Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder, is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.Download high-res image (66KB)Download full-size image

Extracellular vesicles (EVs) are intrinsic mediators of intercellular communication in our body, allowing functional transfer of biomolecules (lipids, proteins, and nucleic acid) between diverse locations. Such an instrumental role evokes a surge of interest within the drug delivery community in tailoring EVs for therapeutic delivery. These vesicles represent a novel generation of drug delivery systems, providing high delivery efficiency, intrinsic targeting properties, and low immunogenicity. In the recent years, considerable research efforts have been directed toward developing safe and efficient EV-based delivery vehicles. Although EVs are shown to harbor great promise in therapeutic delivery, substantial improvements in exploring standardized isolation techniques with high efficiency and robust yield, scalable production, standard procedures for EV storage, efficient loading methods without damaging EV integrity, understanding their in vivo trafficking, and developing novel EV-based nanocarriers are still required before their clinical transformation. In this review, we seek to summarize the recent advance on harnessing EVs for drug delivery with focus on state-of-the-art solutions for overcoming major challenges.Download high-res image (118KB)Download full-size image

A cationic gene delivery vector, guanidinylated disulfide-containing poly(amido amine) (CAR-CBA), was synthesized by Michael addition reaction between N,N′-cystaminebisacrylamide (CBA) and guanidine hydrochloride (CAR). Gel permeation chromatography (GPC) was used to evaluate the molecular weight of synthesized CAR-CBA. Polyethyleneimine (PEI) with molecular weight of 25 kDa was adopted as a reference, and polyethylene glycols (PEG) with different molecular weights were used to establish a standard curve for determining the molecular weight of CAR-CBA. The effects of two critical factors, namely columns and eluents, on the molecular weight measurement of CAR-CBA were investigated to optimize the GPC quantitative method. The results showed that Ultrahydrogel columns (120, 250) and HAc–NaAc (0.5 M, pH 4.5) buffer solution were the optimal column and GPC eluent, respectively. The molecular weight of the synthesized CAR-CBA was analyzed by the optimized GPC method and determined to be 24.66 kDa.Download high-res image (52KB)Download full-size image

Bioequivalence (BE) assessment of topical dermatological products is a long standing challenge. The development of generic topical dermatological products has often been hampered due to the limited number of acceptable approaches, which are capable of determining the BE between generic products and reference list products. The aim of this manuscript is to review different BE assessment approaches of topical dermatological products. Besides, the advances in BE evaluation and biowaivers are also provided. Currently, except in the case of dermatological corticosteroids, the golden rule to establish the BE of most topical dermatological products still heavily relied on clinical endpoint trials, which are often unreliable, time-consuming and expensive. The regulatory agencies and pharmaceutical industries are forging ahead to the development of new surrogate BE assessment approaches for other topical dermatological products. These promising approaches include dermatopharmacokinetic study (DPK), dermal microdialysis (DMD), in vitro studies, pharmacokinetic study (PK), near-infrared spectrometry (NIR), and confocal Raman spectroscopy (CRS). In addition, the expansion of biowaivers for topical dermatological products has been explored by pharmaceutical scientists. In conclusion, to accelerate the development and approval of topical dermatological products, emphasis should be put on the following areas, i.e., optimizing and standardizing the existing BE assessment methods, exploring novel alternatives of BE assessment approaches, and expanding biowaivers for topical dermatological products.

Polycarbophil (PCP), a kind of pharmaceutical polymers with superior bioadhesive properties has been widely used in the field of controlled drug delivery systems. It could be used as a highly efficient thickener, bioadhesive agent, suspending aid and emulsion stabilizer when dispersed in water or other polar solvents. These exceptional utilities of the polymers result from their hydrophilic nature. Hydrogen bonding plays an important role in most adhesion behaviours and becomes the main adhesion force. This paper reviews the applications of PCP in pharmacy over the past decades, and clarifies its unique advantages in the bioadhesive formulations. After an introduction discussing its structural characteristics and action mechanism, the focus turned to the description of its available applications in detail with particular emphasis on the ocular, nasal, vagina and oral drug delivery systems. The other less developed formulations are also described, including the buccal and the transdermal delivery systems.