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Nanomaterials exhibit unique physical and chemical properties and, hence, they have received much attention from scientists and researchers in different areas of environmental sciences, specifically in bioremediation. Bioremediation provides a good clean-up strategy for some types of waste, but as it is expected, it will not be useful for all. For example, bioremediation may not provide a feasible strategy at sites with high concentrations of chemicals that are toxic to most microorganisms. These include heavy metals and salt. Further, the advancement in science and technology has increased standard of living which directly or indirectly contributes to the increase in waste and toxic material. Therefore, the remediation of contaminants by use of existing technology is not effective and efficient in cleaning up the environment. Hence, nanomaterials may be applied for bioremediation, which will not only have less toxic effect on microorganisms, but will also improve the microbial activity of the specific waste and toxic material which will reduce the overall time consumption as well as reduce the overall cost. In this paper we have briefly summarized the major types of nanomaterials that have been used so far in bioremediation of waste and toxic materials.

Poor solubility remains a major challenge for pharmaceutical industry, which is now considered to be an area of prime importance in the field of biomedical research. Approximately 40% new molecular entities (NMEs) synthesized in pharmaceutical R with advanced combinatorial chemistry and computer aided drug designing (CADD) approaches suffer from poor solubility and bioavailability related issues. Apart from these presence of intestinal tight junctional epithelial cells, transporters and enzymatic barriers further reduces the oral absorption of drugs. Implication of the novel lipid based nanocarriers and nanomaterials like dendrimers and carbon nanotubes as a delivery system can effectively enhance the oral bioavailability of drugs by breaching the barriers, and resolve all critics related to solubility and bioavailability. Thus prime objectives of this review are to give in-depth knowledge and critical appraisal on the barriers for poor oral bioavailability of drugs, along with various novel formulation approaches used for bioavailability enhancement such as lipid based formulations, nanosizing techniques, complexation with polymers and nanomaterials like dendrimers, carbon nanotubes, and penetration enhancers. Also it gives a brief account on in vitro, in vivo screening methods used for assessment of oral bioavailability, and regulatory considerations for the approval.

Trimesoyl 1,3,5-tridimethyl malonate (TTDMM), trimesoyl 1,3,5-tridiethyl malonate (TTDEM), trimesoyl 1,3,5-tridipropyl malonate, trimesoyl 1,3,5-tridibutyl malonate, and trimesoyl 1,3,5-tridihexyl malonate first-generation dendrimers, a complete series of dialkyl malonate esters from methyl to hexyl, were synthesized by a divergent growth approach with about a 95% yield. TTDMM and TTDEM members of this series were characterized with 500-MHz NMR and Fourier transform infrared spectroscopy. The 7.469353 and 8.435395 m 2 /g surface areas and 700.1907-and 792.6436-nm pore-average diameters of TTDMM and TTDEM, respectively, implied that they could be used as prospective drug binders. Alkyl chains from methyl to hexyl of dialkyl malonate esters had enhanced interstitial spaces to trap the drugs and toxic heavy metals for their distribution and bioremediation, respectively. Thus, the dendrimers, silibinin (SB) complexes in a 1:1 ratio with acetone, were prepared and studied with Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic light scattering, scanning electron microcopy, and atomic force microscopy. The ultraviolet-visible spectroscopy at a 330-nm lamda max (k max ) showed about 5%/h SB released in phosphate buffered saline with 10% dimethyl sulfoxide. The objective was used to investigate the capacity of dialkyl malonate terminated dendrimers to encapsulate a maximum amount of SB and anticancer drugs and the in vitro releasing activity.