In this work we synthesized Nano hydroxyapatite (HAp) by Solgel method, Then we functionalized hydroxyapatite nanoparticle by use of 3-Aminopropyl trimethoxysilane (APTMS), to improve the loading and control release of sulfasalazine drug bonded to APTMS. The drug release patterns from Sulfasalazine loaded HAp nanoparticles at pH value 8 For 6h, Sulfasalazine loaded functionalized HAp nanoparticles (Sulfasalazine loaded HAp-APTMS) at pH value 8 as in the intestine for 48h. Moreover, the functionalized HAp showed relatively slower release rate of sulfasalazine compare with non functionalized HAp. because the strong ionic interaction between NH2 group in sulfasalazine in HAp-APTMS. On other side, the functionalized HAp loaded more drug than pure HAp. The synthesized nanoparticles and functionalized HAp characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier transform infrared (FT-IR) and UV/Vis analysis techniques. Then the obtained material was studied in the simulated body fluid (SBF) to this investigated storage and release properties.

Acid dissociation constant value (pK a) is key parameter for predicting the extent of the ionization of a drug molecule at different pH. The effect of the mobile phase composition on the acid dissociation constant values was studied by measuring the pK a values at different acetonitrile concentrations, ranging from 25 to 35 % (v/v). pK a values and limiting retention factors of SSZ were calculated chromatographically using equations derived. From calculated pK a values, the aqueous pK a values of SSZ were calculated by various approaches. Moreover, the correlation established between retention factors and the pH of the water-acetonitrile mobile phase was used to determine the optimum separation condition. Optimized condition was also validated with respect to system suitability, linearity, precision, accuracy, limit of detection and limit of quantitation, respectively. A Gemini NX C18 column (250 × 4.6 mm I.D., 5 µm particles) was used for all the determinations.

Rheumatoid arthritis is a chronic systemic inflammatory disease that affects approximately 0.5-1% of the world population. The current approach to this disease is to start an intensive treatment without delay once the disease has developed. Various studies in the literature have shown that combination of disease modifying anti rheumatic drugs such as sulfasalazine and chloroquine offers a more advantageous treatment. Although these drugs may cause central nervous system adverse effects such as serious psychiatric problems including mania and psychosis, these symptoms have been reported to occur only infrequently. The present case study reports a female patient who was hospitalized due to bipolar affective disorder- mixed episode. She had been receiving 250 mg/day chloroquine for 9 months for rheumatoid arthritis without exhibiting any adverse psychiatric effects. However, upon receiving a combination of 250 mg/day chloroquine and 2 gr/day sulfasalazine, she developed serious psychiatric symptoms.