Pharmacokinetics, Tolerability, and Performance of a Novel Matrix Transdermal Delivery System of Fentanyl Relative to the Commercially Available Reservoir Formulation in Healthy Subjects

Implementing physics-based digital patient twins to tailor the switch of oral morphine to transdermal fentanyl patches based on patient physiology

Fentanyl transdermal patches are widely implemented for cancer-induced pain treatment due to the high potency of fentanyl and gradual drug release. However, transdermal fentanyl up-titration for opioid-naïve patients is difficult, which is why opioid treatment is often started with oral/iv morphine. Based on the daily dose of morphine, the initial dose of the fentanyl patch is decided upon. After reaching a stable level of pain, the switch is made from oral/iv morphine to transdermal fentanyl. There are standard calculation tools for transferring from oral/iv morphine to transdermal fentanyl, which is the same for all patients. By considering the variations in the physiology of the patients, a unique switching strategy cannot meet the needs of different patients. This study explores the outcome in terms of pain relief and minute ventilation during opioid therapy. For this, we used physics-based simulations on a virtually-generated population of patients, and we applied the same therapy to all patients. We could show that patients' physiology, such as gender, age, and weight, greatly impact the outcome of the therapy; as such, the correlation coefficient between pain intensity and age is 0.89, and the correlation coefficient between patient's weight and maximum plasma concentration of morphine and fentanyl is -0.98 and -0.97. Additionally, a different combination of the duration of overlap between morphine and fentanyl therapy with different doses of fentanyl was considered for the virtual patients to find the best opioid-switching strategy for each patient. We explored the impact of combining physiological features to determine the best-suited strategy for virtual patients. Our findings suggest that tailoring morphine and fentanyl therapy only based on a limited number of features is insufficient, and increasing the number of impactful physiological features positively influences the outcome of the therapy.

Predicting transdermal fentanyl delivery using physics-based simulations for tailored therapy based on the age

Transdermal fentanyl patches are an effective alternative to the sustained release of oral morphine for chronic pain management. Due to the narrow therapeutic range of fentanyl, the concentration of fentanyl in the blood needs to be carefully monitored. Only then can effective pain relief be achieved while avoiding adverse effects such as respiratory depression. This study developed a physics-based digital twin of a patient by implementing drug uptake, pharmacokinetics, and pharmacodynamics models. The twin was employed to predict the in-silico effect of conventional fentanyl transdermal in a 20–80-year-old virtual patient. The results show that, with increasing age, the maximum transdermal fentanyl flux and maximum concentration of fentanyl in the blood decreased by 11.4% and 7.0%, respectively. However, the results also show that as the patient's age increases, the pain relief increases by 45.2%. Furthermore, the digital twin was used to propose a tailored therapy based on the patient's age. This predesigned therapy customized the duration of applying the commercialized fentanyl patches. According to this therapy, a 20-year-old patient needs to change the patch 2.1 times more frequently than conventional therapy, which leads to 30% more pain relief and 315% more time without pain. In addition, the digital twin was updated by the patient's pain intensity feedback. Such therapy increased the patient's breathing rate while providing effective pain relief, so a safer treatment. We quantified the added value of a patient's physics-based digital twin and sketched the future roadmap for implementing such twin-assisted treatment into the clinics.

Predicting Transdermal Fentanyl Delivery Using Mechanistic Simulations for Tailored Therapy

Transdermal drug delivery is a key technology for administering drugs. However, most devices are “one-size-fits-all”, even though drug diffusion through the skin varies significantly from person-to-person. For next-generation devices, personalization for optimal drug release would benefit from an augmented insight into the drug release and percutaneous uptake kinetics. Our objective was to quantify the changes in transdermal fentanyl uptake with regards to the patient’s age and the anatomical location where the patch was placed. We also explored to which extent the drug flux from the patch could be altered by miniaturizing the contact surface area of the patch reservoir with the skin. To this end, we used validated mechanistic modeling of fentanyl diffusion, storage, and partitioning in the epidermis to quantify drug release from the patch and the uptake within the skin. A superior spatiotemporal resolution compared to experimental methods enabled in-silico identification of peak concentrations and fluxes, and the amount of stored drug and bioavailability. The patients’ drug uptake showed a 36% difference between different anatomical locations after 72 h, but there was a strong interpatient variability. With aging, the drug uptake from the transdermal patch became slower and less potent. A 70-year-old patient received 26% less drug over the 72-h application period, compared to an 18-year-old patient. Additionally, a novel concept of using micron-sized drug reservoirs was explored in silico. These reservoirs induced a much higher local flux (µg cm^-2 h^-1) than conventional patches. Up to a 200-fold increase in the drug flux was obtained from these small reservoirs. This effect was mainly caused by transverse diffusion in the stratum corneum, which is not relevant for much larger conventional patches. These micron-sized drug reservoirs open new ways to individualize reservoir design and thus transdermal therapy. Such computer-aided engineering tools also have great potential for in-silico design and precise control of drug delivery systems. Here, the validated mechanistic models can serve as a key building block for developing digital twins for transdermal drug delivery systems.

