Morphine administered nasally to humans as a simple solution is only absorbed to a limited degree, with a bioavailability of the order of 10% compared with intravenous administration. This article describes the development of novel nasal morphine formulations based on chitosan, which, in the sheep model, provide a highly increased absorption with a 5-to 6-fold increase in bioavailability over simple morphine solutions. The chitosan-morphine nasal formulations have been tested in healthy volunteers in comparison with a slow i.v. infusion (over 30 min) of morphine. The results show that the nasal formulation was rapidly absorbed with a T max of 15 min or less and a bioavailability of nearly 60%. The shape of the plasma profile for nasal delivery of the chitosan-morphine formulation was similar to the one obtained for the slow i.v. administration of morphine. Furthermore, the metabolite profile obtained after the nasal administration of the chitosan-morphine nasal formulation was essentially identical to the one obtained for morphine administered by the intravenous route. The levels of both morphine-6-glucuronide and morphine-3-glucuronide were only about 25% of that found after oral administration of morphine. It is concluded that a properly designed nasal morphine formulation (such as one with chitosan) can result in a noninjectable opioid product capable of offering patients rapid and efficient pain relief.
The gastrointestinal transit of liquid, pellet and tablet formulations was measured under fasted conditions in the domestic pig (n = 4) using the technique of gamma scintigraphy. The mean times for 50% gastric emptying for liquid and pellet systems were 1.4 and 2.2 h, respectively; tablets emptied between 1.5 and 6.0 h. Total transit times were in the order of 50 h. These data conform well to published values for the transit of liquid and solid food materials in the pig. The times are much shorter than those previously published for the transit of solid dosage forms in the pig. We conclude that the domestic pig would be a good model to study the gastrointestinal transit of pharmaceutical formulations and the absorption of drug compounds.
We have evaluated the ability of two carbohydrate biopolymers, chitosan and gellan, to enhance antibody responses to subunit influenza virus vaccines delivered to the respiratory tracts of mice. Groups of mice were vaccinated three times intranasally (i.n.) with 10 g of purified influenza B/Panama virus surface antigens
It was shown conclusively that chitosan nanoparticles did not improve the absorption enhancing effect of chitosan in solution or powder form and that chitosan powder was the most effective for mulation for nasal delivery of insulin in the sheep model.
Amyotrophic lateral sclerosis (ALS) is the commonest form of motor neuron disease and is a fatal, degenerative, multisystem disorder affecting upper and/or lower motor neurons in the motor cortex, brain stem, and spinal cord. ALS is characterized by progressive atrophy of associated bulbar, limb, thoracic, and abdominal muscles and supporting cells manifesting in a range of muscular symptoms such as weakness and wasting and eventual paralysis; the majority of patients will die from respiratory failure within 2–5 years of onset. Riluzole, a synthetic benzothiazole drug with glutamine antagonist activity, is indicated for the treatment of patients with ALS and is the only drug that has been shown to slow the course of the disease and extend survival in ALS patients. The original analyses, and subsequent meta-analyses, of data obtained from randomized controlled trials (RCTs) suggest that riluzole typically extends survival by 2–3 months and increases the chance of an additional year of survival by ~9%. However, published real-world evidence (RWE) from 10 clinical ALS databases indicates that riluzole therapy may afford much greater extension of survival, and improvements in median survival times of more than 19 months have been reported in the overall ALS patient population. This article will review the available data from RCTs and RWE on riluzole therapy.
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