Recent advances in lipid-based long-acting injectable depot formulations

Injectable long-acting formulations (ILAFs) and manufacturing techniques

INTRODUCTION

Most therapeutics delivered using short-acting formulations need repeated administration, which can harm patient compliance and raise failure risks related to inconsistent treatment. Injectable long-acting formulations (ILAFs) are controlled/sustained-release formulations fabricated to deliver active pharmaceutical ingredients (APIs) and extend their half-life over days to months. Longer half-lives of ILAFs minimize the necessity for frequent doses, increase patient compliance, and reduce the risk of side effects from intravenous (IV) infusions. Using ILAF technologies, the immediate drug release can also be controlled, thereby minimizing potential adverse effects due to high initial drug blood concentrations.

AREA COVERED

In this review, we have discussed various ILAFs, their physiochemical properties, fabrication technologies, advantages, and practical issues, as well as address some major challenges in their application. Especially, the approved ILAFs are highlighted.

EXPERT OPINION

ILAFs are sustained-release formulations with extended activity, which can improve patient compliance. ILAFs are designed to deliver APIs like proteins and peptides and extend their half-life over days to months. The specific properties of each ILAF preparation, such as extended-release and improved drug targeting capabilities, make them an effective approach for precise and focused therapy. Furthermore, this is especially helpful for biopharmaceuticals with short biological half-lives and low stability since most environmental conditions can protect them from sustained-release delivery methods.

Human immunodeficiency virus infection challenges: Current therapeutic limitations and strategies for improved management through long-acting injectable formulation

HIV infection has been a severe global health burden, with millions living with the virus and continuing new infections each year. Antiretroviral therapy can effectively suppress HIV replication but requires strict lifelong adherence to daily oral medication regimens, which presents a significant challenge. Long-acting formulations of antiretroviral drugs administered infrequently have emerged as a promising strategy to improve treatment outcomes and adherence to HIV therapy and prevention. Long-acting injectable (LAI) formulations are designed to gradually release drugs over extended periods of weeks or months following a single injection. Critical advantages of LAIs over conventional oral dosage forms include less frequent dosing requirements, enhanced patient privacy, reduced stigma associated with daily pill regimens, and optimised pharmacokinetic/pharmacodynamic profiles. Several LAI antiretroviral products have recently gained regulatory approval, such as the integrase strand transfer inhibitor cabotegravir for HIV preexposure prophylaxis and the Cabotegravir/Rilpivirine combination for HIV treatment. A leading approach for developing long-acting antiretroviral depots involves encapsulating drug compounds in polymeric microspheres composed of biocompatible, biodegradable materials like poly (lactic-co-glycolic acid). These injectable depot formulations enable high drug loading with customisable extended-release kinetics controlled by the polymeric matrix. Compared to daily oral therapies, LAI antiretroviral formulations leveraging biodegradable polymeric microspheres offer notable benefits, including prolonged therapeutic effects, reduced dosing frequency for improved adherence, and the potential to kerb the initial HIV transmission event. The present manuscript aims to review the pathogenesis of the virus and its progression and propose therapeutic targets and long-acting drug delivery strategies that hold substantial promise for enhancing outcomes in HIV treatment and prevention.

Oleogels: Versatile Novel Semi-Solid System for Pharmaceuticals

Oleogels is a novel semi-solid system, focusing on its composition, formulation, characterization, and diverse pharmaceutical applications. Due to their stability, smoothness, and controlled release qualities, oleogels are frequently utilized in food, cosmetics, and medicinal products. Oleogels are meticulously formulated by combining oleogelators like waxes, fatty acids, ethyl cellulose, and phytosterols with edible oils, leading to a nuanced understanding of their impact on rheological characteristics. They can be characterized by methods like visual inspection, texture analysis, rheological measurements, gelation tests, and microscopy. The applications of oleogels are explored in diverse fields such as nutraceuticals, cosmetics, food, lubricants, and pharmaceutics. Oleogels have applications in topical, transdermal, and ocular drug delivery, showcasing their potential for revolutionizing drug administration. This review aims to enhance the understanding of oleogels, contributing to the evolving landscape of pharmaceutical formulations. Oleogels emerge as a versatile and promising solution, offering substantial potential for innovation in drug delivery and formulation practices.

