Metal-organic frameworks MOFs are a class of porous materials composed of metal ions or clusters connected by organic ligands. They have gained significant attention in recent years due to their potential applications in various fields, including gas storage, catalysis, and drug delivery. MOFs can be utilized for the storage and delivery of drugs in the following ways:1. Drug encapsulation: MOFs can encapsulate drug molecules within their porous structures, which can then be released in a controlled manner. The large surface area and tunable pore size of MOFs allow for high drug loading capacities and the possibility to accommodate a wide range of drug molecules.2. Drug conjugation: MOFs can be functionalized with specific organic ligands that can bind to drug molecules, forming a drug-MOF conjugate. This approach can improve the stability and solubility of the drug, as well as provide a means for targeted drug delivery.3. Stimuli-responsive drug release: MOFs can be designed to respond to specific stimuli, such as pH, temperature, or light, which can trigger the release of the encapsulated or conjugated drug. This allows for controlled drug release at the desired site and time, minimizing side effects and improving the efficacy of the treatment.Several factors influence the drug release behavior from MOFs:1. Pore size and structure: The pore size and structure of the MOF play a crucial role in determining the drug loading capacity and release rate. Larger pores can accommodate larger drug molecules and allow for faster release, while smaller pores can lead to slower release rates.2. MOF stability: The stability of the MOF in physiological conditions is essential for drug delivery applications. If the MOF degrades too quickly, the drug may be released prematurely, while if it is too stable, the drug may not be released at all.3. Drug-MOF interactions: The strength of the interactions between the drug and the MOF can influence the release rate. Stronger interactions can lead to slower release rates, while weaker interactions can result in faster release.4. External stimuli: As mentioned earlier, MOFs can be designed to respond to specific stimuli, such as pH, temperature, or light. The sensitivity of the MOF to these stimuli and the rate at which it responds can influence the drug release behavior.5. Surface functionalization: The surface of the MOF can be functionalized with specific organic ligands or other molecules to improve drug loading, stability, and release. The choice of functional groups and their density on the MOF surface can significantly impact drug release behavior.In summary, MOFs offer a promising platform for drug storage and delivery due to their unique properties, such as high surface area, tunable pore size, and the ability to respond to external stimuli. Understanding the factors that influence drug release behavior from MOFs is crucial for designing effective drug delivery systems.