No abstract

A specific GC method has been developed, optimized and validated for the determination of seven related substances namely N,N-dimethyl valpronamide, valeric acid, 2-methyl valeric acid, 2-ethyl valeric acid, 2-isopropyl valeric acid, 2-n-butyl valeric acid and 2-propyl-2-pentenoic acid in divalproex sodium (DPS) drug substance. Chromatographic separations of these seven impurities were achieved on DB-FFAP column (30 m × 0.53 mm, 1.0 μm), which consists nitroterephthalic acid modified polyethylene glycol material as stationary phase. DPS is a coordination complex of the sodium valproate and valproic acid (VPA). Nonanoic acid is used as internal standard. All the seven related substances, VPA and nonanoic acid were extracted into dichloromethane and monitored by GC with flame ionization detector. The performance of the developed method was assessed by evaluating specificity, linearity, sensitivity, precision, accuracy and robustness. Forced degradation experiments were conducted to evaluate the degradation behavior of DPS. The established limits of detection (LODs) and limits of quantification (LOQs) values for the related substances were in the ranges of 4-5 and 12-15 μg mL-1, respectively. Further, for VPA, LOD and LOQ values were 4 and 12 μg mL-1, respectively. The correction factors of these related substances with respect to VPA and lie between 0.92 and 1.44. The average recoveries were in the range of 92.4-108.4%.

The U.S. Food and Drug Administration (FDA) has approved a supplemental new drug application Lurasidone (Latuda, Sunovion Pharmaceuticals), an atypical antipsychotic, for the treatment of schizophrenia in adolescents 13–17 years of age. Lurasidone was previously indicated in the U.S. for the treatment of adults with schizophrenia and major depressive episodes with bipolar I disorder as monotherapy. We present a case of a 29-year-old male patient who was hospitalized with thrombocytopenia (WHO grade-3 toxicity) (unlabeled) along with extrapyramidal disorder, gastritis, and hyperprolactinemia within 2–3 months of initiation of tablet lurasidone 80 mg/day (Lurasid, Intas Pharmaceuticals) in bipolar depression. Dechallenge was found to be positive in three reactions except hyperprolactinemia (outcome unknown) during hospital stay. The terms anemia and leukopenia are well labeled/listed with the drug literatures of lurasidone. Thus, this case presents a strong probability of lurasidone to cause myelosuppression/bone marrow depression.