methylcellulose and Parkinson-Disease

Dopaminergic agonists are drugs that directly stimulate the dopamine receptors of the striatum and have proved useful in treating Parkinson's disease. In the United States, they are primarily used in conjunction with levodopa. Most have long half-lives and have been particularly useful in controlling and attempting to prevent motor fluctuations.

Topics: Apomorphine; Bromocriptine; Dopamine Agents; Humans; Lactose; Lisuride; Methylcellulose; Oxazines; Parkinson Disease; Pergolide; Receptors, Dopamine

Ninety-four patients with early Parkinson's disease were investigated in a double-blind, placebo-controlled evaluation of MK-458 [hydroxypropyl methylcellulose/lactose matrix (HPMC)], a sustained release formulation of a novel naphthoxazine compound with selective D-2 dopamine receptor agonism. Patients were previously untreated with dopaminergic drugs. Efficacy was assessed by clinical rating scales and by patient self-evaluation. MK-458 (HPMC) caused a significant decrease in most parkinsonian symptoms. Though disability rating scores were lowered by the drug, the scores did not differ significantly from placebo. However, statistically significant improvement occurred with MK-458 (HPMC) on both the physician and the patient global assessments. Adverse reactions such as nausea and vomiting, sedation, confusion, and hallucinations occurred more with MK-458 (HPMC) than with placebo. MK-458 (HPMC) possesses antiparkinsonian efficacy in early Parkinson's disease; however, side-effects are frequently associated with its use. Selective D-2 receptor agonists, such as MK-458 (HPMC), may not be the ideal treatment as monotherapy for Parkinson's disease.

Topics: Aged; Delayed-Action Preparations; Double-Blind Method; Female; Humans; Lactose; Male; Methylcellulose; Middle Aged; Oxazines; Parkinson Disease

Piribedil (PBD) is a compound that has shown efficacy in clinical trials to treat motor and non-motor symptoms of Parkinson's disease. However, drug delivery issues like low oral bioavailability, high dosing frequency (3-5 tablets/day), gastrointestinal side-effects reduced the clinical use of PBD. In this work, we have developed lecithin-chitosan hybrid nanoparticles (PBD-LCNs) to improve the direct nose to brain uptake of PBD. PBD-LCNs were optimized using hybrid design approach based on DoE. The mean particle size and drug loading of PBD-LCNs were 147 nm, and 12%, respectively. The PBD-LCNs showed good stability and were found to be nearly spherical in shape. Further, the optimized LCNs were loaded in methylcellulose thermo-responsive in situ gel (PBD-LCN-ISG) to overcome rapid mucociliary clearance upon intranasal administration. Plasma and brain pharmacokinetic studies in rats showed that PBD-LCN-ISG increased the relative bioavailability of PBD in brain (AUC

Topics: Administration, Intranasal; Biological Availability; Biological Transport; Brain; Chitosan; Drug Compounding; Drug Delivery Systems; Drug Design; Drug Stability; Gels; Lecithins; Methylcellulose; Mucociliary Clearance; Nanoparticles; Nasal Mucosa; Parkinson Disease; Particle Size; Piribedil

Topics: Humans; Lactose; Methylcellulose; Oxazines; Parkinson Disease

To investigate the pharmacokinetic profile, bioavailability, and dose proportionality of the D2-agonist MK-458 (hydroxypropylmethylcellulose tablet, a sustained release formulation), a 4-period crossover study was conducted in 10 patients with mild to moderate Parkinson's disease (mean age = 63 y; 1 woman, 9 men). Following a titration phase to induce tolerance, each patient was given single oral doses of 6, 12 and 18 mg and a single intravenous 40 micrograms dose (5 micrograms/h over 8h). The maximum concentrations of MK-458 observed in plasma after oral administration were 139, 240 and 344 ng/L for the 6, 12 and 18 mg doses, respectively, and occurred after 8.0, 9.0 and 5.5 h, respectively. Mean areas under the plasma concentration-time curves were 1728, 2849 and 5484 ng/L.h, respectively. The mean plasma half-life was 3.8 h and mean plasma clearance was 3390 ml/min (203.4 L/h). The bioavailability (approximately 5%) was very similar for the 3 tablet formulations tested. The disposition of MK-458 was independent of the dose over the range of doses studied.

Topics: Administration, Oral; Aged; Antiparkinson Agents; Delayed-Action Preparations; Dopamine Agents; Dose-Response Relationship, Drug; Female; Humans; Lactose; Male; Methylcellulose; Middle Aged; Oxazines; Parkinson Disease; Tablets

Adjunctive treatment with the very potent and selective dopamine D-2 agonist MK-458 (controlled-release formulation) improved the control of parkinsonism in patients with fluctuating responses to levodopa therapy (with carbidopa). We subsequently switched patients to adjunctive treatment with pergolide, a less potent D-2 agonist. Pergolide therapy controlled parkinsonism more effectively than controlled-release MK-458. Unlike MK-458, pergolide mesylate also has D-1 agonist properties, apparently accounting for its greater antiparkinsonism efficacy. Adjunctive treatment with controlled-release MK-458 elicited less choreiform dyskinesias than either pergolide adjunctive therapy or therapy with carbidopa-levodopa alone; this finding suggests that D-1 receptor stimulation contributes to the elicitation of medication-induced chorea. The highest doses of controlled-release MK-458 resulted in paradoxical freezing of gait in almost one third of patients. This finding suggests that gait freezing, common in untreated parkinsonism, can also be elicited by excessive D-2 stimulation.

Topics: Adult; Aged; Antiparkinson Agents; Carbidopa; Dose-Response Relationship, Drug; Drug Combinations; Female; Humans; Lactose; Levodopa; Male; Methylcellulose; Middle Aged; Oxazines; Parkinson Disease; Pergolide

MK 458 is a potent and selective D2 receptor agonist. MK 458 consists of (+)-4-propyl-9-hydroxynaphthoxazine (PHNO) in a hydroxypropyl-methylcellulose-lactose matrix. MK 458, mean dose 8.1 mg (range 2.5 to 13.5 mg), was administered to 14 patients with advanced Parkinson's disease (PD) who were no longer satisfactorily responding to levodopa. The duration of the study was 4 weeks with a titration to maximum dose in 2 weeks. The addition of MK 458 resulted in a mean reduction in levodopa of 41% (range 0 to 81%). This degree of levodopa reduction was not seen in previous studies with other DA agonists. While the reduction in signs of PD was comparable to those on levodopa, MK 458 did not induce dyskinesias or dystonias. It is postulated that MK 458 may be able to replace levodopa as the primary treatment for PD.

Topics: Adult; Aged; Antiparkinson Agents; Carbidopa; Dopamine Agents; Female; Humans; Hypromellose Derivatives; Lactose; Levodopa; Lisuride; Methylcellulose; Middle Aged; Nausea; Oxazines; Parkinson Disease; Pergolide; Psychomotor Performance; Receptors, Dopamine