Protein Peptide Drug Lung Inhalation Nano Preparation
Pulmonary administration has great advantages as a non-invasive route of administration of protein and peptide drugs. The human respiratory tract has a large surface area, which can avoid the first pass effect of the liver. In addition, the viscosity of the epithelial cell barrier is low, and there is a large amount of potential vasculature, low proteolytic activity and low acidity. Compared with the gastrointestinal tract, there is a thinner mucus layer, so the lungs are suitable for local and systemic administration. However, the mucosa of the respiratory tract is very tight and complex, and it is difficult for macromolecular drugs to penetrate. In fact, a single macromolecule is difficult to cross the epithelial cells, is easily degraded by enzymes in the respiratory tract, and is easily cleared by macrophages or mucociliary hairs, so the bioavailability is very low. For example, the systemic bioavailability of insulin nasal administration is very low, only about 1%, and it is difficult to exert a therapeutic effect. The preparation of protein peptide drugs into nano preparations and then pulmonary administration is an effective method to improve the bioavailability of biotechnology drugs. At present, there are many kinds of protein peptide drugs in the lung inhalation nano-formulations that have proved to be effective.
Insulin
Insulin liposomes with average particle diameters of 1.91μm and 2.08μm were prepared by thin film ultrasonic dispersion method and reverse phase evaporation method. After instillation into the rat trachea, the two liposomes had significant blood glucose lowering effects, the minimum blood glucose concentration is less than 5%, the time to reach the lowest blood sugar level is about 180 minutes. In comparison, intratracheal instillation of the same dose of insulin solution can also significantly reduce blood glucose levels. The minimum blood glucose concentration is about 20%, and the time to reach the minimum blood glucose level is about 120 minutes. Therefore, liposomes have the effect of promoting the absorption of the islet cord from the lungs. The relative bioavailability of insulin liposome pulmonary administration and subcutaneous injection of insulin solution is 37%, while that of insulin solution pulmonary administration is 29%. Insulin liposomes and physical suspensions of insulin and blank liposomes have no significant difference in promoting the pulmonary absorption of insulin, enhancing the hypoglycemic effect and prolonging the action time. Therefore, the surface activity of liposomal phospholipids and the activation of alveolar surface macrophages are the main factors that promote the absorption of insulin in the lungs.
Calcitonin
Chitosan-modified nanoparticles have the advantages of bioadhesiveness, slower clearance rate, and longer drug effect time. Taking calcitonin as a model drug, PLGA nanoparticles are prepared by the emulsification-solvent diffusion method, and then modified with chitosan to obtain chitosan-modified calcitonin PLGA nanoparticles with a particle size of 650nm and a particle size of about 6.5 μm after atomization, the effective part deposition rate is 51.3%. It has a significant effect on reducing the blood calcium concentration, reducing the blood calcium concentration to 80% of the total calcium content, and the pharmacological effect time can be extended to 24h, which has significant advantages compared with the nanoparticles that are not modified by chitosan.
Thymopentin
The spray-drying technology is used to prepare lung inhalation microspheres composed of solid lipid nanoparticles loaded with thymopentin. The surface of the microspheres is porous, with a particle size of 4.8 μm, a bulk density as low as 0.48 g/cm3, and a solid density of 0.71 g/cm3. The microspheres have good inhalation characteristics, the emptying rate is 85.0%, the effective site deposition rate is 61.6%, and they can be effectively distributed into the alveoli. Nanoparticles and thymopentin can maintain good stability during the preparation process. This new type of microsphere has suitable inhalation characteristics and is a pulmonary drug delivery system with good application prospects.
Interleukin
Interleukin 2 is a commonly used immunopotentiator for adjuvant treatment of tumors and immunodeficiency diseases. It is usually administered by subcutaneous injection, but it is easy to cause swelling at the injection site. Aerosolized IL-2 liposomes and blank liposomes with a particle size of 1.1 μm to immunodeficiency patients and hepatitis patients. After 12 weeks of continuous administration, no changes in the patient’s lung function were observed. The chest X-ray examination was also No abnormalities were seen. Nine lung cancer patients were inhaled with different doses of IL-2 liposomes 3 times a day for 20 minutes each time, and no obvious toxic reaction was observed. Therefore, the patients were considered to be able to tolerate the inhalation of IL-2 liposomes.
Bovine serum albumin
With bovine serum albumin (BSA) as a model drug, low-density porous particles (PM) were prepared by the W/O/W double-emulsification method. The sulfobutyl ether-β cyclodextrin is used as a protein stabilizer, sodium hyaluronate is used as a base material, and sucrose ethyl acetate (SAIB) is added to obtain the sustained release effect of protein. In vitro studies have shown that due to the high viscosity of SAIB added, BSA can be continuously released from PM for 7 days. PM has a small aerodynamic particle size, which can reach the deep lung; meanwhile, the density of PM is small, and the geometric particle size is greater than 5 pm. Because of the large particle size, macrophages are prevented from phagocytosis, so PM can be used as a protein and peptide drug for the lungs. Therefore, PM can be used as a long-acting dosage form for pulmonary administration of protein and peptide drugs.
Immune antigen
In the early stage of pulmonary tuberculosis infection, EAST-6 secreted by Mycobacterium tuberculosis is an important antigen for T lymphocyte-mediated immunity. Polylactic acid (PLA) particles encapsulating EAST-6 can induce an immune response mediated by lymph node cells in the lungs and mediastinum after being sucked into the lungs. The PLA particles have a smooth surface, good roundness, and an average particle size of 1.179μm. D10, D50 and D90 are 0.82pm, 1.17μm and 2.10μm, respectively. The encapsulation rate of EAST-6 is 0.8%. Intranasal instillation of the microparticle preparation in mice resulted in a strong immune response in the lungs, indicating that the microparticles have a good application prospect as a carrier of lung infection antigens.
Plasmid DNA
Biological macromolecules, such as biologically active peptides, plasmid DNA and small interfering RNA (siRNA) are usually freeze-dried to prepare nano-sized particles, but they tend to aggregate. The spray-drying method is used to prepare PLGA cationic nanospheres as a gene delivery carrier, which can reduce aggregation and improve transfection efficiency. Dissolve PLGA and cationic materials in a mixed solvent of acetone/methanol and add them to stirred water to obtain nanoemulsion. Add mannitol and spray dry to obtain mannitol particles containing PLGA nanospheres. The particle size is 100~250nm, which is better than the freeze-drying method. The obtained PLGA particles have a much smaller particle size. Using cationic PLGA/PEI nanospheres as a carrier of plasmid DNA can avoid damage by nuclease. Taking COS-7 cells as a model in vitro, luciferase has obvious expression. In vivo experiments in mice showed that cationic PLGA/PEI nanospheres, as plasmid DNA carriers, interact with serum proteins in vivo and are easily captured by the pulmonary capillary bed, so the luciferase activity is highest in the lungs. The luciferase activity of the PLGA/PEI nanospheres as a carrier is higher than that of the PLGA/PEI microsphere software, indicating that the particle size affects the efficiency of gene transfection in vivo.