With advances of drug design and preparation technology, the development of long-acting drugs has become an important research focus in precision medicine and chronic disease management. These drugs are designed to improve the patients' compliance and quality of life by achieving prolonged maintenance of an effective drug concentration in the body with a reduced dosing frequency. Small molecule drugs, monoclonal antibodies and nucleic acid drugs all have their own difficulties in achieving long actions, which can be especially challenging for the latter two because of their structural complexity. This review provides an overview of the strategies for designing long-acting small molecule drugs, monoclonal antibodies, and nucleic acid drugs.
Humans ; Drug Design ; Antibodies, Monoclonal/chemistry* ; Nucleic Acids ; Precision Medicine ; Delayed-Action Preparations

OBJECTIVES: To synthesize a temperature-responsive multimodal motion microrobot (MMMR) using temperature and magnetic field-assisted microfluidic droplet technology to achieve targeted drug delivery and controlled drug release. METHODS: Microfluidic droplet technology was utilized to synthesize the MMMR by mixing gelatin with magnetic microparticles. The microrobot possessed a magnetic anisotropy structure to allow its navigation and targeted drug release by controlling the temperature field and magnetic field. In the experiment, the MMMR was controlled to move in a wide range along a preset path by rotating a uniform magnetic field, and the local circular motion was driven by a planar rotating gradient magnetic field of different frequencies. The MMMR was loaded with simulated drugs, which were released in response to laser heating. RESULTS: Driven by a rotating magnetic field, the MMMR achieved linear motion following a predefined path. The planar gradient rotating magnetic field controlled circular motion of the MMMR with an adjustable radius, utilizing the centrifugal force generated by rotation. The drug-loaded MMMR successfully reached the target location under magnetic guidance, where the gelatin matrix was melted using laser heating for accurate drug release, after which the remaining magnetic particles were removed using magnetic field. CONCLUSIONS The MMMR possesses multimodal motion capabilities to enable precise navigation along a predefined path and dynamic regulation of drug release within the target area, thus having great potential for a wide range of biomedical applications.
Drug Delivery Systems/methods* ; Temperature ; Drug Liberation ; Magnetic Fields ; Robotics ; Gelatin/chemistry* ; Delayed-Action Preparations ; Microfluidics ; Motion

Nanocarrier-based drug delivery systems (nDDSs) present significant opportunities for improving disease treatment, offering advantages in drug encapsulation, solubilization, stability enhancement, and optimized pharmacokinetics and biodistribution. nDDSs, comprising lipid, polymeric, protein, and inorganic nanovehicles, can be guided by or respond to biological cues for precise disease treatment and management. Equipping nanocarriers with tissue/cell-targeted ligands enables effective navigation in complex environments, while functionalization with stimuli-responsive moieties facilitates site-specific controlled release. These strategies enhance drug delivery efficiency, augment therapeutic efficacy, and reduce side effects. This article reviews recent strategies and ongoing advancements in nDDSs for targeted drug delivery and controlled release, examining lesion-targeted nanomedicines through surface modification with small molecules, peptides, antibodies, carbohydrates, or cell membranes, and controlled-release nanocarriers responding to endogenous signals such as pH, redox conditions, enzymes, or external triggers like light, temperature, and magnetism. The article also discusses perspectives on future developments.
Humans ; Drug Carriers/chemistry* ; Drug Delivery Systems/methods* ; Delayed-Action Preparations/chemistry* ; Nanoparticles/chemistry* ; Animals ; Drug Liberation ; Nanomedicine

