Search

With the growing availability of mature systems and strategies in biotechnology and the continuously expanding knowledge of cellular processes and involved biomolecules, human sports drug testing has become a considerably complex field in the arena of analytical chemistry. Proving the exogenous origin of peptidic drugs and respective analogs at lowest concentration levels in biological specimens (commonly blood, serum and urine) of rather limited volume is required to pursue an action against cheating athletes. Therefore, approaches employing chromatographic-mass spectrometric, electrophoretic, immunological and combined test methods have been required and developed. These allow detecting the misuse of peptidic compounds of lower (such as growth hormone-releasing peptides, ARA-290, TB-500, AOD-9604, CJC-1295, desmopressin, luteinizing hormone-releasing hormones, synacthen, etc.), intermediate (e.g., insulins, IGF-1 and analogs, 'full-length' mechano growth factor, growth hormone, chorionic gonadotropin, erythropoietin, etc.) and higher (e.g., stamulumab) molecular mass with desired specificity and sensitivity. A gap between the technically possible detection and the day-to-day analytical practice, however, still needs to be closed.

Candesartan is a long-acting and selective nonpeptide AT1 subtype angiotensin II receptor antagonist. The aim of this study was to compare the pharmacokinetics and to evaluate the bioequivalence of two candesartan cilexetil 16 mg formulations. Forty healthy volunteers were randomly assigned into two groups. After a single dose of 16 mg candesartan cilexetil oral administration, blood samples were collected at specific time intervals from 0-36 h. The plasma concentrations of candesartan cilexetil were determined by LC-MS/MS. The pharmacokinetic parameters such as AUC(last), AUC(inf) and C(max) were calculated and the 90% confidence intervals of the ratio (test/reference) pharmacokinetic parameters were obtained by analysis of variance on logarithmically transformed data. The mean for AUC(last) in the reference and the test drug were 1530.1 ± 434.6 and 1315.7 ± 368.6 ng·h/mL. The mean for AUC(inf) in the reference and the test drug were 1670.0 ± 454.5 and 1441.2 ± 397.8 ng·h/mL. The mean value for C(max) in the reference and the test drug was 142.6 ± 41.0 and 134.9 ± 41.4 ng/mL. The 90% confidence intervals for the AUC(last), AUC(inf) and C(max) were in the range of log 0.81-log 0.91, log 0.81-log 0.91 and log 0.88-log1.01, respectively. No adverse events were reported by subjects or found on analysis of vital signs or laboratory tests. This single dose study found that the test and reference products met the regulatory criteria for bioequivalence in these health volunteers. Both formulations were safe and well tolerated in 16 mg of candesartan cilexetil hydrochloride.

Background: The ethyl ester of captopril has been shown to exhibit enhanced permeation across human skin compared to the parent drug. A drug-in-adhesive patch formulation of a captopril ethyl ester was therefore developed for optimum drug release., Method: A wide range of transdermal patches were prepared using two commercially available bioadhesive polymers. Investigational screening was conducted on the patches using microscopy, texture profile analysis, and infrared spectroscopy. Drug release profiles of suitable patches were obtained using both polydimethylsiloxane (Silastic) and porcine skin in vitro., Results: Diffusion results across Silastic showed a gradual plateau in flux with increased drug loading that may be attributable to intramolecular interactions while flux across porcine skin was seen to increase with increasing patch thickness and attained a therapeutic level., Conclusions: This study demonstrated that adhesion and drug loading are significant factors in optimizing a topical patch formulation for the delivery of a captopril prodrug.

CS-8958, a prodrug of laninamivir (R-125489), is currently under development as an inhaled anti-influenza drug. In this study, the pharmacokinetics and disposition of CS-8958 were characterized in rats. After intratracheal administration of 14C-CS-8958, radioactivity was retained over long periods in the target tissues (trachea and lung) as its active metabolite R-125489 - 19.12% of the dose was retained in the lung at 24 h. After intratracheal administration of CS-8958, plasma R-125489 concentration was slowly eliminated, and its half-life (14.1 h) was considerably longer than that after intravenous administration of R-125489. The radioactivity of intratracheally administered 14C-CS-8958 was mainly excreted into the urine (67.5% of dose), and this excretion lasted over long periods. R-125489 accounted for most of the urinary radioactivity recovered after 24 h. These results demonstrated that CS-8958 administered intratracheally to rats was converted/hydrolysed to R-125489 in the target tissues, and that the R-125489 was slowly excreted into the urine via an absorption rate-limiting process. Such distinctive pharmacokinetics attributed to the slow release of R-125489 suggests the potential for a long-acting anti-influenza drug.