Gupta Lokesh, Sharma Ashok Kumar, Gothwal Avinash, Khan Mohammed Shahid, Khinchi Mahaveer Prasad, Qayum Arem, Singh Shashank Kumar, Gupta Umesh
Department of Pharmacy, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer 305817, Rajasthan, India.
Kota College of Pharmacy, Ranpur, Jhalawar Road, Kota 324005, Rajasthan, India.
Int J Pharm. 2017 Aug 7;528(1-2):88-99. doi: 10.1016/j.ijpharm.2017.04.073. Epub 2017 May 19.
Berberine (BBR) is a nitrogenous cyclic natural alkaloid with potential anticancer activity. However it has been less explored due to its poor pharmacokinetic profile. Dendrimers (e.g. PAMAM) have promising potential to deliver anticancer drugs/bio-actives because of their well-defined architecture, monodispersity and tailor-made surface functionality. In the present study it was attempted to deliver berberine through G4 PAMAM dendrimers by conjugation (BPC) as well as encapsulation (BPE) approach. The developed encapsulated and conjugated berberine formulations were found to have size in the approximate range of 100-200nm while zeta potential was almost same as PAMAM G4 dendrimer. The entrapment efficiency in BPE was found to be 29.9%, whereas, the percentage conjugation in BPC was found to be 37.49% indicating high drug payload in conjugation. The developed nano-formulations were characterized through H NMR, FT-IR as well as electron microscopy (SEM and TEM). The in vitro release study in different media (water and PBS 7.4) showed sustained release pattern of BBR. Almost 72% and 98% drug was released within 24h respectively; whereas in PBS almost 80% and 98% release was observed within 24h, respectively. The formulations followed Higuchi release and first order release as best fit release kinetic model. MTT assay results showed significantly higher anticancer activity for the PAMAM-BBR (BPC) (p<0.01) against MCF-7 and MDA-MB-468 breast cancer cells. The time dependent ex vivo hemolytic toxicity of the BPC and BPE was significantly less (<5%) even after 24h, which indicated that the formulations can be regarded as significantly safe and biocompatible. Similarly, the in vivo hematological parameters were analyzed through auto-analyzer and the formulations were found to be safer and biocompatible with very least but insignificant (p>0.05) effects. The in vivo pharmacokinetic parameters were found to be impressively improved in albino rat model. The pharmacokinetic parameters such as half-life (t) and AUC of berberine were impressively improved in the plasma level time in vivo studies in albino rat model. The obtained t was 14.33h for BPC compared to 6.7h for BBR alone. The overall conclusion says that among both the developed formulations the conjugated formulation (BPC) was found to be more prominent than the encapsulated one (BPE). Therefore conclusively conjugation can be a better option for the delivery of natural bio-actives through dendrimers.
小檗碱（BBR）是一种具有潜在抗癌活性的含氮环状天然生物碱。然而，由于其药代动力学特性较差，对其研究较少。树枝状大分子（如聚酰胺-胺，PAMAM）因其结构明确、单分散性和可定制的表面功能，在递送抗癌药物/生物活性物质方面具有广阔的潜力。在本研究中，尝试通过共轭（BPC）和包封（BPE）方法，利用G4 PAMAM树枝状大分子递送小檗碱。所制备的包封和共轭小檗碱制剂的粒径约为100 - 200nm，zeta电位与PAMAM G4树枝状大分子几乎相同。发现BPE中的包封率为29.9%，而BPC中的共轭率为37.49%，表明共轭制剂的载药量较高。通过核磁共振氢谱（H NMR）、傅里叶变换红外光谱（FT-IR）以及电子显微镜（扫描电子显微镜SEM和透射电子显微镜TEM）对所制备的纳米制剂进行了表征。在不同介质（水和磷酸盐缓冲液PBS 7.4）中的体外释放研究表明，BBR呈现出持续释放模式。在24小时内，分别有近72%和98%的药物释放；而在PBS中，24小时内分别观察到近80%和98%的释放。这些制剂最符合Higuchi释放和一级释放动力学模型。MTT法检测结果显示，PAMAM - BBR（BPC）对MCF - 7和MDA - MB - 468乳腺癌细胞的抗癌活性显著更高（p<0.01）。即使在24小时后，BPC和BPE的时间依赖性离体溶血毒性也显著较低（<5%），这表明这些制剂可被视为具有显著的安全性和生物相容性。同样，通过自动分析仪分析了体内血液学参数，发现这些制剂更安全且具有生物相容性，其影响极小但不显著（p>0.05）。在白化大鼠模型中，发现体内药代动力学参数得到了显著改善。在白化大鼠模型的体内血浆水平时间研究中，小檗碱的药代动力学参数如半衰期（t）和曲线下面积（AUC）得到了显著改善。与单独的BBR的6.7小时相比，BPC获得的t为14.33小时。总体结论是，在所制备的两种制剂中，共轭制剂（BPC）比包封制剂（BPE）更突出。因此，结论性地说，共轭可能是通过树枝状大分子递送天然生物活性物质的更好选择。
