Kaushik Thanki

Oral delivery of anticancer drugs: challenges and opportunities.

The present report focuses on the various aspects of oral delivery of anticancer drugs. The significance of oral delivery in cancer therapeutics has been highlighted which principally includes improvement in quality of life of patients and reduced health care costs. Subsequently, the challenges incurred in the oral delivery of anticancer agents have been especially emphasized. Sincere efforts have been made to compile the various physicochemical properties of anticancer drugs from either literature or predicted in silico via GastroPlus™. The later section of the paper reviews various emerging trends to tackle the challenges associated with oral delivery of anticancer drugs. These invariably include efflux transporter based-, functional excipient- and nanocarrier based-approaches. The role of drug nanocrystals and various others such as polymer based- and lipid based-nanocarriers in the bioavailability enhancement along with their clinical outcomes has also been discussed exhaustively. Furthermore, an insight on the various absorption mechanisms of these nanocarriers across the gastrointestinal tract has also been highlighted.

Co-encapsulation of tamoxifen and quercetin in polymeric nanoparticles: implications on oral bioavailability, antitumor efficacy, and drug-induced toxicity.

The present investigation reports the preparation, optimization, and characterization of orally administrable PLGA-NPs co-encapsulated with tamoxifen (Tmx) and quercetin (QT). The developed formulation was found to have particle size 185.3 ± 1.20 nm, PDI 0.184 ± 0.004, entrapment efficiency 67.16 ± 1.24% Tmx, 68.60 ± 1.58% QT at a Tmx/QT ratio of 1:2 w/w. The stability of the freeze-dried formulation was established in simulated gastrointestinal fluids for 8 h and at accelerated stability condition for 3 months. DPPH free radical scavenging assay confirmed that the functional architecture of QT was retained in freeze-dried NPs. Higher cellular uptake, cytotoxicity, and nuclear co-localization of Tmx-QT-NPs in MCF-7 cells revealed higher efficiency of the formulation. At the same time, higher Caco-2 cell uptake revealed its potential for oral delivery, which was well corroborated with in vivo pharmacokinetics, which suggested ∼ 5-fold and ∼ 3-fold increase in oral bioavailability as compared to the free Tmx citrate and free QT, respectively. Concomitantly, significantly higher tumor suppression was observed in the case of the developed formulation in contrast to respective free drug(s) and their combination when tested against a DMBA-induced breast cancer model in female SD rats. Multiple oral administrations of Tmx-QT-NPs efficiently controlled the tumor angiogenesis as revealed by normalized levels of respective markers (MMP-2 and MMP-9). The safety profile of Tmx-QT-NPs was also established, and no measurable hepatotoxicity or oxidative stress was observed when measured as a function of respective biochemical markers in contrast to free drug(s) and their combinations. In a nutshell, the co-encapsulation strategy with PLGA-NPs could be a promising approach in improving oral delivery of Tmx and QT for cancer therapy.

Improved stability and antidiabetic potential of insulin containing folic acid functionalized polymer stabilized multilayered liposomes following oral administration.

The present study reports the folic acid (FA) functionalized insulin loaded stable liposomes with improved bioavailability following oral administration. Liposomes were stabilized by alternating coating of negatively charged poly(acrylic acid) (PAA) and positively charged poly(allyl amine) hydrochloride (PAH) over liposomes. Furthermore, folic acid was appended as targeting ligand by synthesizing folic acid-poly(allyl amine) hydrochloride conjugate. The insulin entrapped within the freeze-dried formulation was found stable both chemically as well as conformationally and developed formulation exhibited excellent stability in simulated biological fluids. Caco-2 cell and ex vivo intestinal uptake studies revealed higher uptake of folic acid functionalized layersomes in comparison with their plain counterparts. In vivo pharmacodynamic and pharmacokinetic studies further revealed almost double hypoglycemia and approximately 20% relative bioavailability in comparison with subcutaneously administered standard insulin solution. Overall the proposed strategy is expected to contribute significantly in the field of designing ligand-anchored, polyelectrolyte-based stable systems in drug delivery.

