No abstract

A number of formulations have been developed and reported in literature as a carrier for drug, gene, and diagnostic agents. Amphiphilic block copolymers have achieved increasing attention due to their high stability both in vitro and in vivo and their good biocompatibility. In comparison to other long-circulating nanocarriers, micelles possess a number of advantages such as tissue penetrability, reduced toxicity, and controlled drug release. The characteristic features of micelle as carriers, such as particle size, shape, drug loading, cellular internalization, stability, and release kinetics of drugs can be improved by altering the physicochemical properties of the constituent block copolymers and method of preparation. Polymeric micelles formed from amphiphilic blocks have been successfully used for delivery of drugs that lack water solubility. Chelation or incorporation of a diagnostic agent in ligand conjugated micelle may help in tracing in vivo biodistribution. We review a number of research articles demonstrating that micelle formulations can be used efficiently in clinical situations by taking care of the toxicity of surfactants, and the interaction between polymer and drug, to prepare a formulation carrying a more therapeutic agent with a minimum amount of polymer.

Abstract. Lamotrigine (LTG), a sodium and calcium channel blocker, has demonstrated efficacy for the treatment of neuropathic pain in multiple, randomized, controlled trials. However, its potential clinical applications in neuropathic pain are limited due to the risk of dose-dependent severe rashes associated with high dose and prompt dose escalation. Further, the poor pharmacokinetic profile due to non-selective distribution to organs other than brain reduces the efficacy of dosage regimen. Therefore, the aim of present investigation is to develop surface-engineered LTG nanoparticles (NPs) using transferrin and lactoferrin as ligand to deliver higher amount of drug to brain and improve the biodistribution and pharmacokinetic profile of drug with prolonged duration of action and reduced accumulation in nontarget organs. The LTG NPs were prepared by nanoprecipitation and optimized by factorial design for high entrapment and optimized particle size. The optimized NPs were surface functionalized by conjugating with the lactoferrin (Lf) and transferrin (Tf) as ligands. The developed NPs were characterized for different physicochemical parameters and stability. The in vivo biodistribution showed preferential targeting to brain and reduced accumulation in non-target organs over a prolonged duration of time. Finally, partial sciatic nerve injury model was used to demonstrate the increased pharmacodynamic response as antinociceptive effect. Both biodistribution and pharmacodynamic study in mice confirmed that the approach used for LTG can help to increase clinical applications of LTG due to brain targeting and reduced side effects.

This study was aimed to develop poly(dl-lactide-co-glycolide) (PLGA) nanoparticle of highly water soluble antibiotic drug, netilmicin sulfate (NS) with improved entrapment efficiency (EE) and antibacterial activity. Dextran sulfate was introduced as helper polymer to form electrostatic complex with NS. Nanoparticles were prepared by double emulsification method and optimized using 2(5-1) fractional factorial design. EE was mainly influenced by dextran sulfate: NS charge ratio and PLGA concentration, whereas particle size (PS) was affected by all factors examined. The optimized NS-loaded-NPs had EE and PS of 93.23 ± 2.7% and 140.83 ± 2.4 nm respectively. NS-loaded-NPs effectively inhibited bacterial growth compared to free NS. Sustained release protected its inactivation and reduced the decline in its killing activity over time even in presence of bronchial cells. A MIC value of 18 μg/mL was observed for NPs on P. aeruginosa. Therefore, NPs with sustained bactericidal efficiency against P. aeruginosa may provide therapeutic benefit in chronic pulmonary infection, like cystic fibrosis.

Transport of a drug across the biological membrane of the gastrointestinal tract has turned out to be a critical barrier against the success of any oral drug delivery technology. The unique advantages of the oral route, along with need for an oral substitute of invasive parenteral formulations and the reduction of intersubject variability in plasma profiles, has been an incentive for the use of excipients with absorption-enhancing properties to boost the bioavailability of poorly absorbed drugs. The development of such excipients is not a simple task, so understanding enhancement mechanisms in relation to physiology can facilitate the identification of structure-function relationships as well as the development of newer agents for customary applications. The literature is replete with reports of absorption promoters, the selection of which is influenced by the mechanisms, safety, pharmacological inertness, rapidity of action, reversibility of induced membrane alterations and excipient compatibility. Despite promising results in preliminary screenings, the development process is hindered by low reproducible efficacy and pharmacologically driven safety issues. In this review, we elaborate on the importance of permeation enhancers in oral drug delivery, their current status, and issues at the forefront of the development of formulations using absorption promoter technologies.