The dosage of mesoporous materials in the field of high - efficiency drug delivery is not a fixed value and is comprehensively affected by various factors:
I. Influence of Drug Properties
1.1 Drug Solubility
For drugs with low solubility, more mesoporous materials may be required to achieve a sufficient drug - loading capacity. For example, some poorly - soluble lipophilic drugs like paclitaxel have extremely low solubility in water. When using mesoporous materials for loading, the mass ratio of mesoporous materials to the drug may reach 5:1 or even higher to ensure that there are enough pores to accommodate the drug and improve the dispersion and stability of the drug in the system. However, for drugs with better solubility, the amount of mesoporous materials used is relatively less, and the mass ratio may be between 1:1 - 2:1.
Synthesis methods of paclitaxel
1.2 Drug Dose Requirements
The dose requirements for drugs vary greatly among different diseases and patients in clinical treatment. For drugs that require high - dose administration, more mesoporous materials are correspondingly needed for loading. Take antibiotics for treating some severe infectious diseases as an example. To ensure a sufficient amount of drug release to achieve the therapeutic effect, the amount of mesoporous materials added will be adjusted according to the required drug dose, and it may account for a relatively large proportion in the preparation.
II. Varying with the Characteristics of Mesoporous Materials
2.1 Pore Volume and Specific Surface Area
Mesoporous materials with large pore volume and high specific surface area can load more drugs per unit mass, so the amount used is relatively small. For example, mesoporous carbon materials with ultra - large pore volume, when loading the same drug, may only require 30% - 50% of the amount of mesoporous materials with smaller pore volume. This is because the large pore volume and high specific surface area provide more space and adsorption sites to accommodate and bind drug molecules.
The drug - loading capacity of mesoporous materials is restricted by various factors. The drug - loading capacity of mesoporous silica for the small - molecule drug ibuprofen is 10% - 30% (mass fraction). When the pore diameter of mesoporous silica increases from 3 nm to 8 nm, the drug - loading capacity for ibuprofen increases from 12% to 25%. Ordered mesoporous carbon, with its regular pore structure and ultra - high specific surface area (up to more than 2000 m²/g), can have a drug - loading capacity for the hydrophobic drug curcumin exceeding 65%. In practical applications, parameters such as the molecular size and solubility of the drug, as well as the pore diameter and specific surface area of the mesoporous material, need to be considered to optimize the drug - loading conditions. For example, for macromolecular protein drugs, mesoporous materials with larger pore diameters are selected, and the loading time is appropriately extended and the drug concentration is increased to improve the drug - loading capacity.
2.2 Material Stability
Mesoporous materials with poor stability may degrade or have their structure damaged relatively quickly in the body. To maintain the effectiveness of the drug delivery process, the amount used may need to be increased to compensate for the loss during the process. Conversely, for mesoporous materials with good stability, the amount required for a single administration can be appropriately reduced.
III. Adjustment According to the Route of Administration and Dosage Form
3.1 Injection Administration
For injection dosage forms, the preparation is required to have good fluidity and stability, and there are strict restrictions on particle size, etc. The amount of mesoporous materials needs to be precisely controlled to ensure that the final preparation meets the injection requirements. Generally, in injectable nano - scale mesoporous material - drug preparations, the mass fraction of mesoporous materials in the entire preparation may be controlled at around 10% - 30%. This is to ensure sufficient drug loading while avoiding excessive materials causing the preparation to be too viscous or triggering adverse reactions.
In animal experiments and pre - clinical studies, the in - vivo dosage of the mesoporous material - drug delivery system needs to be strictly controlled. For example, in mouse intravenous injection experiments, when using a mesoporous material - drug delivery system to deliver anti - tumor drugs, the dose is usually controlled at 5 - 50 mg per kilogram of body weight (calculated by the mass of mesoporous materials). When the dosage is less than 5 mg per kilogram of body weight, tumor growth cannot be effectively inhibited in some mice. When the dosage exceeds 50 mg per kilogram of body weight, about 30% of the mice show obvious weight loss, liver and kidney function damage and other toxic and side effects. If the drug - loading capacity of the mesoporous material is 30%, to achieve a drug treatment dose of 10 mg per kilogram of body weight, for a 20 - gram mouse, a drug - loaded system containing about 6.7 mg of mesoporous materials needs to be injected.
Intravenous injection experiment of tumor drugs in mice
3.2 Oral Administration
Oral preparations need to consider the tolerance of the gastrointestinal tract and the drug - release environment. The amount of mesoporous materials used is usually relatively high. On the one hand, it is necessary to ensure that the drug can be stably released in the complex environment of the gastrointestinal tract. On the other hand, it is necessary to ensure that the preparation has good dispersion in the gastrointestinal tract. In oral tablets or capsules, mesoporous materials may account for 30% - 60% of the total mass of the preparation.
3.3 Auxiliary Additives
During the drug - loading process, some auxiliary additives are sometimes added to improve the drug - loading efficiency or stability. For example, a small amount of surfactant (such as sodium dodecyl sulfate, SDS) is added to improve the dispersion of the drug on the surface of the mesoporous material. Its dosage is generally controlled at 0.1% - 1% of the mass of the mesoporous material. Excessive use may affect the drug - release behavior and the biocompatibility of the mesoporous material.
IV. Determination According to the Treatment Goal
4.1 Local Treatment
When used for local treatment, such as skin wound healing and treatment of eye diseases, the drug only needs to act locally, and the amount of mesoporous materials used is relatively small. Take eye drops for treating eye inflammation as an example. The content of mesoporous materials in the mesoporous material - drug preparation may be low to avoid irritation to the eyes, usually 5% - 15% in the mass fraction of the preparation.
Nano - hydrogel eye drops are highly effective in treating eye inflammation.
4.2 Systemic Treatment
For systemic diseases, such as chemotherapy for cancer and long - term drug treatment for some chronic diseases, the drug needs to circulate continuously in the body and play a role. High requirements are placed on the drug - loading capacity and release stability, and the amount of mesoporous materials used is generally relatively large. In some nano - drug preparations for cancer chemotherapy, mesoporous materials may account for 20% - 50% of the total mass of the preparation.