The application of intraocular drug delivery is usually limited due to special anatomical and physiological barriers, and the elimination mechanisms in the eye. Organic nano-drug delivery carriers exhibit excellent adhesion, permeability, targeted modification and controlled release abilities to overcome the obstacles and improve the efficiency of drug delivery and bioavailability. Solid lipid nanoparticles can entrap the active components in the lipid structure to improve the stability of drugs and reduce the production cost. Liposomes can transport hydrophobic or hydrophilic molecules, including small molecules, proteins and nucleic acids. Compared with linear macromolecules, dendrimers have a regular structure and well-defined molecular mass and size, which can precisely control the molecular shape and functional groups. Degradable polymer materials endow nano-delivery systems a variety of size, potential, morphology and other characteristics, which enable controlled release of drugs and are easy to modify with a variety of ligands and functional molecules. Organic biomimetic nanocarriers are highly optimized through evolution of natural particles, showing better biocompatibility and lower toxicity. In this article, we summarize the advantages of organic nanocarriers in overcoming multiple barriers and improving the bioavailability of drugs, and highlight the latest research progresses on the application of organic nanocarriers for treatment of ocular diseases.
Drug Carriers ; Delayed-Action Preparations ; Drug Delivery Systems ; Nanoparticles/chemistry*

In this study, insulin (insulin, INS)/Ca₃PO₄ complex and glucose oxidase (glucose oxidase, GOx)/Cu₃(PO₄)₂ complex were prepared by coprecipitation method. The mineralized insulin (mineralized insulin, m-INS) showed irregular crystalline clusters, and the mineralized glucose oxidase (m-GOx) showed flower spherical morphology, with a diameter of about 1-2 μm. In vitro simulated release experiment showed that m-INS released INS as the pH value of the medium decreased. When the pH value was 4.5, the release amount reached 96.68%. The enzyme activity detection experiment showed that the enzyme activity stability of m-GOx was higher than that of free GOx. It still maintained high activity after 10 days at room temperature, while the activity of GOx was less than 60%. The glucose solution was prepared to simulate the state of normal blood glucose (5.6 mmol/L) and hyperglycemia (22.2 mmol/L). When m-INS and m-GOx were added to the glucose solution, the release amount of INS showed a significant glucose concentration dependence. The higher the glucose concentration, the greater the release amount and release rate of INS. Finally, m-INS, m-GOx and hyaluronic acid (HA) solution were mixed to prepare HA microneedle arrays loaded with m-INS and m-GOx. Type 1 diabetes mice were constructed to evaluate the effect of drug-loaded HA microarray on blood glucose control in diabetic rats. The results show that the HA microneedles loaded with m-INS/m-GOx could deliver drugs effectively. The average blood glucose concentration in diabetic rats dropped to about 7 mmol/L within 1 h, normal blood glucose concentration could be maintained for 10 h, and the overall blood glucose concentration was lower than the level before administration for 36 hours. Compared with HA microneedles loaded with INS only, m-ins microneedles showed better glucose tolerance, longer-lasting glucose control effect and less risk of hypoglycemia. Compared with other sustained-release systems, the preparation process of the core components in this study is simple, efficient, safe and effective, and has great commercial potential.
Animals ; Blood Glucose ; Delayed-Action Preparations/therapeutic use* ; Diabetes Mellitus, Experimental/drug therapy* ; Drug Delivery Systems/methods* ; Glucose Oxidase/chemistry* ; Hyaluronic Acid ; I Blood-Group System ; Insulin/therapeutic use* ; Mice ; P Blood-Group System ; Rats

OBJECTIVE: To study the plasma concentration and pharmacokinetics of 3, 29-Dibenzoyl Karounitriol (3, 29-DK) from sustained- release pellets and extracts of Trichosanthes at different time points in rats using high-performance liquid chromatography- tandem mass spectrometry (LC-MS/MS). METHODS: Healthy male SD rats were given a single gavage of Trichosanthes sustained-release pellets or Trichosanthes extract, and orbital blood samples were taken at different time points within 48 h after drug administration in the pellet group and within 5 h in Trichosanthes extract group for determination of the plasma concentrations of 3, 29-DK using LC-MS/MS. The standard curve of 3, 29-DK content was established, and the specificity, minimum detection limit, precision and accuracy, extraction recovery, stability and matrix effect of LC-MS/MS analysis were assessed. The mean plasms levels of 3, 29-DK at different time points after the drug administration were determined and its pharmacokinetic parameters were calculated using Das 2.0 software. RESULTS: LC-MS/MS analysis showed a good linearity of 3, 29-DK concentration within the range of 0.5-32 ng/mL, and the results of methodological validation confirmed the validity of this method for biological sample determination. Trichosanthes sustained-release pellets and Trichosanthes extract showed significant differences in their AUC, AUC, MRT, MRT, t and T of 3, 29-DK after administration in rats ( < 0.05). CONCLUSIONS Trichosanthes sustained-release pellets are capable of sustained-release of 3, 29-DK in rats, and thus provides a basis for the study of new dosage forms of Trichosanthes.
Animals ; Area Under Curve ; Benzoates ; pharmacokinetics ; Chromatography, Liquid ; Delayed-Action Preparations ; Male ; Rats ; Rats, Sprague-Dawley ; Reproducibility of Results ; Tandem Mass Spectrometry ; Trichosanthes ; chemistry

