RESUMO
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors in mammals that contain seven transmembrane helices. The human genome encodes about 800 different types of GPCRs, which are widely involved in the pathological processes underlying different diseases, e.g. metabolic diseases and tumors, rendering them popular therapeutic targets. Peptides are organic substances consisted of two to dozens of amino acids linked by peptide bonds. They are bioactive substances involved in various cellular activities. To date, over 7 000 natural peptides have been identified as hormones, neurotransmitters, growth factors, ion channel ligands and antibiotics. Peptide drugs are valued for being selective and efficacious, and at the same time relatively safe and with low costs of production. In recent years, based on the increased understanding of GPCR structures, the development of GPCR-targeting peptide drugs has made great progress. Up to now, there have been nearly 50 peptide drugs targeting GPCRs approved by FDA for the treatment of metabolic diseases, nervous system diseases, cancer or other diseases. The research and development of peptide drugs have gone through three stages: development based on human peptides, on natural peptides and by modern biotechnology. At present, most of the marketed GPCR-targeting peptide drugs are derivatives of human natural peptides. In this review, we sum up the recent marketed GPCR-targeting peptide drugs, and also summarize the current strategies and further directions of peptide drug development.
RESUMO
@#As one of the most important biological drugs, protein and peptide drugs have been increasingly used in the prevention, diagnosis and treatment of diseases in recent years. However, most of them need to be injected and lack of long-acting formulations, which brings many troubles to patients suffering from chronic diseases. In this review, we summarized the strategies for engineering long-acting formulations for proteins and peptides via preparation means, including extended-release injection, implant, oral preparations and transdermal drug delivery systems, and analyzed their release mechanisms, research advances, advantages and shortcomings, thereby providing potential approaches for promoting the formulation improvement of these drugs.
RESUMO
Objective To find the efficient modification groups of anti-proteinase hydrolyzation in polypeptide by investigat-ing and comparing the relation between the functional groups and their ability to inhibit proteinase hydrolyzation. Methods Reverse phase-high performance liquid chromatography(RP-HPLC)method was developed to investigate in vitro metabolisms of new drug LXT101 and its structural modified analogs LZN series and LMP series in pancreatin system. All the separations of peptide drugs and their digested fragments were monitored at 225 nm. Results The good linear range was 4.0-400 μg/ml(r>0.9990)for new drug LXT101 and its structural modified analogs,i.e.,LZN series and LMP series. The recoveries of all peptide drugs ranged from 95.0%to 98.7%in pancreatin systems. The relative standard derivations(RSD)of intra-day and inter-day were less than 1.5%and 2.5%,re-spectively. The revealed order of digested half-life of the peptide drugs was LZN series>LMP series>LXT101. Conclusion The study of different sites and different functional groups on the lifetime indicates that the half-lives of peptides are prolonged by introducing the functional groups in the suitable sites of peptide,which feature as proteinase inhibitors,such as carbamoyl(Cbm),acetyl(Ac),para-amino-phenylalanine(Aph)or para-uramido-phenylalanine(Uph),which work as either proton donor or acceptor. Our results can pro-vide some useful and valuable information on structural design of peptide drug with long lifetime and high activity.