4.8
药物与血液成分的结合
当药物进入体循环时，它们会与血液的各种成分相互作用，包括人血清白蛋白 (HSA)、α_1-酸性糖蛋白 (AAG)、脂蛋白、球蛋白和红细胞 (RBC)。
HSA 是最丰富的血浆蛋白，在药物结合中至关重要。它包含不同的药物结合位点，不同的药物对特定位点表现出亲和力。 HSA 有三个主要药物结合域：位点…
当药物进入体循环时，会与血液成分相互作用，例如人血清白蛋白（HSA）、α1-酸性糖蛋白（AAG）、脂蛋白、球蛋白以及红细胞（RBCs）。
HSA 是最丰富的血浆蛋白，具有特定的药物结合位点。例如， 华法林、某些非甾体抗炎药（NSAIDs）和丙戊酸钠结合于位点 I。位点 II 结合苯二氮䓬类药物、布洛芬和氯唑西林。极少药物结合于位点 III 和 IV。
AAG 可结合丙米嗪、利多卡因和普萘洛尔等药物。
亲脂性药物（如环孢素和胺碘酮）会与脂蛋白结合，而这种结合受到药物脂质含量的影响。
皮质醇和泼尼松等类固醇可与血浆球蛋白（如α1-球蛋白）结合。
亲脂性药物比亲水性药物对红细胞具有更高的亲和力。红细胞的特定组分，如血红蛋白、碳酸酐酶和细胞膜，能够结合不同的药物。
苯妥英等药物与血红蛋白结合，而乙酰唑胺则与碳酸酐酶结合。丙米嗪可与红细胞膜结合。
View the full transcript and gain access to JoVE Core videos
Q1: What is human serum albumin and why is it important for drug binding?
Human serum albumin (HSA) is the most abundant plasma protein in blood and plays a vital role in drug binding. HSA contains distinct drug-binding sites—sites I, II, III, and IV—each with different drug affinities. For example, warfarin and NSAIDs bind to site I, while benzodiazepines and ibuprofen bind to site II. Understanding HSA binding is essential for predicting drug distribution and pharmacokinetic behavior.
Q2: Which drugs bind to different sites on human serum albumin?
Different drugs exhibit affinity for specific HSA binding sites. Warfarin, certain NSAIDs, and sodium valproate bind to site I. Benzodiazepines, ibuprofen, and cloxacillin bind to site II. Diazepam and insulin detemir bind to site III, while tamoxifen binds to site IV. Only a few drugs bind to sites III and IV compared to the more commonly used sites I and II.
Q3: How do lipophilic drugs interact with blood lipoproteins?
Lipophilic drugs with high lipid content, such as cyclosporine and amiodarone, exhibit strong binding to lipoproteins in the bloodstream. This binding is influenced by the drug's lipid solubility and can significantly impact the drug's distribution and elimination from the body. Understanding lipoprotein binding helps predict how lipophilic drugs move through circulation.
Q4: What role do red blood cells play in drug binding?
Red blood cells (RBCs) bind drugs through specific components including hemoglobin, carbonic anhydrase, and cell membranes. Lipophilic drugs show higher affinity for RBCs than hydrophilic drugs. For example, phenytoin binds to hemoglobin, acetazolamide binds to carbonic anhydrase, and imipramine binds to the RBC membrane. This binding affects factors affecting protein drug binding patient related factors and overall drug distribution.
Q5: How does alpha-1-acid glycoprotein differ from human serum albumin in drug binding?
Alpha-1-acid glycoprotein (AAG) is another plasma protein that binds drugs like imipramine, lidocaine, and propranolol. Unlike HSA, which has multiple defined binding sites, AAG binds a more specific set of drugs and influences their distribution and pharmacokinetics. AAG levels can vary among patients, affecting individual drug responses and therapeutic outcomes.
Q6: Which steroids bind to plasma globulins and what is the significance?
Steroids like cortisone and prednisone bind to plasma globulins, particularly alpha-1-globulin. This binding influences the distribution and pharmacological effects of these drugs throughout the body. The extent of globulin binding affects how much free, active drug is available for therapeutic action, making it important for understanding steroid pharmacokinetics.
Q7: Why is understanding drug-blood component interactions important in pharmacology?
Understanding how drugs interact with blood components—HSA, AAG, lipoproteins, globulins, and RBCs—is vital for predicting drug distribution, metabolism, and pharmacokinetic behavior. This knowledge helps optimize drug therapy, identify potential drug-drug interactions, and ensure effective and safe pharmacological outcomes for patients receiving medications.