Safety, Tolerability, and Dose Proportionality of a Novel Transdermal Fentanyl Matrix Patch and Bioequivalence With a Matrix Fentanyl Patch: Two Phase 1 Single-Center Open-Label, Randomized Crossover Studies in Healthy Japanese Volunteers

Two open‐label, single‐dose, randomized crossover studies were conducted in healthy Japanesemen to (1) assess dose proportionality of 5 doses (1.38, 2.75, 5.5, 8.25, and 11.0 mg) of Lafenta, a novel matrix‐type transdermal fentanyl patch with a rate‐controlling membrane; and (2) compare patch bioequivalence (11.0 mg) with a commercially available reference patch (Durotep MT Patch [16.8 mg]). Pharmacokinetics, adhesion performance, residual fentanyl, and safety parameters were assessed. Increases in mean AUC_0‐t and C_max after application of the test patch were dose proportional. The test patch (11.0 mg) was bioequivalent to the 16.8‐mg reference patch in terms of mean AUC_0‐inf, AUC_0‐t, and C_max. Residual fentanyl levels 72 hours postapplication were lower in the test than in the reference patch. Differences in adhesion performance between the test and the reference patch did not affect delivery efficacy and reliability of the novel matrix patch. Safety findings were in line with previous experiences with fentanyl. Both studies showed low variation in fentanyl exposure and delivery via the test patch. The test patch provided equivalent fentanyl exposure at a lower dose than the reference patch formulation with lower variability and the potential to lower medicinal waste.

Treatment with subcutaneous and transdermal fentanyl: results from a population pharmacokinetic study in cancer patients

Purpose

Transdermal fentanyl is effective for the treatment of moderate to severe cancer-related pain but is unsuitable for fast titration. In this setting, continuous subcutaneous fentanyl may be used. As data on the pharmacokinetics of continuous subcutaneous fentanyl are lacking, we studied the pharmacokinetics of subcutaneous and transdermal fentanyl. Furthermore, we evaluated rotations from the subcutaneous to the transdermal route.

Methods

Fifty-two patients treated with subcutaneous and/or transdermal fentanyl for moderate to severe cancer-related pain participated. A population pharmacokinetic model was developed and evaluated using non-linear mixed-effects modelling. For rotations from subcutaneous to transdermal fentanyl, a 1:1 dose conversion ratio was used while the subcutaneous infusion was continued for 12 h (with a 50 % tapering after 6 h). A 6-h scheme with 50 % tapering after 3 h was simulated using the final model.

Results

A one-compartment model with first-order elimination and separate first-order absorption processes for each route adequately described the data. The estimated apparent clearance of fentanyl was 49.6 L/h; the absorption rate constant for subcutaneous and transdermal fentanyl was 0.0358 and 0.0135 h⁻¹, respectively. Moderate to large inter-individual and inter-occasion variability was found. Around rotation from subcutaneous to transdermal fentanyl, measured and simulated plasma fentanyl concentrations rose and increasing side effects were observed.

Conclusions

We describe the pharmacokinetics of subcutaneous and transdermal fentanyl in one patient cohort and report several findings that are relevant for clinical practice. Further research is warranted to study the optimal scheme for rotations from the subcutaneous to the transdermal route.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-015-2005-x) contains supplementary material, which is available to authorized users.

A new once-a-day fentanyl citrate patch (Fentos Tape) could be a new treatment option in patients with end-of-dose failure using a 72-h transdermal fentanyl matrix patch

PURPOSE

The recommended dosing interval for transdermal fentanyl is every 72 h. However, some patients will have "end-of-dose failure," which may be seen as an increase of episodes of severe pain flares at the third day after application of the patch. A new once-a-day fentanyl patch was developed in Japan since 2010. This study aimed to assess the efficacy of the once-a-day fentanyl citrate patch for patients with cancer-related pain receiving the 72-h transdermal fentanyl not lasting 72 h.

