From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO–LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C_7, C₉ and C₁₈ as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.

从过去几年开始，药物和 DNA 之间的相互作用模式是一个有吸引力的研究领域，因为它连接了化学、分子生物学和医学科学。小杂环分子与人类 DNA 之间的相互作用是药理学研究药物机制和设计更有效和靶向特异性药物的一个值得注意的特征，副作用更少。目前的研究工作重点是通过使用高斯 (16 W) 软件预测优化几何结构、HOMO-LUMO 间隙、键长、键角、二面角、电子和振动光谱。在 SASA 中观察到的可能反应位点是 C _7、 C ₉和 C ₁₈因为这些原子显示出最大电荷密度。后来，SASA 与人类 DNA 的相互作用分别在 pH 值 4.7（胃 pH 值）和 7.4（血液 pH 值）的生理缓冲液中进行了光谱研究和粘度研究。SASA-DNA 复合物之间的最大吸光度在 pH 3.4 的缓冲溶液中在 370 nm 的波长处观察到，而在 7.4 之间具有最大吸光度。光谱结果反映了添加人类 DNA 后的红移和增色变化。在粘度测量过程中，分别检测溶液中低浓度和高浓度药物的嵌入和静电相互作用模式。随着药物浓度的增加，观察到速率常数值增加。与 pH 3.5 相比，在 pH 7.4 下观察到更大的速率常数值。