Efficacy and tolerability of a topical NSAID patch (local action transcutaneous flurbiprofen) and oral diclofenac in the treatment of soft-tissue rheumatism

Nonlinear Pharmacokinetics of Topical Flurbiprofen Gel in a Phase I Study Among Chinese Healthy Adults

INTRODUCTION

PDX-02 (Flurbiprofen sodium) is a topical nonsteroidal anti-inflammatory drug in gel formulation for local analgesia and anti-inflammation. A Phase I clinical trial was conducted to assess the safety, tolerability, and pharmacokinetics of single and multiple doses of PDX-02 gel in Chinese healthy adults.

METHODS

The trial comprised three parts: (1) a single-dose ascending study with three dose levels (0.5%, 1% to 2% PDX-02 gel) applied on a 136 cm2 skin area; (2) a multiple-dose study with either 1% or 2% PDX-02 gel applied on a 136 cm2 skin area for 7 consecutive days; and (3) a high dose group with 2% PDX-02 gel on an 816 cm2 skin area and a frequent multiple dose group with 2% PDX-02 gel on a 272 cm2 skin area four times a day for 7 consecutive days. The safety, tolerability and pharmacokinetics of the PDX-02 gel were evaluated in each part.

RESULTS

A total of sixty participants completed the trial, with all adverse events recovered and all positive skin reaction being transient and recovered. The overall absorption of topical PDX-02 gel was slow with a mean peak time exceeding 9 h. The elimination rate remained consistent between dose groups. A less-than-dose-proportional nonlinear pharmacokinetics relationship was observed within the studied dose range, and this is likely due to the autoinduction of skin first-pass metabolism.

CONCLUSION

The topical PDX-02 gel showed favorable safety and tolerability in both single and multiple dosing studies, with a less-than-dose-proportional nonlinear pharmacokinetics observed.

Sustained release from a metal - Analgesics entrapped within biocidal silver

Matrices for sustained release of drugs have been based on polymers, biomaterials and oxides. The use of the major family of metals as matrices for sustained release is, to the best of our knowledge, unknown. In this context we describe a new family of bio-composites for sustained release of drugs, namely analgesic drugs entrapped within metallic silver. Synthetic methodologies were developed for the preparation of ibuprofen@Ag, naproxen@Ag, tramadol@Ag and bupivacaine@Ag composites. Detailed kinetic analysis of the release of the drugs from within the metal, is provided, demonstrating that metals can indeed serve as reservoirs for drug release. The metal in our case acts not only as a drug releasing source, but also as an antibacterial agent and this property of the composites was studied. Unexpectedly, it was found that the entrapment of the analgesics within silver, dramatically enhances the growth inhibition activity of wild type Pseudomonas aeruginosa, exceeding by far the inhibition activity of the separate components. A mechanism for this interesting observation is provided. The strong antimicrobial activity combined with the analgesic activity open the road for future applications of these materials as dual-purpose components in wound treatment.

Efficacy of S-flurbiprofen plaster in knee osteoarthritis treatment: Results from a phase III, randomized, active-controlled, adequate, and well-controlled trial

OBJECTIVES

S-flurbiprofen plaster (SFPP) is a novel non-steroidal anti-inflammatory drug (NSAID) patch, intended for topical treatment for musculoskeletal diseases. This trial was conducted to examine the effectiveness of SFPP using active comparator, flurbiprofen (FP) patch, on knee osteoarthritis (OA) symptoms.

METHODS

This was a phase III, multi-center, randomized, adequate, and well-controlled trial, both investigators and patients were blinded to the assigned treatment. Enrolled 633 knee OA patients were treated with either SFPP or FP patch for two weeks. The primary endpoint was improvement in knee pain on rising from the chair as assessed by visual analogue scale (rVAS). Safety was evaluated through adverse events (AEs).

RESULTS

The change in rVAS was 40.9 mm in SFPP group and 30.6 mm in FP patch group (p < 0.001). The incidence of drug-related AEs at the application site was 9.5% (32 AEs, 29 mild and 3 moderate) in SFPP and 1.6% in FP patch (p < 0.001). Withdrawals due to AE were five in SFPP and one in FP patch.

