ABSTRACT
Introduction
Clay minerals are a class of silicates with chemical inertness, colloid, and thixotropy, which have excellent physicochemical properties, good biocompatibility, low toxicity, and have high application potential in biomedical fields. These inorganic materials have been widely used in pharmaceutical excipients and active substances. In recent years, nanoclay mineral materials have been used as drug vehicles for the delivery of a variety of drugs based on their broad specific surface area, rich porosity, diverse morphology, good adsorption performance, and high ion exchange capacity.
Areas covered
This review introduces the structures, properties, and applications of various common natural and synthetic nanoclay materials as drug carriers. Natural nanoclays have different morphologies including nanoplates, nanotubes, and nanofibers. Synthetic materials have controllable sizes and flexible structures, where mesoporous silica nanoparticles, laponite, and imogolite are typical ones. These inorganic nanoparticles are often linked to polymers to form multifunctional drug delivery systems for better pharmaceutical performance.
Expert opinion
The clay nanomaterials have typical properties, including enhanced solubility of insoluble drugs, targeting therapeutic sites, controlled release, and stimulation of responsive drug delivery systems.
List of abbreviations
FA | = | Folic acid |
FR | = | Folic acid receptor |
T:O | = | Tetrahedral: Octahedral |
MMT | = | Montmorillonite |
SEM | = | Scanning electron microscope |
5-FU | = | 5-fluorouracil |
CS | = | Chitosan |
TPU | = | Thermoplastic polyurethane |
CA | = | Chlorhexidine acetate |
PBS | = | Phosphate-buffered saline |
BSA | = | Bovine serum albumin |
BLG | = | Betalactoglobulin |
APM | = | Adenosine monophosphate |
ADM | = | Adenosine diphosphate |
ATM | = | Adenosine-triphosphate |
RNAi | = | RNA interference |
DOX | = | Doxorubicin |
CLSM | = | Confocal laser scanning microscope |
TEM | = | Transmission electron microscope |
SA | = | Sodium alginate |
GE | = | Gelatin |
D-PA | = | D-Penicillamine |
FTIR | = | Fourier transform infrared |
CIP | = | Ciprofloxacin |
HNTs | = | Halloysite nanotubes |
PLGA | = | Poly lactic-co-glycolic acid |
MTC | = | Metoclopramide hydrochloride |
CINV | = | Chemotherapy induced nausea and vomiting |
COS | = | Chitosan oligosaccharides |
CPT | = | Camptothecin |
ATAB | = | Alkyl trimethyl ammonium bromide |
MPs | = | Microparticles |
PAL | = | Palygorskite |
ATP | = | Attapulgite |
INH | = | Isoniazid |
5-ASA | = | 5-aminosalicylic acid |
PEI | = | Polyethyleneimine |
FI | = | Fluorescein isothiocyanate |
DS | = | Diclofenac sodium |
SEP | = | Sepiolite |
PZQ | = | Praziquantel |
CDs | = | Cyclodextrin |
BCS | = | Biopharmaceutical Classification System |
HCT | = | Hydrochlorothiazide |
OXA | = | Oxaprozin |
MSN | = | Mesoporous silica nanoparticle |
MCM-41 | = | Mobile crystalline material |
SBA-15 | = | Santa barbara amorphous material-15 |
EPR | = | Enhanced permeability and retention |
HA | = | Hyaluronic acid |
PDA | = | Polydopamine |
PTT | = | Photothermal therapy |
NIR | = | Near-infrared light irradiation |
ICG | = | Indocyanine green |
HA | = | Hyaluronic acid |
HMSN | = | Hollow mesoporous silica nanoparticle |
PEI | = | Polyethylene imide |
CD | = | Carbon dots |
LMWH | = | Low molecular weight heparin |
HP | = | Heparin-poloxamer |
oHA-APBA | = | Oligomer hyaluronic acid-aminophenylboric acid |
DEX | = | Dexamethasone |
LAP | = | Laponite® |
PAH | = | Polyampholyte hydrogel |
INT | = | Imogolite nanotube |
Acknowledgments
The authors are grateful to professor Yang Huaming for his advice and guidance on the manuscript. We sincerely thank professor Tan Songwen for revising this manuscript, which has provided us with great help. And the work was financially supported by the Strategic Priority Research Program of Central South University (ZLXD2017005).
Article highlights
Nanoclays have excellent physicochemical properties for drug delivery system.
Natural nanoclay materials have various morphologies: planar and non-planar nanoclay.
Planar nanoclay such as montmorillonite and non-planar nanoclay represented by halloysite, are good drug carriers and can deliver a variety of drugs.
Synthetic nanomaterials can successfully deliver therapeutic agents to target sites in the body due to controllable morphology and easy modification.
As drug delivery carriers, the safety, degradation, and dispersion of nano-clay materials still need to be improved.
This box summarizes key points contained in the article.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.