The extracts of Piper sarmentosum, a medicinal plant, are being used to prepare phytopharmaceuticals while the information about chemical kinetics of constituents of the extract is unavailable to assign precise shelf life (t90) and find optimum storage conditions of the product for patient safety, and to avoid economic repercussions of launching an unstable product. The extract was exposed to three different conditions of high temperature and relative humidity (RH) for six months. The samples were then analyzed at 0, 1, 2, 4 and 6 months by high performance liquid chromatography (HPLC) using pellitorine, sarmentine and sarmentosine as markers. Different chemical kinetic parameters of the markers were evaluated by Arrhenius equation to predict shelf life (t90) at different storage conditions and at room temperature. The markers in the extract followed the zero order degradation, and the activation energy, pre exponential factor and rate constant of the reaction of the markers were found to be varying in samples stored at different conditions. The contents of the markers were found to be decreasing at high temperature and humidity with the passage of time. The predicted shelf life (t90) of the markers at room temperature was found to be 16 months approximately. Results of this study indicate that extracts of the plant are stable at room temperature for 16 months. Moreover, the chemical kinetic data of the markers and the analytical method used to quantify the markers may be useful for phytopharmaceutical industry to produce efficacious and stable products from extracts of the plant.
Few studies have explored diagnosis delay by tuberculosis (TB) patients and its effects on the rate of infection among their close contacts. A cross-sectional study of the close contacts of 505 newly diagnosed TB patients was conducted in a TB referral centre in Sana'a, Yemen from 2008 to 2010. Only the close contacts of 89 new TB patients agreed to participate and completed the tuberculin skin test (TST). Of the 239 close contacts investigated, 133 (55.6%) had a positive TST result. Index patients were classified as long or short diagnosis delay (above or below the median). There was no significant difference in the number of infected close contacts between long and short delay index patients (Mann-Whitney U-test). A larger sample size, with more incentives for patients to participate and the use of other investigative tools could provide a better picture of the pattern of TB transmission among all contacts.