Effects of iontophoretic versus injection administration of dexamethasone

Onychomycosis: Current Understanding and Strategies for Enhancing Drug Delivery into Human Nail Tissue

BACKGROUND

Onychomycosis is by far the most common finger or toe nail fungal infectious disease caused by dermatophytes, non-dermatophytic molds or yeast. It accounts for 50% of the total nail disorders, and affects patients physically, socially, and psychologically and can seriously influence their quality of life.

OBJECTIVES

Oral antifungals are routinely used to treat the nail fungal disease; however oral therapy is associated with severe side effects and longer treatment times. In recent years, drug delivery directly into the nail or nail bed has gained attention and various topical products have been tested that can cure the disease when applied topically or transungually. Nevertheless, drug penetration into and through the nail is not straightforward and requires chemicals to improve its permeability or by applying physical stress to promote drug penetration into and through the nail. This lucid review presents an overview of various causes of onychomycosis, current therapeutic approaches, and efforts aimed at increasing the permeability of nails through various strategies such as chemical, physical and mechanical methods for permeation enhancement.

CONCLUSION

Various strategies have been proposed for the treatment of onychomycosis, however, much research into a more precise and effective therapy is still required.

Rehabilitation of the Overhead Athlete's Elbow

The activities required during overhead sports, particularly during baseball pitching, produce large forces at the elbow joint. Injuries to the elbow joint frequently occur in the overhead athlete because of the large amount of forces observed during the act of throwing, playing tennis, or playing golf. Injuries may result because of repetitive overuse, leading to tissue failure. Rehabilitation following injury or surgery to the throwing elbow is vital to fully restore normal function and return the athlete to competition as quickly and safely as possible. Rehabilitation of the elbow, whether following injury or postsurgical, must follow a progressive and sequential order, building on the previous phase, to ensure that healing tissues are not compromised. Emphasis is placed on restoring full motion, muscular strength, and neuromuscular control while gradually applying loads to healing tissue. In addition, when one is creating a rehabilitation plan for athletes, it is imperative to treat the entire upper extremity, core, and legs to create and dissipate the forces generated at each joint.

Graphical process design tools for iontophoretic transdermal drug-delivery devices

A graphical procedure was proposed for the optimum design of transdermal drug-delivery systems enhanced by iontophoresis. Contour plots displayed the relationships among steady-state plasma level, current density and initial drug concentration in a vehicle. This information was combined with a closed-form expression of the process time constant, estimated as the medicament in the blood reaches a plateau after application of the electric field. Analysis was conducted using Laplace-transformed variables and did not require time-domain solutions. Simulation results show that a current density of 0.044 mA/cm(2) and a loading of 3500 μg/ml of dexamethasone sodium m-sulfobenzoate were necessary to achieve an equilibrium plasma concentration of 1.254 ng/cm(3) with a time constant of 8.34 h.

Tendinopathy in athletes

Overuse related tendon pain is a significant problem in sport and can interfere with and, in some instances, end an athletic career. This article includes a consideration of the biology of tendon pain including a review of tendon anatomy and histopathology, risk factors for tendon pain, semantics of tendon pathology, and the pathogenesis of tendon pain. Evidence is presented to guide the physical therapist in clinical decision-making regarding the examination of and intervention strategies for athletes with tendon pain.

Corticosteroid injections in the treatment of foot & ankle disorders: an AOFAS survey

BACKGROUND

Evidence-based guidelines for the use of injectable corticosteroids are lacking, and the true incidence of complications is unknown.

MATERIALS AND METHODS

The 2007--2008 AOFAS membership (969 members) was electronically queried to identify corticosteroid injection practices for certain clinical entities and rates of complications. One hundred ninety-seven surveys were returned. Eleven clinical diagnoses were evaluated for number of injections per year per respondent, rate of injection, plans to change injection pattern, and use of immobilization. Thirteen possible complications were analyzed for observed frequencies and total number of complications.

RESULTS

Those in practice less than 5 years showed the lowest rate of injections at 14.1 per month, which increased to 26.1 for those in practice 6 to 10 years. An overall average of 20.6 injections per month per clinician was reported. Injections for midsubstance Achilles tendinopathy was largely avoided as demonstrated by a 98% no-inject rate. Insertional Achilles tendonitis was similar, albeit lower with an 88% no-inject rate. Non-Achilles tendonitis showed a varied response for injections. Posterior tibial tendonitis was injected 26% of the time, whereas peroneal tendonitis was injected 54% of the time. Complications including skin depigmentation were observed most frequently (5.1%), followed by atrophy (4%), flare reaction (3.5%), MTPJ dislocation (2.7%), plantar fascia rupture (1.5%), and heel pad atrophy (1.4%).

CONCLUSION

Despite many case reports of complications, our survey indicates that the incidence of complications was perceived to be low and generally related to the injection site (skin depigmentation, atrophy, flare reaction).

Development of natural calcium- and phosphate-donating microparticles and a new iontophoretic apparatus for the topical treatment of local osteoporosis. Preliminary in vitro and in vivo studies

AIM

We wished to develop a new iontophoretic device suitable for the treatment of local bone loss such as after fractures or in osteodystrophy.

METHODS

The new iontophoretic apparatus consists of two parts. The first part consists of two natural-based, chemically modified particles as potential medicines, while the other part is a 3-electrode electrophoretic device based on a new principle. This device 'knocks out' Ca²(+) and PO₄ ³⁻ ions from the particles with its impulse-like positive and negative charges transmitted through its electrodes placed on the skin. The current and the voltage of the electrodes can be adjusted separately in both leads. Subsequently, these 'knocked out' ions are channelled into the porotic bones with the help of the 3rd-reference-electrode.