METHODS

We performed a cross-sectional retrospective analysis of 445 inpatients with the 72-h transdermal fentanyl at Higashi Sapporo Hospital. We could switch to the once-a-day fentanyl citrate patch if patients reported inadequate pain relief beyond 48 h after application of the 72-h transdermal fentanyl. Patients recorded baseline scores for background pain intensity (PI) and the frequency of use of daily rescue medication for breakthrough cancer pain (BTcP).

RESULTS

Of all patients, 10.1% showed the increase in PI of 30% or more baseline PI on the third day after application of the 72-h transdermal fentanyl. Of patients, 84.4% were converted from equivalent dose of the 72-h transdermal fentanyl to the once-a-day fentanyl citrate patch. On the third day after switching, 60.5% of patients showed a reduction of more than 30% from baseline PI. Switching to the once-a-day fentanyl citrate patch significantly reduced the mean frequency of daily rescue dose for BTcP.

CONCLUSIONS

A once-a-day fentanyl citrate patch provided stable pain control. Its use may be considered as the dominant strategy for patients receiving a 72-h transdermal fentanyl not lasting 72 h.

Recent developments in silicones for topical and transdermal drug delivery

Silicones have been used in medicines, cosmetics and medical devices for over 60 years. Polydimethylsiloxanes are polymers that are typically used either as an active in oral drug products or as excipients in topical and transdermal drug products. Inherent characteristics like hydrophobicity, adhesion and aesthetics allow silicones to offer function and performance to drug products. Recent technologies like swollen crosslinked silicone elastomer blend networks, sugar siloxanes, amphiphilic resin linear polymers and silicone hybrid pressure sensitive adhesives promise potential performance advantages and improved drug delivery efficacy. This article presents a review of recent silicone material developments focusing on their function as excipients influencing drug delivery in topical and transdermal systems.

Quantitative low-volume assay for simultaneous determination of fentanyl, norfentanyl, and minor metabolites in human plasma and urine by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

A rapid and sensitive liquid chromatography/tandem mass spectrometric (LC-MS/MS) method for simultaneous quantification of fentanyl (F), norfentanyl (NF), despropionylfentanyl (DPF), and hydroxynorfentanyl (OHNF) in human plasma and urine specimens has been developed and validated according to international guidelines. Analytes were extracted from 250-μL plasma or urine by liquid-liquid extraction. OHNF in urine affords a second extraction step and analysis with a different column. Calibration curves in plasma were linear from 0.05-10 ng/mL for F, 0.07-0.5 ng/mL for NF, 0.02-1.0 ng/ml for DPF, and 0.67-3.0 ng/mL for OHNF; in urine, from 0.09-10.0, 0.17-50, 0.08-1.0, and 1.0-5.0 ng/mL for F, NF, DPF, and OHNF, respectively. Analytical bias and intra- and inter-assay imprecision were within ± 15 % of target, except for OHNF in plasma and DPF in urine at the respective lower quality control level. All analytes were stable in processed samples when stored for 24 h at room temperature. Recoveries and process efficiencies were above 82.9 and 75.1 % for all analytes in plasma and urine. The low level of DPF in plasma indicated with a matrix effect of 71.3 % moderate ion suppression, all other analytes in plasma and urine showed no matrix effects. The lower limit of quantification (LOQ) in plasma was 0.05, 0.07, 0.02 and 0.67 ng/mL for F, NF, DPF, and OHNF, respectively. In urine, the LOQ of F, NF, DPF, and OHNF were 0.09, 0.17, 0.08, and 1.28 ng/mL, respectively. This assay has been applied to human specimens collected during a clinical drug-drug interaction study.