CONCLUSIONS

The superiority of SFPP in efficacy was demonstrated. Most of AEs were mild and few AEs led to treatment discontinuation. Therefore, SFPP provides an additional option for knee OA therapy.

Skin Matters: A Review of Topical Treatments for Chronic Pain. Part Two: Treatments and Applications

In Part One of this two-part series, we discussed skin physiology and anatomy as well as generalities concerning topical analgesics. This modality of therapy has lesser side effects and drug-drug interactions, and patients tolerate this form of therapy better than many oral options. Unfortunately, this modality is not used as often as it could be in chronic pain states, such as that from neuropathic pain. Part Two discusses specific therapies, local anesthetics, and other drugs, as well as how a clinician might use specific aspects of a patient's neuropathic pain presentation to help guide them in the selection of a topical agent.

Gastrointestinal injury associated with NSAID use: a case study and review of risk factors and preventative strategies

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective anti-inflammatory and analgesic agents and are among the most commonly used classes of medications worldwide. However, their use has been associated with potentially serious dose-dependent gastrointestinal (GI) complications such as upper GI bleeding. GI complications resulting from NSAID use are among the most common drug side effects in the United States, due to the widespread use of NSAIDs. The risk of upper GI complications can occur even with short-term NSAID use, and the rate of events is linear over time with continued use. Although gastroprotective therapies are available, they are underused, and patient and physician awareness and recognition of some of the factors influencing the development of NSAID-related upper GI complications are limited. Herein, we present a case report of a patient experiencing a gastric ulcer following NSAID use and examine some of the risk factors and potential strategies for prevention of upper GI mucosal injuries and associated bleeding following NSAID use. These risk factors include advanced age, previous history of GI injury, and concurrent use of medications such as anticoagulants, aspirin, corticosteroids, and selective serotonin reuptake inhibitors. Strategies for prevention of GI injuries include anti-secretory agents, gastroprotective agents, alternative NSAID formulations, and nonpharmacologic therapies. Greater awareness of the risk factors and potential therapies for GI complications resulting from NSAID use could help improve outcomes for patients requiring NSAID treatment.

Improving acute pain management in emergency medicine

Undertreatment of pain (oligoanalgesia) in the emergency department is common, and it negatively impacts patient care. Both failure of appropriate pain assessment and the potential for unsafe analgesic use contribute to the problem. As a result, achieving satisfactory analgesia while minimizing side effects remains particularly challenging for emergency physicians, both in the emergency department and after a patient is discharged. Improvements in rapid pain assessment and in evaluation of noncommunicative populations may result in a better estimation of which patients require analgesia and how much pain is present. New formulations of available treatments, such as rapidly absorbed, topical, or intranasal nonsteroidal anti-inflammatory drug formulations or intranasal opioids, may provide effective analgesia with an improved risk-benefit profile. Other pharmacological therapies have been shown to be effective for certain pain modalities, such as the use of antidepressants for musculoskeletal pain, γ-aminobutyric acid agonists for neuropathic and postsurgical pain, antipsychotics for headache, and topical capsaicin for neuropathic pain. Nonpharmacological methods of pain control include the use of electrical stimulation, relaxation therapies, psychosocial/manipulative therapies, and acupuncture. Tailoring of available treatment options to specific pain modalities, as well as improvements in pain assessment, treatment options, and formulations, may improve pain control in the emergency department setting and beyond.

Effectiveness and safety of topical versus oral nonsteroidal anti-inflammatory drugs: a comprehensive review

INTRODUCTION

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) represent a relatively recent alternative to oral NSAIDs. Topical NSAIDs are designed to target their therapeutic effect locally to damaged tissue while minimizing systemic exposure. To better inform patients considering topical NSAIDs as an alternative to oral NSAIDs, this is the first comprehensive review to present all available evidence comparing topical NSAIDs with oral NSAIDs in the treatment of both acute and chronic musculoskeletal injury.

