Conflicting reports in the literature exist, regarding the role of dopamine in the genesis of gastric and duodenal ulceration, gastric cytoprotection, gastric acid secretion, gastro-intestinal motility and in the strengthening of gastric mucosal barrier. Dopamine and its agonists have been shown to exert a protective role against the formation of gastric and duodenal ulcers, whereas, dopamine antagonists are reported to produce pro-ulcerogenic effects. However, many reports conflict with this view as selective dopamine D2 receptor antagonists have been shown to be beneficial when used as an adjunct in peptic ulcer disease. After reviewing the available literature and taking into consideration our own findings it appears that dopamine D1 and D2 receptors have opposing effects on gastric and duodenal ulceration, gastrointestinal motility, gastric mucosal blood flow and gastric acid secretion. While dopamine D2-receptor antagonists like sulpiride and domperidone produce anti-ulcer effect, dopamine D1-receptor antagonists like SCH 23390, SCH 39166, pimozide, butaclamol and spiperone, which possess more dopamine D1-activity have been reported to produce ulcerogenic activity in various models of gastric and duodenal ulcers. The above observations pinpoint the functional importance of the dopamine receptor subtypes namely the D1 and D2-receptors, present both centrally and peripherally in modulating the normal gastro-intestinal functions. Existence of a functionally significant dopaminergic brain-gut axis has also been proposed.

Insulin is used in the treatment of Diabetes Mellitus. It is a small protein having a molecular weight of 5808. An ideal insulin delivery system should deliver insulin in a pulsatile manner, control the rate of insulin delivery depending on blood glucose concentration, should be delivered into the portal circulation. In addition there should be minimum intraindividual variation, it should be easy to administer and economical. The current insulin treatment does not meet these requirements, hence alternate routes are being developed. The oral delivery though the most convenient and acceptable route however is degraded by intestinal enzymes therefore. insulin was administered with enzyme inhibitors, coated with azoaromatic polymer in the form of nanocapsules, liposomes, microemulsions. But oral delivery showed variable responses and could lead to immunological problems. Increased absorption of insulin by the nasal mucosa was tried by adding various surfactants and by increasing the time of contact. However these surfactants caused irritation and could lead to anti-insulin antibodies. The advantage of pulmonary aerosol is that significant absorption of insulin takes place without the use of absorption promoting agents. The long term effects of this delivery has to be assessed. Besides these the other routes tried are ocular, transdermal. buccal, rectal and vaginal.

lsoproturon a herbicide produces a CNS depressant effect. Pretreatment of mice with isoproturon at different doses increased the duration of pentobarbitone induced sleep in mice and potentiated the effect of subhypnotic dose of pentobarbitone. lsoproturon also decreased the onset and increased the duration of barbitone induced sleep in mice. However, four days pretreatment with two divided doses of isoproturon significantly decreased the duration of sleep and increased the mean liver weight in mice. The results indicate that isoproturon might have direct CNS depressant action. Decrease in pentobarbitone sleeping time in isoproturon pretreated mice appears to be due to induction of hepatic microsomal enzymes.

Five peptides related to the b-receptor agonist, dermorphin gene associated peptide (DGAP), having structural modifications at the positions 2, 6 and 7 were synthesised by the solid phase method using 9-fluorenylmethoxycarbonyl amino acid trichlorophenyl esters as coupling agents and p-alkoxybenzyl alcohol resin as the solid support. The biological activities of these peptides were determined in vitro using guinea pig ileum and mouse vas deferens assays and in vivo employing the analgesic and antidiarrhoeal assays. The S-receptor selectivity was determined by the ratio of IC50 values in the MVD assay to that of the GPI assay and all the synthetic peptides were found to possess b-receptor selectivity; [Nva6] DGAP being the most selective in the present series. [Eth6] DGAP exhibits a higher selectivity with regard to analgesic to antidiarrhoeal activity in the in vivo assay.

Effect of ethanolic extract (50% v/v) of Plumbago zeylanica (root) alone and combined with vitamin E (an antioxidant)was studied in experimentally induced hyperlipidaemic rabbits. There was significant reduction in serum total cholesterol, LDL cholesterol and triglyceride levels. Marked reduction was observed with the formulation of P.zeylanica and vitamin E. The total cholesterol/HDL and LDL/HDL cholesterol ratios were found significantly decreased (P<0.05). P.zeylanica showed good margin of safety as determined by acute toxicity studies in albino rats and albino rabbits, as well as by the absence of adverse effects on haematological and biochemical parameters in albino rabbits upto 60 days of administration.

Effects of three calcium channel blockers viz., verapamil, nifedipine and diltiazem were studied against experimentally induced duodenal ulcers. The parameters studied include ulcer incidence, score for intensity, total lesion area and mortality rate using cysteamine-induced duodenal ulcer model. Verapamil (i.p.)was found to produce significant reduction in both score for intensity and total lesion area at 32 mglkg dose. Nifedipine (p.o)showed significant reduction in total lesion area at 32 mg/kg dose. Paradoxically diltiazem (i.p.) and low dose of nifedipine exacerbated the cysteamine ulcers.