Pharmacokinetics of non-intravenous formulations of fentanyl

Fentanyl was structurally designed by Paul Janssen in the early 1960s as a potent opioid analgesic (100-fold more potent than morphine). It is a full agonist at μ-opioid receptors and possesses physicochemical properties, in particular a high lipophilicity (octanol:water partition coefficient >700), which allow it to cross quickly between plasma and central nervous target sites (transfer half-life of 4.7-6.6 min). It undergoes first-pass metabolism via cytochrome P450 3A (bioavailability ~30 % after rapid swallowing), which can be circumvented by non-intravenous formulations (bioavailability 50-90 % for oral transmucosal or intranasal formulations). Non-intravenous preparations deliver fentanyl orally-transmucosally, intranasally or transdermally. Passive transdermal patches release fentanyl at a constant zero-order rate for 2-3 days, making them suitable for chronic pain management, as are iontophoretic transdermal systems. Oral transmucosal and intranasal routes provide fast delivery (time to reach maximum fentanyl plasma concentrations 20 min [range 20-180 min] and 12 min [range 12-21 min], respectively) suitable for rapid onset of analgesia in acute pain conditions with time to onset of analgesia of 5 or 2 min, respectively. Intranasal formulations partly bypass the blood-brain barrier and deliver a fraction of the dose directly to relevant brain target sites, providing ultra-fast analgesia for breakthrough pain. Thanks to the development of non-intravenous pharmaceutical formulations, fentanyl has become one of the most successful opioid analgesics, and can be regarded as an example of a successful reformulation strategy of an existing drug based on pharmacokinetic research and pharmaceutical technology. This development broadened the indications for fentanyl beyond the initial restriction to intra- or perioperative clinical uses. The clinical utility of fentanyl could be expanded further by more comprehensive mathematical characterizations of its parametric pharmacokinetic input functions as a basis for the rational selection of fentanyl formulations for individualized pain therapy.

Assessment of extended-release opioid analgesics for the treatment of chronic pain

Approximately 3.8 million patients annually receive extended-release (ER) or long-acting opioid prescriptions in the outpatient setting, around half of which are written by primary care physicians. Compared with short-acting, immediate-release (IR) formulations, ER and oral long-acting opioid analgesics are associated with clinical advantages, such as extended periods of time during which drug plasma levels are within the therapeutic range, decreased peak-to-trough fluctuations, and prolonged analgesia over the dosing period. Additionally, ER opioids offer a more convenient, less frequent dosing regimen to chronic pain patients who are often taking several concomitant medications. The increased utilization of ER opioids has been accompanied by a rise in the misuse and abuse of these formulations. Certain pharmacokinetic parameters (e.g., longer time to maximum drug plasma concentration, lower maximum drug plasma concentration) may decrease the abuse potential of intact ER opioids by limiting the positive subjective and reinforcing effects relative to IR formulations. Putative abuse-deterrent formulations have also recently been introduced to impede physical manipulation of these formulations, or reduce the harm resulting from such behavior. Such formulations may represent an incremental advance to reduce non-oral forms of abuse. This article reviews the pharmacokinetic profiles and abuse-deterrent features of newer ER opioid analgesics for the treatment of moderate to severe chronic pain.

Multicenter clinical study for evaluation of efficacy and safety of transdermal fentanyl matrix patch in treatment of moderate to severe cancer pain in 474 chinese cancer patients

OBJECTIVE

Although a new matrix formulation fentanyl has been used throughout the world for cancer pain management, few data about its efficacy and clinical outcomes associated with its use in Chinese patients have been obtained. This study aimed to assess the efficacy and safety of the new system in Chinese patients with moderate to severe cancer pain.

METHODS

A total of 474 patients with moderate to severe cancer pain were enrolled in this study and were treated with the new transdermal fentanyl matrix patch (TDF) up to 2 weeks. All the patients were asked to record pain intensity, side effects, quality of life (QOL), adherence and global satisfaction. The initial dose of fentanyl was 25 μg/h titrated with opioid or according to National Comprehensive Cancer Network (NCCN) guidelines. Transdermal fentanyl was changed every three days.

RESULTS

After 2 weeks. The mean pain intensity of the 459 evaluated patients decreased significantly from 5.63±1.26 to 2.03±1.46 (P<0.0001). The total remission rate was 91.29%, of which moderate remission rate 53.16%, obvious remission rate 25.49% and complete remission rate 12.64%. The rate of adverse events was 33.75%, 18.78% of which were moderate and 3.80% were severe. The most frequent adverse events were constipation and nausea. No fatal events were observed. The quality of life was remarkably improved after the treatment (P<0.0001).

CONCLUSION

The new TDF is effective and safe in treating patients with moderate to severe cancer pain, and can significantly improve the quality of life.

