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Biomedical subjects

M U Naidu

Publications and source records attributed to M U Naidu.

22 records · Page 2Linked to original sources
PubMed1985

Polysorbate 80: a pharmacological study.

Polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80), a surfactant, has been widely used as a solvent for pharmacological experiments. In the present study, polysorbate 80 was found to have toxicity of a low order in both the mice and rats when given by i.p. and p.o. routes. It produced mild to moderate depression of the central nervous system with a marked reduction in locomotor activity and rectal temperature, exhibited ataxia and paralytic activity and potentiated the pentobarbital sleeping time. On intravenous administration in dogs, it had a dose-dependent hypotensive effect. Polysorbate 80 did not have a direct stimulant or relaxant effect on either guinea pig ileum or rat uterus, however, it antagonised the contractions induced by acetylcholine, histamine, barium, 5-hydroxytryptamine and carbachol in a dose-dependent manner. A direct relaxant effect was observed on rabbit jejunum. A dose-dependent myocardial depressant effect was observed on guinea pig and rabbit paired atrial preparations. On the electrically-driven guinea pig left atrial preparation, polysorbate 80 exhibited a dose-dependent negative inotropic action. Polysorbate 80 did not induce diuresis in rats upto a dose of 2.5 ml/kg. The results of the present study indicate that polysorbate 80 can neither be used as a solvent for isolated tissue experiments nor when considered for intravenous administration. However, polysorbate 80 can be employed safely as a vehicle for neuropsychopharmacological experiments in doses not exceeding 1 ml/kg.

Animals↗
PubMed1982

A pharmacological study of propane-1,2-diol.

Propane-1,2-diol (propylene glycol, PG), considered to be a safe solvent and commonly used as a vehicle in pharmacological and toxicological investigations, showed various neuropsychopharmacological activity in albino mice and rats. In lower concentrations (10-20%), at dose level of 10 ml/kg, PG did not show any significant neuropsychopharmacological activity either by i.p. or p.o. routes. But higher concentrations (50-100%), at same dose level by i.p. route, were found to have moderate to marked effect. There was decrease in locomotor activity, body and limb tone, respiration, rectal temperature and suppression of secondary conditioned responses. Significant potentiation of pentobarbitone (pentobarbital) hypnosis, slight increase in d-amphetamine toxicity in aggregated mice and pronounced analgesic and anti-inflammatory activity were also observed. Most of the above effects were also observed on p.o. treatment but the effects were of lesser degree. PG did not produce any effect on dog or cat blood pressure up to 100% concentration at the dose level 0.5 ml/kg. However, it potentiated the adrenaline (epinephrine) and noradrenaline (norepinephrine) response. On isolated smooth muscle preparations, in 50-100% concentrations, a dose-dependent non-specific blockade was observed against agonists viz. acetylcholine, histamine, 5-HT and barium chloride. No effect was seen on cardiac tissue preparation. On the basis of present findings, it is suggested that propylene glycol as a solvent be used only in low concentration of not more than 10% for pharmacological and toxicological investigations.

Analgesics↗
PubMedDate not supplied

Evaluation of ketorolac, ibuprofen-paracetamol, and dextropropoxyphene-paracetamol in postoperative pain.

STUDY OBJECTIVE: To compare the analgesic efficacy of ketorolac, ibuprofen-paracetamol (acetaminophen), and dextropropoxyphene-paracetamol in postoperative pain. DESIGN: Randomized, double-blind, parallel, single-dose study. SETTING: Multicenter, with five centers participating. PATIENTS: One hundred sixty patients with moderate to severe postoperative pain requiring oral analgesics were enrolled. Seventeen patients were excluded from final analysis due to deviation from protocol. INTERVENTIONS: Ketorolac tromethamine 10 mg, a combination of ibuprofen 400 mg plus paracetamol 325 mg, or a combination of dextropropoxyphene 65 mg plus paracetamol 400 mg was given orally to patients with moderate to severe baseline pain. MEASUREMENTS AND MAIN RESULTS: Pain intensity and pain relief scores were rated at baseline, at 30 minutes, and hourly to 6 hours. Until the end of first hour, analgesia was similar for all three regimens. Ketorolac had a significantly higher analgesic effect than the two combinations between hours 2 and 6. Analgesia was similar for the two combinations. For all three test drugs the frequency of adverse effects was similar. CONCLUSIONS: Ketorolac 10 mg is a superior analgesic to ibuprofen-paracetamol or dextropropoxyphene-paracetamol in the treatment of postoperative pain.

Acetaminophen↗