Improved Stability of a Stable Crystal Form C of 6S-5-Methyltetrahydrofolate Calcium Salt, Method Development and Validation of an LC–MS/MS Method for Rat Pharmacokinetic Comparison

Abstract

Folate is a vitamin beneficial for humans that plays an important role in metabolism, but it cannot be well supplemented by food; it is necessary to supplement it in other ways. Based on this consideration, a novel crystal form C of 6S-5-methyltetrahydrofolate calcium salt (MTHF CAC) was obtained. To explore the difference between MTHF CAC and the crystal form Ⅰ of 6S-5-methyltetrahydrofolate calcium salt (MTHF CA) as well as an amorphous product of 6S-5-methyltetrahydrofolate glucosamine salt (MTHF GA), their stability and pharmacokinetic behaviours were compared. The results of high-performance liquid chromatography coupled with ultraviolet detection analysis indicated that MTHF CAC showed a better stability than MTHF CA and MTHF GA. After oral administration of MTHF CAC, MTHF CA, and MTHF GA to male rats, the MTHF concentrations were analysed using a validated liquid chromatography–tandem mass spectrometry, and the pharmacokinetic parameters were compared. The mean residence times (0–t) of MTHF CAC, MTHF CA, and MTHF GA were 3.7 ± 1.9 h, 1.0 ± 0.2 h (p < 0.01), and 1.5 ± 0.3 h (p < 0.05), respectively. The relative bioavailability of MTHF CAC was calculated to be 351% and 218% compared with MTHF CA and MTHF GA, respectively, which suggests that MTHF CAC can be better absorbed and utilized for a longer period of time.

Evaluation of In Vivo Folic Acid Bioavailability in Different Mouse Strains Using Enzymatic Digestion Combined with Ultra Performance Liquid Chromatography

“…5-Methyltetrahydrofolate is a highly active compound that oxidizes readily to tetrahydrofolate during the extraction process, a compound that is subsequently transformed into folic acid . The determination of folic acid content in the brain was restricted to the total amount due to drawbacks associated with the analytical instrument and the extraction procedure, which compromised precision.…”

“…Folic acid bioavailability was reliant on several factors, as discussed previously regarding the food or host. − In the current study, an in vitro model was used to explore the effects of food source, food matrix, food processing method, and conversion of polyglutamate folic acid on folic acid bioavailability. Two primary animal-based methods were used to assess folic acid bioavailability: short-term kinetics , and long-term studies. , Due to variations in the bioavailability of folic acid among different mouse strains, which rendered long-term experiments more appropriate, the current study employed a ten-day cycle experiment . The mice were administered folic acid at a rate of 4 mg/kg on a daily basis.…”

“…5-Methyltetrahydrofolate is a highly active compound that oxidizes readily to tetrahydrofolate during the extraction process, a compound that is subsequently transformed into folic acid. 39 The determination of folic acid content in the brain was restricted to the total amount due to drawbacks associated with the analytical instrument and the extraction procedure, which compromised precision. The rates of folic acid entranced into the brains of eight mouse groups are Conversely, these groups exhibited a notable distinction in comparison to the remaining six groups (P < 0.001).…”