Simple and rapid HPLC-UV method using an ultrafine particle octadecylsilane for determination of residual fentanyl in applied Durotep MT transdermal matrix patches and its clinical application

A few complicated and time-consuming methods are available for the determination of residual fentanyl in Durotep MT transdermal patches, however, their application to clinical settings is limited. The aim of this study was to develop a simple and rapid HPLC-UV method using an ultrafine particle octadecylsilane (ODS) for the determination of residual fentanyl in applied Durotep MT transdermal matrix patches. Patch extraction involved sonicating a shredded Durotep MT patch in acetonitrile for 15 min. Fentanyl separation was completed within 2 min using a 2.3-μm particle ODS column (50 × 4.6 mm i.d.) at a flow rate of 1.5 mL/min. No peaks interfering with fentanyl (1.27 min) and papaverine (0.89 min) as an internal standard were observed. The calibration curve for fentanyl was linear over the range of 0.015-9.0 mg as a Durotep MT patch. The intra- and inter-assay precisions and accuracies of each patch were within 5.3% and 103.9-110.5% and within 8.2% and 97.1-104.3%, respectively. The validated method was applied to determine residual fentanyl in Durotep MT patches used in 35 cancer patients. Although the plasma fentanyl concentration was significantly correlated with its measured absorption rate, the measured absorption rate normalized fentanyl concentration showed a large inter-individual variation. The validated simple and rapid HPLC-UV method established in the present study is helpful for evaluating the absorption rate of fentanyl in patients receiving Durotep MT patches.

Challenges and opportunities in dermal/transdermal delivery

Transdermal drug delivery is an exciting and challenging area. There are numerous transdermal delivery systems currently available on the market. However, the transdermal market still remains limited to a narrow range of drugs. Further advances in transdermal delivery depend on the ability to overcome the challenges faced regarding the permeation and skin irritation of the drug molecules. Emergence of novel techniques for skin permeation enhancement and development of methods to lessen skin irritation would widen the transdermal market for hydrophilic compounds, macromolecules and conventional drugs for new therapeutic indications. As evident from the ongoing clinical trials of a wide variety of drugs for various clinical conditions, there is a great future for transdermal delivery of drugs.

Bioequivalence criteria for transdermal fentanyl generics: do these need a relook?

With the increasing appearance of transdermal fentanyl generics since 2004 when patent protection of the reference Duragesic expired, opportunities to switch between different generics have arisen. Transdermal fentanyl is subject to bioequivalence regulation because only approximately 92% of the dose is absorbed as a result of the need to maintain a diffusion gradient from plaster to skin. Considering the high potency of fentanyl and the potential dangerous adverse effects of full mu opioid receptor agonists, we assessed evidence suggesting a revision of the confidence limits of bioequivalence of 80-125%. A few cases have been reported where a prescribed ascension in transdermal fentanyl dosing triggered respiratory depression. Values of concentration that produce a 50% effective response for decreasing the ventilatory volume lie within the plasma concentration range of 1.4-2.5 ng/mL during transdermal fentanyl analgesia. However, an exchange of the reference with a generic with higher bioavailability would trigger respiratory depression only in extreme situations and is clinically supported by only a single case report. Experimental or clinical evidence is required to provide the necessary database for final judgement of bioequivalent limits of fentanyl generics. At present, the evidence is not sufficient to advise other bioequivalence criteria than those previously applied to transdermal fentanyl.

Transdermal fentanyl: pharmacology and toxicology

OBJECTIVE

To evaluate the underlying pharmacology, safety, and misuse/abuse of transdermal fentanyl, one of the cornerstone pharmacotherapies for patients with chronic pain.

METHODS

Literature was identified through searches of Medline (PubMed) and several textbooks in the areas of pharmacology, toxicology, and pain management. A bibliographical review of articles identified by these searches was also performed. Search terms included combinations of the following: fentanyl, transdermal, patch, pharmacology, kinetics, toxicity, and poisoning. All pertinent clinical trials, retrospective studies, and case reports relevant to fentanyl pharmacology and transdermal fentanyl administered by any route and published in English were identified. Each was reviewed for data regarding the clinical pharmacology, abuse, misuse, and safety of transdermal fentanyl. Data from these studies and information from review articles and pharmaceutical prescribing information were included in this review.

RESULTS

Fentanyl is a high-potency opioid that has many uses in the treatment of both acute and chronic pain. Intentional or unintentional misuse, as well as abuse, may lead to significant clinical consequences, including death. Both the US Food and Drug Administration (FDA) and Health Canada have warned of potential pitfalls associated with transdermal fentanyl, although these have not been completely effective in preventing life-threatening adverse events and fatalities related to its inappropriate use.

