Betulinic acid shows anticancer activity against equine melanoma cells and permeates isolated equine skin in vitro.

BACKGROUND: Equine malignant melanoma (EMM) is a frequently occurring dermoepidermal tumor in grey horses. Currently available therapies are either challenging or inefficient. Betulinic acid (BA), a naturally occurring triterpenoid, is a promising compound for cancer treatment. To evaluate the potential of BA as a topical therapy for EMM, its anticancer effects on primary equine melanoma cells and dermal fibroblasts and its percutaneous permeation through isolated equine skin were assessed in vitro. RESULTS: BA showed antiproliferative and cytotoxic effects on both primary equine melanoma cells and fibroblasts in a time- and dose-dependent manner. The lowest half-maximal inhibitory concentrations were obtained 96 h after the beginning of drug exposure (12.7 µmol/L and 23.6 µmol/L for melanoma cells eRGO1 and MelDuWi, respectively, in cytotoxicity assay). High concentrations of the compound were reached in the required skin layers in vitro. CONCLUSION: BA is a promising substance for topical EMM treatment. Further clinical studies in horses are necessary to assess safety and antitumoral effects in vivo.

Dapsone for topical use in extemporaneous preparations.

BACKGROUND: The sulfone dapsone has an established role in systemic therapy. Its pharmacological and toxicological properties are well known. Topically, dapsone is used in a gel formulation for the treatment of acne vulgaris. In addition, there have been individual case reports on the efficacy of topical dapsone preparations in the treatment of various neutrophilic dermatoses. To date, no finished medicinal product for topical use has been available in Germany. MATERIAL AND METHODS: Against this background, we set out to develop extemporaneous preparations containing dapsone (5 %) that meet the quality requirements of the European Pharmacopoeia as well as the manufacturing requirements of the German Ordinance on the Operation of Pharmacies (ApBetrO). These formulations included the incorporation of dapsone in a hydrophobic cream base ("hydrophobe Basiscreme DAC") as well as in methylprednisolone aceponate 0.1 % ointment (alternatively, in the latter's cream base without active ingredient). RESULTS: Tests aimed at investigating the physical, chemical, and microbiological stability of these formulations showed them to meet the aforementioned quality requirements. CONCLUSION: The extemporaneous formulations presented herein broaden the therapeutic options for topical treatment, in particular for patients with chronic inflammatory dermatoses associated with a neutrophilic pathogenesis.

Ex vivo Cutaneous Bioavailability of Topical Mometasone Furoate in an O/W Preparation.

Mometasone furoate (MMF) is a modern glucocorticoid of the 4th generation, which has been proven not only for inhalation but also for cutaneous treatment. Due to its lipophilic character, it is mainly used in ointments and creams with an outer lipophilic phase (W/O type). However, this study investigated the cutaneous cytotoxicology of MMF and tried to characterize its pharmacokinetic effects on the skin using an O/W preparation. An HPLC method has been developed and validated for the detection of MMF in cutaneous tissue, and concentration-time curves of MMF were created after cutaneous application on unaffected as well as lesional skin. Cytotoxicological characterization was carried out using scratch assays on keratinocytes and cutaneous fibroblasts. Results showed that the condition of the skin had no significant impact on the cutaneous bioavailability of MMF, but the intrinsic effect of the O/W vehicle could be utilized in periods of acute inflammation. Cytotoxicological data gave no new indications regarding the safety of MMF.

Methotrexate for topical application in an extemporaneous preparation.

BACKGROUND: The antifolate agent methotrexate is routinely used for systemic therapy of cancer and chronic inflammatory diseases. Successful topical use has been described for individual therapeutic attempts, in case series, and small studies, especially for mycosis fungoides (premycotic stage) and lymphomatoid papulosis. With respect to its clinical use in selected treatment scenarios, there have been no approved preparations or regulated instructions for pharmaceutical compounding. MATERIAL AND METHODS: Two high performance liquid chromatography methods were established for the determination of the active substance within a galenic formulation as well as within extracts of biological material. Suitable vehicles for epicutaneous application were developed and preclinically tested for stability, release, and pharmacokinetics of the active substance as well as their safety. RESULTS: The tests show that methotrexate may be readily incorporated into "Basiscreme DAC". It remains stable up to a concentration of 0.5%. This preparation releases enough active substance to achieve relevant local bioavailability in the respective target compartments of the skin. There is no evidence of safety risks due to relevant systemic bioavailability after topical application on a limited area of the skin. CONCLUSIONS: In summary, this approved prescription for extemporaneous preparation complies with the requirements of the German Ordinance on the Operation of Pharmacies (Article 7 ApBetrO), and the available data proves its stability and pharmaceutical quality.

Concentration-response studies and modelling of the pharmacodynamics of linezolid: Staphylococcus aureus versus Enterococcus faecium.

