Development and evaluation in vitro and in vivo of injectable hydrolipidic gels with sustained-release properties for the management of articular pathologies such as osteoarthritis

Intra-articular drug delivery systems for osteoarthritis therapy: shifting from sustained release to enhancing penetration into cartilage

Osteoarthritis (OA) is a progressive chronic inflammation that leads to cartilage degeneration. OA Patients are commonly given pharmacological treatment, but the available treatments are not sufficiently effective. The development of sustained-release drug delivery systems (DDSs) for OA may be an attractive strategy to prevent rapid drug clearance and improve the half-life of a drug at the joint cavity. Such delivery systems will improve the therapeutic effects of anti-inflammatory effects in the joint cavity. Whereas, for disease-modifying OA drugs (DMOADs) which target chondrocytes or act on mesenchymal stem cells (MSCs), the cartilage-permeable DDSs are required to maximize their efficacy. This review provides an overview of joint structure in healthy and pathological conditions, introduces the advances of the sustained-release DDSs and the permeable DDSs, and discusses the rational design of the permeable DDSs for OA treatment. We hope that the ideas generated in this review will promote the development of effective OA drugs in the future.

Quality Risk Management and Quality by Design for the Development of Diclofenac Sodium Intra-articular Gelatin Microspheres

The aim of the present study was to evaluate the development of an intra-articular nonsteroidal anti-inflammatory drug gelatin microsphere formulation based on quality risk management and quality by design approaches. Specifically, after setting the quality target product profile and the critical quality attributes, risk assessment was performed by constructing Ishikawa fishbone diagrams based on preliminary hazard analysis. A Plackett-Burman screening experimental design was applied in order to identify the factors (previously classified by risk assessment analysis as having high risk of failure) having a statistically significant impact on the formation of gelatin microspheres. Particle size, polydispersity index, and drug loading were used as responses, while diclofenac sodium was selected as a model drug. All drug-loaded gelatin microspheres were prepared by emulsion-crosslinking process. Screening results showed that gelatin type, surfactant type and quantity, oil phase type, emulsification speed, and glutaraldehyde's concentration had a statistically significant impact on microsphere's final and intermediate critical quality attributes. A design space was then constructed based on central composite design overlaying contour plots, while verification experiments for the optimum suggested formulation (derived from a set control strategy) showed good agreement between the predicted and the experimentally observed results. In addition, the physicochemical characterization of the optimum formulation showed the formation of significant molecular interactions between the drug and the gelatin matrix, leading to the complete amorphization of diclofenac within the microsphere structure, while dissolution release experiments showed a biphasic release profile which extended the drug's release for up to 30 days, governed by a Fickian diffusion release mechanism.

Cubic Liquid Crystalline Gels Based on Glycerol Monooleate for Intra-articular Injection

In situ gels containing sinomenine hydrochloride (SMH) for intra-articular (IA) administration to treat rheumatoid arthritis (RA) were designed and investigated in this study. Glycerol monooleate (GMO) was used due to the potential to generate viscous crystalline phase structures upon water absorption. The gels were evaluated using different parameters: syringeability, gelation, viscosity, and drug release. And, polarized light microscopy (PLM), small-angle X-ray scattering investigation (SAXS), and rheological studies were used to analyze their internal structures. In vitro drug release studies were performed by the dialysis membrane diffusion method. The syringeability, viscosity, gelation time, and water for gelation of the obtained preparation met the requirements of IA injection. PLM, SAXS, and rheological analysis showed that all samples had transformed from flowable isotropic solution phases to the inverse cubic (V₂) phases upon excess water. And, the gels were found to be able to maintain the drug release for more than 1 week. Results showed that in situ gels based on GMO liquid crystalline could provide a sustained system for SMH. Due to its sustained release, the in situ cubic gels were suitable for IA injection to treat RA.

Cartilage-targeting drug delivery: can electrostatic interactions help?

Current intra-articular drug delivery methods do not guarantee sufficient drug penetration into cartilage tissue to reach cell and matrix targets at the concentrations necessary to elicit the desired biological response. Here, we provide our perspective on the utilization of charge-charge (electrostatic) interactions to enhance drug penetration and transport into cartilage, and to enable sustained binding of drugs within the tissue's highly negatively charged extracellular matrix. By coupling drugs to positively charged nanocarriers that have optimal size and charge, cartilage can be converted from a drug barrier into a drug reservoir for sustained intra-tissue delivery. Alternatively, a wide variety of drugs themselves can be made cartilage-penetrating by functionalizing them with specialized positively charged protein domains. Finally, we emphasize that appropriate animal models, with cartilage thickness similar to that of humans, must be used for the study of drug transport and retention in cartilage.