Continuous Transdermal Delivery Research Articles

Poly(acrylic acid)/Poly(vinyl alcohol) Microarray Patches for Continuous Transdermal Delivery of Levodopa and Carbidopa: In Vitro and In Vivo Studies.

Levodopa (LD) has been the most efficacious medication and the gold standard therapy for Parkinson's disease (PD) for decades. However, its long-term administration is usually associated with motor complications, which are believed to be the result of the fluctuating pharmacokinetics of LD following oral administration. Duodopa® is the current option to offer a continuous delivery of LD and its decarboxylase inhibitor carbidopa (CD); however, its administration involves invasive surgical procedures, which could potentially lead to lifelong complications, such as infection. Recently, dissolving microarray patches (MAPs) have come to the fore as an alternative that can bypass the oral administration route in a minimally invasive way. This work explored the potential of using dissolving MAPs to deliver LD and CD across the skin. An acidic polymer poly(acrylic acid) (PAA) was used in the MAP fabrication to prevent the potential oxidation of LD at neutral pH. The drug contents of LD and CD in the formulated dissolving MAPs were 1.82 ± 0.24 and 0.47 ± 0.04 mg/patch, respectively. The in vivo pharmacokinetic study using female Sprague-Dawley® rats (Envigo RMS Holding Corp, Bicester, UK) demonstrated a simultaneous delivery of LD and CD and comparable AUC values between the dissolving MAPs and the oral LD/CD suspension. The relative bioavailability for the dissolving MAPs was calculated to be approximately 37.22%. Accordingly, this work highlights the use of dissolving MAPs as a minimally invasive approach which could potentially bypass the gastrointestinal pathway and deliver both drugs continuously without surgery.

A comparative analysis of deferoxamine treatment modalities for dermal radiation-induced fibrosis.

The iron chelator, deferoxamine (DFO), has been shown to potentially improve dermal radiation‐induced fibrosis (RIF) in mice through increased angiogenesis and reduced oxidative damage. This preclinical study evaluated the efficacy of two DFO administration modalities, transdermal delivery and direct injection, as well as temporal treatment strategies in relation to radiation therapy to address collateral soft tissue fibrosis. The dorsum of CD‐1 nude mice received 30 Gy radiation, and DFO (3 mg) was administered daily via patch or injection. Treatment regimens were prophylactic, during acute recovery, post‐recovery, or continuously throughout the experiment (n = 5 per condition). Measures included ROS‐detection, histology, biomechanics and vascularity changes. Compared with irradiated control skin, DFO treatment decreased oxidative damage, dermal thickness and collagen content, and increased skin elasticity and vascularity. Metrics of improvement in irradiated skin were most pronounced with continuous transdermal delivery of DFO. In summary, DFO administration reduces dermal fibrosis induced by radiation. Although both treatment modalities were efficacious, the transdermal delivery showed greater effect than injection for each temporal treatment strategy. Interestingly, the continuous patch group was more similar to normal skin than to irradiated control skin by most measures, highlighting a promising approach to address detrimental collateral soft tissue injury following radiation therapy.

Continuous Transdermal Delivery of L-DOPA Based on a Self-Assembling Nanomicellar System.

When levodopa (L-DOPA) is administered orally, it is eliminated from the body very quickly resulting in a series of sharp fluctuations in its blood concentrations. These frequent changes in blood levels are considered to be responsible for the development of late motor complications and dyskinesias, which are troubling clinical and treatment issues in Parkinson's disease. Transdermal drug delivery is a patient-compliant method for delivering therapeutics into the systemic circulation in a continuous and controlled manner. Transdermal delivery of L-DOPA can achieve continuous dopaminergic stimulation (CDS), thus reducing motor fluctuations. However, there are two technical difficulties in the development of a transdermal patch for L-DOPA: (a) L-DOPA is poorly soluble in most pharmaceutically-acceptable solvents, and (b) L-DOPA has a limited permeability through the skin even from saturated solutions. We have, therefore, investigated the transdermal delivery of L-DOPA using an innovative self-assembling nano-micellar system (SANS), loaded with 2% L-DOPA and 1% carbidopa. In vitro testing as well as in vivo pharmacokinetic studies (multiple-dose regimen) in rabbits have demonstrated for the first time a significantly increased percutaneous permeation and systemic absorption of L-DOPA. It has therefore been proposed that either a once-daily or a twice-daily regimen could be therapeutically effective depending on the severity of the disease.

