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Biomedical subjects

V K Jha

Publications and source records attributed to V K Jha.

14 recordsLinked to original sources
PubMed1989

Disposition kinetics and distribution of demeclocycline in various biological fluids in female goats.

A pharmacokinetic study of demeclocycline was carried out following intravenous administration at 5 mg/kg body weight in lactating goats. Demeclocycline appeared within 5 min in plasma, interstitial fluid (isf) and urine, while it appeared at 1 h in milk. Peak concentrations of 21.70 +/- 4.06, 2.67 +/- 0.23, 5.65 +/- 0.45 and 82.23 +/- 10.06 micrograms/ml were attained at 5 min and at 6, 8 and 8 h in plasma, isf, milk and urine respectively. A potentially therapeutic concentration of greater than or equal to 0.5 micrograms/ml was maintained from 5 min-36 h, 30 min-30 h, 1-36 h and 5 min-48 h in plasma, isf, milk and urine respectively. The drug was detectable in all the above biological fluids for at least 48 h. A low distribution half life (t1/2 alpha) of 0.44 +/- 0.04 h and a high elimination half life (t1/2 beta) of 19.24 +/- 1.22 h denote rapid distribution but very slow elimination of the drug in goats. A high tissue plasma concentration ratio [K12:(K21-beta)] of 5.12 +/- 0.97 during the elimination phase and a Vdarea of 1.59 +/- 0.18 L/kg indicate uniform distribution of demeclocycline in the tissues and body fluids of goats. The dosage regimen for maintaining minimum plasma concentration (Cp infinity min = MIC) of 0.5, 1.0 and 1.5 micrograms/ml at selected dosage intervals of 12 and 24 h was also calculated.

Animals↗
PubMed1989

Pharmacokinetic data on doxycycline and its distribution in different biological fluids in female goats.

A pharmacokinetic study of doxycycline after intravenous administration at 5 mg/kg body weight in goats revealed that a concentration of greater than or equal to 0.5 microgram/ml was maintained for 5 min-2 h, 4-12 h, 2-12 h and 5 min-greater than 48 h in plasma, interstitial fluid, milk and urine respectively. The low t1/2 alpha of 0.73 +/- 0.11 h and high t1/2 beta of 16.63 +/- 1.58 h show that the drug is rapidly distributed but slowly eliminated from the body. The tissue:plasma concentration of 4.86 +/- 1.06 during the elimination phase [K12/(K21-beta)] indicates a high expected tissue concentration, which is supported by similarly increased drug concentration in interstitial fluid and milk. The high Vdarea of 9.78 +/- 0.86 L/kg observed denotes that, apart from its wide distribution, the drug may be stored in fat depots as it is known to be highly lipophilic. As the drug maintained a therapeutic concentration for a shorter time in plasma, and the calculated dose rate for maintaining a minimal plasma concentration of 0.5-1.5 micrograms/ml is relatively high, it may not be of much use in treating septicaemia in this species. Since the observed tissue:plasma concentration was higher and a therapeutic concentration was maintained in interstitial fluid and milk for longer, the drug can be used for other systemic infections at a lower dose rate than that required for treating septicaemia. As the drug maintained a very high concentration in urine, it may be of particular value in treating urinary tract infections caused by sensitive micro-organisms.

Animals↗
PubMed1988

Single dose kinetics of rifampicin and isoniazid in well-nourished and malnourished patients of tuberculosis.

A single dose kinetics of isoniazid and rifampicin alone, and combination was studied in well-nourished and malnourished patients of tuberculosis. The elimination half-life of isoniazid was significantly increased when administered in combination with rifampicin in well-nourished and malnourished patients, while no significant difference was observed in any of the pharmacokinetic parameters of rifampicin in combination with isoniazid or alone in both groups of patients. Results are discussed on the basis of pharmacokinetic drug interaction.

Acetylation↗
PubMed1976

Magnesium and the heart.

Magnesium is a most important cation in the body mostly distributed in the skeleton, muscles and liver. The most important causes of magnesium deficiency in the body include wide range of gastrointestinal disorders, diuretic therapy, endocrine disorders, renal diseases, alcoholism, etc. The demonstration of hypomagnesemia in patients of digitalis toxicity is of great clinical significance since magnesium can be replaced among these patients and toxicity and mortality due to this drug can be minimised. In patients with low serum magnesium, the cellular content of this ion may be normal. Therefore, it is of great interest to study the myocardial level of this ion in cardiovascular diseases. The clinical features of magnesium deficit are related to neuromuscular disorders. However, ST and T waves changes are quite commonly seen in the electrocardiogram and cardiac arrhythmias rarely have also been described. Magnesium administration on the other hand causes hypotention, bradycardia, and conduction defects. Magnesium depresses central nervous system, neuromuscular transmission and conductivity of the heart. Magnesium therapy is indicated when clinical features of magnesium deficiency are present in association with low serum or tissue levels.

Arrhythmias, Cardiac↗