Immunoglobulin Y (IgY) is an effective orally administered antibody used to protect against various intestinal pathogens, but which cannot tolerate the acidic gastric environment. In this study, IgY was microencapsulated by alginate (ALG) and coated with chitooligosaccharide (COS). A response surface methodology was used to optimize the formulation, and a simulated gastrointestinal (GI) digestion (SGID) system to evaluate the controlled release of microencapsulated IgY. The microcapsule formulation was optimized as an ALG concentration of 1.56% (15.6 g/L), COS level of 0.61% (6.1 g/L), and IgY/ALG ratio of 62.44% (mass ratio). The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%, a loading capacity of 33.75%, and an average particle size of 588.75 μm. Under this optimum formulation, the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface, and thus the GI release rate of encapsulated IgY was significantly reduced. The release of encapsulated IgY during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions, respectively. The microcapsule also allowed the IgY to retain 84.37% immune-activity after 4 h simulated GI digestion, significantly higher than that for unprotected IgY (5.33%). This approach could provide an efficient way to preserve IgY and improve its performance in the GI tract.
Alginic Acid/chemistry* ; Chitin/chemistry* ; Chitosan ; Delayed-Action Preparations ; Digestion ; Drug Compounding ; Drug Liberation ; Gastrointestinal Tract/metabolism* ; Immunoglobulins/metabolism* ; Oligosaccharides

In the present study, a gastric retention floating system for Brucea javanica oil, composed of alginate and carrageenan, was prepared using ionotropic gelation. Parameters for floatability, drug load, encapsulation efficiency, bead morphology, in vitro release, and in vivo gastric retention were evaluated. The optimized formulation via Box-Behnken design consisted of 1.7% alginate (W/V), 1.02% carrageenan (W/V), 1.4% CaCO (W/V), and a gelling bath of pH 0.8. The alginate-carrageenan-Brucea javanica oil beads had a porous structure and exhibited up to 24 h of in vitro floatability with a load capacity of 45%-55% and an encapsulation efficiency of 70%-80%. A 6-h sustained release was observed in vitro. The beads had a prolonged gastric retention (> 60% at 6 h) in fasted rats, compared to non-floating beads (15% at 6 h), as measured by gamma scintigraphy with single-photon emission tomography/computed tomography (SPET/CT). In conclusion, the alginate-carrageenan-Brucea javanica oil system showed enhanced oil encapsulation efficiency, excellent floating and gastric retention abilities, and a favorable release behavior.
Alginates ; chemistry ; Animals ; Biological Availability ; Brucea ; chemistry ; Carrageenan ; chemistry ; Delayed-Action Preparations ; administration & dosage ; chemistry ; pharmacokinetics ; Drug Carriers ; chemistry ; Drug Delivery Systems ; methods ; Drug Evaluation, Preclinical ; Gastric Mucosa ; metabolism ; Glucuronic Acid ; chemistry ; Hexuronic Acids ; chemistry ; Microspheres ; Plant Oils ; administration & dosage ; chemistry ; pharmacokinetics ; Rats ; Rats, Sprague-Dawley