Gelatin Coated Hybrid Lipid Nanoparticles for Oral Delivery of Amphotericin B

Amphotericin B (AmB) loaded polymer lipid hybrid nanoparticles (AmB-PLNs) comprised of lecithin (anionic lipid) and gelatin (Type A, cationic below its isoelectric point 7.0-9.0) were prepared by a two-step desolvation method to improve the oral bioavailability of AmB. The optimized AmB-PLNs were found to have particle size 253 ± 8 nm, polydispersity index (PDI) 0.274 ± 0.008, and entrapment efficiency 50.61 ± 2.20% at 6% w/w of initial theoretical drug loading. Scanning electron microscopy (SEM) revealed spherical shaped nanoparticles whereas confocal laser scanning electron microscopy (CLSM) and fluorescent resonance energy transfer (FRET) analysis confirmed the orientation of the lecithin (located in the core) and gelatin (exterior coat) within the system. The developed formulation exhibited a sustained drug release profile with a release pattern best fitted to Higuchi kinetics. Experiments on Caco-2 cell lines revealed a 5.89-fold increase in the intestinal permeability of AmB-PLNs whereas in vivo pharmacokinetic studies exhibited a 4.69-fold increase in the oral bioavailability upon incorporation of AmB into PLNs as compared to that of free drug. The developed formulation showed significantly lesser hemolytic toxicity as compared to the free drug, Fungizone (micellar solution of AmB) and Fungisome (liposomal formulation of AmB). Furthermore, blood urea nitrogen (BUN) and plasma creatinine levels, indicative of nephrotoxicity, were also found to be significantly lesser for developed PLN formulation as compared to free drug and Fungizone while comparable to that of Fungisome. The histopathology of the kidney tissues further confirmed the absence of any changes in the morphology of the renal tubules.

Novel self-emulsifying formulation of quercetin for improved in vivo antioxidant potential: implications for drug-induced cardiotoxicity and nephrotoxicity.

Quercetin (QT) was formulated into a novel self-emulsifying drug delivery system (SEDDS) to improve its oral bioavailability and antioxidant potential compared to free drug. Capmul MCM was selected as the oily phase on the basis of optimum solubility of QT in oil. Tween 20 and ethanol were selected as surfactant and cosurfactant from a large pool of excipients, depending upon their spontaneous self-emulsifying ability with the selected oily phase. Pseudoternary-phase diagrams were constructed to identify the efficient self-emulsification regions in various dilution media, viz., water, pH 1.2, and pH 6.8. The ratio of 40:40:20 w/w, Capmul MCM:QT (19:1)/Tween 20/ethanol was optimized based on its ability to form a spontaneous submicrometer emulsion in simulated gastrointestinal fluids. DPPH scavenging assay showed comparable antioxidant activity of QT-SEDDS to free QT. QT-SEDDS was robust in terms of stability against short-term excursion of freeze/thaw cycles and accelerated stability for 6 months as per International Conference on Harmonisation guidelines. A fluorescent dye-loaded SEDDS formulation showed rapid internalization within 1h of incubation with Caco-2 cells as evident by confocal laser scanning microscopy. QT-SEDDS showed a significant increase in cellular uptake by 23.75-fold in comparison with free QT cultured with Caco-2 cells. The SEDDS demonstrated ~5-fold enhancement in oral bioavailability compared to free QT suspension. The in vitro-in vivo relation between in vitro Caco-2 cell uptake and in vivo pharmacokinetics of QT-SEDDS showed a correlation coefficient of ~0.9961, as evident from a Levy plot. Finally, QT-SEDDS showed a significantly higher in vivo antioxidant potential compared to free QT when evaluated as a function of ability to combat doxorubicin- and cyclosporin A-induced cardiotoxicity and nephrotoxicity, respectively.

