Globally, oral drug delivery still remains the most patient compliant route of administering drugs. Many researchers within pharmaceutics have looked at ways to minimize dosing frequency, or dosage form size, with the aim of further facilitating patient compliance. One area of current interest, is that of taste masking; both for orally disintegrating tablets (ODTs), as well as for those products that transit the oral cavity. It is generally known that most drugs have an inherently bitter taste, and oral products have often been coated to negate this issue. However, with varying drug product requirements, coating is not necessarily the only option for a formulator.
In this themed issue, a selection of research articles explore various aspects related to oral drug administration. The first paper is a review article by Xavier-Júnior et al., it describes the latest understanding in microemulsion formation, and further describes recent applications of natural oil-loaded ME systems with the incorporation of bioactive compounds. Following this, in the first of three papers focusing on the challenges associated with taste masking, Taki et al. describe the preparation of spray-dried nanocomposite particles with the model bitter taste agent, quinine. Using poorly water-soluble methacrylate polymers, the investigators utilize a bitterness testing apparatus to compare formulations, which is useful in studies for both food and pharmaceutical industries. Drašković et al. look at taste masking ODTs. The researchers use a commercially available preparation to manufacture coated or uncoated model drug containing ODTs, and determine whether there is a correlation between a small volume dissolution method and a human taste panel (commonly used in the food industry). Rajesh and Popat prepared drug release complexes using ion exchange resins to taste mask azithromycin. The complexes, entrapped in a biopolymer matrix, were studied for drug release at various pH values associated with the GI tract.
The subsequent research articles in this themed issue are related to various formulation science aspects of oral drug delivery. Another article, investigating the formulation of ODTs by Moqbel et al. compares two preparation methods for chlorzoxazone using compendial testing methods for tablets, and a palatability evaluation. Gastric retention of eplerenone with oral bioadhesive pellets is the focus of study for Kendre and Chaudhari, whereas Alves-Silva et al. report on the stability aspects of immediate release pellets comprised of benznidazole prepared using an extrusion-spheronization method. Rekkas and colleagues utilize Quality by Design (QbD) to study a single step processing method for water-soluble excipients, in the development of novel, fast disintegrating, effervescent pellets. Pan et al. report on enhanced absorption of metformin hydrochloride and glipizide, from a tablet formulation that uses a pH-modifying agent or drug release retardant. Alsulays et al. explore hot-melt extrusion (HME) technology to improve the physiochemical properties of lansoprazole, and a comparison of HME and spray drying on the stability of albendazole was the subject of investigation by Hengsawas Surasarang and colleagues.
Absorption kinetics and bioavailability were the focus of the next four articles. As an ever-expanding field, Pgp efflux has been identified as a major barrier to drug absorption, Surampalli et al. looked at the effect of morin (a natural flavonoid plant extract) on Caco-2 permeability, as well as the in vivo pharmacokinetics of olmesartan. A Franz cell diffusion technique is described in detail for novel doxorubicin-loaded nanoparticles by Sintov and Enden demonstrating a simplified linear model for the determination of the permeability coefficient. Shi et al. report on the oral bioavailability in rats of positively charged solid lipid nanoparticles loaded with the cancer chemotherapy drug, docetaxel. In another cancer drug study evaluating PK as well as tumor reduction in rodent models, the incorporation of the naturally occurring curcumin into a self-nanoemulsifying drug-delivery system (SNEDDS) was described by Shukla et al.
The final article in this themed edition highlights a common thread for formulation scientists around the word: how to manufacture more patient friendly dosage form? To that end, Moqbel and coworkers look at how to convert an insulin injection to an oral product, with the ultimate goal of being a painless and more comfortable treatment for diabetics.
On behalf of the editorial board and readers of Drug Development and Industrial Pharmacy, I would like to thank all of the authors for their outstanding contributions.
Jason T. McConville
College of Pharmacy, University of New Mexico, Albuquerque, New Mexico, USA