CONCLUSIONS

Clinically consequential adverse effects may occur unexpectedly with normal use of transdermal fentanyl, or if misused or abused. Misuse and therapeutic error may be largely preventable through better education at all levels for both the prescriber and patient. The prevention of intentional misuse or abuse may require regulatory intervention.

Pediatric palliative care: use of opioids for the management of pain

Pediatric palliative care (PPC) is provided to children experiencing life-limiting diseases (LLD) or life-threatening diseases (LTD). Sixty to 90% of children with LLD/LTD undergoing PPC receive opioids at the end of life. Analgesia is often insufficient. Reasons include a lack of knowledge concerning opioid prescribing and adjustment of opioid dose to changing requirements. The choice of first-line opioid is based on scientific evidence, pain pathophysiology, and available administration modes. Doses are calculated on a bodyweight basis up to a maximum absolute starting dose. Morphine remains the gold standard starting opioid in PPC. Long-term opioid choice and dose administration is determined by the pathology, analgesic effectiveness, and adverse effect profile. Slow-release oral morphine remains the dominant formulation for long-term use in PPC with hydromorphone slow-release preparations being the first rotation opioid when morphine shows severe adverse effects. The recently introduced fentanyl transdermal therapeutic system with a drug-release rate of 12.5 microg/hour matches the lower dose requirements of pediatric cancer pain control. Its use may be associated with less constipation compared with morphine use. Though oral transmucosal fentanyl citrate has reduced bioavailability (25%), it inherits potential for breakthrough pain management. However, the gold standard breakthrough opioid remains immediate-release morphine. Buprenorphine is of special clinical interest as a result of its different administration routes, long duration of action, and metabolism largely independent of renal function. Antihyperalgesic effects, induced through antagonism at the kappa-receptor, may contribute to its effectiveness in neuropathic pain. Methadone also has a long elimination half-life (19 [SD 14] hours) and NMDA receptor activity although dose administration is complicated by highly variable morphine equianalgesic equivalence (1 : 2.5-20). Opioid rotation to methadone requires special protocols that take this into account. Strategies to minimize adverse effects of long-term opioid treatment include dose reduction, symptomatic therapy, opioid rotation, and administration route change. Patient- or nurse-controlled analgesia devices are useful when pain is rapidly changing, or in terminal care where analgesic requirements may escalate. In this article, we present detailed pediatric pharmacokinetic and pharmacodynamic data for opioids, their indications and contraindications, as well as dose-administration regimens that include practical strategies for opioid switching and dose reduction. Additionally, we discuss the problem of hyperalgesia and the use of adjuvant drugs to support opioid therapy.

Transdermal matrix fentanyl membrane patch (matrifen): in severe cancer-related chronic pain

The matrix fentanyl membrane patch is a new transdermal patch designed with a reduced drug load compared with established reservoir and matrix fentanyl patches. The drug is contained within a silicone matrix with a rate-controlling membrane designed to maintain constant serum fentanyl concentrations over the 72-hour application period. The matrix fentanyl membrane patch was equivalent to the reservoir fentanyl patch in terms of transdermal delivery of fentanyl, as demonstrated after both single (100 microg/h) and multiple (50 microg/h) applications by the peak serum fentanyl concentration and the area under the serum concentration-time curve over 72 hours. In a randomized, nonblind, multicentre trial, the transdermal matrix fentanyl membrane patch was noninferior to standard opioid therapy (transdermal reservoir or matrix fentanyl patch or an oral opioid) in terms of analgesic efficacy over 30 days in patients with cancer-related chronic pain requiring long-term opioid use. The transdermal matrix fentanyl membrane patch was as well tolerated as standard opioid therapy; patient-rated tolerability scores for constipation, nausea, daytime drowsiness and sleep disturbance were similar between treatments.

Efficacy, safety and pharmacokinetic study of a novel fentanyl-containing matrix transdermal patch system in Japanese patients with cancer pain

BACKGROUND AND OBJECTIVES

A novel transdermal matrix patch delivery system for fentanyl has been developed to deliver improved management of cancer pain compared with that obtained using current fentanyl reservoir patches. This study was carried out to assess the efficacy, safety and pharmacokinetic profiles of a 12.5 microg/h transdermal matrix fentanyl patch administered with the objective of replacing morphine, oral oxycodone or fentanyl injection formulations. The study also evaluated how the pharmacokinetic profiles of higher dose fentanyl patches (25, 37.5 and 50 microg/h) changed following dose adjustments to optimize management of cancer pain.

