Dose-Response Analysis of the Effect of Carbidopa-Levodopa Extended-Release Capsules (IPX066) in Levodopa-Naive Patients With Parkinson Disease

Moxibustion Protects Dopaminergic Neurons in Parkinson's Disease through Antiferroptosis

Ferroptosis is associated with neural degeneration of dopaminergic neurons in Parkinson's disease (PD). However, how to control the level of ferroptosis in PD remains unclear. Clinically, moxibustion has been used to treat PD and has an apparent therapeutic effect on improving the motor symptoms of PD. In the present study, the PD rat model was constructed by two-point stereotactic 6-hydroxydopamine injection. Then, moxibustion was used to treat the PD rats. The expression of glutathione peroxidase 4 (GPX4) and Ferritin Heavy Chain 1 (FTH1), the level of reactive oxygen species (ROS), and the morphology of mitochondrial were detected to evaluate the level of ferroptosis. The results showed that moxibustion treatment of Shi's moxa sticks could reduce the behavioral score, alleviate the level of ferroptosis, decrease mitochondrial damage, and improve dopaminergic neuron survival. In conclusion, the present study results indicated that Shi's moxa sticks could effectively suppress the level of ferroptosis, thereby improving the survival of dopaminergic neurons in the SNpc of PD rats, which may provide a promising complementary and alternative therapy for PD patients.

Sensitive LC–MS/MS method for quantitation of levodopa and carbidopa in plasma: application to a pharmacokinetic study

Aim: The combination of levodopa with carbidopa has been used for treatment of Parkinson's disease being an important therapy in dopamine level control in the brain. Both are very polar compounds becoming a challenge for analysis by LC–MS/MS.Materials & methods: In this work, it was developed and validated a sensitive bioanalytical method by UHPLC–MS/MS for simultaneous levodopa and carbidopa quantification in human plasma using a fast protein precipitation method. Moreover, the bioanalytical method was applied to a pharmacokinetic study in healthy volunteers. Results/Conclusion: The results demonstrated a sensitive and adequate method for application to pharmacokinetic/bioequivalence studies.

Pharmacokinetics of Rytary®, An Extended-Release Capsule Formulation of Carbidopa-Levodopa

Parkinson's disease (PD) is a chronic progressive neurological disorder characterized by resting tremor, rigidity, bradykinesia, gait disturbance, and postural instability. Levodopa, the precursor to dopamine, coadministered with carbidopa or benserazide, aromatic amino acid decarboxylase inhibitors, is the most effective and widely used therapeutic agent in the treatment of PD. With continued levodopa treatment, a majority of patients develop motor complications such as dyskinesia and motor 'on-off' fluctuations, which are, in part, related to the fluctuations in plasma concentrations of levodopa. A new extended-release (ER) carbidopa-levodopa capsule product (also referred to as IPX066) was developed and approved in the US as Rytary^® and in the EU as Numient^®. The capsule formulation is designed to provide an initial rapid absorption of levodopa comparable to immediate-release (IR) carbidopa-levodopa, and to subsequently provide stable levodopa concentrations with reduced peak-to-trough excursions in plasma concentrations in order to reduce motor fluctuations associated with pulsatile stimulation of dopamine receptors and to minimize dyskinesia. Phase III studies of this ER carbidopa-levodopa capsule formulation in patients with PD have shown a significant reduction in 'off' time compared with IR carbidopa-levodopa and carbidopa-levodopa-entacapone. We present a review of the clinical pharmacokinetics and pharmacodynamics of this ER product of carbidopa-levodopa in healthy subjects and in patients with PD.

Extended-release oral capsule of carbidopa-levodopa in Parkinson disease

Motor fluctuations complicate the treatment of patients with Parkinson's disease receiving levodopa. Extended-release carbidopa-levodopa has a pharmacokinetic profile that provides a more continuous levodopa serum concentration. Patients taking this formulation can expect longer duration of action and fewer doses per day, similar clinical improvement when compared to other levodopa formulations, and with a theoretically lower risk of developing motor fluctuations. Several studies, including three randomized control trials provide evidence for the efficacy, safety and tolerability of extended release carbidopa-levodopa in patients with both early and advanced Parkinson's disease are reviewed here. Also provided is guidance for dosing of and conversion to extended release carbidopa-levodopa as well as a discussion of its place in the clinical practice.

Recent advances in treating Parkinson's disease

This article summarizes (1) the recent achievements to further improve symptomatic therapy of motor Parkinson’s disease (PD) symptoms, (2) the still-few attempts to systematically search for symptomatic therapy of non-motor symptoms in PD, and (3) the advances in the development and clinical testing of compounds which promise to offer disease modification in already-manifest PD. However, prevention (that is, slowing or stopping PD in a prodromal stage) is still a dream and one reason for this is that we have no consensus on primary endpoints for clinical trials which reflect the progression in prodromal stages of PD, such as in rapid eye movement sleep behavior disorder (RBD) —a methodological challenge to be met in the future.