ABSTRACT
Background: In Iranian traditional medicine, gum obtained from Astragalus gummifer and some other species of Astragalus was used as analgesic agent. Objective: In this study, we investigated the antinociceptive effect of several concentrations (125, 250, and 500 μg/kg body weight) of Astragalus gummifer gum (AGG) on thermal and acetic acid induced pain in mice. Materials and Methods: AGG was dissolved in distillated water and injected i.p to male mice 15 minute before the onset of experiment. Writhing and hot‑plate tests were applied to study the analgesic effect of AGG and compared with that of diclofenac sodium (30 mg/kg, i.p.) or morphine (8 mg/kg, i.p). To investigate the mechanisms involved in antinociception, yohimbine, naloxone, glibenclamide, and theophylline were used in writhing test. These drugs were injected intraperitoneally 15 min before the administration of AGG. The number of writhes were counted in 30 minutes and analyzed. Results: AGG exhibited a significant antinociceptive effect and the most effective dose of AGG was 500 μg/kg. The most maximum possible effect (%MPE) was observed (117.4%) 15 min after drug administration. The %inhibition of acetic acid‑induced writhing in AGG 125, 250 and 500 was 47%, 50% and 54% vs %15 of control and 66.3% of diclofenac sodium group. The antinociceptive effect induced by this gum in the writhing test was reversed by the systemic administration of yohimbine (α2‑adrenergic antagonist), but naloxone, glibenclamide, and theophylline did not reverse this effect. Conclusions: The findings of this study indicated that AGG induced its antinociceptive through the adrenergic system.
ABSTRACT
The main objective of the present work was to develop sustained release matrix tablets of Atenolol. To reduce the frequency of administration and to improve the patient compliance, a once daily sustained release formulation of Atenolol is desirable. So sustained release Matrix Tablet of Atenolol was designed by using different polymers viz.Starch, Xanthan Gum, Vee Gum , Guar Gum, Gum Accacia, Tragacanth, Hupu Gum were used as natural polymers and Eudragit-L100, Ethyl Cellulose, Sodium Carboxy Methyl Cellulose (Na-CMC) ,Hydroxy Propyl Methyl Cellulose (HPMC) (5&15cps), Methyl Cellulose, Kollidon were used as synthetic polymers. After fixing the ratio of drug and polymer for control the release of drug up to desired time, the release rates were modulated by Single polymer, combination of two different rates controlling material. The FT-IR study revealed that there was no chemical interaction between drug and excipients. The granules were prepared by dry granulation method. Precompressional parameters i.e. angle of repose, percent compressibility, and Hausner’s ratios were studied. These results indicate that granules are good flowing characteristics. After evaluation of physical properties like Weight variation, Hardness, Thickness, Friability of tablet, the different formulations checked for the Percentage Drug content which having good uniformity. The results of drug dissolution studies showed improved drug release, retardation effects of the polymers and could achieve better performance. After eight hours dissolution test, dissolution profiles showed that better sustained release was observed from starch and veegum containing formulation and eudragit and ethyl cellulose containing formulation of atenolol matrix tablet. It was also observed that the presence of starch caused an increase in the release rate of atenolol matrix tablet. The present study shows a relatively simple method to design and develop Atenolol matrix tablet.