Rotigotine may control drooling in patients with Parkinson’s Disease: Preliminary findings

ObjectiveTo evaluate the efficacy of rotigotine in controlling the drooling of Parkinson’s Disease (PD) patients. Patients and methodsWe assessed 7 PD patients (Hoehn and Yahr scale >2.5) with three different clinical scores (Drooling Severity and Frequency Scale − DSFS, Drooling Rating Scale – DRS and Sialorrhea Clinical Scale for PD – SCS) before and after 4 weeks of therapy. Statistical differences were analyzed with Wilcoxon signed-rank test. ResultsWe observed that rotigotine significantly improves drooling as measured by the lowering of the three scores (p<0.05). ConclusionsAmong non-motor symptoms of PD, drooling is one of the most embarrassing and disabling for patients. Current treatments are unsatisfactory and novel approaches are thus desirable. In this open-label pilot study we demonstrated on a small sample of patients that up to 4mg/24h of rotigotine, a non-ergolinic dopamine agonist with continuous transdermal delivery, may be helpful in the management of drooling in advanced PD.

Pharmacokinetics, Safety and Tolerability of Rotigotine Transdermal Patch in Healthy Japanese and Caucasian Subjects

Background and ObjectivesRotigotine is a dopamine receptor agonist with activity across the D1 through to D5 receptors as well as select serotonergic and adrenergic sites; continuous transdermal delivery of rotigotine with replacement of the patch once daily maintains stable plasma concentrations over 24 h. Rotigotine is indicated for the treatment of early and advanced-stage Parkinson’s disease and moderate-to-severe idiopathic restless legs syndrome. The pharmacokinetics and pharmacodynamics of a drug may vary between subjects of different ethnic origin. This study evaluated the pharmacokinetics, safety, and tolerability of single-dose treatment with rotigotine transdermal patch in Japanese and Caucasian subjects.MethodsIn this open-label, parallel-group study, healthy male and female subjects of Japanese or Caucasian ethnic origin were matched by sex, body mass index, and age. A single transdermal patch delivering 2 mg/24 h rotigotine (patch content 4.5 mg) was applied to the ventral/lateral abdomen for 24 h. The main outcome measures were the plasma concentrations of unconjugated and total rotigotine and its desalkyl metabolites and derived pharmacokinetic parameters (area under the concentration–time curve from time zero to last quantifiable concentration [AUClast], maximum plasma concentration [C max], and body weight- and dose-normalized values).ResultsThe pharmacokinetic analysis included 48 subjects (24 Japanese, 24 Caucasian). The mean apparent dose of rotigotine was 2.0 ± 0.5 mg for Japanese subjects and 2.08 ± 0.58 mg for Caucasians. Plasma concentration–time profiles of unconjugated rotigotine and of the main metabolites were similar for both ethnic groups. Parameters of model-independent pharmacokinetics, C max, time to C max (t max), and AUClast, for unconjugated rotigotine showed no statistically significant differences between Japanese and Caucasian subjects. Values of concentration-dependent pharmacokinetic parameters were higher in female subjects; this difference was minimized after correction for body weight. A statistically significant difference between ethnic groups was observed for total rotigotine concentrations (total rotigotine = unconjugated rotigotine + conjugated rotigotine), with slightly lower values in Caucasians after correction for body weight and apparent dose. No relevant differences were observed between males and females. Inter-individual variability was high. The terminal half-life for unconjugated rotigotine was 5.3 h in Japanese subjects and 5.7 h in Caucasians; corresponding values for total rotigotine were 8.6 h and 9.6 h. Less than 0.1 % of the apparent dose was renally excreted as the parent compound. Renal elimination of total rotigotine covers 11.7 % of absorbed dose in Japanese subjects and 10.8 % of the absorbed dose in Caucasians, whereas the renal elimination via total despropyl rotigotine was 8.2 and 7.1 %, respectively. The corresponding values for total desthienylethyl rotigotine were 3.5 % in Japanese subjects and 4.2 % Caucasians. Most adverse events were mild in intensity and typical for dopamine agonists or for transdermal therapeutics.ConclusionAdministration of a single patch delivering 2 mg/24 h rotigotine resulted in comparable pharmacokinetic profiles in Japanese and Caucasian subjects. The rotigotine transdermal patch was generally well-tolerated. Our findings suggest similar dose requirements for Japanese and Caucasian populations.

