RESUMEN
Shelf life determination of herbal medicines is of paramount importance as it relates to activity of constituents of theproduct. This work sought to determine shelf life of four herbal products (Nibima, Asena, Lippia tea, and NPK 500capsules). The method involved the determination of marker content of products (three batches each) at time points(0, 3, 6, 9, 12, and 18 months) at storage temperature and humidity of 30°C ± 2°C/70% RH ± 5% RH using highperformance liquid chromatography (HPLC) analyses. Batch blending was employed for preparation of referencesamples of products. In UV analyses, λmax of 289, 291, 327, and 289 nm were obtained from spectra for (Nibima,Asena, Lippia tea, and NPK 500 capsules, respectively. A common 230 nm UV marker was observed for all theproducts. Optimized HPLC conditions were developed for products using methanol: water: 0.1%v/v acetic acidsystem with mobile phase ratios of 9:0:1 (Nibima), 7:2:1 (Asena), 8:1:1 (Lippia tea), and 90:5:5 (NPK 500 capsules).Wavelength of detection used for HPLC analyses were 283, 290, 332, and 290 nm for Nibima, Asena, Lippia tea, andNPK 500 capsules, respectively. HPLC marker content analyses with time produced shelf life of 23.14, 21.16, 62.97and 32.91 months for Nibima, Asena, Lippia tea, and NPK 500 capsules, respectively. Obtained shelf life indicatesrelative stability of products.