You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Pharmacokinetic and pharmacodynamic evaluation of floating microspheres of metformin hydrochloride. Metformin hydrochloride (MH), a biguanide antidiabetic, is the drug of choice in obese patients. It is well absorbed from the upper part of gastrointestinal tract and has oral bioavailability of 50% to 60%. The objective of this study was to formulate MH into floating microspheres in order to increase its residence time at the site of absorption and thus improve its bioavailability; and to extend the duration of action along with possibilities of dose reduction. Microspheres were prepared by emulsion solvent evaporation method and evaluated for particle size, entrapment efficiency, buoyancy, and in vitro release; and further characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry. The pharmacokinetic and pharmacodynamic evaluation of selected formulation was carried out in male Wistar diabetic rats. The data was statistically analyzed by unpaired t-test. A 3.5-fold increase in relative bioavailability was observed. The prolongation of half-life (t(1/2)) from 4.5 ± 2.41 h to 14.12 ± 4.81 h indicated extended duration of action. Oral glucose tolerance test (OGTT) was analyzed by one-way analysis of variance followed by Dunnet multiple comparison test, a significant decrease (p < 0.05) in the blood glucose levels was observed when formulations were compared with control rats. Hence, MH floating microspheres were tested at 50 mg/kg and 100 mg/kg body weight, OGTT data showed nonsignificant difference (p >0.05). In conclusion, an effective oral antidiabetics treatment can be achieved by formulating MH into floating microspheres which results in increase in bioavailability along with extended duration of action resulting in possible reduction in dose.
{"Chemical": ["Metformin hydrochloride", "biguanide", "glucose", "metformin hydrochloride"]}