salicylates and diethylamine-salicylate

The aim of this confirmative, monocentre, double-blind, controlled clinical trial was to investigate whether different escin combinations show differences in comparison to placebo with regard to pain reactions in the topical treatment of sports injuries. A total of 126 patients with blunt injuries of the extremities were randomly allocated to four parallel groups: Reparil-Gel N (n = 32), Reparil-Gel (n = 31), Reparil-Sportgel (n = 32) and a placebo gel (n = 31). All patients were evaluated for efficacy (intention to treat) and tolerability. A per-protocol analysis was also carried out, in which 12 of the 126 patients were excluded due to protocol violations. The intention-to-treat and per-protocol analyses produced similar results. The patients had suffered contusions while participating in soccer, hockey, karate, tae-kwon-do, handball, American football, rugby or tennis. The measured variable was the pressure required at the centre of the lesion to elicit the first pain reaction (tenderness reaction) at measuring time 0 (baseline) and then 1, 2, 3, 4, 6 and 24 h after the injury. The primary variable was the area under the curve (AUC) for tenderness over a six-hour period. The mean AUC differed significantly in the four groups (Kruskal-Wallis test p = 0.0001). Then six pairwise comparisons of two treatment groups each were carried out using the Mann-Whitney test. To control the multiple significance level of 5%, the adjusted p-values according to the Holm-Shaffer method were used in these tests. The three active gels were significantly superior to the placebo gel (Mann-Whitney test, p = 0.0004 in each case) in terms of the AUC. There were no significant differences between the active test substances in terms of the primary variable. The intensity of the pain was also measured on a visual analogue scale (VAS). The pain diminished more rapidly with the Reparil gels than with the placebo. The tolerability of all test substances was good. No adverse events were observed in any of the 126 patients. Escin combination gels are more effective than a placebo and are also well tolerated. Therefore, they can be recommended for the treatment of blunt injuries caused during sports and leisure activities.

Topics: Administration, Topical; Adult; Anti-Inflammatory Agents, Non-Steroidal; Area Under Curve; Arm Injuries; Athletic Injuries; Double-Blind Method; Drug Combinations; Escin; Female; Gels; Humans; Leg Injuries; Male; Pain; Pain Measurement; Patient Satisfaction; Salicylates; Wounds, Nonpenetrating

The purpose was to investigate the in vivo skin penetration of four 14C-salicylic compounds using microdialysis and to relate dermal concentrations to structural features. Furthermore, to compare two in vivo retrodialysis recovery methods for estimation of true unbound extracellular concentrations. Microdialysis probes were inserted in the dermis of hairless rats. Equimolal 14C-salicylic formulations were applied topically and dialysate sampled consecutively for 4h. True extracellular concentrations were estimated by retrodialysis by drug method (the 14C-salicylic compounds themselves) and by retrodialysis by calibrator method (3H-salicylic acid as internal standard). Probe depth was measured by ultrasound scanning. High dermal concentrations were found after application of 14C-salicylamide (low protein-binding) and the lipophilic ester 14C-butyl salicylate, which was completely hydrolysed to 14C-salicylic acid during skin diffusion. Protein binding and dissociation may explain the lower dermal concentrations of 14C-salicylic acid and 14C-diethylamine salicylate, respectively. Probe depth did not significantly influence dialysate concentrations. The two in vivo recovery correction methods did not reduce the variation in concentration-time curves. In conclusion, differentiated penetration kinetics was found ranking: 14C-salicylamide >/= 14C-butyl salicylate > 14C-salicylic acid > 14C-diethylamine salicylate. Dermal concentrations were related to structural features of the model compounds. The two correction methods performed alike; however, the calibrator method has the advantage of serving as a quality control during experiments.

Topics: Administration, Cutaneous; Animals; Female; In Vitro Techniques; Microdialysis; Models, Biological; Permeability; Rats; Rats, Sprague-Dawley; Salicylamides; Salicylates; Skin; Skin Absorption; Time Factors

There is a strong need for antipruritic substances for treating itch in clinical dermatology. In one recent human study, topically applied acetylsalicylic acid has been described to rapidly decrease histamine-induced itch. We have established a model for periferally elicited pruritus by injecting serotonin into the rostral back area (neck) in rats. Using this model, we aimed to investigate the antipruritic potential of four different salicylic compounds, which all possess different skin penetration characteristics. Eighteen rats were studied for 6 weeks. Prior to serotonin injections (2 mg/ml, 50 micro l), 10 micro l of test substances was applied to a circular area 18 mm in diameter. The four substances were salicylic acid, butyl salicylate, diethylamine salicylate and salicylamide, all solubilized in dimethyl isosorbide to a concentration of 5% w/w. Diethylamine salicylate and salicylamide were previously shown to be slowly absorbed through rat skin in contrast to salicylic acid and butyl salicylate. After serotonin injections, scratching was monitored by video recording for 1.5 h. Compared with the vehicle, a lower number of scratch sequences were seen when diethylamine salicylate (P < 0.001) and salicylamide (P = 0.005) had been applied. The numbers of scratch sequences were lower with diethylamine salicylate and salicylamide than with the vehicle throughout the 1.5-h study period. We conclude that topical application of diethylamine salicylate and salicylamide could suppress serotonin-induced scratching in rats. The antipruritic effect seems to be related to the slow drug release of the two substances. The results may be clinically relevant as serotonin induces itch in humans.

Topics: Administration, Topical; Animals; Antipruritics; Female; Pruritus; Rats; Rats, Mutant Strains; Salicylamides; Salicylates; Salicylic Acid; Serotonin

Topics: Administration, Topical; Anti-Inflammatory Agents; Double-Blind Method; Drug Combinations; Female; Humans; Male; Middle Aged; Pain; Placebos; Rheumatic Diseases; Salicylates; Terpenes

Topics: Permeability; Salicylates; Skin Absorption; Surface-Active Agents

Topics: Dairy Products; Musculoskeletal Pain; Rheumatic Diseases; Salicylates