Iontophoretic delivery of lidocaine hydrochloride through ex-vivo human skin

Toward a solid microneedle patch for rapid and enhanced local analgesic action

Analgesic creams find widespread application as adjuncts for localized anesthesia prior to surgical procedures. Nevertheless, the onset of analgesic action is protracted due to the skin barrier's inherent characteristics, which necessitates prolonged intervals of patient and clinician waiting, consequently impinging upon patient compliance and clinician workflow efficiency. In this work, a biodegradable microneedles (MNs) patch was introduced to enhance the intradermal administration of lidocaine cream to achieve rapid analgesia through a minimally invasive and conveniently accessible modality. The polylactic acid (PLA) MNs were mass-produced using a simple hot-pressing method and served the purpose of creating microchannels across the skin's surface for rapid absorption of lidocaine cream. Optical and electron microscopes were applied to meticulously scrutinize the morphology of the fabricated MNs, and the comprehensive penetration tests involving dynamometer tests, evaluation on porcine cadaver skin, artificial film, optical coherence tomography (OCT), transepidermal water loss, and analysis on rats' skins, demonstrated the robust mechanical strength of PLA MNs for successful intradermal penetration. The behavioral pain sensitivity tests on living rats using Von Frey hair filaments revealed that the MN-assisted lidocaine treatment expeditiously accelerated the onset of action from 40 to 10 min and substantially enhanced the efficacy of localized anesthesia. Furthermore, different treatment protocols encompassing the sequence of drug application relative to MN treatment, MN dimensions, and the frequency of MN insertions exhibited noteworthy influence on the resultant local anesthesia efficacy. Together, these results demonstrated that the lidocaine cream followed by diverse PLA MN treatments would be a promising strategy for rapid clinical local anesthesia with wide-ranging applications.

Transcutaneous Delivery of Dexamethasone Sodium Phosphate Via Microneedle-Assisted Iontophoretic Enhancement - A Potential Therapeutic Option for Inflammatory Disorders

AIM

This study aimed to fabricate dexamethasone sodium phosphate loaded microneedle arrays (MNA) and investigate their efficiency in combination with iontophoresis for the treatment of hind paw oedema in rats.

METHODS

Drug loaded polyvinyl alcohol, polyvinyl pyrrolidone and D-sorbitol-based MNA11 were fabricated by vacuum micromolding. Physicochemical, morphological, thermal, in-silico, in-vitro insertion ability (on parafilm) and drug release studies were performed. Ex-vivo permeation, in-vivo insertion and anti-inflammatory studies were performed in combination with iontophoresis.

RESULTS

MNA11 displayed sharp-tipped projections and acceptable physicochemical features. Differential scanning calorimetry results indicated that drug loaded MNA11 were amorphous solids. Drug interacted with PVP and PVA predominately via hydrogen bonding. Parafilm displayed conspicuously engraved complementary structure of MNA11. Within 60 min, 91.50 ± 3.1% drug released from MNA11. A significantly higher i.e., 95.06 ± 2.5% permeation of drug was observed rapidly (within 60 min) from MNA11-iontophoresis combination than MNA11 i.e., 84.07 ± 3.5% within 240 min. Rat skin treated using MNA11 and MNA11-iontophoresis showed disruptions / microchannels in the epidermis without any damage to underlying anatomical structures. MNA11-iontophoresis combination led to significant reduction (83.02 ± 3.9%) in paw oedema as compared to MNA11 alone (72.55 ± 4.1%).

CONCLUSION

MNA11-iontophoresis combination can act as a promising candidate to deliver drugs transcutaneously for treating inflammatory diseases.

Kinetic assessment of iontophoretic delivery efficiency of niosomal tetracycline hydrochloride incorporated in electroconductive gel

The purpose of this study was to conduct the kinetic assessment of iontophoretic delivery of niosomal tetracycline-HCl formulated in an electroconductive gel. Tween-80 and Span-80 were used to obtain tetracycline-HCl niosomes with an average diameter of 101.9 ± 3.3 nm, a polydispersity index of 0.247 ± 0.004, a zeta potential of - 34.1 mV, and an entrapment efficiency of 70.08 ± 0.16%. Four different gel preparations, two of which contained niosomal tetracycline-HCl, were transdermally delivered using Franz diffusion cells under the trigger effect of iontophoresis, applied at 0.2, 0.5, and 1 mA/cm2 current density. The control group was the passive diffusion results of the preparation made using a tetracycline-HCl-based drug marketed in Turkey. The control group was compared with the groups that contained (a) tetracycline-HCl in an electroconductive gel, (b) the niosomal tetracycline-HCl formulation in water, and (c) the niosomal tetracycline-HCl formulation in the electroconductive gel. The group with the niosomal formulation in the electroconductive gel displayed the highest increase in iontophoretic transdermal delivery relative to the control group, displaying a 2-, 2.1-, and 2.2-fold increase, respectively, by current density. The experimental results of transdermal delivery using the synergistic effect of niosomal formulation in electroconductive gel and the trigger effect of iontophoresis appeared to divert slightly from zero-order kinetics, demonstrating a statistically significant increase in the rate of controlled transdermal drug delivery. Considering that about 20% of the formulation is transdermally delivered in the first half-hour, the iontophoretic transdermal delivery of niosomal tetracycline-HCl can be efficiently used in local iontophoretic therapy.