METHODS

This open-label, multicentre study involved 87 patients of both sexes (> or =20 years) with a confirmed diagnosis of cancer. Patients were receiving any one of the following at the time of enrollment for the management of their cancer pain: (a) morphine <45 mg/day orally, <30 mg/day as suppositories, or <15 mg/day by injection; (b) oral oxycodone <30 mg/day; or (c) fentanyl injectable preparations <0.3 mg/day. The patients were administered a 3-day course of fentanyl transdermal matrix patch application three times. The initial dose was 12.5 microg/h, which could be increased when a new patch was applied if the physician deemed this to be appropriate based on pain intensity ratings and use of rescue medications. Efficacy outcomes included patients' global assessment scores (primary efficacy endpoint) measured on a five-step scale and dichotomous scores for physicians' global assessment. The occurrence of adverse events and changes in laboratory tests were evaluated as safety variables. Serum fentanyl levels were measured immediately after removal of the old patch on days 4, 7 and 10 to obtain data on trough serum concentrations.

RESULTS

The percentage of patients in category 3 or higher (very satisfied, satisfied, or neither satisfied nor dissatisfied) for the patient's global assessment score was 89.4% (76/85), indicating high patient satisfaction and attainment of sufficient pain control after patients switched from their previously used opioid analgesics. Similar findings were obtained on physicians' global assessment scores. A total of 316 adverse events occurred in 78 (90.7%) of 86 patients who were administered at least one patch. These included nausea (31 [36.0%]), somnolence (26 [30.2%]), vomiting (22 [25.6%]), diarrhoea (17 [19.8%]), constipation (14 [16.3%]), pyrexia (11 [12.8%]) and insomnia (9 [10.5%]). The mean (+/- SD) serum fentanyl concentration determined on day 4 was 169.9 +/- 103.4 pg/mL (n = 83). Serum fentanyl measurement results indicated that the same fentanyl patch dose resulted in similar serum fentanyl levels, while increased doses produced higher serum fentanyl concentrations.

CONCLUSION

The fentanyl matrix transdermal patch formulation employed in this study demonstrated sufficient cancer pain control for patients switching from morphine or oral oxycodone preparations. The patch tested was well tolerated and its use did not result in any increased incidence of adverse drug reactions over those commonly found with opioid analgesics.

A randomized, open, parallel group, multicenter trial to investigate analgesic efficacy and safety of a new transdermal fentanyl patch compared to standard opioid treatment in cancer pain

A new 72-hour transdermal fentanyl matrix patch has been designed, which has a 35%-50% reduction of the absolute fentanyl content compared with other currently available transdermal fentanyl patches that are using the matrix technology. The new patch has previously been shown to be pharmacokinetically bioequivalent to the marketed fentanyl patch. To determine noninferiority in efficacy in cancer patients and to compare safety, a clinical trial comparing the new fentanyl patch with standard oral or transdermal opioid treatment was planned. The design was an open, parallel group, multicenter trial, in which 220 patients were randomized to receive either the fentanyl patch or standard opioid treatment for 30 days. The primary efficacy variable, pain intensity (PI) on a 0-10-point numerical rating scale, was recorded once daily. The primary endpoint was the relative area under the curve of PI expressed as a percentage of the maximum possible PI area under the curve. Any adverse events were recorded; four tolerability endpoints, constipation, nausea, daytime drowsiness, and sleeping disturbances, were assessed daily. Noninferiority was shown; the upper 95% confidence interval limits of the mean difference in relative PI area under the curve between the fentanyl patch and standard opioid treatment were less than 10% for both the intention-to-treat and per-protocol populations. Scores for the tolerability endpoints were similar in the treatment groups. The new fentanyl matrix patch with a lower drug load was found noninferior and as safe as established standard oral and transdermal opioid treatment.

