Pharmacokinetics of the transdermal delivery of benfotiamine.

AIMS: Accumulation of advanced glycation endpoints is a trigger to the development of diabetic peripheral neuropathy, which is a common complication of diabetes. Oral administration of benfotiamine (BFT) has shown some preclinical and clinical promise as a treatment for diabetic peripheral neuropathy. The purpose of this study was to evaluate the method of transdermal delivery of BFT as a possible, viable route of administration for the treatment of diabetic peripheral neuropathy. METHODS: A single application of 10 mg of BFT was given to guinea pigs topically. The levels of thiamine (T), thiamine monophosphate, thiamine diphosphate, S-benzoylthiamine and BFT were measured in the blood, skin and muscle at different time points within 24 h. RESULTS: At the 24-h time point, following the single BFT dose, the T level was increased 10× in the blood, more than 7× in the skin and almost 4× in the muscle compared to the untreated animals. The total T content (total) was increased 7× in the blood, 17× in the skin and 3× in the muscle compared to the untreated animals. CONCLUSIONS: This strong increase in the tissue levels of T and the associated metabolic derivatives levels found in the blood and local tissues following a single dose indicate that topically applied BFT may be a viable and advantageous delivery method for the treatment of diabetic peripheral neuropathy.

Randomized clinical trial evaluating transdermal Ibuprofen for moderate to severe knee osteoarthritis.

BACKGROUND: Osteoarthritis is a common condition, typically treated with orally administered analgesics and non-steroidal anti-inflammatory drugs (NSAIDs). Chronic administration of NSAIDs, serotonin-norepinephrine reuptake inhibitors (SNRIs, i.e., duloxetine), and opioid medications (i.e., tramadol) is regularly associated with multiple, serious side effects, in part due to the route of administration. Transdermal delivery of NSAIDs, such as ibuprofen, represents a potentially alternative treatment for this inflammatory pain condition with a better therapeutic profile. OBJECTIVE: Investigate the safety and efficacy of a novel transdermal ibuprofen formulation (VALE®-ibuprofen) containing 10% ibuprofen, compared to a placebo in a randomized, double-blinded clinical trial, for clinical improvement in patients with moderate to severe painful osteoarthritis of the knee. STUDY DESIGN: A randomized, placebo-controlled, double blind, multi-center Phase 2 clinical trial. SETTING: An academic medical center, and private rheumatology and interventional pain management practices. METHODS: The Phase 2 clinical study included patients with primary osteoarthritis in a single knee joint with a progression level of moderate to severe based in part on a grade II or III designation according to the Kellgren and Lawrence classification system. Patients received the corresponding, randomly assigned study formulation (VALE-ibuprofen or placebo) for application to the target knee at a dose of 2.0 grams of drug product (200 mg ibuprofen) twice daily for 14 days. The evaluation of the efficacy of the treatments utilized the widely accepted methods of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index and the Visual Analog Scale (VAS) scores for the patients. RESULTS: The results indicate that the transdermal VALE-ibuprofen formulation was very well tolerated from a safety perspective during the 2-week trial and also produced significant, positive clinical improvements superior to the placebo in all clinical endpoints tested. In particular, the WOMACTotal and WOMACPhysical Functioning, for the VALE-ibuprofen, were superior compared to the placebo (P = 0.0283 and P = 0.0201, respectively). Other clinical endpoints including the WOMACPain, WOMACStiffness, and VASResting scores were superior to those obtained from the placebo group, trending towards statistical significance compared to placebo (P = 0.0811, 0.1103, and 0.0785, respectively). Based on the Patient and Physician Global Impression of Change survey, patient satisfaction slightly improved across both groups; however, no statistical significance was detectable as compared to the baseline. LIMITATIONS: The sample size of 64 subjects in the final data analysis and the lack of including an orally administered drug group are limitations of this study. CONCLUSIONS: The use of transdermal VALE-ibuprofen has beneficial clinical effects on the pain levels experienced in some patients with moderate to severe osteoarthritis of the knee as measured by the WOMAC Osteoarthritis Indices for stiffness, pain, physical function, and total. Visual Analog Scales (VAS) tests, VASMotion and VASWeight-bearing, again while appeared superior to placebo, were not statistically different from placebo. CLINICAL TRIAL REGISTRATION: NCT01496326.

Vasomodulation influences on the transdermal delivery of Ibuprofen.

The purpose of the study was to evaluate the effect of adding peripheral vasodilators, tolazoline, or papaverine, to transdermal drug delivery vehicles with the goal of improving the tissue bioavailability of transdermally delivered ibuprofen. Ibuprofen (150 mg) formulations with several concentrations of two different vasodilators and/or a penetration enhancer (PE) complex were topically applied to rabbits. Plasma levels of ibuprofen were determined by a validated high-performance liquid chromatography method and evaluated at 0, 0.5, 1, 2, and 3 h. The PE complex enhanced the plasma ibuprofen level approximately sevenfold versus control, and tolazoline (0.005%) added to the PE complex increased the plasma levels of ibuprofen approximately another twofold compared with the PE. Higher concentrations of tolazoline paradoxically did not exhibit vasodilator enhancement to ibuprofen delivery. Papaverine was tested in the same manner. In this set of experiments, PE increased the plasma ibuprofen 3.7-fold versus control, and addition of papaverine (0.0005%) increased plasma ibuprofen an additional 3.3-fold compared with the PE formulation. Transdermal formulations of ibuprofen containing low concentrations of tolazoline or papaverine increased plasma ibuprofen levels in the presence of passive PE components.