Enhanced antitumor efficacy and counterfeited cardiotoxicity of combinatorial oral therapy using Doxorubicin- and Coenzyme Q10-liquid crystalline nanoparticles in comparison with intravenous Adriamycin

UNLABELLED Present study focuses on enhancing oral antitumor efficacy and safety of Dox-LCNPs in combination with CoQ10-LCNPs. Drug-loaded-LCNPs were prepared by solvent-diffusion-evaporation method and optimized. Median effect analysis suggested dose-reduction-index of 16.84- and 5.047-fold and strong synergism for combination at 1:10 dose ratio owing to higher cellular uptake, nuclear colocalization, higher apoptotic index and 8-OHdG levels. The prophylactic antitumor efficacy of the CoQ10-LCNPs was also established using tumor induction and progression studies. Finally, therapeutic antitumor efficacy was found to be significantly higher (~1.76- and ~4.5-fold) for the combination as compared to Dox-LCNPs (per oral) and Adriamycin (i.v.) respectively. Notably, level of residual tumor burden was insignificant (P>0.05) after 30days in case of combination and LipoDox® (i.v.). Interestingly, with Dox-induced-cardiotoxicity was completely counterfeited in combination. In nutshell, LCNPs pose great potential in improving the therapeutic efficacy of drugs by oral route of administration. FROM THE CLINICAL EDITOR This study describes the use of liquid crystalline nanoparticles containing coenzyme Q10 and doxorubicin. The nano-conjugates not only provided an enhanced oral treatment option for a tumor model, but prevented cardiotoxicity, a major complication of this drug when delivered via conventional methods.

Positively charged self-nanoemulsifying oily formulations of olmesartan medoxomil: Systematic development, in vitro, ex vivo and in vivo evaluation

The current research work explores the potential applications of cationic self-nanoemulsifying oily formulations (CSNEOFs) for enhancing the oral bioavailability of olmesartan medoxomil. Initial preformulation studies, risk assessment and factor screening studies revealed selection of oleic acid, Tween 40 and Transcutol HP as the critical factors. Systematic optimization of SNEOFs was carried out employing D-optimal mixture design and evaluating them for responses viz. emulsification efficiency, globule size and in vitro drug release. The CSNEOFs were prepared from the optimized SNEOFs by adding oleylamine as cationic charge inducer. In vitro cell line studies revealed markedly better drug uptake along with safer and biocompatible nature of CSNEOFs than free drug suspension. In situ perfusion, and in vivo pharmacokinetic and pharmacodynamic studies in Wistar rats revealed significant improvement in the biopharmaceutical performance of the drug from CSNEOFs and SNEOFs vis-à-vis the marketed formulation. Successful establishment of various levels of in vitro/in vivo correlations (IVIVC) substantiated high degree of prognostic ability of in vitro dissolution conditions in predicting the in vivo performance. In a nutshell, the present studies report successful development of CSNEOFs of olmesartan medoxomil with distinctly improved biopharmaceutical performance.

Enhanced transfection efficiency and reduced cytotoxicity of novel lipid-polymer hybrid nanoplexes.

The present study reports the development, characterization, and evaluation of novel polyelectrolytes stabilized lipoplexes as a nonviral vector for gene delivery. In order to achieve the advantage of both DOTAP (1,2-dioleoyl-3-trimethylammonium propane) and PEI (high transfection efficiency) a system was hypothesized in which DOTAP/phosphatidyl choline (PC) lipoplexes were electrostatically coated with anionic poly(acrylic acid) (PAA) and cationic polyethylenimine (PEI) alternatively to finally shape a robust structure PEI-PAA-DOTAP/PC-lipoplexes (nanoplexes). The nanoplexes were found to have size of 242.6 ± 9.4 nm and zeta potential of +23.1 ± 1.5 mV. Following development nanoplexes were evaluated for cellular uptake, nuclear colocalization, transfection efficiency, and cellular toxicity in MCF-7, HeLa, and HEK-293 cell lines. In support of our hypothesis nanoplexes exhibited higher uptake and nuclear colocalization in comparison with DOTAP/PC, DOTAP/DOPE lipoplexes, and PEI polyplexes. Nanoplexes also exhibited 50-80, 11-12, 6-7, and 5-6 fold higher transfection efficiency in comparison with DOTAP/PC-lipoplexes, DOTAP/DOPE-lipoplexes, PEI-polyplexes, and lipofectamine, respectively, and significantly lower toxicity in comparison with DOTAP/PC, DOTAP/DOPE lipoplexes, PEI polyplexes, and commercial lipofectamine.

