Lercanidipine Hydrochloride

Tamoxifen, a selective estrogen receptor modulator (SERM) used in breast cancer therapy, requires metabolic activation by CYP3A4 to exert its biological effects. This study evaluated the effects of calcium channel blockers nimodipine, nitrendipine and felodipine on tamoxifen metabolism by studying their interactions with tamoxifen in vitro and in vivo. Rat liver microsomes (RLM) and human liver microsomes (HLM) were used in this study to evaluate the inhibitory potential of nimodipine, nitrendipine and felodipine on tamoxifen metabolism in vitro. A total of 28 cardiovascular drugs, including calcium channel blockers, were screened in an RLM incubation system in vitro. In RLM, nimodipine, nitrendipine and felodipine had half-maximum inhibitory concentration (IC₅₀) values of 5.55 µM, 11.86 µM and 7.71 µM, respectively. In HLM, the IC₅₀ values were increased to 20.38 µM, 30.06 µM, and 44.45 µM for nimodipine, nitrendipine and felodipine, respectively. The kinetic assays indicated that nimodipine and felodipine inhibited the metabolism of tamoxifen in a competitive way, whereas nitrendipine showed non-competitive inhibition in RLM. However, felodipine exhibited non-competitive inhibition, and nimodipine and nitrendipine showed competitive inhibition in HLM. Pharmacokinetic studies in rats revealed that pretreatment with nimodipine and nitrendipine significantly increased the systemic exposure of tamoxifen, as demonstrated by increasing the area under the curve (AUC), the maximum concentration (C_max) and decreasing the clearance (CL_z/F). Finally, molecular docking studies supported these findings, showing potential interactions at the active site of CYP3A4. These results suggested the necessity for careful monitoring and possible dose adjustments of tamoxifen when co-administered with calcium channel blockers in clinic.

The International Council for Harmonisation of Tech. Requirements for Pharmaceuticals for Human Use (ICH) guidelines are commonly used in the pharmaceutical industry to assess drug degradationWhile most studies focus on anal. protocols like impurity isolation and stability assessment, they often neglect detailed structural characterization of degradants thus potentially limiting the development of new chem.The present study investigates the degradation profile of Lercanidipine hydrochloride (LER.HCl), an antihypertensive drug belonging to the calcium channel blocker class with a dihydropyridine moiety, under ICH-guided acidic hydrolytic conditions and subsequent detailed characterization of the isolated degradation products.The acid-mediated hydrolytic condition (at 60 °C for 12 h) led to degradation of LER HCl (20.3 %) to five degradation products (LER-P1- 3.2 %, LER-P2- 4.3 %, LER-P3-5.5 %, LER-P4- 2.1 % and LER-P5-5.2 %).The compounds were initially detected by a simple mass-compatible UHPLC-MS and tentatively characterized by HRMS.The reaction mixture was separated using preparative HPLC with high recovery percentage (>90 %) and their structures were characterized comprehensively using a variety of techniques including 1D (¹H, ¹³C) and 2D (COSY, HSQC, and HMBC) NMR spectroscopy, FT-IR spectroscopy, and Single Crystal X-ray Diffraction (SC-XRD).LER-P1, previously identified as a process impurity with min. characterization data, was thoroughly characterized using advanced spectroscopic techniques.Moreover, the exhaustive characterization of LER-P2, LER-P3, LER-P4, and LER-P5 (which were not reported in previous LER degradation studies) confirmed the transformation of dihydropyridine ring to cyclohexenone with multiple chiral centers under acidic hydrolysis.The proposed mechanisms rationalized all structures, aiming to connect the thorough characterization of new degradation products with their transformation process.The present study provides a guideline about systematic investigations of the stress-induced degradation of pharmaceutical candidates.