Detection of genetic polymorphism by RAPD-PCR among isolates of Bacillus thuringiensis.

Sixteen isolates of Bacillus thuringiensis recovered from different Jordanian habitats were compared using random amplification of polymorphic DNA (RAPD) to determine whether they could be differentiated at the molecular level. Total genomic DNA from each isolate and three reference strains were amplified using 10-mer primers. Electrophoretic analysis of the amplification products revealed the incidence of polymorphism among the isolates. Pair-wise comparisons of polymorphic products were used to construct a dendrogram applying the cluster analysis. Fifteen of the isolates were all in one major cluster which was divided into six small groups. Such analysis showed some regional variation among the isolates, but did not indicate a clearly defined habitat locational pattern of the DNA polymorphism.     

<Emphasis Type="Italic">Arbutus andrachne</Emphasis> L. Reverses Sleep Deprivation-Induced Memory Impairments in Rats

Sleep deprivation (SD) is associated with cognitive deficits. It was found to affect the hippocampus region of the brain by impairing memory formation. This impairment is suggested to be caused by elevation in oxidative stress in the body, including the brain during SD. It was hypothesized that the methanolic extract of the fruits of Arbutus andrachne L. (Ericaceae) will prevent chronic SD-induced impairment of hippocampal memory via its antioxidative properties. The methanolic extract of the fruits of A. andrachne was evaluated for its beneficial properties to reverse SD-induced cognitive impairment in rats. Animals were sleep deprived for 8 weeks using a multiple platform model. The extract was administered i.p. at three doses (50, 200, and 500 mg/kg). Behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM). In addition, the hippocampus was dissected to analyze the following oxidative stress markers: glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG, glutathione peroxidase (GPx), and catalase. Chronic SD impaired short- and long-term memories (P < 0.05). Treatment of animals with A. andrachne fruit extract at all doses prevented long-term memory impairment induced by SD while such treatment prevented short-term memory impairment only at 200 and 500 mg/kg dose levels. Moreover, A. andrachne fruit extract normalized the reduction in the hippocampus GSH/GSSG ratio and activity of GPx, and catalase (P < 0.05) induced by chronic sleep deprivation. Chronic sleep deprivation impaired both short- and long-term memory formation, while methanolic extract of A. andrachne fruits reversed this impairment, probably through normalizing oxidative stress in the hippocampus.     

Intranasal Drug Delivery of Olanzapine-Loaded Chitosan Nanoparticles

The aim of this study was to investigate olanzapine (OZ) systemic absolute bioavailability after intranasal (i.n.) administration in vivo to conscious rabbits. Furthermore, the study investigated the potential use of chitosan nanoparticles as a delivery system to enhance the systemic bioavailability of olanzapine following intranasal administration. Olanzapine-loaded chitosan nanoparticles were prepared through ionotropic gelation of chitosan with tripolyphosphate anions and studied in terms of their size, drug loading, and in vitro release. The OZ nanoparticles were administered i.n. to rabbits, and OZ plasma concentration at predetermined time points was compared to i.n. administration of OZ in solution. The concentrations of OZ in plasma were analyzed by ultra performance liquid chromatography mass spectroscopy (UPLC/MS). OZ-loaded chitosan nanoparticles significantly (p < 0.05) enhanced systemic absorption with 51 ± 11.2% absolute bioavailability as compared to 28 ± 6.7% after i.n. administration of OZ solution. The results of the present study suggest that intranasal administration of OZ-loaded chitosan nanoparticles formulation could be an attractive modality for delivery of OZ systemically.KEY WORDS: bioavailability, intranasal, nanoparticles, olanzapine, pharmacokinetic     

Effect of pH on sublingual absorption of oxycodone hydrochloride

The purpose of this study was to develop a sublingual spray drug delivery formulation of oxycodone and evaluate the effect of formulation pH on sublingual absorption of oxycodone for acute pain management using rabbit as the animal model. Using a new, sensitive, and specific liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization detector assay, the absorption bioavailability of sublingual oxycodone was determined in rabbits by comparing plasma concentration after sublingual spray delivery with equivalent intravenous dose. The effect of formulation pH on sublingual absorption of oxycodone was also tested on rabbits that had received oxycodone sublingually at a dose of 0.1 mg/0.1 mL (pH 4.0 and 9.0). Blood samples were collected at different time points, and plasma oxycodone concentrations were determined by LC/MS. Following administration of a 0.1 mg dose, the average C_max values were found to be 64.9±12.1 and 95.2±10.1 ng/mL, for pH 4.0 and 9.0, respectively. The area under the curve (AUC) values were found to be 5807.0, and 8965.3 ng.min/mL for formulation pH 4.0 and 9.0, respectively. The mean sublingual bioavailability of oxycodone was 45.4%±20.1% and 70.1%±17.9%, for pH 4.0 and 9.0, respectively. the formulation pH had no significant influence on oxycodone bioavailability (P<.05). A sublingual spray dosage form of oxycodone hydrochloride would be a good alternative for fast onset pain management, especially in children. Published: March 10, 2006