Determination of LCt50 of aerosolized paraquat and its pulmonary toxic implications in non-anesthetized rats.

Paraquat (PQ), a highly popular agricultural herbicide, is a serious occupational hazard with lethality reported at doses as low as 35 mg/kg body weight with intoxication occurring via inhalation or dermal route. The main objective of this study was to determine the median lethal concentration (LCt50) of paraquat through whole body exposure in adult male Wistar rats. Aerosolized PQ dissolved in water was delivered in a dose-dependent manner, to fully conscious rats confined in whole body plethysmograph (WBP), in a nebulized form with concentrations ranging from 40-200 mg/kg of air over a 4 h exposure period. Animals were observed up to 24-48 h post-exposure to observe any lethality. LCt50 estimates (±95% confidence interval) were obtained from the sequential stage-wise experiments using probit analysis. Rat lungs were examined radiologically and histopathologically. Gas chromatography-mass spectrometry (GC-MS) analysis determined the correlation of PQ accumulation in the lungs with the actual exposed dose of PQ. The actual LCt50 was found to be 218 g·min/m3 whereas 57.9 ± 2.90 µg/g of PQ accumulated in the lungs of each lifeless animal. All animals exhibited severe respiratory changes and pulmonary abnormalities. This study demonstrated that when compared with the actually exposed dose, the amount of PQ that accumulated in the lungs was very low, but enough to cause death in 50% of animal population and cause pulmonary abnormalities in each of the experimental animal. The PQ exposure carried out in WBP also facilitated the dermal absorption of aerosolized PQ, which replicated the real-life situation in workers operating with PQ.

Formulation development and accelerated stability testing of a novel sunscreen cream for ultraviolet radiation protection in high altitude areas.

The present study is aimed at the development of a sunscreen cream for use in high altitude areas which have been found to possess superior sun protection factor (SPF) along with remarkable antioxidant activity. The topical formulation is a standard oil-in-water emulsion of a combination of United States Food and Drug Administration (US FDA) approved ultraviolet filters; along with melatonin and pumpkin seed oil. The in-silico optimized formulation was characterized using established methods and the stability study was carried out as per International Conference on Harmonization guidelines. The formulation was prepared after requisite pre-formulation analysis by Fourier-transform infrared spectroscopy, differential scanning calorimetric and thermogravimetric analyses; followed by characterization based on color, odor, phase separation, spreadability, specific gravity, homogeneicity, centrifugation and sensitivity. For the stability study, a total of three samples from three batches of the finished product were subjected to the stability study. The samples were analyzed for content uniformity, pH, in vitro SPF, rheology, zeta potential, droplet diameter and microbial analysis of the 0th day and also the the end of the storage period. Results obtained from the stability study indicated that the formulation possesses 50+ in vitro SPF value and remained stable for 6 months and 12 months under storage at 40 ± 2 °C and 75 ± 5% relative humidity; and -20 °C ± 5 °C respectively.

Validated RP-HPLC/DAD Method for the Quantification of Insect Repellent Ethyl 2-Aminobenzoate in Membrane-Moderated Matrix Type Monolithic Polymeric Device.

A simple, accurate and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for the estimation of ethyl 2-aminobenzoate (EAB) in a matrix type monolithic polymeric device and validated as per the International Conference on Harmonization guidelines. The analysis was performed isocratically on a ZORBAX Eclipse plus C18 analytical column (250 × 4.4 mm, 5 µm) and a diode array detector (DAD) using acetonitrile and water (75:25 v/v) as the mobile phase by keeping the flow-rate constant at 1.0 mL/min. Determination of EAB was not interfered in the presence of excipients. Inter- and intra-day relative standard deviations were not higher than 2%. Mean recovery was between 98.7 and 101.3%. Calibration curve was linear in the concentration range of 0.5-10 µg/mL. Limits of detection and quantification were 0.19 and 0.60 µg/mL, respectively. Thus, the present report put forward a novel method for the estimation of EAB, an emerging insect repellent, by using RP-HPLC technique.