Study on Pharmacokinetic Interactions Between HS-10234 and Emtricitabine in Healthy Subjects: An Open-Label, Two-Sequence, Self-Controlled Phase I Trial.

INTRODUCTION: HS-10234, a novel prodrug of tenofovir (TFV), functions by inhibiting nucleotide reverse transcriptase against retroviral infections including hepatitis B virus and human immunodeficiency virus (HIV). As it is a possible substitute for TFV co-administration with emtricitabine, determining the drug-drug interactions (DDI) between HS-10234 and emtricitabine therapy will be helpful for researchers to design and conduct future phase II/III studies and merits careful examination in the era of evolving new combination antiretroviral therapy regimens. METHODS: We conducted an open-label, two-sequence, two-period, self-controlled phase I trial that enrolled 36 healthy volunteers randomized into two groups (group 1 and group 2). Eighteen subjects in group 1 were orally administered HS-10234 at a 25-mg daily dose for 7 days during period 1 (D1-D7) followed by co-administration of emtricitabine at a 200-mg dose once daily (QD) for 7 additional days during period 2 (D8-D14). Participants in group 2 were orally administered emtricitabine 200 mg QD for 7 days during period 1 (D1-D7) and then co-administered HS-10234 25 mg QD for 7 additional days during period 2 (D8-D14). Pharmacokinetics (PK) of HS-10234 and emtricitabine were characterized when administered alone and in combination. The concentrations of HS-10234 and its metabolites TFV and emtricitabine were determined using high performance liquid chromatography-mass spectrometry (HPLC-MS)/MS. Peripheral blood monocyte cells (PBMCs) were isolated for detection of intracellular concentrations of HS-10234's active metabolite, intracellular tenofovir diphosphate (TFV-DP) pre-dose and 2, 4, 8, 12 and 24 h post-dose on D7 and D14 in group 1. WinNonlin software was used to calculate PK parameters. RESULTS: After multiple-dose administration of HS-10234 with emtricitabine, the AUC0-tau of HS-10234 and TFV-DP was 1.327- and 1.403-fold higher than that with HS-10234 administration alone. The Cmax and AUC0-tau were increased 1.120- and 1.077-fold compared to emtricitabine administration alone. Co-administration of HS-10234 with oral emtricitabine was well tolerated. No serious adverse events were observed. CONCLUSIONS: Although a slightly increased steady-state PK exposure of HS-10234 and TFV-DP was observed with co-administration of oral HS-10234 with emtricitabine, these changes were not considered clinically relevant. Thus, dose adjustments are not recommended for HS-10234 combination with emtricitabine. TRIAL REGISTRATION: NCT04477096, July 20, 2020.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects.

BACKGROUND AND OBJECTIVES: Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K+ of the H+, K+-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects. METHODS: Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms. RESULTS: No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (Tmax) at 0.5 h and declined with a terminal (elimination) half-life (t1/2) of 3.87-4.57 h. The maximum measured plasma concentration (Cmax) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the corresponding area under the concentration-time curve (AUC) from time zero to infinity (AUC0-inf) was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of Cmax and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender. CONCLUSIONS: Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mg in multiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

Design, synthesis, structure-function relationship, bioconversion, and pharmacokinetic evaluation of ertapenem prodrugs.

Described here are synthesis and biological evaluations of diversified groups of over 57 ertapenem prodrugs which include alkyl, methylenedioxy, carbonate, cyclic carbonate, carbamate esters, and esters containing active transport groups (e.g., carboxyl, amino acid, fatty acids, cholesterol) and macrocyclic lactones linking the two carboxyl groups. Many of the prodrugs were rapidly hydrolyzed in rat plasma but not in human plasma and were stable in simulated gastrointestinal fluid. The diethyl ester prodrug showed the best total absorption (>30%) by intredeudenal dosing in dogs, which could potentially be improved by formulation development. However, its slow rate of the hydrolysis to ertapenem also led to the presence of large amounts of circulating monoester metabolites, which pose significant development challenges. This study also suggests that the size of susbtituents at C-2 of carbapenem (e.g., benzoic acid of ertapenem) has significant impact on the absorption and the hydrolysis of the prodrugs.

Design, synthesis, and evaluation of prodrugs of ertapenem.

Carbapenems are intravenous lifesaving hospital antibiotics. Once patients leave the hospital, they are sent home with antibiotics other than carbapenems since they cannot be administered orally due to lack of oral absorption primarily because of very highly polarity. A prodrug approach is a bona fide strategy to improve oral absorption of compounds. Design and synthesis, in vitro and in vivo evaluation of diversified prodrugs of ertapenem, one of the only once daily dosed carbapenems is described. Many of the prodrugs prepared for evaluation are rapidly hydrolyzed in rat plasma. Only bis-(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl (medoxomil) ester prodrug was rapidly hydrolyzed in most of the plasmas including rat, human, dog, and monkey. Although the rate of conversion of ertapenem diethyl ester prodrug (6) was slow in in vitro plasma hydrolysis, it showed the best in vivo pharmacokinetic profile in dog by an intraduodenal dosing giving >31% total oral absorption.

Cloning of a novel protease required for the molting of Locusta migratoria manilensis.

Molting is required for progression between larval stages in the life cycle of an insect. The essence of insect molting is the laying down of new cuticle followed by shedding of the old cuticle. Degradation and recycling of old cuticle are brought about by enzymes present in the molting fluid, which fills the space between the old and new cuticle. Here, we describe the cloning of a novel protease gene from Locusta migratoria manilensis, designated as Lm-TSP. The cDNA and its deduced protein sequences were deposited in GenBank (accession numbers EF081255 and ABN13876, respectively). Sequence analysis indicated that Lm-TSP belongs to the trypsin-like serine protease family. We show, by RNA interference (RNAi), that silencing of Lm-TSP leads to dramatic reductions in protease and cuticle-degrading activity of a molting fluid, which leads to molting defects from fourth-instar larvae (L4) to fifth-instar larvae (L5), and between L5 and adult stages. These observations suggest that Lm-TSP plays a critical role in L. migratoria manilensis ecdysis.