Novel self-nanoemulsifying formulation of quercetin: Implications of pro-oxidant activity on the anticancer efficacy

UNLABELLED The present work focuses on the anticancer potential of quercetin (QT) loaded self-nanoemulsifying drug delivery system (QT-SNEDDS) composed of Capmul MCM, Tween 20 and ethanol. In vitro cell culture studies revealed potential cell cytotoxicity of developed formulation mediated by its ability to induce DNA damage and apoptosis in MCF-7 cells. QT-SNEDDS at a dose of 50mg/kg demonstrated the antioxidant activity measured as function of prophylactic antitumor efficacy against DMBA induced breast tumors which revealed higher latency to the tumor growth as compared to free QT. This appreciation was further supported by normalized levels of tumor angiogenesis markers (MMP-2, MMP-9, TNF-α and IL-6). At higher doses (100mg/kg) the pro-oxidant activity was noted and exhibited significantly higher therapeutic anticancer efficacy (~65% tumor suppression) in the same model as compared to that of free QT (~20%). Finally, safety profile of developed formulation was established assessing various hepatotoxicity markers. FROM THE CLINICAL EDITOR This basic science study focuses on the anticancer potential of a specific quercetin loaded self-nanoemulsifying drug delivery system. At higher doses significantly higher therapeutic anticancer efficacy (~65% tumor suppression) was noted in the same model as compared to that of free quercetin (~20%).

Enhanced Antitumor Efficacy and Reduced Toxicity of Docetaxel Loaded Estradiol Functionalized Stealth Polymeric Nanoparticles.

In spite of extensive research over the decades, breast cancer treatment is still a major challenge due to nonspecific distribution of the chemotherapeutics. This void can be filled by restricting the distribution of chemotherapeutics toward the cancerous cells. In the present report estradiol (E2) functionalization of docetaxel (DTX) loaded PLGA nanoparticles was supposed to have specific distribution of DTX to cancerous cells simultaneously avoiding the nonspecific distribution toward the normal cells. In line, E2-PEG-PLGA conjugate was synthesized and characterized by FTIR and NMR spectroscopy. Extensive optimization of different process variables resulted in the formation of spherical E2-PEG-PLGA NPs in the size range of 228.5 ± 11.8 nm and entrapment efficiency of 94.25 ± 2.49. Trehalose (5% w/v) resulted in the formation of a fluffy, easy to redisperse freeze-dried cake of nanoparticles. PXRD analysis revealed the amorphous nature of DTX encapsulated within the nanoparticles. X-ray photoelectron spectroscopy confirmed the presence of E2 over the surface of nanoparticles. In line with our hypothesis, cellular uptake studies on ER positive MCF-7 cells revealed relatively higher uptake and efficient localization into the nuclear region of E2-PEG-PLGA NPs in comparison with plain counterparts, while in the case of ER negative HeLa cells E2-PEG-PLGA NPs showed no difference in fluorescence pattern as compared to MCF-7 cells incubated with unmodified nanoformulation, indicating nonspecific delivery of DTX. Moreover, MTT assay revealed relatively higher cytotoxicity of E2-PEG-PLGA NPs in comparison with free DTX. Furthermore, in vivo pharmacokinetic studies revealed 9.36- and 4.79-fold enhancement in circulation half-life and AUC(0-∞), respectively, of E2-PEG-PLGA NPs in comparison with Taxotere. In vivo antitumor efficacy in DMBA induced rat model demonstrated significant reduction in tumor volume in comparison with the plain counterpart (PLGA-NPs) and a marketed formulation, Taxotere. Moreover, the safety of the estradiol functionalized PLGA NPs was confirmed by hepato- and nephrotoxicity studies.