Rotigotine for Apathy in Limbic Autoimmune Encephalitis

Rotigotine for Apathy in Limbic Autoimmune Encephalitis

Transdermal rotigotine for the perioperative management of restless legs syndrome

BackgroundImmobilisation, blood loss, sleep deficiency, and (concomitant) medications during perioperative periods might lead to acute exacerbation of symptoms in patients with the restless legs syndrome (RLS). Continuous transdermal delivery of the dopamine agonist rotigotine provides stable plasma levels over 24 h and may provide RLS patients with a feasible treatment option for perioperative situations. To assess the feasibility of use of rotigotine transdermal patch for the perioperative management of moderate to severe RLS, long-term data of an open-label extension of a rotigotine dose-finding study were retrospectively reviewed.MethodsThe data of all 295 patients who had entered the 5-year study were screened independently by two reviewers for the occurrence of surgical interventions during the study period. The following data were included in this post-hoc analysis: patient age, sex, surgical intervention and outcome, duration of hospital stay, rotigotine maintenance dose at the time of surgery, rotigotine dose adjustment, and continuation/discontinuation of rotigotine treatment. All parameters were analysed descriptively. No pre-specified efficacy assessments (e.g. IRLS scores) were available for the perioperative period.ResultsDuring the study period, 61 surgical interventions were reported for 52 patients (median age, 63 years; 67% female); the majority of patients (85%) had one surgical intervention. The mean rotigotine maintenance dose at time of surgery was 3.1 ± 1.1 mg/24 h. For most interventions (95%), rotigotine dosing regimens were maintained during the perioperative period. Administration was temporarily suspended in one patient and permanently discontinued in another two. The majority (96%) of the patients undergoing surgery remained in the study following the perioperative period and 30 of these patients (61%) completed the 5-year study.ConclusionsAlthough the data were obtained from a study which was not designed to assess rotigotine use in the perioperative setting, this post-hoc analysis suggests that treatment with rotigotine transdermal patch can be maintained during the perioperative period in the majority of patients and may allow for uninterrupted alleviation of RLS symptoms.Trial RegistrationThe 5-year rotigotine extension study is registered with ClinicalTrials.gov, identifier NCT00498186.

Abstract 4844: A novel mechanism of immune escape in cancer and its regulation by nitric oxide

