ABSTRACT
The aim of this investigation was to improve the storage stability and survival rate of an intravesical BCG product, manufactured with an attenuated strain of Mycobacterium bovis [Pasteur strain 1173P2 of BCG] in the presence of sodium glutamate. Formulations with various concentrations of trehalose [a known protectant] were developed as liquid and lyophilized forms. Formulations were evaluated by different methods, including optical density measurement, safety assessment, skin reaction test, moisture content determination, viability assay, bacterial and fungal contaminations and the results were compared with those obtained for sodium glutamate-containing formulations. The stability tests were also carried out in various storage durations and different temperatures. To develop the lyophilization protocol, glass transition temperatures in the presence of both stabilizers were determined using differential scanning calorimetry. In general, results showed that trehalose could considerably increase the stability of the product against freezing and drying processes, increase the survival rate even in the liquid formulations, as well as the production of an acceptable cake. However, further studies are required to optimize the product characteristics
ABSTRACT
Penicillin G acylase was immobilized onto iron oxide nanoparticles coated with polyethyleneimine and then cross linked with glutaraldehyde solution. The FTIR spectrum of immobilized enzyme showed peak at 1648cm-1 which can be attributed to the C=N bonds of Schiff’s base linkage formed between glutaraldehyde and amino group of penicillin G acylase. By considering the FTIR spectrum of nano particle coated with polyethyleneimine, adsorption of penicillin G acylase has taken place and then glutaraldehyde cross linked enzyme onto activated support. Catalytic properties of nano penicillin G acylase were improved upon immobilization as compared to its free counterpart. The optimal pH and temperature were determined to be 7.0, 10.0, 50 and 75ºC for free and immobilized penicillin G acylase, respectively. Thermal stabilities of both nano and free penicillin G acylase were studied .The Km value of immobilized nanozyme was calculated from Lineweaver Burck plot to be 0.23 μM while that of free penicillin G acylase was 0.28μM. In this way nano penicillin G acylase with improved catalytic properties was developed as compared to its soluble counterpart.
ABSTRACT
The aim of this study was to evaluate the effects of dexamethasone on striatal dopaminergic, glutamatergic and gamma amino butyric acid [GABA] ergic neurotransmission in normal and parkinsonian rats. Dexamethasone [0.15, 0.30, 0.60 and 0.8 mg/kg] was administered to normal or parkinsonian rats [i.p.] followed by the analysis of the striatal neurotransmitters concentrations. Additionally, the effect of dexamethasone on the damaged Substantian nigra pars compata [SNc] neurons has been investigated. Dexamethasone resulted in decreased level of striatum glutamatergic-GABAergic and enhanced dopaminergic neurotransmission in normal and parkinsonian rats. In addition, acute treatment with dexamethasone did not improve the lesion at all. These findings suggest the new therapeutic mechanism of action for dexamethasone in Parkinson's disease animal model