Poly(lactic acid) (PLA) microspheres refer to the presence of PLA in the form of microspheres. PLA microsphere carriers can overcome some of the drawbacks of existing drug formulations and have the advantages of controlling the release rate of drugs to achieve long-lasting and slow release, increasing drug targeting, reducing toxic side effects, and improving therapeutic efficacy.
Depending on the nature of the drug and the requirements of the formulation, the particulate formulation of the drug can be prepared by different methods. The main methods are emulsification solvent volatilization method, spray drying method, phase separation method and melting method.
Polylactic acid (PLA) has become one of the most valued materials in the biomedical field due to its good biocompatibility and biodegradability, its degradation products can participate in human metabolism and its performance can be adjusted in a wide range by copolymerization with other monomers. It is less irritating and can be easily excreted from the body without accumulation, and the undegraded ones can be excreted with feces, avoiding secondary harm to patients.
PLA and its copolymers are used as controlled release carriers for drugs with short half-life, poor stability, easy degradation and high toxic side effects, such as antibiotics, anti-cancer drugs, vaccines, hormones, birth control drugs, antipyretic and analgesic drugs and neurological drugs, which can effectively increase the route of drug delivery, reduce the number and amount of drug delivery, improve drug utilization and reduce the side effects of drugs on liver and kidney.
PLA and its copolymer-based extended release formulations have been commercialized, including luteinizing hormone-releasing hormone LHRH class drug goserelin subcutaneous implant, leuprolide intramuscular injection suspension, thyrotropin-releasing hormone TRH class drug treprostin, antibiotic benzocillin, etc. There are many drugs under investigation, mainly anticancer chemotherapy drugs, antipyretic and analgesic drugs, neurological drugs, hormonal and family planning drugs, etc., all of which are in the laboratory research or animal testing stage. In addition, according to the nature of the drug, release requirements and route of administration, specific drug dosage forms can be made.