Hypercholesterolemia was developed in mice fed with hypercholesterolemic diet (HC) made of 1 g cholesterol, 0.2 g cholic acid and 98.8 g standard diet. Mice were fed HC diet for 15, 30, 45 and 60 days, and serum and liver cholesterol, triglycerides (TG) and total lipids (TL) were measured. Cholesterol level increased substantially at 15 days in serum and liver. It increased further at later time points upto 8 weeks. Treatment of 5% turmeric extract (TE) mixed with standard diet to hypercholesterolemic mice significantly decreased serum and hepatic cholesterol, triglycerides (TG) and total lipids (TL) levels. Feeding with 10% TE diet brought the levels comparable to those in normal untreated mice.

Anticancer therapy can be made more effective by targeting the delivery of anticancer drugs to the tumor site more quantitatively. In this direction attempts have been made to activate and exploit macrophages in delivering niosomal and thermosensitive niosomal bleomycin more quantitatively to tumor site using niosome encapsulated immunomodulators muramyl dipeptide and tuftsin. Niosomal bleomycin and thermosensitive niosomal bleomycin were prepared by lipid layer hydration method. The antitumor efficacy was assessed using two tumor models viz. Sarcoma-180 and ehrlich ascites using Balb/C mice. Tumor distribution profiles of bleomycin before and after macrophage activation were studied in tumor bearing mice. The mean survival time of enrich ascites infected mice increased significantly after macrophage activation. Accumulation of higher bleomycin levels after macrophage activation exerted increased antitumor effect. The present study suggested that a more quantitative delivery of bleomycin encapsulated in niosomes, to the tumor site is possible after macrophage activation.

Hydroxyethyl starch (HES) 6% has been shown to improve hypovolaemia, with minimum side effects and long duration of action. Thirty patients showing signs of hypovolaemia post-operatively, in the form of tachycardia and hypotension received 500 ml of 6% HES intravenously over 30-60 minutes. Administration of HES, significantly improved hypovolaemia in all the patients. Within 30 minutes after infusion, systolic blood pressure (SBP) increased from 85ñ 6 to 98ñ 8 mm Hg. Heart rate decreased from 124ñ 3 beats per minute (bpm) to 99ñ 6 bpm and central venous pressure (CVP) increased from 1ñ 1 to 3.5k1.2 cm of saline, at one hour post HES administration. This improvement persisted till the end of sixth hour observation period. All patients tolerated HES well without any side effects and hematological or biochemical abnormalities.

Compressed rectal suppositories which are suitable and stable in tropical climates were formulated using diclofenac sodium, a potent NSAID, in polyethylene glycol 4000 base. These suppositories were evaluated for pharmacokinetic performance in rabbits at the dose of 10 mg/kg and the results were compared with those obtained after oral administration. A computer programme using model independent formulae was used to calculate different pharmacokinetic parameters. There was no difference in pharmacokinetic parameters such as Cmax, AUC0-(, t1/2 and the mean residence time (MRT) between oral and rectal formulations. But tmax was faster in case of oral administration (0.58ñ 0.08 h vs 1.08ñ 0.15 h, P < 0.05) indicating quicker drug absorption from oral suspension. Relative rectal bioavailability was 98.35ñ 3.58% which indicates comparable pharmacokinetic performance of rectal suppositories of diclofenac sodium in rabbits.

The protective effect of glutathione was assessed against cytotoxic antitumour agents like cyclophosphamide, methotrexate, 5-fluorouracil (CMF) and X-ray irradiated rats. Glutathione supplementation into the CMF and X-ray irradiated rats showed decrease in the level of thiobarbituric acid reacting substances (TBARS) in plasma, liver and intestine. It was increased in the lung even after receiving the glutathione. The level of antioxidant enzymes were restored in the RBC hemolysate.

The calcium channel blocking activities of equimolar concentration of chloroquine, amodiaquine, mepacrine, quinine and mefloquine were examined on the rat isolated aortic strip and compared with that of diltiazem, a classical organic Ca2+ channel blocker. All antimalarial drugs as well as diltiazem non-competitively inhibited the contractile effect of calcium chloride. They displaced response curve in a non-parallel fashion to the right with depressed maxima. Amon antimalarial drugs, chloroquine and amodiaquine were equipotent with Ic70 of 2.15(0.2 x 10-6 M, while mefloquine was the least potent (lc70 of 5.2(0.4 x 10-6 M) although chloroquine was at least 1,000 times less potent (on molar basis) than diltiazem as a Ca2+channel blocker in this preparation. It was concluded that antimalarial drugs possessed appreciable Ca2+ channel blocking activities, although much less than diltiazem.