Abstract One key to malignant progression is the acquired ability of tumor cells to escape immune-mediated lysis. Whereas tumor hypoxia is known to play a causal role in cancer metastasis and resistance to therapy, the link between hypoxia and immune escape in cancer remains poorly understood. Previously, we showed that hypoxia induces resistance to natural killer (NK) cell-mediated lysis in tumour cells through a mechanism that involves the shedding of the NK cell-activating ligand, MHC Class I Chain Related molecule A (MICA), from the cell surface. Additionally, we reported that activation of NO signalling in the tumour cells was able to block this hypoxia-induced shedding of MICA, as well as resistance to NK-mediated lysis. Here, we show that hypoxia-induced tumor resistance to lysis is mediated by a HIF-1-dependent increased expression of the metalloproteinase ADAM10, which is required for the hypoxia-induced shedding of MICA. Our findings demonstrate that HIF-1α knock down attenuated the hypoxia-induced expression of ADAM10 and MICA in tumour cells. Also, siRNA-mediated knockdown of HIF-1α or ADAM10 prevented the hypoxia-induced resistance of DU145 cells to innate immune effector cell-mediated lysis. Treatment with nitric oxide mimetic agents interfered with the hypoxia-induced accumulation of HIF-1α, and with the hypoxia-induced up-regulation of ADAM10 expression required for decreased surface MICA expression and resistance to lysis. To validate the in vitro results, we adopted a model in which human DU145 cells were injected subcutaneously into Swiss nude mice (T and B cell-deficient). Continuous transdermal delivery of nitroglycerine (1.8 µg/h for up to 62 days) significantly attenuated attenuated the tumor growth (P &amp;lt; 0.05). This tumor growth-inhibitory effect of nitroglycerine was absent in mice depleted of innate immune effector cells. Within the tumours, areas of hypoxia co-localized with the metalloproteinase ADAM10 expression. Our results demonstrate a novel mechanism by which hypoxia contributes to immune escape in tumor cells and provide evidence that activation of nitric oxide signalling interferes with this mechanism. The findings described here are important because they indicate that nitric oxide mimetics could potentially be used as immunosensitizers in the treatment and/or prevention of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4844. doi:1538-7445.AM2012-4844

Hypoxia Increases Tumor Cell Shedding of MHC Class I Chain-Related Molecule: Role of Nitric Oxide

The MHC class I chain-related (MIC) molecules play important roles in tumor immune surveillance through their interaction with the NKG2D receptor on natural killer and cytotoxic T cells. Thus, shedding of the MIC molecules from the tumor cell membrane represents a potential mechanism of escape from NKG2D-mediated immune surveillance. Tumor hypoxia is associated with a poor clinical outcome for cancer patients. We show that hypoxia contributes to tumor cell shedding of MIC through a mechanism involving impaired nitric oxide (NO) signaling. Whereas hypoxia increased MIC shedding in human prostate cancer cells, activation of NO signaling inhibited hypoxia-mediated MIC shedding. Similar to incubation in hypoxia, pharmacologic inhibition of endogenous NO signaling increased MIC shedding. Parallel studies showed hypoxia-mediated tumor cell resistance to lysis by interleukin 2-activated peripheral blood lymphocytes (PBL) and NO-mediated attenuation of this resistance to lysis. Inhibition of NO production also led to resistance to PBL-mediated lysis. Interference of MIC-NKG2D interaction with a blocking anti-MIC antibody abrogated the effect of hypoxia and NO signaling on tumor cell sensitivity to PBL-mediated lysis. Finally, continuous transdermal delivery of the NO mimetic glyceryl trinitrate (7.3 mug/h) attenuated the growth of xenografted MIC-expressing human prostate tumors. These findings suggest that the hypoxic tumor microenvironment contributes to resistance to immune surveillance and that activation of NO signaling is of potential use in cancer immunotherapy.

A randomized comparison of continuous combined transdermal delivery of estradiol-norethindrone acetate and estradiol alone for menopause

Objective: To determine whether a continuous estradiol-norethindrone acetate transdermal delivery system reduces incidence of endometrial hyperplasia in postmenopausal women more than transdermal estradiol (E2) alone. Methods: Six hundred twenty-five postmenopausal women were assigned randomly to one of four treatments, transdermal E2 50 μg/day, or transdermal E2-norethindrone acetate with 50 μg E2 and 140, 250, or 400 μg/day of norethindrone acetate. Follow-up visits to collect information on safety and efficacy were scheduled at 3, 6, 9, and 12 months after initiation of treatment. Endometrial biopsy for histologic evaluation was done at baseline and upon exit from the study (completion or withdrawal). Endometrial histology was evaluated by two independent gynecologic pathologists. In the event of a disparate reading, a third gynecologic pathologist evaluated the tissue using predetermined criteria. Results: Endometrial hyperplasia was found in 37.9% (39 of 103) in the E2 alone group versus 0.8% (one of 123), 1% (one of 98), and 1.1% (one of 89) in the E2-norethindrone acetate 50-140, 50-250, and 50-400 groups, respectively ( P < .001). Uterine bleeding was less frequent in the E2-norethindrone acetate 50-140 group than other treatments. The mean number of hot flushes per day decreased to less than one in each treatment group at endpoint. The E2-norethindrone acetate combination patch showed skin tolerance comparable to that of E2 alone. Conclusion: Continuous transdermal delivery of E2 combined with norethindrone acetate effectively prevented endometrial hyperplasia in healthy postmenopausal women. Continuous combined transdermal delivery systems provide increased dosing flexibility and might improve convenience and compliance with hormone replacement therapy.

