A sensitive analytical strategy of oligonucleotide functionalized fluorescent probes for detection of nusinersen sodium in human serum.

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disease. Nusinersen sodium (NS) is the world's first antisense oligonucleotide (ASO) drug for SMA precise targeted therapy. However, the limited half-life of oligonucleotides and their tendency to accumulate in hepatic and renal tissues presented significant challenges for clinical investigation and therapeutic drug monitoring. In this study, we proposed an analytical strategy based on the specific capture of oligonucleotide functionalized fluorescent probes by single stranded binding proteins (SSB) for ultra-sensitive and high-throughput detection of nusinersen sodium in human serum. The magnetic nanoparticles modified with single-strand binding protein (MNPs-SSB) selectively bonded to the red fluorescent quantum dots functionalized with oligonucleotides (RQDs-ssDNA) that were complementary to nusinersen sodium. Upon interaction with nusinersen sodium, RQDs-ssDNA formed a double-stranded complex (RQDs-ssDNA-NS), resulting in enhanced red fluorescence after magnetic separation as it was no longer captured by MNPs-SSB but remained in the supernatant. A quantitative analysis of nusinersen sodium in biological samples was successfully achieved by establishing a relationship between fluorescence intensity and its concentration. The detection signal F/F0 exhibited a linear correlation (R2 = 0.9871) over a wide range from 0.1 nM to 200 nM, with a limit of detection (LOD) of 0.03 nM, demonstrating the high specificity and rapid analysis time (only 30 min). This method provided a novel approach for sensitive, high-throughput, and specific analysis of nusinersen sodium and similar ASO drugs.

Conjugation of sulpiride with a cell penetrating peptide to augment the antidepressant efficacy and reduce serum prolactin levels.

Depression ranks as the fourth most prevalent global disease, with suicide incidents occurring at a younger age. Sulpiride (SUL), an atypical antidepressant drug acting as a dopamine D2 receptor antagonist and possessing anti-inflammatory properties, exhibits limited ability to penetrate the blood brain barrier (BBB). This weak penetration hampers its inhibitory effect on prolactin release in the pituitary gland, consequently leading to hyperprolactinemia. In order to enhance the central nervous system efficacy of sulpiride and reduce serum prolactin levels, we covalently linked sulpiride to VPALR derived from the nuclear DNA repair protein ku70. In vivo study on depressive mice using intraperitoneal injection of VPALR-SUL demonstrated a significant increase in struggle time and total distance compared to those treated with only sulpiride while also reducing serum prolactin concentration. The pharmacokinetic study results showed that VPALR-SUL prolonged half-life and increased bioavailability. In conclusion, VPALR-SUL exhibited potential for enhancing sulpiride transport across the BBB, augmenting its antidepressant effects, and reducing serum prolactin levels. This study laid a foundation for improving sulpiride delivery and developing novel antidepressants.

A sensitive and specific LC-MS/MS method for determination of a novel antihypertensive peptide FR-6 in rat plasma and pharmacokinetic study.

The investigation of peptide drugs has become essential in the development of innovative medications for hypertension. In this study, a sensitive high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to determine the plasma concentration and stability of the antihypertensive peptide FR-6 in rats. An isotopically labeled peptide (with an unchanged sequence) was utilized as an internal standard (IS) for validation purposes. Subsequently, this assay was employed to examine the pharmacokinetics of different administration methods (tail vein and gavage) in Sprague Dawley (SD) rats. Extracted plasma samples underwent sample preparation through methanol protein precipitation, followed by elution of FR-6 on Wondasil C18 Superb column (4.6 × 150 mm, 5 µm), using a mobile phase consisting of formic acid (0.1%) in water (A) and formic acid (0.125%)-ammonium formate (2 mM) in methanol (B). Ion pairs corresponding to FR-6 and IS were monitored via multiple reaction monitoring (MRM) under positive ion mode: m/z 400.7 â†’ 285.1 for FR-6 and m/z 406.1 â†’ 295.1 for IS detection respectively. The method exhibited excellent linearity with respect to FR-6 concentrations. In addition, the inter-day and intra-day precision were 0.61-6.85% and 1.76-11.75%; the inter-day and intra-day accuracy were -7.28-0.13% and -7.20-2.28%, respectively. In conclusion, the matrix effect, extraction recovery, and stability data were validated according to FDA recommended acceptance criteria for bioanalytical methods. This validated method serves as a reliable tool for determining the concentration of antihypertensive peptide FR-6, and has been successfully applied in pharmacokinetic studies involving rats.