RESULTS

In our preliminary in vitro studies, we used porcine tissues to test their calcium and phosphate content after iontophoresis; with or without using molecules. This preliminary analysis revealed that both calcium and phosphate ions became incorporated into the bone. Some in vivo data are also presented. Iontophoretic treatment increased speed of sound (SOS) as determined by ultrasonography in ovariectomized rats.

CONCLUSION

Our results suggest that topical iontophoresis may be suitable to treat local osteoporosis or bone defects.

The effect of skin thickness and time in the absorption of dexamethasone in human tendons using iontophoresis

STUDY DESIGN

Experimental laboratory study.

OBJECTIVES

To measure the transmission of dexamethasone sodium phosphate (DEX-P) using iontophoresis as a function of skinfold tissue thickness and time elapsed between treatment and tissue extraction.

BACKGROUND

Iontophoresis is a modality used in physical therapy with the intent to drive medications through the skin to underlying tissues using a direct electrical current. DEX-P is the most commonly used medication with iontophoresis and is used to treat a variety of connective tissue conditions.

METHODS AND MEASURES

Sixteen adults undergoing anterior cruciate ligament reconstructive surgery using the semitendinosis/gracilis autograft received a 40-mA-min dose of iontophoresis with 0.4% DEX-P superficial to a slip of the distal semitendinosis tendon prior to surgery. The tendon slip was extracted within 4 hours. Time between treatment and tissue extraction and skinfold thickness were measured. Analysis was performed on the slip of the semitendinosis using high-performance liquid chromatography mass spectrum.

RESULTS

Of the 16 subjects (10 female, 6 male; mean age, 33 years), 7 had measurable amounts of DEX-P in the tendon slip (4 female, 3 male; mean age, 34 years). The average concentration in the 16 subjects was 2.9 ng/g of tendon tissue. There was no correlation between DEX-P absorbed and skinfold thickness (r = -0.08, P = .79) or time elapsed (r = 0.25, P = .38). In a subset of the 7 individuals that showed measurable levels of DEX-P absorbed, the average concentration of DEX-P was 6.6 ng/g of tendon tissue, and there was a relationship between DEX-P concentrations and time elapsed that did not reach statistical significance (r = 0.71, P = .11).

CONCLUSIONS

Iontophoresis appears to facilitate the transmission of dexamethasone to connective tissues in humans with skinfold thickness up to at least 30 mm. The absorption of the dexamethasone seemed to continue to occur for up to 4 hours after delivery. It is not clear why DEX-P was measured in only 7 of the 16 subjects.

LEVEL OF EVIDENCE

Therapy, level 5.

Anti-hyperalgesic and anti-inflammatory effects of ketorolac tromethamine gel using pulsed ultrasound in inflamed rats

The aim of this study was to determine if a ketorolac tromethamine (KT) gel solution could be administered in vivo via phonophoretic transdermal delivery using pulsed ultrasound by examining its anti-hyperalgesic and anti-inflammatory effects in a rat carrageenan inflammation model. 1% carrageenan was injected into the plantar surface of the right hindpaw of a rat, and anti-hyperalgesic and anti-inflammatory effects of KT via phonophoretic transdermal delivery were examined. The changes in the mechanical and thermal hyperalgesia, nociceptive flexor reflex (NFR), as well as the swelling changes were determined. According to the anti-hyperagesia and anti-inflammation tests, which were used to determine the change in the pain threshold, NFR and swelling showed that the group given the phonophoretic transdermal delivery of KT exhibited significantly more noticeable anti-hyperalgesic and anti-inflammatory effects than those treated with the simple application of a KT gel. The transdermal application of KT gel using phonophoresis had significant anti-hyperalgesic and anti-inflammatory effects. These findings suggest that the transdermal administration of a KT gel using phonophoresis using pulsed ultrasound might be useful for treating acute inflammation and pain.

Absorption of dexamethasone sodium phosphate in human connective tissue using iontophoresis

BACKGROUND

Iontophoresis ostensibly facilitates the delivery of medications through the skin to underlying tissues using a direct electrical current. Dexamethasone is the most commonly used medication with iontophoresis to treat a variety of connective tissue disorders.

HYPOTHESIS

Iontophoresis will facilitate the absorption of dexamethasone into connective tissue compared with diffusion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-nine adults undergoing anterior cruciate ligament reconstructive surgery using the semitendinosus/gracilis autograft were randomly assigned to either a true iontophoresis (TI) or sham iontophoresis (SI). In the TI group, a 40-mA/min dose of iontophoresis using a 0.4% (4 mg/mL) solution of dexamethasone was used targeting the semitendinosus tendon just before surgery. The SI group underwent the same treatment, but the machine was not turned on. Tissue was extracted within 4 hours of treatment and analyzed for dexamethasone. In addition, 2 control samples were sent to the laboratory for analysis.

RESULTS

There was a statistically significant difference in dexamethasone concentrations between the groups (P = .0216). Of the 16 samples in the TI group, 8 had measurable amounts of dexamethasone, with an average concentration of 2.906 ng/g of tendon tissue. In the SI group, 1 of the 13 samples had measurable amounts of dexamethasone with an average concentration of 0.205 ng/g of tendon tissue. The control samples contained no dexamethasone.

CONCLUSION

Iontophoresis facilitates the transmission of dexamethasone to connective tissues in humans.

CLINICAL RELEVANCE

Iontophoresis can deliver dexamethasone to connective tissues in humans.