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.

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We present the accretion disk size estimates for a sample of 19 active galactic nuclei (AGN) using the optical g, r, and i band light curves obtained from the Zwicky Transient Facility (ZTF) survey. All the AGN have reliable supermassive black hole (SMBH) mass estimates based on previous reverberation mapping measurements. The multi-band light curves are cross-correlated, and the reverberation lag is estimated using the Interpolated Cross-Correlation Function (ICCF) method and the Bayesian method using the javelin code. As expected from the disk reprocessing arguments, the g − r band lags are shorter than the g − i band lags for this sample. The interband lags for all, but 5 sources, are larger than the sizes predicted from the standard Shakura Sunyaev (SS) analytical model. We fit the light curves directly using a thin disk model implemented through the javelin code to get the accretion disk sizes. The disk sizes obtained using this model are on an average 3.9 times larger than the prediction based on the SS disk model. We find a weak correlation between the disk sizes and the known physical parameters, namely, the luminosity and the SMBH mass. In the near future, a large sample of AGN covering broader ranges of luminosity and SMBH mass from large photometric surveys would be helpful in a better understanding of the structure and physics of the accretion disk.