Removal of Phosphorus from an Aqueous Solution by Nanocalcium Hydroxide Derived from Waste Bivalve Seashells: Mechanism and Kinetics.

Excessive supply of phosphorus, a vital macronutrient for all organisms, can cause unwanted environmental consequences such as eutrophication. An increase in agricultural and industrial activities has created a considerable imbalance in the phosphorus cycle with continuing adverse effects on sustainability and ecosystem health, thereby stipulating/postulating the significance of phosphorus removal. A unique and sustainable concept for the removal of phosphorus through the utilization of waste bivalve seashells was proposed in the present study. Flat-surfaced and hexagonally shaped nanocalcium hydroxide particles (∼96% purity) with size ranging from 100 to 400 nm have been synthesized, and phosphorus from its aqueous solution is treated via precipitation. An optimization study has been conducted using the Box-Behnken design of response surface methodology, which highlights that with a calcium/phosphorus mass ratio, pH, and temperature of 2.16, 10.20, and 25.48 °C, a phosphorus removal efficiency of 99.33% can be achieved in a residence time of 10 min. Also, under the same conditions, diluted human urine was analyzed and phosphorus removal efficiency of ∼95% was observed. Through experimental results, semiquantitative phase analysis, and transmission electron microscopy, it has been found that the reaction was diffusion-controlled, which was further confirmed through shrinking core diffusion modeling. The present study manifests the promising potential of waste seashell-derived nanocalcium hydroxide for phosphorus treatment and its precipitation in the form of value-added hydroxyapatite.

Pre-Investigational New Drug Meetings With the FDA: Evaluation of Meeting Content and Characteristics of Applications for New Drug and Biologic Products.

INTRODUCTION: Prior studies suggested that holding preinvestigational new drug application (PIND) meetings with FDA has a positive effect on clinical development time (CDT). METHODS: New product marketing applications submitted to FDA CDER during fiscal years 2008-2012 were assessed for whether a PIND meeting was held and, if so, a qualitative assessment of meeting content was performed. RESULTS: Discussions contained in the PIND meeting minutes tended to reflect topics appropriate to an early phase of drug development, including chemistry, manufacturing, and controls (CMC) and safety topics (eg, nonclinical and clinical domains). Additionally, FDA commonly provided additional advice most often in the clinical and CMC domains. Applications for which a PIND meeting was held during drug development had shorter CDTs than those that did not. CONCLUSIONS: This analysis showed the importance of early communication with FDA during development, and small companies with limited regulatory experience may gain the greatest benefit from early communication with FDA.