Context: Surface-modified pH-sensitive liposomal system may be useful for intracellular delivery of chemotherapeutics. Objective: Achieving site-specific targeting with over-expressed hyaluronic acid (HA) receptors along with using pH sensitive liposome carrier for intracellular drug delivery was the aim of this study. Materials and methods: Stealth HA-targeted pH-sensitive liposomes (SL-pH-HA) were developed and evaluated to achieve effective intracellular delivery of doxorubicin (DOX) vis–a-vis enhanced antitumor activity. Results: The in vitro release studies demonstrated that the release of DOX from SL-pH-HA was pH-dependent, i.e. faster at mildly acidic pH ∼5, compared to physiological pH ∼7.4. SLpH-HA was evaluated for their cytotoxicity potential on CD44 receptor expressing MCF-7 cells. The half maximal inhibitory concentration (IC50) of SL-pH-HA and SL-HA were about 1.9 and 2.5 μM, respectively, after 48 h of incubation. The quantitative uptake study revealed higher localization of targeted liposomes in the receptor positive cells, which was further confirmed by fluorescent microscopy. The antitumor efficacy of the DOX-loaded HA-targeted pH-sensitive liposomes was also verified in a tumor xenograft mouse model. Discussion: DOX was efficiently delivered to the tumor site by active targeting via HA and CD44 receptor interaction. The major side-effect of conventional DOX formulation, i.e. cardiotoxicity was also estimated by measuring serum enzyme levels of LDH and CPK and found to be minimized with developed formulation. Overall, HA targeted pH-sensitive liposomes were significantly more potent than the non-targeted liposomes in cells expressing high levels of CD44. Conclusion: Results strongly implies the promise of such liposomal system as an intracellular drug delivery carrier developed for potential anticancer treatment.

The present work reports the development of doxorubicin (DOX) encapsulated α-tocopherol polyethylene glycol 1000 succinate (TPGS)-coated liposomal system (DOX-LIPO-TPGS) by quality by design (QbD) approach and evaluated for its anticancer and hemocompatibility potential. The screening and optimization of formulation variables were performed by the systematic design of experiments (DoE), using Taguchi and Box–Behnken design (BBD) for their desired quality attributes. The QbD optimized DOX-LIPO (DOX encapsulated uncoated liposome) and DOX-LIPO-TPGS formulation showed nano-metric vesicle size (98.2 ± 3.1 and 117.6 ± 3.5 nm) with favourable development parameters, i.e. PDI (0.262 ± 0.008 and 0.123 ± 0.005); ZP (−38.7 ± 0.5 and −36.4 ± 0.7 mV) and % EE (66.8 ± 3.3 and 73.5 ± 3.5%) respectively. The release kinetics parameters suggested, sustained release behaviour of developed liposomal formulations (83.6 ± 2.8 and 69.8 ± 2.2% releases in 72 h, respectively). Cytotoxicity (MTT assay) on the MCF-7 breast cancer cell line and haemolysis assay on RBCs stipulates comparatively higher anticancer potential and better hemocompatibility of DOX-LIPO-TPGS with respect to DOX-LIPO and the plain DOX solution. The study concluded that the QbD based three levels by three factors BBD optimization could be utilized for obtaining liposomal formulations with desired quality attributes. TPGS could be set out as a vital additive to improve the various quality parameters including stealthing character, stability, kinetic release, cytotoxicity, and hemocompatibility of liposomal formulations. This may serve as a focal paradigm for using TPGS-coated liposomes as anticancer drug delivery vehicle in normal and MDR carcinoma.

The nanostructured drug-delivery systems for colon-targeted drug delivery are a promising field of research for localized diseases particularly influencing the colonic region, in other words, ulcerative colitis, Crohn's disease, and colorectal cancer. There are various drug-delivery approaches designed for effective colonic disease treatment, including stimulus-based formulations (enzyme-triggered systems, pH-sensitive systems) and magnetically driven drug-delivery systems. In addition, targeted drug delivery by means of overexpressed receptors also offers site specificity and reduces drug resistance. It also covers GI tract-triggered emulsifying systems, nontoxic plant-derived nanoformulations as advanced drug-delivery techniques as well as nanotechnology-based clinical trials toward colonic diseases. This review gives insight into advancements in colon-targeted drug delivery to meet site specificity or targeted drug-delivery requirements.

Background: Nanopharmaceuticals serve as emerging forms of modern medicines, which include nanomedicines, nanosimilars, nanotheranostics, nanodevices, and many more. In the last two decades, a large number of nano-based products have reached the market and are being used clinically. Objectives: Unlike conventional pharmaceutical products, nanopharmaceuticals behave differently both in vitro and in vivo, and therefore, the development of their generic versions needs special attention to replicate the similar drug release pattern leading to an identical therapeutic outcome. Further, drug-device combinations and 3D products are the latest advancements in precision medicine delivery and development. Methods: The regulatory guidelines for these products are being framed at many stages by various regulatory agencies like USFDA/EMA and still are in infancy at the moment if we look at wider perspectives and applications of nanomedicine. Results: For a formulation scientist, it is much needed that well-explained and directive guidelines should be made available before leading to the development of the generic versions of these nano-cargos. Conclusion: Here, in this review, we have summarized the silent features of the regulatory perspectives related to nanotechnology based next generation therapeutics and diagnostics.