METHODS

Six studies, including 600 subjects, compared the use of topical versus oral NSAIDs in the treatment of a variety of acute injuries. Nine trials, including 2403 subjects, studied topical versus oral NSAIDs for chronic injury treatment, almost exclusively for osteoarthritis (OA) of the knee. This review included all available comparative studies, the majority of which were well-designed, double-dummy, placebo-controlled trials. Relevant meta-analyses were also reviewed.

RESULTS

Topical and oral NSAIDs performed statistically better than placebo for chronic injury treatment. Limited evidence comparing topical NSAIDs with placebo for acute injury treatment was available in the included studies, but supported greater effectiveness for topical NSAIDs. In all head-to-head comparisons, topical and oral NSAIDs demonstrated similar efficacy for treatment of both acute and chronic injuries. There were more gastrointestinal side effects in patients receiving oral NSAIDs, while local skin reactions occurred more frequently in patients treated with topical NSAIDs.

CONCLUSION

Overall, topical NSAIDs may be considered as comparable alternatives to oral NSAIDs and are associated with fewer serious adverse events (specifically GI reactions) when compared with oral NSAIDs. Caution should be exercised with the use of both topical and oral NSAIDs, including close adherence to dosing regimens and monitoring, particularly for patients with previous adverse reactions to NSAIDs.

Evaluation of percutaneous permeation of flurbiprofen and ketoprofen after application of transdermal patches using a lateral sectioning approach in hairless rats

OBJECTIVES

The dispositions and pharmacokinetic parameters of non-steroidal anti-inflammatory drugs (NSAIDs) after patch applications have typically been evaluated on a whole-skin basis, and the detailed permeation profiles remain unclear. The aim of this study was to establish a new method for clearly analyzing the flow of drugs in the skin layers and evaluating the drug levels in the target area of the skin tissue.

METHODS

The skin tissue areas where flurbiprofen and ketoprofen patches were applied were cut into 20 μm-thick lateral slices from the surface to the deepest layer and the drug concentrations in the slices were measured.

RESULTS

The results revealed the presence of depth-dependent concentration gradients from the surface to the deep layer and that the drug concentration in the deepest layer was less than one tenth of the surface concentration for both flurbiprofen and ketoprofen. In addition, flurbiprofen yielded higher and more rapid concentrations in the deepest skin layer adjacent to the intramuscular tissue.

CONCLUSIONS

The present data suggest that our technique involving lateral slicing of skin tissues and measurement of drug concentrations allows visual understanding of drug dispositions in the skin layers and makes it possible to evaluate the drug levels in the target area of the skin tissue.

Effect of nonsteroidal anti-inflammatory drug plasters for knee osteoarthritis in Japanese: a randomized controlled trial

The objective of this study was to examine the effect of a nonsteroidal anti-inflammatory drug (NSAID) plaster for knee osteoarthritis among Japanese patients. An open-labeled, randomized, controlled, multiclinic trial was performed involving outpatient clinic groups. Two comparative groups-plaster NSAIDs and oral NSAIDs-were randomly allocated. The drugs used were limited to the current top three in both groups in Japan. Treatments were assessed after four weeks and compared with the baseline scores. Outcomes were evaluated by two psychometric measures: Japanese knee osteoarthritis measure, and pain with the visual analogue scale. The total number of patients included in the final evaluation was 165 (87 for the plaster group and 78 for the oral group). Between these two groups there were no significant differences in gender, age, body height and weight, body mass index, and X-ray grading. The subjects in both groups showed improvements in both scores at the end of intervention. The differences in the improvements in scores between the two groups were not significant, though the mean rank score and the 95% CI of the plaster group were slightly better than those of the oral group. In conclusion, the local application of a plaster with NSAIDs leads to the same level of improvement in knee osteoarthritis as oral NSAIDs.

