2. EFFECT OF PHYSICAL MODIFICATION AND IONIC STRENGTH ON THE SOLUBILITY AND DISSOLUTION OF PARACETAMOL By M.M.Nafadi From Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo university, Egypt.

3.  Aim of work The objective of the work was to study the influence of different modifications and dissolution media on the solubility and dissolution behavior of paracetamol to elucidate the aqueous solubility of paracetamol and its in vitro behavior and to interpret the resuls with respect to the in vivo aspects.

4.  It was found that the addition of sodium chloride at concentrations of 0.75% and 0.9% increases the solubility of paracetamol and accelerates its dissolution. The latter concentration was the suitable one because it was within the physiological range. Optical microscope revealed that paracetamol and paracetamol treated samples depicted different crystal shapes which affected greatly the solubility and dissolution of the drug.

5.  Conclusion  the solubility and dissolution of paracetamol can be improved by using paracetamol treated with phosphate buffer (pH 6) and using 0.9% sodium chloride in the dissolution medium or in the formulation

6. Fig(1):Photomicrographs of paracetamol (A),paaracetamol treated with phosphate buffer pH 4.5 (B), paracetamol treated with phosphate buffer pH 6 (C), paracetamol treated with phosphate buffer pH 6.8 (D), paracetamol treated with citrate buffer pH 4.5 (E), paracetamol treated with citrate buffer pH 6 (F), paracetamol treated with citrate buffer PH 6.8 (G), paracetamol treated with distilled water (H) (magnification 1:200).