The delivery of drugs through the oral route is regarded as most optimal to achieve desired therapeutic effects and patient compliance. However, poor pharmacokinetic profiles of oral drug candidates remains an area of concern, and approaches to enhance their bioavailability are widely cited in the literature. Traditionally, the approaches have been confined to molecular optimization of the drug molecule, which has gradually evolved into development of microsized and nanosized formulations. Nanoformulations, by virtue of their nanosize, are widely acclaimed for circumventing the obstacles of poor pharmacokinetics. In this review, an attempt has been made to discuss existing challenges of bioavailability and approaches to overcome the same, with in-depth compilation of the literature on nanoformulations. The nanoformulations reviewed include nanocrystals, nanoemulsions, polymeric nanoparticles, self-nanoemulsifying drug delivery systems, dendrimers, carbon nanotubes, polymeric micelles and lipid nanocarriers. This review confirms the potential of nanomedicines to improve the pharmacokinetics of drugs via nanoformulations. Chemotherapeutic applications and patent reports are also compiled in the review. Despite the promising benefits, nanomedicines are associated with hazards to human health. Hence, the review also deals with toxicological consequences of nanomedicines, and with in vitro/in vivo screening methods to assess bioavailability as per regulatory considerations. Nanotechnology has been shown to facilitate the clinical translation of drug candidates that were deemed to be bioavailability failures. Conclusively, nanotechnological approaches to particle design and formulation are beginning to expand the market for many drugs with improved bioavailability and therapeutics. However, dedicated efforts are needed to develop advanced nanomedicines with minimal or no adverse effects.

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Low solubility causing low dissolution in gastrointestinal tract is the major problem for drugs meant for systemic action after oral administration, like cinnarizine. Pharmaceutical products of cinnarizine are commercialized globally as immediate release preparations presenting low absorption with low and erratic bioavailability. Approaches to enhance bioavailability are widely cited in the literature. An attempt has been made to review the bioavailability complications and clinical therapeutics of poorly water soluble drug: cinnarizine. The interest of writing this paper is to summarize the pharmacokinetic limitations of drug with special focus on strategies to improvise bioavailability along with effectiveness of novel dosage forms to circumvent the obstacle. The paper provides insight to the approaches to overcome low and erratic bioavailability of cinnarizine by cyclodextrin complexes and novel dosage forms: self-nanoemulsifying systems and buoyant microparticulates. Nanoformulations need to systematically explored in future, for their new clinical role in prophylaxis of migraine attacks in children. Clinical reports have affirmed the role of cinnarizine in migraine prophylaxis. Research needs to be dedicated to develop dosage forms for efficacious bioavailability and drug directly to brain.

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The present study deals with the biofiltration of methyl isobutyl ketone (MIBK), which is considered to be a highly toxic volatile organic compound. It is released from the paint and petrochemical industries and is one of the major contributors to air pollution. The biofiltration study was carried out on a lab scale for two months in the presence of acclimated mixed culture. The performance of the biofilter column was evaluated for different inlet loads of MIBK at air flow rates ranging from 0.18 to 0.3 m3 h(-1). The maximum removal efficiency of 93% was obtained after 60 days of biofilter operation for an inlet MIBK concentration of 0.45 g m(-3), and a microbial concentration of 2.36 x 10(8) CFU g(-1) of packing material was obtained. This led to a study of shock loadings for 20 days, by varying the inlet MIBK load and air flow rate after every five days, to observe the behaviour of the biofilter column in removing sudden loads of MIBK. The biokinetic constants r(max) and Ks were obtained using the Michaelis-Menten kinetics and were found to be 1.046 g m(-3) and 0.115 g m(-3) h(-1),respectively, with a coefficient of determination (R2) of 0.993. The obtained experimental results were validated with the Ottengraf and Van den Oever kinetic model. The critical inlet concentration, critical inlet load and biofilm thickness were also estimated using the results obtained from the model predictions.