Smart Physical-Based Transdermal Drug Delivery System:Towards Intelligence and Controlled Release

Transdermal drug delivery systems based on physical principles have provided a stable, efficient, and safe strategy for disease therapy. However, the intelligent device with real-time control and precise drug release is required to enhance treatment efficacy and improve patient compliance. This review summarizes the recent developments, application scenarios, and drug release characteristics of smart transdermal drug delivery systems fabricated with physical principle. Special attention is paid to the progress of intelligent design and concepts in of physical-based transdermal drug delivery technologies for real-time monitoring and precise drug release. In addition, facing with the needs of clinical treatment and personalized medicine, the recent progress and trend of physical enhancement are further highlighted for transdermal drug delivery systems in combination with pharmaceutical dosage forms to achieve better transdermal effects and facilitate the development of smart medical devices. Finally, the next generation and future application scenarios of smart physical-based transdermal drug delivery systems are discussed, a particular focus in vaccine delivery and tumor treatment.

Improved Transdermal Delivery of Rabies Vaccine using Iontophoresis Coupled Microneedle Approach

AIM

This study was aimed to develop rabies vaccine incorporated microneedle (MN) patches and evaluate the immunogenicity of prepared formulations in combination with iontophoresis.

METHODS

Patches comprising of polyvinyl pyrrolidone, hyaluronic acid and polyethylene glycol 400 were engineered by vacuum micromolding technique. Physical evaluation of patches included determination of folding endurance, % swelling and morphological features. In vitro release study was performed in skin simulant agarose gel using model drug (methylene blue) loaded patches. In vitro insertion ability was assessed using stratum corneum simulant parafilm. In vivo insertion study was performed in rats. Immunogenicity was evaluated in dogs by determining immunoglobulin G (IgG) and rabies virus neutralizing antibodies (RVNA) titer.

RESULTS

Patches displayed uniformly distributed microprojections with pointed tips and smooth surface,  ~ 70% swelling, remained intact for  ~ 200 foldings and successfully penetrated the parafilm. The area covered by model drug across agarose gel was almost double following treatment with MN-iontophoresis combination (MNdi) compared to MN alone (MNdo). Histological examination of rat skin treated with vaccine laden MN (MNvo) and MN-iontophoresis combination (MNvi) confirmed the formation of grooves in epidermis without any damage to the deep vasculature. A ~ 73% and  ~ 206% increase (compared to untreated counterpart) was observed in the IgG titer of MNvo and MNvi treated dogs, respectively. The RVNA titer was increased by  ~ 1.2 and  ~ 2.2 times (compared to threshold value) after MNvo and MNvi treatment, respectively.

CONCLUSION

MN-iontophoresis combination provided relatively potent immunogenic response over the conventional intramuscular injection, hence, can be used for administering vaccines transcutaneously.

Vibration anesthesia during carboxytherapy for cellulite: a study protocol

Background: To date, there has been no investigation addressing the effects of vibration anesthesia during carboxytherapy. Aim: Investigate the analgesic effect of different vibratory devices during carboxytherapy for the treatment of cellulite. Materials & methods: A total of 78 women between 18 and 49 years of age with cellulite in the gluteal region will be randomly allocated to three groups: Group A (carboxytherapy and vibratory device A), Group B (carboxytherapy and vibratory device B) and control group. Pain intensity will be assessed using a numerical rating scale after each puncture. Expected outcome: Vibration anesthesia is expected to be effective at diminishing the pain intensity caused by carboxytherapy comparison with the control group, with no differences between the vibratory devices. Trial registry: Brazilian Registry of Clinical Trials- ReBEC (RBR-8jcqy7c).

