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Background and purpose: Solubility behavior of a drug is one of the key determinants of its oral bioavailability. The bioavailability may be enhanced by increasing the solubility and dissolution rate of drug by combining the drug with a hydrophilic carrier. Naproxen is a poor water non-soluble analgesic and anti- inflammatory drug. A possible way of overcoming the naproxen low aqueous solubility is to alter the physical properties of the drug by preparing a solid dispersion. In this study, Gelucire 50/13 and PEG 4000 were employed to produce solid dispersions with naproxen. Material and methods: Naproxen solid dispersions were prepared in various amounts of drug and polymer (PEG4000) using hot melting method. The influence of several amounts of gelucire 50/13 was also studied. Dissolution studies, Differential scanning calorimetry (DSC), Fourier–transform infrared spectroscopy (FTIR), and X-ray powder diffractometry (XRD) were used to evaluate any interaction between the drug and other components in solid dispersions. Results: According to dissolution study, drug release from solid dispersions and physical mixture were higher than that of the pure drug. Also, dissolution rate of solid dispersions and physical mixtures enhanced by increasing the concentration of polyetilen glycol. The result of DSC and FTIR showed that there was no chemical interaction between the drug and the polymer. XRD patterns showed the change of Naproxen Crystalline Material into Amorphous Materials. Conclusion: The increased dissolution rate of naproxen by solid dispersion technique could be due to increase wettability and hydrophilic nature of carrier and surfactants.

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Background and purpose: Piroxicam is a non-steroidal anti- inflammatory drug that is characterized by low solubility and high permeability. According to the biopharmaceutic drug classification system, piroxicam is a class 2 drug with low solubility and high permeability. The solid dispersion, ammroach is commonly used to improve the dissolution of poorly water soluble drugs using hydrophilic polymeric carriers as dispersing agents. In this study, the solid dispersion of piroxicam were prepared with different carriers for improving the dissolution rate of the drug and also the physicochemical properties of solid dispersions were evaluated. Materials and methods: Piroxicam solid dispersions were prepared by hot melting and melting–solvent methods using PEG4000. The influence of tween 40 was also studied. The prepared solid dispersion properties of the drug were evaluated by dissolution studies, Differential scanning calorimetry (DSC), Fourier–transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). Results: The results showed a significant increase in dissolution rate of piroxicam from solid dispersions. Tween 40 also increased the dissolution rate of solid dispersions. XRD patterns indicated that piroxicam exists in its solid state in all solid dispersions. The DSC and FTIR results showed no chemical interaction between the drug and the polymer. Conclusion: This study showed significant improvements in dissolution rate of piroxicam solid dispersion prepared by PEG4000 and tween 40.