Murali Mohan Babu Gedela V, Kumar Namballa R, Sankar Kasina H, Ram Battu J, Kumar Namburu K, Murthy Kolapalli V R
Division of Industrial Pharmacy, Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam-0 003 AP, India.
AAPS PharmSciTech. 2002;3(2):E12. doi: 10.1208/pt030212.
This work examines the influence of modified gum karaya (MGK) on the oral bioavailability of a poorly water-soluble drug, nimodipine (NM), in comparison with that of gum karaya (GK). A cogrinding method was selected to prepare mixtures of NM and GK or MGK in a 1:9 ratio (NM:GK/MGK). Differential scanning calorimetry (DSC), Fourier transmission infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), solubility studies, and in vitro release studies were performed to characterize the properties of the cogrinding mixtures. No drug-carrier interactions were found, as confirmed by DSC and FT-IR studies. The XRD study revealed that the crystallinity of NM was identical in both the cogrinding mixtures and was decreased when compared to that of physical mixtures or pure NM. The in vitro release rate of NM from both cogrinding mixtures was significantly higher than that of physical mixtures or pure NM. The in vivo study revealed that the bioavailability of NM from pure drug was significantly lower when compared to the cogrinding mixtures. The oral bioavailability was found to be NM powder < cogrinding mixtures of NM and GK < cogrinding mixtures of NM and MGK < NM solution. It can be inferred from the above results that MGK, an economical carrier, could be used for the dissolution enhancement of NM.
本研究考察了与刺梧桐树胶（GK）相比，改性刺梧桐树胶（MGK）对难溶性药物尼莫地平（NM）口服生物利用度的影响。选择共研磨法制备NM与GK或MGK以1:9比例（NM:GK/MGK）的混合物。采用差示扫描量热法（DSC）、傅里叶变换红外（FT-IR）光谱法、X射线衍射（XRD）、溶解度研究和体外释放研究来表征共研磨混合物的性质。DSC和FT-IR研究证实，未发现药物-载体相互作用。XRD研究表明，两种共研磨混合物中NM的结晶度相同，与物理混合物或纯NM相比结晶度降低。两种共研磨混合物中NM的体外释放速率均显著高于物理混合物或纯NM。体内研究表明，与共研磨混合物相比，纯药物中NM的生物利用度显著较低。发现口服生物利用度为NM粉末 < NM与GK的共研磨混合物 < NM与MGK的共研磨混合物 < NM溶液。从上述结果可以推断，MGK作为一种经济的载体，可用于提高NM的溶出度。
