3,4,7-Trimethylcoumarin from Trigonella foenum-graecum stems

A trimethylcoumarin has been isolated, for the first time from the stem of Trigonelia foenum-graecum along with some known compounds. Based upon spectral and analytical data and comparison with a synthetic sample, it has been assigned the structure 3, 4, 7-trimethylcoumarin.     

Evaluating Current Practices in Shelf Life Estimation

The current International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) methods for determining the supported shelf life of a drug product, described in ICH guidance documents Q1A and Q1E, are evaluated in this paper. To support this evaluation, an industry data set is used which is comprised of 26 individual stability batches of a common drug product where most batches are measured over a 24 month storage period. Using randomly sampled sets of 3 or 6 batches from the industry data set, the current ICH methods are assessed from three perspectives. First, the distributional properties of the supported shelf lives are summarized and compared to the distributional properties of the true shelf lives associated with the industry data set, assuming the industry data set represents a finite population of drug product batches for discussion purposes. Second, the results of the ICH “poolability” tests for model selection are summarized and the separate shelf life distributions from the possible alternative models are compared. Finally, the ICH methods are evaluated in terms of their ability to manage risk. Shelf life estimates that are too long result in an unacceptable percentage of nonconforming batches at expiry while those that are too short put the manufacturer at risk of possibly having to prematurely discard safe and efficacious drug product. Based on the analysis of the industry data set, the ICH-recommended approach did not produce supported shelf lives that effectively managed risk. Alternative approaches are required.     

Sex-linked differences in phenol oxidase in the fairy shrimp Streptocephalus dichotomus Baird and their possible role (Crustacea: Anostraca)

Phenol oxidase activity in the hemolymph of male Streptocephalus dichotomus is only 1/3rd of that of females. About 70% of this activity resides in cell lysate and 30% in plasma. Electrophoretic analysis revealed that male plasma has a single fraction of tyrosine hydroxylase, evidenced by positivity towards tyrosine methylester-PMS-NBT. Female hemolymph has as many as three isozymes showing diphenoloxidase activity. The significance of these results is discussed with reference to sex-linked enzyme activity and its possible role in longevity. This revised version was published online in July 2006 with corrections to the Cover Date.