Self-Assembled Nanocarrier Delivery Systems for Bioactive Compounds

Although bioactive compounds (BCs) have many important functions, their applications are greatly limited due to their own defects. The development of nanocarriers (NCs) technology has gradually overcome the defects of BCs. NCs are equally important as BCs to some extent. Self-assembly (SA) methods to build NCs have many advantages than chemical methods, and SA has significant impact on the structure and function of NCs. However, the relationship among SA mechanism, structure, and function has not been given enough attention. Therefore, from the perspective of bottom-up building mechanism, the concept of SA-structure-function of NCs is emphasized to promote the development of SA-based NCs. First, the conditions and forces for occurring SA are introduced, and then the SA basis and molecular mechanism of protein, polysaccharide, and lipid are summarized. Then, varieties of the structures formed based on SA are introduced in detail. Finally, facing the defects of BCs and how to be well solved by NCs are also elaborated. This review attempts to describe the great significance of constructing artificial NCs to deliver BCs from the aspects of SA-structure-function, so as to promote the development of SA-based NCs and the wide application of BCs.

Advances in local drug delivery technologies for improved rheumatoid arthritis therapy

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by an inflammatory microenvironment and cartilage erosion within the joint cavity. Currently, antirheumatic agents yield significant outcomes in RA treatment. However, their systemic administration is limited by inadequate drug retention in lesion areas and non-specific tissue distribution, reducing efficacy and increasing risks such as infection due to systemic immunosuppression. Development in local drug delivery technologies, such as nanostructure-based and scaffold-assisted delivery platforms, facilitate enhanced drug accumulation at the target site, controlled drug release, extended duration of the drug action, reduced both dosage and administration frequency, and ultimately improve therapeutic outcomes with minimized damage to healthy tissues. In this review, we introduced pathogenesis and clinically used therapeutic agents for RA, comprehensively summarized locally administered nanostructure-based and scaffold-assisted drug delivery systems, aiming at improving the therapeutic efficiency of RA by alleviating the inflammatory response, preventing bone erosion and promoting cartilage regeneration. In addition, the challenges and future prospects of local delivery for clinical translation in RA are discussed.

Novel poly(lactic-co-glycolic acid) nanoliposome-encapsulated diclofenac sodium and celecoxib enable long-lasting synergistic treatment of osteoarthritis

BACKGROUND

Diclofenac sodium (DS) and celecoxib (CEL) are primary anti-inflammatory agents used in the treatment of osteoarthritis (OA). Formulating these drugs into extended-release versions can effectively address the issue of multiple daily doses. In this study, we designed and synthesized a novel poly(lactic-co-glycolic acid) (PLGA) nanoliposome as a dual-drug delivery sustained-release formulation (PPLs-DS-CEL) to achieve long-lasting synergistic treatment of OA with both DS and CEL.

METHODS

PPLs-DS-CEL was synthesized by the reverse evaporation method and evaluated for its physicochemical properties, encapsulation efficiency, drug release kinetics and biological properties. A rat OA model was established to assess the therapeutic efficacy and biosafety of PPLs-DS-CEL.

RESULTS

The particle size of PPLs-DS-CEL was 218.36 ± 6.27 nm, with a potential of 32.56 ± 3.28 mv, indicating a homogeneous vesicle size. The encapsulation of DS and CEL by PPLs-DS-CEL was 95.18 ± 4.43% and 93.63 ± 5.11%, with drug loading of 9.56 ± 0.32% and 9.68 ± 0.34%, respectively. PPLs-DS-CEL exhibited low cytotoxicity and hemolysis, and was able to achieve long-lasting synergistic analgesic and anti-inflammatory therapeutic effects in OA through slow release of DS and CEL, demonstrating good biosafety properties.