For assessing antibiotic effects, the minimum inhibitory concentration (MIC) neglects that most antibiotics display different rates of bacterial killing. Time-kill curves, on the other hand, provide details on these killing rates but their interpretation is more complex and hardly standardised. The aim of the present study was to develop an analysis method to easily compare the pharmacodynamics of linezolid (LZD) against Staphylococcus aureus and Enterococcus faecium via in vitro time-kill curve experiments and to describe it by mathematical modelling. The effect of LZD against both organisms was investigated in a static in vitro infection model using 0.5-32.0 µg/mL LZD over 24h. LZD concentrations were quantified by a validated HPLC assay. A modified sigmoidal maximum effect (Emax) pharmacokinetic/pharmacodynamic (PK/PD) model that accounts for time-dependent effects was developed in 'R'. As a continuous, growth-control-normalised pharmacodynamic measure, the relative bacterial reduction (RBR) was introduced and derived. LZD was more effective against S. aureus than against E. faecium (Emax 1.8-fold higher) at a comparable potency (EC50, 3.02 µg/mL vs. 1.80 µg/mL). The time delay of the maximum effect was predominantly observed within 6h of exposure. Model evaluation demonstrated its precision, robustness and predictive performance. In conclusion, the presented PK/PD analysis method provides quantitative measures (EC50, Emax) for the antibacterial drug effect as easy to interpret as point estimates, but more informative than the MIC since time- and concentration-dependent effects were considered. Application of the presented model developed as a flexible, robust tool in the free software 'R' appears promising.

Cutaneous drug delivery of capsaicin after in vitro administration of the 8% capsaicin dermal patch system.

OBJECTIVE: Epicutaneous application of capsaicin causes a long-lasting analgesic effect by binding to the membrane transient receptor potential vanilloid 1 (TRPV1) on mechanoheat-sensitive C and Aδ fibres, changing axonal integrity and inhibiting neurogenic inflammatory processes. To date, no information is available regarding the cutaneous drug delivery of capsaicin following patch application. METHODS: Using a Franz diffusion cell, the cutaneous concentration-time profiles 30, 60 and 90 min after application of a patch containing 8% capsaicin (640 µg/cm(2)) on ex vivo thin (mamma) and thick (plantar) human skin were investigated at 32 °C, and additionally at 42 °C for thin skin and 10 °C for thick skin. An HPLC-MS method was used for the analytic detection of capsaicin. RESULTS: The results show that already after a 30-min application of the 8% capsaicin patch, an equilibrium reservoir can be found in the stratum corneum in both thick and thin skin. Under physiological temperature conditions, a sufficient bioavailability of capsaicin in the cutaneous target compartments can be found. Raising the temperature to 42 °C has no relevant impact on the concentration-time profile, while reducing the temperature to 10°C leads to a significantly lower bioavailability. CONCLUSION: After 30 min of application, a sufficient cutaneous bioavailability of capsaicin is reached in thick as well as thin skin. Whether shorter application times may suffice to achieve therapeutic effectiveness requires further investigation.

Glycoprotein IIb/IIIa receptor antagonists and risk of bleeding: a single-center experience in 1020 patients.

The safety of glycoprotein (GP) IIb/IIIa inhibitors has been well documented in clinical trials. Although these trials have included a broad patient population, the strict enrollment criteria may have resulted in exclusion of patients at a higher risk of bleeding complications. The authors conducted a retrospective chart review of 1020 consecutive patients who received GP IIb/IIIa inhibitors and underwent percutaneous coronary intervention in a large community hospital. They used Thrombolysis in Myocardial Infarction (TIMI) criteria to define major or minor bleeding complications. Bleeding complications developed in 214 (21%) patients, with major bleeding in 89 (9%). Univariate predictors of bleeding were older age, lower body weight, elevated serum creatinine, higher activated partial thromboplastin time (aPTT) level, history of diabetes mellitus (DM), peripheral vascular disease (PVD), congestive heart failure (CHF), and emergency procedure for acute myocardial infarction (AMI). Multivariate predictors of major bleeding were PVD (20% in bleeding group vs 11% in nonbleeders, odds ratio [OR] = 1.8, 95% confidence interval [CI] = 1.2-2.6, P < .004), age (68 +/- 2 years, 95% CI = 66-70 in bleeding group vs 63 +/- 13 years, 95% CI = 61.2-63 in nonbleeders, P < .001), and higher aPTT level (66 +/- 27 seconds, 95% CI = 63-70 in bleeding group vs 53 +/- 28 seconds, 95% CI = 51-56 in nonbleeders, P < .001). The risk of bleeding in the large community hospital setting may be higher than in randomized clinical trials. This increased risk is associated with higher hospitalization costs. Recognition of predictors of bleeding should further enhance the safety of these antiplatelet agents.