Mechanism of Propofol-Lidocaine Hydrochloride Nano-Emulsion on Retinal Ganglion Cytopathic Effect in Diabetic Rats

The study drew attention to the influence mechanism of propofol and lidocaine hydrochloride nanoemulsion (NE) in the retinal ganglion cell pathology in diabetic rats. Specifically, the propofollidocaine hydrochloride NE was prepared using the emulsification method. The microscope and laser particle size analyser were used to observe the morphology and particle size of NE, respectively. Also, the viscosity of the NE and the recovery rate of the main ingredient were explored. 45 adult male Wistar rats were randomly divided into control group (PBS control), model group (diabetes model), and test group (diabetes model+propofol-lidocaine hydrochloride NE), with 15 rats in each group. The three groups were compared for the blood glucose, body weight, TNF-α and IL-1β mRNA levels in retinal tissue, and the number and apoptosis rate of ganglion cells. It was found that the average particle size of the NE was 89.76 nm, the maximum absorption wavelength was 280.0 nm, and the viscosity was 106.49 N/m/s. The average recovery rate of propofol in NE was 99.91%, and that of lidocaine hydrochloride was 99.80%. At 12th week after modeling, the blood glucose of the test group was lower versus the model group (P < 0.05); the blood glucose and body weight of rats in the control group were lower than those in the other two groups (P < 0.001). The test group exhibited lower mRNA levels of TNF-α and IL-1β and apoptosis index of retinal ganglion cells versus the model group (P < 0.05). The model group showed a lower number of retinal ganglion cells versus the other two groups (P < 0.05). It was inferred that propofol-lidocaine hydrochloride NE of a small particle size and good syringeability can notably reduce blood glucose, TNF-α and IL-1β mRNA levels, and retinal ganglion cell apoptosis index, and at the same time increase the number of retinal ganglion cells.

Transdermal Drug Delivery Systems and Their Use in Obesity Treatment

Transdermal drug delivery (TDD) has recently emerged as an effective alternative to oral and injection administration because of its less invasiveness, low rejection rate, and excellent ease of administration. TDD has made an important contribution to medical practice such as diabetes, hemorrhoids, arthritis, migraine, and schizophrenia treatment, but has yet to fully achieve its potential in the treatment of obesity. Obesity has reached epidemic proportions globally and posed a significant threat to human health. Various approaches, including oral and injection administration have widely been used in clinical setting for obesity treatment. However, these traditional options remain ineffective and inconvenient, and carry risks of adverse effects. Therefore, alternative and advanced drug delivery strategies with higher efficacy and less toxicity such as TDD are urgently required for obesity treatment. This review summarizes current TDD technology, and the main anti-obesity drug delivery system. This review also provides insights into various anti-obesity drugs under study with a focus on the recent developments of TDD system for enhanced anti-obesity drug delivery. Although most of presented studies stay in animal stage, the application of TDD in anti-obesity drugs would have a significant impact on bringing safe and effective therapies to obese patients in the future.

Electrically controlled transdermal delivery of naproxen and indomethacin from porous cis-1,4-polyisoprene matrix

This study is focused on the inquiry of using a porous polymeric structure to absorb and release transdermally two drugs through a skin from deproteinized natural rubber latex (DPNR). The porous DPNR films were fabricated from the internal formation of surfactant micelles and their subsequent leaching out to generate porous structures. The pore size of DPNR films increased with increasing surfactant amount. The model drugs were naproxen and indomethacin; their releases and release-permeations were investigated under the effects of surfactant amount, electrical potential, and drug size. Without electric field, the drug release mechanism was mainly driven by concentration gradient. The higher amount of drug released was obtained from the matrix with a larger pore size. Under electric field, the higher amounts of drug release were obtained in the shorter drug release durations, via the electrorepulsive force between the negatively charged drugs and the cathode electrode. The molecular drug size was a factor for the drug absorption, release rate and amount. For the drug release-permeation experiment through the pig skin, there were two release-permeation periods as governed by the combination of concentration gradient and swelling in the first period, and the matrix erosion in the second period. The fabricated porous DPNR films have been shown here to be potential to be used as a transdermal patch with electrically controllable drug release rate, amount and duration along with the facile drug-matrix loading and absorption.

Effect of Pulsed Direct Current on Iontophoretic Delivery of Pramipexole across Human Epidermal Membrane In Vitro

PURPOSE

Pulsed direct current (PDC) iontophoresis, by allowing skin depolarization, was suggested to provide more efficient ion transport, but the extent of its enhancement effect was unclear. PDC could also offer electric-customized drug delivery. This study examined the effect of PDC iontophoresis on transdermal delivery of pramipexole dihydrochloride (PXCl).