In vitro pulsatile and continuous transdermal delivery of buserelin by iontophoresis

Transdermal delivery of buserelin, a nonapeptide, from hydroxyethylcellulose hydrogel through isolated human stratum comeum was studied. In vitro studies were carried out in a drug release apparatus (DAB 10/USP XII) using self designed rotary disk cells equipped with platinum electrodes. Different forms of current were examined. A pulsatile application of continuous current resulted in a step-like permeation profile. Different on/off ratios (5 min/55 min; 10 min/50 min; 15 min/45 min)) were studied. When continuous non-interrupted current with different current densities (0.1–0.3 mA·cm −2) was applied, linear dependence of the final cumulative amount of buserelin on current duration and density was observed. Passive permeation of buserelin through human stratum comeum was not detectable either before current flow or after a current period of 4 h (0.2 mA·cm −2). A comparison of iontophoretic release and passive release of buserelin from hydroxyethylcellulose hydrogel through a cellulose membrane showed matrix release for both. Iontophoretic enhancement was also significant for release behavior. In aqueous solution significant electrolysis was observed. Electrolysis of buserelin in hydrogel occurred less and was dependent on current density. The pH-shift in donor medium after electrically assisted permeation was examined for different current densities, current duration and ionic strength of buffer. The influence of donor pH and ionic strength on permeation was studied. Pulsed (2000 Hz; 0.1 mA·cm −2; square wave form) and continuous (0.1 mA·cm −2; 0.2 mA·cm −2) direct current were compared.

Rationale for intermittent nitrate therapy

Tolerance to the pharmacologic and therapeutic effects of nitrate therapy is now well established. This phenomenon may be defined as either a decreased response to a given amount of nitrate or the need for an increased amount of nitrate to maintain a constant effect. Tolerance has been demonstrated with all forms of nitrate therapy that maintain continuous blood levels of the drug, including frequent oral dosing, constant intravenous infusion, and continuous transdermal delivery. It can develop rapidly after only a few doses of a nitrate preparation and tends to be partial rather than absolute. Strategies for the prevention of nitrate tolerance include the avoidance of maximum nitrate doses and the use of intermittent nitrate dosing regimens. Providing a relatively brief nitrate-free interval restores vascular responsiveness to nitrates, most likely due to a recovery of the metabolic mechanisms responsible for the therapeutic effect of these drugs. The duration of this period of nitrate abstinence varies, depending on the nitrate preparation used but is generally in the range of 8–12 hours. Such intermittent therapy not only reduces the risk of nitrate tolerance, but also provides a convenient approach to outpatient management.

Transdermal fentanyl for pain control in patients with cancer

Five cancer patients experienced satisfactory pain relief for periods of 3–156 days using continuous transdermal delivery of the narcotic fentanyl. The patients, aged 16–68 years, had all been experiencing pain and were either unable to take oral analgesic medications or these agents were ineffective in controlling pain. Doses were adjusted to individual patient needs and varied from 75 μg/h to 350 μ/h ( median = 225 μg/ h). Plasma fentanyl levels reflected the administered dose and remained constant throughout the treatment. Transdermal delivery of narcotics provides a new option for the cancer patient unable to achieve satisfactory analgesia with oral medications.