Alzheimer's disease treatment: assessing caregiver preferences for mode of treatment delivery

INTRODUCTION

Management of patients with Alzheimer's Disease (AD) can exert a substantial burden upon caregivers. As new modes of treatment administration are developed, it is important to assess caregiver satisfaction and preference in a standardized manner. This study describes the development of the Alzheimer's Disease Caregiver Preference Questionnaire (ADCPQ) to assess AD caregivers' satisfaction with and preference for patch or capsule treatments in AD patients.

METHODS

Twenty-five published articles (1987-2002) were reviewed to identify potential ADCPQ domains. Three caregiver focus groups (n=24) were conducted to develop a first draft of the questionnaire. After evaluating the acceptance of ADCPQ to caregivers through in-depth interviews (n=10), its psychometric properties were assessed using data from 986 patients enrolled in a multicenter, randomized, double-blind, four-arm, placebo- and active-controlled, 24-week trial.

RESULTS

Focus groups indicated that caregivers expressed dissatisfaction with current AD treatment routines including limitations related to: efficacy, administration schedule, number of pills, adherence to treatment, side effects, and taking pills. In-depth interviews with caregivers found the ADCPQ to be comprehensible with an acceptable layout. The resultant ADCPQ comprises three modules: A) baseline, 11 items assessing treatment expectations; B) week 8, 33 items on satisfaction and preferences with treatment options; C) week 24, 10 items assessing overall opinions of treatment options. Missing data per item was low (<or=0.3%) and domain internal consistency reliability was good (0.71-0.91). Preference items were also valid when evaluating concordance and discordance between convenience and satisfaction patch and capsule domain scores.

CONCLUSION

AD treatment puts a significant strain on caregivers. New modes of treatment delivery may be less burdensome to caregivers, thereby increasing satisfaction and potential treatment adherence. The ADCPQ was well accepted by AD caregivers and its domains demonstrated satisfactory psychometric properties. The ADCPQ is a useful tool to understand caregiver preferences for patch versus oral therapies in AD.

Microemulsions as carriers for drugs and nutraceuticals

Microemulsions are potentially excellent carriers for bioactive molecules. They offer the advantage of spontaneous formation, ease of manufacture, thermodynamic stability, and improved solubilization of bioactive materials. This review explores some of the new trends in microemulsion research through analysis of some representative studies. The solubilization of different classic drugs, peptides, and nutraceuticals in various oral microemulsion compositions and microstructures was reviewed. It was found that even W/O microemulsions, which are expected to break upon dilution in the digestive tract, increase the permeability and bioavailability of drugs. Thus, it seems that component selection (the use of molecules that can act as permeability enhancers) is of great importance. Structures such as self-microemulsifying drug delivery systems (SMEDDS), W/O, bicontinuous, and O/W microemulsions, were closely examined, and their potential to serve as drug carriers was evaluated. It seems that for microemulsion systems to be used as vehicles for bioactive materials, the formulations should be based on SMEEDS, which form O/W upon dilution to a specific water content. U-type microemulsions are actually an improved SMEDDS formulation, capable of being diluted with any given water concentration. Much research is being conducted on microemulsion microstructure since there is an obvious direct connection between the microstructure, solubilization capacity, and bioavailability of the active molecules.

Topical agents for the treatment of chronic pain

Unlike systemic analgesics, topical analgesics exert their analgesic activity locally and without significant systemic absorption. This is in contrast to transdermal analgesics, which require systemic absorption for clinical benefit. The mechanism of action of a particular topical analgesic is unique to the specific medication being used as a topical analgesic. Topical analgesics have been studied in an increasing number of painful clinical conditions, and the results of some of these studies are summarized in this article. The potential role of topical analgesics acting peripherally in affecting the central processing of pain as well as painful states considered to be "central," not "peripheral," also are reviewed.

Targeted peripheral analgesics therapy for neuropathic pain

The term targeted peripheral analgesics has been suggested to describe analgesics with a mechanism of action that appears to be primarily through reducing pain transmission within the peripheral nervous system. Key differences between targeted peripheral (topical) and systemic analgesics and the difference between topical and transdermal analgesics are discussed in this article. A review of the clinical conditions, which have been reported to respond to targeted peripheral analgesics, also is described in detail.