METHODS

Iontophoretic delivery of PXCl across human epidermal membrane from pH 7.0 solution was conducted in vitro using continuous direct current (DC) and 6- and 12-cycle PDC iontophoresis (0.5 mA/cm² and total applied duration of 6 h). Different parameters of PDC iontophoresis were studied, including current density (0.1, 0.2 and 0.5 mA/cm²) and on-off current dosing pattern (1 h/3 h, 0.5 h/3.5 h, and 0.2 h/3.8 h).

RESULTS

Both 6- and 12-cycle PDC iontophoresis protocols provided modulation of the permeation profile but delivered smaller amounts of PXCl (396 and 400 μg/cm², respectively) as compared with continuous DC iontophoresis (482 μg/cm²) at 24 h after 0.5 mA/cm² and 180 mA/cm² × min current dose application. Increasing applied current density from 0.1 to 0.5 mA/cm² increased the PDC iontophoretic flux of PXCl linearly from 5.3 to 14.6 μg/cm²·h (R² = 0.887). Varying the current level and duration but at the same applied current dose (36 mA/cm² × min), the total amount of PXCl delivered by PDC iontophoresis at 24 h was independent of the on-off dosing pattern studied (114-128 μg/cm²).

CONCLUSIONS

The results indicate that PDC iontophoresis can benefit transdermal delivery of PXCl in terms of controlling its permeation but does not enhance iontophoretic transport compared to continuous DC iontophoresis under the conditions studied.

Enhanced Transdermal Delivery of Bisoprolol Hemifumarate via Combined Effect of Iontophoresis and Chemical Enhancers: Ex Vivo Permeation/In Vivo Pharmacokinetic Studies

Bisoprolol hemifumarate (BH) is an antihypertensive drug that is used as first-line treatment for chronic hypertension and angina pectoris. Our study was performed to enhance the transdermal delivery of BH, a hydrophilic drug active with high molecular weight, through differently prepared hydrogels. The synergistic effect of permeation enhancers and iontophoresis was investigated via both ex vivo and in vivo permeation studies. Ex vivo iontophoretic permeation studies were performed by using male albino Wistar rat skin. Cellosolve® hydrogel (F7) showed a 1.5-fold increase in Q180, Jss, and FER compared to F5 (lacking permeation enhancer). BH pharmacokinetic data were studied in human volunteers, following transdermal delivery of F7, using Phoresor® Unit II iontophoresis device, compared to conventional oral tablets. F7 showed 1.9- and 2-fold higher values of Cmax and AUC0-40, respectively compared to Concor® tablets, as well as a smaller Tmax (2.00 ± 2.00 h). The relative bioavailability of F7 was found to be 201.44%, relative to Concor® tablets, demonstrating the significantly enhanced transdermal permeation of BH from the selected hydrogel by iontophoresis, in human volunteers. Finally, results showed the successful utility of permeation enhancers combined with iontophoresis in significantly enhanced transdermal permeation of BH, despite its large molecular weight and hydrophilic nature. Therefore, this strategy could be employed as a successful alternative route of administration to conventional oral tablets.

Permeation kinetics of active drugs through lanolin-based artificial membranes

Skin-penetration studies play an essential role in the selection of drugs for dermal or transdermal application. In vivo experiments in humans are not always possible for ethical, practical, or economic reasons, especially in the first part of the drug development. It is necessary to develop alternative methods using accessible and reproducible surrogates for in vivo human skin. The in vitro methodologies using biological membranes (human and animal skin) are recognized and well accepted as an alternative but present high inter- and intra-individual variability. Therefore, the formation of synthetic membranes has been studied to obtain skin- mimicking models for permeation studies. The aim of this work is to create lanolin-based artificial membranes that can mimic the absorption through the skin of compounds applied topically. A series of synthetic membranes using two different types of lanolin (water-extracted (WE) and solvent-extracted (SE)) were prepared. Next, the in vitro release test of three drugs (diclofenac sodium, ibuprofen and lidocaine) was performed on artificial membranes and on porcine skin placed on Franz cells. The percentage of release, flux, permeability coefficient, lag time, area under the curve, maximal concentration and time were determined for each compound in the different types of membrane. The results showed that lanolin membranes presented a strong diminution of permeability compared to most artificial membranes, leading to a very similar permeability to that of skin. The SE and WE membranes showed a diminution of transepidermal water loss and permeability of compounds compared with membranes alone. The results from WE membranes were similar to those found for the skin. The lanolin membranes were not capable of perfectly mimicking permeation through the skin, but they did have the same rank order of drug penetration as the skin. It may be deduced from these tests that these systems provide more reliable results for compounds with low to medium lipophilicity. The results demonstrated that new lanolin-based artificial membranes have the potential to be exploited as screening models for determining the permeability of a compound destined to be topically delivered.

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.