Metabolism and Pharmacokinetics of 3-n-Butylphthalide (NBP) in Humans: The Role of Cytochrome P450s and Alcohol Dehydrogenase in Biotransformation

Abstract

3-n-Butylphthalide (NBP) is a cardiovascular drug currently used for the treatment of cerebral ischemia. The present study aims to investigate the metabolism, pharmacokinetics, and excretion of NBP in humans and identify the enzymes responsible for the formation of major metabolites. NBP underwent extensive metabolism after an oral administration of 200 mg NBP and 23 metabolites were identified in human plasma and urine. Principal metabolic pathways included hydroxylation on alkyl side chain, particularly at 3-, v-1-, and v-carbons, and further oxidation and conjugation. Approximately 81.6% of the dose was recovered in urine, mainly as NBP-11-oic acid (M5-2) and glucuronide conjugates of M5-2 and mono-hydroxylated products. 10-Keto-NBP (M2), 3-hydroxy-NBP (M3-1), 10-hydroxy-NBP (M3-2), and M5-2 were the major circulating metabolites, wherein the areas under the curve values were 1.6-, 2.9-, 10.3-, and 4.1-fold higher than that of NBP. Reference standards of these four metabolites were obtained through microbial biotransformation by Cunninghamella blakesleana. In vitro phenotyping studies demonstrated that multiple cytochrome P450 (P450) isoforms, especially CYP3A4, 2E1, and 1A2, were involved in the formation of M3-1, M3-2, and 11-hydroxy-NBP. Using M3-2 and 11-hydroxy-NBP as substrates, human subcellular fractions experiments revealed that P450, alcohol dehydrogenase, and aldehyde dehydrogenase catalyzed the generation of M2 and M5-2. Formation of M5-2 was much faster than that of M2, and M5-2 can undergo b-oxidation to yield phthalide-3-acetic acid in rat liver homogenate. Overall, our study demonstrated that NBP was well absorbed and extensively metabolized by multiple enzymes to various metabolites prior to urinary excretion.

CYP267A1 and CYP267B1 from Sorangium cellulosum So ce56 are Highly Versatile Drug Metabolizers

“…(Zhang et al, 1996;Asha and Vidyavathi, 2009;Bright et al, 2011;Murphy and Sandford, 2012;Diao et al, 2013), the systems were not selective and side products were usually observed. In addition, the nonoptimized media conditions used in these approaches could also interfere with the product identification.…”

“…To circumvent such limitations, alternative approaches of using microorganisms have been practiced, in which several microorganisms such as the fungus Cunninghamella sp. or bacterial variants of Streptomyces strains were shown to transform drugs and xenobiotics to mammalian metabolites (Zhang et al, 1996;Asha and Vidyavathi, 2009;Bright et al, 2011;Murphy and Sandford, 2012;Diao et al, 2013). However, because of the release of side products and the difficulty on handling the microbes during such biotransformation process, there is now a great interest in cytochrome P450 (P450) enzymes for the production of drug metabolites.…”

High-Resolution Mass Spectrometry for Characterizing the Metabolism of Synthetic Cannabinoid THJ-018 and Its 5-Fluoro Analog THJ-2201 after Incubation in Human Hepatocytes

“…3C). We propose M9 as 4Ј-OH-THJ-018 because -hydroxylation and -1-hydroxylation were usually the primary biotransformations for drugs with aliphatic side chains and displayed similar physicochemical properties (22)(23)(24). This phenomenon also was observed for 5Ј-OH-JWH-018 and 4Ј-OH-JWH-018 (11 ).…”

“…3D). 4Ј-Carbonylation products also were major metabolites of drugs with aliphatic side chain such as 3-n-butylphthalide and sameridine (22,24 ). Metabolite M1 shared fragments m/z 145.0399, 213.1017, and 231.1128 with M9 (Fig.…”

Studies on the Interaction Between Triptolide and Bovine Serum Albumin (Bsa) by Spectroscopic and Molecular Modeling Methods

“…Most drugs and biological active small molecules bind with serum-albumin strongly and reversibly, forming a drugprotein complex (Diao et al, 2013); the drug-protein interaction affects the distribution, metabolism, efficacy, toxicity and stability during the therapeutic process (Diao et al, 2015).…”