Chitosan/alginate multilayer film for controlled release of IDM on Cu/LDPE composite intrauterine devices

Recent progress in advanced biomaterials for long-acting reversible contraception

Unintended pregnancy is a global issue with serious ramifications for women, their families, and society, including abortion, infertility, and maternal death. Although existing contraceptive strategies have been widely used in people's lives, there have not been satisfactory feedbacks due to low contraceptive efficacy and related side effects (e.g., decreased sexuality, menstrual cycle disorder, and even lifelong infertility). In recent years, biomaterials-based long-acting reversible contraception has received increasing attention from the viewpoint of fundamental research and practical applications mainly owing to improved delivery routes and controlled drug delivery. This review summarizes recent progress in advanced biomaterials for long-acting reversible contraception via various delivery routes, including subcutaneous implant, transdermal patch, oral administration, vaginal ring, intrauterine device, fallopian tube occlusion, vas deferens contraception, and Intravenous administration. In addition, biomaterials, especially nanomaterials, still need to be improved and prospects for the future in contraception are mentioned.

[New frontiers in contraception research]

Improving current contraceptives and discover novel methods easy to use with added health benefits would meet the needs of couples who seek alternatives to current methods. New delivery systems target user-controlled, longer-acting options to provide choice, user's autonomy and improve compliance. Self-injections, microarray patches, pod rings able to deliver several molecules aim to prevent both pregnancies and sexually transmitted infections. Improved intrauterine systems and non-surgical permanent methods are also on the research agenda. The search for novel methods must continue, to curb maternal mortality led by multiple pregnancies and unsafe abortion, still a burden in many countries.

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

Chitosan-based smart hybrid materials: a physico-chemical perspective

Chitosan is one of the most studied cationic polysaccharides. Due to its unique characteristics of being water soluble, biocompatible, biodegradable, and non-toxic, this macromolecule is highly attractive for a broad range of applications. In addition, its complex behavior and the number of ways it interacts with different components in a system result in an astonishing variety of chitosan-based materials. Herein, we present recent advances in the field of chitosan-based materials from a physico-chemical perspective, with focus on aqueous mixtures with oppositely charged colloids, chitosan-based thin films, and nanocomposite systems. In this review, we focus our attention on the physico-chemical properties of chitosan-based materials, including solubility, mechanical resistance, barrier properties, and thermal behaviour, and provide a link to the chemical peculiarities of chitosan, such as its intrinsic low solubility, high rigidity, large charge separation, and strong tendency to form intra- and inter-molecular hydrogen bonds.

Local and controlled release of tamoxifen from multi (layer-by-layer) alginate/chitosan complex systems

Herein, multilayer polysaccharide films were proposed and characterized as biomaterials for the local and controlled release of an antitumoral drug. To that aim, multilayer films of alginate (Alg) and chitosan (Chi) were built up through spray assisted layer-by-layer (LbL) technique employing an automatic equipment. A specific drug against breast cancer, tamoxifen (TMX), was incorporated in different intermediate positions of the multilayer Alg/Chi films. Our findings highlight that Alg/Chi multilayer films can be employed for sustained and local TMX delivery and their therapeutic effect can be modulated and optimized by the number of bilayers deposited over the loaded tamoxifen, the quantity of tamoxifen loaded in several intermediate positions and the total area of the film.

Micropatterned fabrication of chitosan-based thermoresponsive membranes for improving cell adhesion and gene expression

A simple, rapid, and economical method to fabricate micropatterned thermoresponsive chitosan membranes was developed. Porous polystyrene films were prepared by liquid-induced phase separation. The size of pores on polystyrene films could be regulated by adjusting the composition of coagulation bath and changing the solvent evaporation rate. Subsequently, chitosan-based thermoresponsive membranes with island protrusions were fabricated using porous polystyrene films as templates. The effects of the micropatterns on the behaviors of mouse fibroblast L929 were investigated. The presence of micropatterns altered the cell cycle distribution and enhanced the gene expression of cyclin D1 and integrin β1. The micro-convex surface could promote the adhesion and proliferation of L929 cells. These results provided valuable guidance to design appropriate topographic surfaces for tissue engineering applications.

Sorption and release of drugs in/from cross-linked poly(ethyleneimine) multilayer films deposited onto silica microparticles

Multilayer thin films are useful materials in fabrication of controlled drug delivery systems and in controlling drug release processes. Herein, we report the fabrication of single polycation multilayers based on branched poly(ethylene imine) (PEI) mediated by dianhydrides (DA), as cross-linker and source of carboxylic groups, deposited onto Daisogel silica microparticles, and their sorption/release properties for some anionic drugs as a function of the cross-linker concentration. Pyromellitic dianhydride (PM) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTCDA) were used as DA reagents. The monotonous increase of the (PEI-DA)n multilayers was demonstrated by Fourier transform infrared spectroscopy, point of zero charge (pzc), and X-ray photoelectron spectroscopy. The sorption properties of the PEI multilayer films for two drugs (diclofenac sodium, DS, and indomethacin, IDM) and a model dye (Ponceau SS, PSS) were influenced by the number of PEI layers and the weight ratio between cross-linker and silica microparticles during the cross-linking steps. It was found that the adsorbed amount of drugs increased with the number of PEI layers and with the decrease of DA concentration. The Langmuir, Sips, and Dubinin-Radushkevich model isotherms were applied to fit the sorption equilibrium data of IDM onto the Daisogel//(PEI-DA)n composites. The maximum equilibrium sorption capacity, qm, evaluated by the Langmuir model, at 25 °C, was 37.05 mg IDM/g of Daisogel//(PEI-BTCDA)8.5, and 39.99 mg IDM/g of Daisogel//(PEI-PM)8.5, for a weight percentage of DA/silica of 0.1% w/w. Cumulative release of DS was almost 100% within 180 min, while IDM was desorbed at a level of 35%, in 320 min, supporting a sustained release was gained with the cross-linked PEI films. The stability of the (PEI-DA)n multilayers during the successive sorption/desorption cycles of PSS was demonstrated.