Rapid and sensitive determination of fentanyl in dog plasma by on-line solid-phase extraction integrated with a hydrophilic column coupled to tandem mass spectrometry

We have developed and validated a method for the quantification of fentanyl, a synthetic opioid, in dog plasma by on-line SPE with a hydrophilic column coupled to tandem mass spectrometry in positive electrospray mode. A column-switching instrument with 10-port valve and two HPLC pumping systems were employed. Deuterated fentanyl served as the internal standard. A Waters Oasis HLB extraction column and a Waters Atlantis HILIC Silica analytical column in a column-switching set-up with gradient elution were utilized. Both fentanyl (analyte) and the internal standard (fentanyl-d5) were determined via multiple reaction monitoring (MRM) and the MS/MS ion transitions monitored were m/z 337.0/188.0 and 342.0/188.0, respectively. Each plasma sample was chromatographed within 5 min. The calibration curves were linear over a widely range of 0.01-50 ng/mL using weighted linear regression analysis (1/x). The low limit of quantitation was 0.01 ng/mL. The intra- and inter-day accuracy ranged from 102 to 112% and the overall precision was less than 3%. The recoveries ranged from 90 to 105% in plasma at the concentrations of 0.04, 0.4, 4 and 40 ng/mL. No influence of freeze/thaw and long-term stability were observed. This validated method has been successfully applied to analyze the dog plasma samples of a pharmacokinetics study.

Transdermal fentanyl in childhood and adolescence: a comprehensive literature review

The recently introduced fentanyl transdermal therapeutic system (TTS) with a drug release rate of 12.5 microg/h matches the lower dosing requirements of cancer pain control in children. It is likely that fentanyl TTS will be used in pediatrics with increasing frequency. We compiled the published evidence on pediatric applications of this drug formulation to help physicians get the most benefit from its use. Within this systematic review, a total of 11 observational clinical or pharmacokinetic studies were identified. There are no pediatric randomized or controlled cohort studies. Pharmacokinetic studies poorly described time-concentration profiles after application. The time to reach steady-state serum drug concentrations seems to be longer, clearance (expressed as liters per kilogram per hour) higher, and elimination half-life shorter in children than in adults. There are no fundamental differences in effect or profile of adverse effects compared with adults. Fentanyl TTS may be associated with less constipation compared with morphine use. Frequently, pediatric patients need supplemental mechanical fixation of the fentanyl TTS by means of medical tape. Younger patients tend to have a higher fentanyl requirement when referenced to body weight. Both parents and medical professionals are satisfied with fentanyl TTS to a higher degree than with individual analgesic pretreatment regimens. Fentanyl TTS is a promising option for chronic pain control in children. An approximate conversion factor of 45 mg/day oral morphine to 12.5 microg/h fentanyl TTS is used for initial therapy dose estimation in children receiving long-term morphine therapy. This is conservatively low to avoid respiratory depression. Daily oral morphine equivalent dose should be at least 30 mg/d before fentanyl TTS therapy is started with 12.5 microg/h. Evidence for superiority of fentanyl TTS treatment above conventional opioid administration is both scarce and of low quality.

PERSPECTIVE

The article gives a comprehensive overview of all pediatric data concerning the fentanyl TTS. Children may take longer to reach steady-state fentanyl serum concentrations than adults, and younger children may require higher doses referenced to body weight than older children or adults. Consequently, there is a need to provide sufficient medication in the phase of therapy initiation to prevent breakthrough pain. The 72-hour dosing schedule recommended by the manufacturers may not be applicable to children because of poor patch adhesiveness. The authors suggest to ensure firm fixation of the fentanyl TTS with additional medical tape if necessary and to change the fentanyl TTS after 48 hours. Transdermal fentanyl in children may exhibit fewer side effects when compared with other opioids, especially constipation. Randomized studies are urgently needed to definitively answer this question.

Comparative bioequivalence study between a novel matrix transdermal delivery system of fentanyl and a commercially available reservoir formulation

AIM

To determine the pharmacokinetics, safety and performance of a novel matrix formulation of fentanyl.

METHODS

Transdermal fentanyl was administered as the novel matrix and the Durogesic reservoir formulations (24 subjects, 100 microg h(-1)) in a randomized, fully replicate, four-way crossover study. Serum concentrations of fentanyl were assayed by LC/MS/MS. Pharmacokinetic parameters of fentanyl and performance (adherence and skin irritability) were evaluated.

RESULTS

Test/reference ratio (90% confidence intervals) for AUC(0-t), AUC(inf) and C(max) were 105.5% (99.4, 112.0), 105.3% (99.3, 111.6) and 111.4% (100.4, 123.6), respectively. Adherence and skin irritability results of the two formulations were similar.

CONCLUSION

The two formulations are expected to result in similar efficacy for the management of severe pain.