-modifying effects of glucosamine are limited to administration through oral route with dearth of empirical data on the use of electromotive force.

Objective:

The study determined the effects of glucosamine sulphate (GS) iontophoresis (IoT) on radiographic parameters of patients with knee osteoarthritis (OA).

Methods:

Fifty-three patients were randomly assigned to three groups. About 1 g each of GS was administered using IoT and cross-friction massage (CFM) for participants in groups 1 (IoT) and 2 (CFM), respectively. Group 3 ((Combined therapy) CoT) received 1 g of GS using both IoT and CFM. Interventions were twice a week for 12 weeks. Analysis of variance (ANOVA) was used to analyze the data (p<0.05).

Results:

After 12 weeks, the medial joint space width (JSW) of the CFM group was significantly higher than that of IoT and CoT groups (p=0.005 and p=0.004). Lateral JSW of IoT group was significantly higher than both CFM (p=0.001) and CoT groups (p=0.01). There were significant decreases in pain intensities; increase in knee flexion and physical functions across the groups (F=9.33,p=0.01;F=3.23,p=0.01; H=4.97,p=0.01, respectively).

Conclusion:

It was concluded that there were significant decreases in the degenerative changes at the knee joint.

Topical iontophoretic administration of acyclovir for the episodic treatment of herpes labialis: a randomized, double-blind, placebo-controlled, clinic-initiated trial

BACKGROUND

Multiple studies of the use of acyclovir for the treatment of herpes labialis have suggested that the nominal efficacy of the topical formulation is the result of inadequate penetration of the drug into the target site of infection, the basal epidermis.

METHODS

We developed a low-voltage, wireless, hand-held, computer-controlled, iontophoretic applicator to enhance the skin penetration of topical acyclovir in the treatment of herpes labialis. We performed a multicenter, placebo-controlled, clinic-initiated, pilot trial of a single, topical, iontophoretic application of 5% acyclovir cream for the episodic treatment of herpes labialis among 200 patients with an incipient cold sore outbreak at the erythema or papular/edema lesion stage.

RESULTS

The median classic lesion healing time (aborted lesions were assigned a value of 0 h) was 1.5 days shorter for the active treatment group than for the vehicle group (113 h vs. 148 h; P = .02). In the subgroup of patients who presented with lesions in the erythema stage, the median classic lesion healing time was 3 days shorter for the acyclovir group, compared with the control group (49 h vs. 120 h; P < .03), and the acyclovir group tended to have more aborted lesions than did the control group (46% vs. 24%; P = .10).

CONCLUSIONS

Single-dose topical iontophoresis of acyclovir appears to be a convenient and effective treatment for cold sores and merits further clinical investigation.

Iontophoretic drug delivery

The composition and architecture of the stratum corneum render it a formidable barrier to the topical and transdermal administration of therapeutic agents. The physicochemical constraints severely limit the number of molecules that can be considered as realistic candidates for transdermal delivery. Iontophoresis provides a mechanism to enhance the penetration of hydrophilic and charged molecules across the skin. The principal distinguishing feature is the control afforded by iontophoresis and the ability to individualize therapies. This may become significant as the impact of interindividual variations in protein expression and the effect on drug metabolism and drug efficacy is better understood. In this review we describe the underlying mechanisms that drive iontophoresis and we discuss the impact of key experimental parameters-namely, drug concentration, applied current and pH-on iontophoretic delivery efficiency. We present a comprehensive and critical review of the different therapeutic classes and molecules that have been investigated as potential candidates for iontophoretic delivery. The iontophoretic delivery of peptides and proteins is also discussed. In the final section, we describe the development of the first pre-filled, pre-programmed iontophoretic device, which is scheduled to be commercialized during the course of 2004.

Evaluation of the impact of transthoracic endoscopic sympathectomy on patients with palmar hyperhydrosis

OBJECTIVES

We assessed the impact of transthoracic endoscopic sympathectomy (TES) on the quality of life of patients with palmar hyperhydrosis.

DESIGN

A retrospective questionnaire based study.

METHODS

Patients undergoing TES at our institution between 1997 and 2002 received a SF-36 quality of life postal questionnaire. The pre- and post-operative symptoms were assessed. Statistical analysis was by means of the Student's t test.

RESULTS

Ninety-four TES were carried out in 62 patients. Forty-one cases were female. The age range was 17-64 years. The mean follow-up period was 38.46 months. Mean hospital stay was 3 days. Compensatory hyperhydrosis was reported in 29 cases and only considered severe in four cases (9.7%). Forty-one patients replied to the questionnaire (66%). The overall quality of life (as assessed by the SF-36 form) was unanimously improved (p<0.0009) and demonstrated significant improvements in social functioning (p<0.0002), physical role limitations (p<0.0007), emotional well-being (p<0.0007) and overall energy levels (p<0.05).

CONCLUSION

TES resulted in significant improvements inpatient's overall quality of life, social and emotional functioning. The procedure is associated with minimal morbidity and only a short inpatient stay is required. Patients should be cautioned on the possibility of compensatory hyperhydrosis which may occur in a small number of cases.

Topical anesthetics in dermatology

Topical anesthetics are valuable tools for the dermatologists. The purpose of this study is to educate dermatologists about the pharmacology and clinical applications of topical anesthetics. A review of the current topical anesthetics was conducted. Several topical anesthetics are available to provide safe and effective cutaneous analgesia. Patient care can be improved by reducing the discomfort of local procedures and by minimizing the side effects of the anesthetics.

Mechanistic studies of molecular transdermal transport due to skin electroporation

The application of electrical high voltage pulses has been shown to greatly enhance the transdermal transport of water-soluble compounds. The resistance of the skins most important barrier, the stratum corneum, drops within less than 1 µs by orders of magnitude. This effect is attributed to electroporation, a nonthermic phenomena known to occur in phospholipid double layers. The striking difference between the stratum corneum lipid layers and the usually investigated phospholipid systems is the phase transition temperature. While lipid layers used for electroporation experiments are in liquid crystal phase above the phase transition temperature, the stratum corneum lipids (phase transition at approximately 70 degrees C) form a rigid quasi-crystalline membrane at room temperature.After the electrical stimulus a recovery of the passive flux was found making high voltage pulsing a suitable tool for controlling transdermal drug delivery. By ordinary light microscopy no dramatic changes in skin structure were found supporting the thesis of electroporation. However the microstructure shows clearly persistent structural changes. Recently the involvement of Joule heating due to the electric stimulus was shown as an important factor for skin permeabilization and molecular transport.

Follow-up of clinical efficacy of iontophoresis therapy for postherpetic neuralgia (PHN)

A great variety of therapies have been attempted for PHN, including pharmacotherapy and physical therapy. However, there has been no decisive treatment, and reports of the clinical efficacy of all available therapies have been rather controversial. Almost all studies conducted so far have looked only at short-term therapeutic efficacy, and only a few investigators have conducted long-term observations or studies on long-term outcome. We followed up the clinical efficacy of iontophoresis therapy using lidocaine and methylprednisolone in 197 PHN patients. Monitoring conducted for an average of 4 years after completion of the treatment showed that pain remained unchanged or improved compared to pain observed upon completion of the treatment in 90.4% of patients. Although 42.6% of patients were still continuing some treatment, 90.9% were found to be able to take care of themselves. Findings obtained were reviewed and discussed from various viewpoints. Our findings showed that iontophoresis therapy is not only effective at the end of the treatment, but its efficacy is maintained over a long period of time, indicating that it is clinically very useful for the treatment of PHN.