Topical treatments for pain

Topical analgesics exert their analgesic benefit locally and without significant systemic absorption. The mechanism of the topical analgesic is unique to the specific medication. Key differences between topical and transdermal analgesics are discussed in this article. A new term, targeted peripheral analgesics, has been suggested to replace the term topical analgesics, but is not in widespread use. Topical analgesics have been studied in an increasing number of painful clinical conditions; the results of many of these studies are summarized in this review. Recent data suggest that at least one topical analgesic, although applied peripherally, may result in central nervous system alterations of pain processing.

Targeted topical peripheral analgesics in the management of pain

The term "targeted peripheral analgesics" has been developed to describe analgesics whose mechanism of action appears to be primarily through reducing pain transmission within the peripheral nervous system. Key differences between targeted peripheral and systemic analgesics and the difference between topical and transdermal analgesics are discussed. A review of the clinical conditions that have reportedly responded to targeted peripheral analgesics is described in detail in this article.

A review of the use of topical analgesics for myofascial pain

Numerous treatment strategies for myofascial pain syndrome are available, including physical therapy, behavioral pain management techniques, acupuncture, various types of injections, and the use of various pharmacotherapeutic approaches. The use of topical analgesics for myofascial pain syndrome is the focus of this review. The use of topical analgesics in other painful states is also reviewed.

Oral versus topical NSAIDs in rheumatic diseases: a comparison

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed drugs worldwide and are responsible for approximately one-quarter of all adverse drug reaction reports. NSAIDs are widely prescribed for patients with rheumatic disease--a population at increased risk for serious gastrointestinal (GI) complications. Topical administration of NSAIDs offers the advantage of local, enhanced drug delivery to affected tissues with a reduced incidence of systemic adverse effects, such as peptic ulcer disease and GI haemorrhage. NSAIDs administered topically penetrate slowly and in small quantities into the systemic circulation; bioavailability and maximal plasma NSAID concentration after topical application are generally less than 5 and 15%, respectively, compared with equivalent oral administration. Product formulation may have a dramatic impact, not only on absorption rates but also on penetration depth. Compared with oral administration, topical application leads to relatively high NSAID concentrations in the dermis. Concentrations achieved in the muscle tissue below the site of application are variable, but are at least equivalent to that obtained with oral administration. NSAIDs applied topically do reach the synovial fluid, but the extent and mechanism (topical penetration versus distribution via the systemic circulation) remain to be determined. In addition, marked interindividual variability was noted in all studies; percutaneous absorption may be strongly influenced by individual skin properties. In general, interpretation of clinical studies measuring efficacy of topical NSAIDs in rheumatic disease states is difficult because of a remarkably high placebo response rate, use of rescue paracetamol (acetaminophen), and significant variability in percutaneous absorption and response rates between patients. Overall efficacy rates attributable to topical NSAIDs in patients with rheumatic disorders ranged from 18 to 92% of treated patients. Topically applied NSAIDs have a superior safety profile to oral formulations. Adverse effects secondary to topical NSAID application occur in approximately 10 to 15% of patients and are primarily cutaneous in nature (rash and pruritus at site of application). GI adverse drug reactions are rare with topically applied NSAIDs, compared with a 15% incidence reported for oral NSAIDs. Available clinical studies suggest, but do not document, equivalent efficacy of topical over oral NSAIDs in rheumatic diseases.

Topical agents in the treatment of rheumatic disorders

Topical drug delivery may be the optimal route for the treatment of localized musculoskeletal disorders because higher drug concentrations can be achieved at the sites of clinical significance. The rationale for the use of topical salicylates and other nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of soft-tissue rheumatic complaints and osteoarthritis is reviewed. Topical capsaicin offers another potentially beneficial therapy for the treatment of osteoarthritis of selected joints. Although there are extensive, uncontrolled experiences with DMSO that suggests its effectiveness in the treatment of musculoskeletal disorders, controlled trials yield conflicting results. The basis for the use of physical modalities such as phonophoresis and iontophoresis to improve topical drug efficacy is summarized.