In vivoperformance of pentaestergum-coated aspirin microcapsules

The in vivo study of the pentaestergum-coated aspirin microcapsules was carried out in two healthy female dogs. Blood samples were collected at different time intervals and analysed for total salicylate content. The results were compared with plain aspirin granules. A delayed release of drug was observed from pentaestergumcoated drug microcapsules. Various pharmacokinetic parameters have been calculated and reported. The drug is absorbed from the dosage form and is made available for further therapeutic action at a particular receptor site. This is known as the bioavailability of the drug. The extent of drug absorbed and the rate of absorption are affected by a number of factors dependent upon the physicochemical properties of the drug, its biological properties and patient’s factors. The extent of drug absorption also depends upon the variable nature of the chemical environment throughout the length of the gastrointestinal tract. The extent of bioavailability is usually determined either by measuring the area under the blood concentration-time curve or from cumulative amounts of drug excreted in the urine. These are three parameters describing a blood level curve that are considered to be important in evaluating the bioequivalence of two formulations. These are (1) the peak height concentration, (2) the time of peak concentration and (3) the area under the plasma concentration-time curve. Although many in vitro methods are available and useful, there is no totally satisfactory in vitro substitute for the in viwo determination of drug availability in the evaluation of various dosage forms. We have reported the effect of pH on release characteristics of pentaestergum microcapsules (Pentaerythritol rosin ester) and the dissolution kinetics (Pathak and Dorle 1986). This communication deals with the in vivo evaluation of pentaestergum aspirin microcapsules in bitches. The drug was fed orally to the experimental animals. Blood samples were withdrawn at specified time intervals and analysed for total salicylates in the plasma. On the basis of plasma drug concentration various pharmacokinetic parameters have been studied and are discussed. Pentaestergum aspirin microcapsules were prepared by encapsulating aspirin I .I’. granules using a standard coating technique (Pathak et al. 1985). To study the in vivo performance two healthy bitches (A, 15 kg and B, 16kg) were used as experimental animals. They were fasted for 12 h before drug administration. Pentaestergum aspirin microcapsules were suspended in 20 ml of 5 per cent acacia solution, and 20 mg/kg aspirin dose equivalent microcapsules were administered through a stomach tube. An additional 50 ml of purified water was also given at the