CONCLUSION

This study developed a novel sustained-release nanoliposomes formulation capable of co-loading two drugs for the long-acting synergistic treatment of OA. It offers a new and effective therapeutic strategy for OA treatment in the clinic settings and presents a promising approach for drug delivery systems.

A New Approach for Preparing Stable High-Concentration Peptide Nanoparticle Formulations

The subcutaneous administration of therapeutic peptides would provide significant benefits to patients. However, subcutaneous injections are limited in dosing volume, potentially resulting in high peptide concentrations that can incur significant challenges with solubility limitations, high viscosity, and stability liabilities. Herein, we report on the discovery that low-shear resonant acoustic mixing can be used as a general method to prepare stable nanoparticles of a number of peptides of diverse molecular weights and structures in water without the need for extensive amounts of organic solvents or lipid excipients. This approach avoids the stability issues observed with typical high-shear, high-intensity milling methods. The resultant peptide nanosuspensions exhibit low viscosity even at high concentrations of >100 mg/mL while remaining chemically and physically stable. An example nanosuspension of cyclosporine nanoparticles was dosed in rats via a subcutaneous injection and exhibited sustained release behavior. This suggests that peptide nanosuspension formulations can be one approach to overcome the challenges with high-concentration peptide formulations.

Lyotropic liquid crystalline phases: Drug delivery and biomedical applications

Liquid crystal (LC)-based nanoformulations may efficiently deliver drugs and therapeutics to targeted biological sites. Lyotropic liquid crystalline phases (LLCPs) have received much interest in recent years due to their unique structural characteristics of both isotropic liquids and crystalline solids. These LLCPs can be utilized as promising drug delivery systems to deliver drugs, proteins, peptides and vaccines because of their improved drug loading, stabilization, and controlled drug release. The effects of molecule shape, microsegregation, and chirality are very important in the formation of liquid crystalline phases (LCPs). Homogenization of self-assembled amphiphilic lipids, water and stabilizers produces LLCPs with different types of mesophases, bicontinuous cubic (cubosomes) and inverse hexagonal (hexosomes). Moreover, many studies have also shown higher bioadhesivity and biocompatibility of LCs due to their structural resemblance to biological membranes, thus making them more efficient for targeted drug delivery. In this review, an outline of the engineering aspects of LLCPs and polymer-based LLCPs is summarized. Moreover, it covers parenteral, oral, transdermal delivery and medical imaging of LC in targeting various tissues and is discussed with a scope to design more efficient next-generation novel nanosystems. In addition, a detailed overview of advanced liquid crystal-based drug delivery for vaccines and biomedical applications is reviewed.

Temperature-Sensitive Nanocarbon Hydrogel for Photothermal Therapy of Tumors

Background

Intelligent hydrogels continue to encounter formidable obstacles in the field of cancer treatment. A wide variety of hydrogel materials have been designed for diverse purposes, but materials with satisfactory therapeutic effects are still urgently needed.

Methods

Here, we prepared an injectable hydrogel by means of physical crosslinking. Carbon nanoparticle suspension injection (CNSI), a sentinel lymph node imaging agent that has been widely used in the clinic, with sodium β-glycerophosphate (β-GP) were added to a temperature-sensitive chitosan (CS) hydrogel (CS/GP@CN) as an agent for photothermal therapy (PTT). After evaluating the rheological, morphological, and structural properties of the hydrogel, we used 4T1 mouse breast cancer cells and B16 melanoma cells to assess its in vitro properties. Then, we intratumorally injected the hydrogel into BALB/c tumor-bearing mice to assess the in vivo PTT effect, antitumor immune response and the number of lung metastases.

Results

Surprisingly, this nanocarbon hydrogel called CS/GP@CN hydrogel not only had good biocompatibility and a great PTT effect under 808nm laser irradiation but also facilitated the maturation of dendritic cells to stimulate the antitumor immune response and had an extraordinary antimetastatic effect in the lungs.

Discussion

Overall, this innovative temperature-sensitive nanocarbon hydrogel, which exists in a liquid state at room temperature and transforms to a gel at 37 °C, is an outstanding local delivery platform with tremendous PTT potential and broad clinical application prospects.