No abstract

The pharmacokinetics and bioavailability of glyceryl trinitrate (GTN, CAS 55-63-0) and of its main metabolites, i.e. 1,2-glyceryl dinitrate (1,2-GDN, CAS 621-65-8) and 1,3-glyceryl dinitrate (1,3-GDN, CAS 623-87-0), were compared during a single 24-h application of a new GTN transdermal patch (Epinitril 10, hereinafter called EPI-10) or a reference patch (hereinafter called ND-10) releasing 10 mg GTN in 24 h. The study was an open, randomized balanced cross-over study on 24 healthy male volunteers to whom the patches were applied to the antero-lateral part of the thorax in two periods separated by a 3-day wash-out. Blood samples were collected before administration, during the 24-h patch application and at 0.5, 2 and 3 h after patch removal. Assayed in plasma were GTN, 1,2-GDN and 1,3-GDN using validated GC/MS methods with stable isotope-labeled internal standards (15N3-GTN, 15N2-1,2-GDN, and 15N2-1,3-GDN). The ratios of the AUCs of GTN, 1,2-GDN and 1,3-GDN measured during application of EPI-10 or of ND-10 were within the 0.85-1.25 limits required to assess equivalence of the extent of bioavailability. The ratios of the Cmax were within said limits for the signal metabolite 1,2-GDN and only slightly below (0.78-1.16) for the parent GTN. EPI-10 can therefore be considered equivalent to ND-10 also with regard to the rate of bioavailability. Under both patches GTN reached steady-state levels after 3-6 h of patch application and remained on sustained levels during the whole 24-h application. The plasma levels of 1,2-GDN were about 6 times higher than those of GTN. The plasma levels of 1,3-GDN were similar to those of GTN. Upon removal of the patches the concentrations of the three nitrates fell to negligible values within 3 h. Both patches were well tolerated at the application site. For its small size, thinness and transparency, EPI-10 is very patient friendly, a quality that improves compliance with the therapeutic regimen.

Dehydroepiandrosterone (DHEA) and its sulfate conjugate (DHEAS) are the major secretory steroidal products of the adrenal gland. Some epidemiologic studies have found an association between low DHEA serum levels in patients and many important diseases. To prevent all such pathological conditions and, in any case, in aging, a DHEA supplementation has been proposed. DHEA shows a low oral bioavailability; taking the bioavailability obtained by the subcutaneous route as 100%, it was estimated that the potencies of DHEA by the percutaneous and oral routes were approximately 33% and 3%, respectively. Thus, transdermal patches could be considered a promising formulation as a continuous and controlled delivery of DHEA in replacement therapy is desired. With the aim of evaluating the effect of the matrix composition in terms of polymers and enhancers on the DHEA skin permeation flux, 10 types of monolayer self-adhesive patches containing 0.25mg/cm2 of active ingredient were designed. The matrices were based on three different acrylic copolymers: an acrylate-vinylacetate copolymer, a polyaminomethylmethacrylate (PAMA), and a polymethylmethacrylate. Transcutol (TR), mint essential oil, Lauroglycol, Brij 58, and propylene glycol (PG) were evaluated as DHEA skin permeation enhancers. All prepared patches were characterized by drug content, light microscopy, and in vitro skin permeation, performed using a modified Franz-type diffusion cell and human stratum corneum and epidermis as a membrane. The in vitro skin permeation studies are particularly significant in the development studies of DHEA patches as the in vivo determination of DHEA is affected b the fact that the endogen substance in the plasma is not constant over time. Among the testedpatches, highest DHEA fluxes were obtained using the formulation based on PAMA. Moreover, the introduction in the matrix of binary mixtures of TR and PG, used also for their plasticizer properties, permitted enhancing DHEA skin permeation. On the basis of these studies, the transdermal administration of DHEA using patches seems feasible.

The pharmacokinetic characteristics and the bioavailability of glyceryl trinitrate (GTN, CAS 55-63-0) and of its main metabolities 1,2-glyceryl dinitrate (1,2-GDN, CAS 621-65-8) and 1,3-glyceryl dinitrate (1,3-GDN, CAS 623-87-0) during a single 24-h application of three strengths of a newly developed GTN transdermal patch (Epinitril) were investigated. The three strengths coded in this paper EPI-5, EPI-10 and EPI-15 have a nominal release rate of GTN of 5, 10 and 15 mg, respectively, in 24 h. The study was an open, randomized balanced cross-over study on 18 healthy male volunteers, to whom the patches were applied for 24 h to the antero-lateral part of the thorax in three periods, separated by an at least 3-day wash-out. Blood samples were collected before administration, during the 24-h patch application and 1, 3 and 6 h after patch removal. Assayed in plasma were GTN, 1,2-GDN and 1,3-GDN using validated GC/MS methods with stable isotope labeled internal standards (15N3-GTN, 15N2-1,2-GDN, and 15N2-1,3-GDN). GTN and its two metabolites reached the plateau already 3 h after application of the patches and remained on extended and fairly constant levels during the whole 24-h application. The plasma levels of the three nitrates were proportional to the strengths of the patches. The plasma levels of 1,2-GDN were about 6 times higher than those of GTN. The plasma levels of 1,3-GDN were similar to those of GTN. Upon removal of the patches the concentrations of the three nitrates fell to negligible values within 3 h, an important property when an intermittent GTN therapy is needed in order to avoid tolerance to the drug. The patches were well tolerated at the application site. For their good tolerability, small size and transparency, the new GTN patches are very patient friendly, a quality that improves compliance with the therapeutic regimen.

In a prospective, randomized, double-blind therapeutic trial, 191 patients with non-alcoholic steatohepatitis were treated for 8 weeks daily b.i.d. orally either with betaine glucuronate combined with diethanolamine glucuronate and nicotinamide ascorbate (Ietepar) (96 patients) or with undistinguishable placebo capsules (95 patients). The verum treatment effectively reduced by 25% hepatic steatosis (p < 0.01) and by 6% hepatomegaly (p < 0.05), while placebo did not significantly reduce the disorders. Verum was also more effective than placebo on discomfort in abdominal upper right quadrant. The global efficacy of treatment was rated by the doctor "very good" or "good" in 48% of verum treated patients and only in 17% after placcbo (P of difference = 9 x 10(-6)). 52% of patients self-rated efficacy as "very good" or "good" after verum and only 34% after placebo (P of difference = 0.017). The verum treatment provoked a significant reduction of the increased liver transaminases (ALT, AST and gamma-GT) while placebo was ineffective. Adverse events were recorded in 10% of verum-treated patients and in 7% under placebo (no significant difference). In both groups the adverse events were mild and transient, did not require treatment discontinuation and were undistinguishable from common symptoms of liver disorders. In conclusion, the 8-week treatment with betaine glucuronate combined with diethanolamine glucuronate and nicotinamide ascorbate was found effective in non-alcoholic steatohepatitis, a disorder for which the hitherto pharmacological interventions were poorly and inconsistently effective.