sildenafil-citrate and andrographolide

Novel sample preparation approaches for HPLC bioanalysis based on the phenomenon that acetonitrile can be separated from water by adding salts or cooling at subzero temperatures have been reported. These two methods are superior to conventional liquid-liquid extraction since the separated acetonitrile phase can be directly injected to the RP-LC system. However, the salting-out method suffers from a potential problem that the remained salt in the acetonitrile phase may harm the MS detector, while the subzero-temperature method is troublesome to operate. Here, we have reported a similar phase separation phenomenon that the acetonitrile aqueous mixture can be separated by adding a hydrophobic solvent; and capitalising on this phase transition phenomenon, we have proposed an alternative approach, named solvent induced phase transition extraction (SIPTE), to extract drug from plasma for HPLC-MS analysis. The proposed SIPTE method is much simpler and avoids contaminating the MS detector. Three structurally diverse drugs were selected as test compounds to design the SIPTE method and to validate the efficiency of this method. The four goals of plasma sample pretreatment for HPLC-MS analysis, i.e. removal of proteins, removal of other low-molecular interferences, preconcentration of the analytes of interest, and matching the sample solvent with the HPLC-MS system, can be rapidly performed in a very simple step by using the SIPTE method.

Topics: Acetonitriles; Chemical Fractionation; Chloroform; Chromatography, High Pressure Liquid; Diterpenes; Finasteride; Humans; Hydrophobic and Hydrophilic Interactions; Mass Spectrometry; Models, Molecular; Pharmaceutical Preparations; Piperazines; Purines; Reproducibility of Results; Sensitivity and Specificity; Sildenafil Citrate; Sulfones

In this study, effects of andrographolide from Andrographis paniculata on sexual functions, vascular reactivity and serum testosterone level in experimental animals were observed. The suspension of andrographolide in 5% DMSO was administered orally at the dose of 50mg/kg to male ICR mice. The female mice involved in mating were made receptive by hormonal treatment. The mating behaviors, mounting latency and mounting frequency, were determined and compared with the standard reference drug sildenafil citrate. Administration of andrographolide significantly decreased the mounting latency at 120 and 180 min and increased mounting frequency at 180 min after treatment. In endothelium-intact rat aortic strips, norepineprine-induced contraction was reduced by preincubation with andrographolide. Administration of 50mg/kg andrographolide orally to male mice once daily for 2, 4, 6 or 8 weeks had no significant effects on sperm morphology and motility. Interestingly, at week 4, serum testosterone level in mice treated with andrographolide was significantly increased when compared to the control. Thus, the effects of andrographolide on vascular response to norepinephrine and testosterone level observed in this study might be contributed to the sexual enhancing properties observed.

Topics: Animals; Aorta, Thoracic; Blood Vessels; Diterpenes; Female; In Vitro Techniques; Male; Mice; Mice, Inbred ICR; Muscle Contraction; Muscle, Smooth, Vascular; Piperazines; Purines; Rats; Rats, Sprague-Dawley; Sexual Behavior, Animal; Sildenafil Citrate; Sperm Count; Sperm Motility; Sulfones; Testosterone; Vasodilator Agents