As the carrier of water-insoluble drugs, microspheres can play a role in increasing solubility and delaying releasing essence. The objective of this study was to improve the solubility and to delay the release of a newly discovered antitumor compound 3β-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester (T-OA). Early-stage preparation discovery concept (EPDC) was employed in the present study. The preparation, physicochemical characterization, and drug release properties of PLGA microspheres were evaluated. T-OA-loaded PLGA microspheres were prepared by an oil-in-water (O/W) emulsification solvent evaporation method. Characterization and release behaviors of the T-OA PLGA microspheres were evaluated by X-ray diffract (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high performance liquid chromatography (HPLC). The results demonstrated that T-OA-loaded PLGA microspheres could be successfully obtained through solvent evaporation method with appropriate morphologic characteristics and high encapsulation efficiency. The XRD analysis showed that T-OA would be either molecularly dispersed in the polymer or distributed in an amorphous form. The DSC and FTIR analysis proved that there were interactions between T-OA and PLGA polymer. SEM observations displayed the morphology of the microspheres was homogeneous and the majority of the spheres ranged between 50 and 150 μm. The drug release behavior of the microspheres in the phosphate buffered saline medium exhibited a sustained release and the duration of the release lasted for more than 23 days, which was fit with zero-order release pattern with r = 0.9947. In conclusion, TOA-loaded PLGA microspheres might hold great promise for using as a drug-delivery system in biomedical applications.
Antineoplastic Agents ; chemistry ; Calorimetry, Differential Scanning ; Chemistry, Pharmaceutical ; Delayed-Action Preparations ; chemistry ; Drug Carriers ; chemical synthesis ; chemistry ; Lactic Acid ; chemical synthesis ; chemistry ; Microscopy, Electron, Scanning ; Microspheres ; Oleanolic Acid ; chemistry ; Polyglycolic Acid ; chemical synthesis ; chemistry ; Polylactic Acid-Polyglycolic Acid Copolymer ; Pyrazines ; chemistry ; Solubility ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction

OBJECTIVETo prepare insulin-loaded polymeric nanoparticles based on polyethyleneimine-polycaprolactone- polyethylene glycol-polycaprolactone-polyethyleneimine pentablock copolymers and evaluate its in vitro release of insulin.

METHODSPolycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) triblock copolymer was synthesized by ring-opening polymerization method, and the pentablock copolymer was prepared by Michael addition reaction. The copolymers obtained were characterized by Fourier-transform infrared (FT-IR) spectroscopy and (1)H-NMR and their critical aggregation concentration (CAC) was measured by fluorescence technique with pyrene as the probe. Insulin-loaded polymeric nanoparticles based on the pentablock copolymers were prepared by solvent evaporation method that exploited the cationic nature of PEI-PCL-PEG-PCL-PEI to allow the formation of ionic complexes with anionic biomolecules such as insulin. The prepared nanoparticles were further characterized by Malvern laser particle sizer and transmittion electron microscopy (TEM). The drug loading, encapsulation efficiency and in vitro release profile of the nanoparticles were analyzed using Bradford method.

RESULTSUsing copolymer PEI10K-PCL4K-PEG2K-PCL4K-PEI10K as the drug carrier, the spherical nanoparticles prepared with an optimal insulin-coplymer mass ratio of 40% allowed the maximum insulin loading of (18.63∓0.07)% and had an average particle size of 175.30∓19.51 nm. The prepared nanoparticles was capable of sustained release of insulin for as long as 48 h in vitro, and the burst release could be minimized by incorporation of PEI in the triblock copolymer.

CONCLUSIONThe insulin-loaded polymeric nanoparticles based on the pentablock copolymers allow sustained release of insulin in vitro, and PEI can enhance sustained drug release and reduce burst drug release.

Delayed-Action Preparations ; Drug Carriers ; chemistry ; Drug Liberation ; Insulin ; pharmacokinetics ; Nanoparticles ; chemistry ; Particle Size ; Polyesters ; chemistry ; Polyethylene Glycols ; chemistry ; Polymers ; chemistry ; Spectroscopy, Fourier Transform Infrared