Search

The study focuses on widening up the therapeutic perspective of anti-cancer therapy by entrapping a hydrophilic anticancer drug, topotecan hydrochloride (TOPO) in biodegradable poly (lactide-co-glycolide) (PLGA) matrix to form topotecan nanoparticles (TOPO NPs) by a double emulsion solvent evaporation technique. Statistical optimization using Box-Behnken design showed that sonication time of primary emulsion for 120 s, drug: polymer ratio of 1:12.65, organic phase: external aqueous phase ratio of 1:2.82 and 0.5% w/v of polyvinyl alcohol in the drug containing phase produced TOPO NPs with a size of 243.2 ± 4 nm and an entrapment efficiency of 60.9 ± 2.2%. TOPO NPs illustrated sustained release of TOPO for a week in phosphate buffer saline (PBS) at simulating physiological (pH 7.4) and acidic tumor microenvironmental (pH 6.5) conditions. A dramatic increase in cellular uptake with a corresponding enhanced cytotoxic potency was also displayed by TOPO NPs against human ovarian cancer cells (SKOV3) over time as compared to native drug, TOPO. These findings were further supported by the enhancement of bioavailability (13.05 fold) conferred by TOPO NPs from the in vivo pharmacokinetic study. The study represents a logistic approach for formulating TOPO NPs which can be used as an effective drug delivery system for the treatment of ovarian cancer., (Copyright © 2018. Published by Elsevier B.V.)

Topotecan (TPT) is indicated against a variety of solid tumors, but has restricted clinical use owing to associated pharmaceutical caveats. This study is focused at formulating a successful TPT PLGA nanosystem which ameliorates the rapid conversion of active lactone form of drug to its inactive carboxylate form and consequently improvises its efficacy. TPT PLGA nanoparticles were formulated by a double emulsion-solvent evaporation technique with sequential optimization to obtain desired particle size, PDI, zeta potential, and entrapment efficiency. Stability of TPT was ensured by maintaining an acidic pH in the drug-containing phase and the system was evaluated for in vitro-in vivo performance including cytotoxic potency. The optimized nanosystem had a particle size of 187.33 ± 7.50 nm, a PDI of 0.179 ± 0.05, and an entrapment efficiency of 56 ± 1.2%. Low pH in the interior of nanoparticles stabilized the drug to remain in its active lactone form and revealed a biphasic release pattern till 15 d. Additionally, an in vitro cytotoxicity testing as well as in vivo antitumor efficacy demonstrated a significant potential of higher proliferation inhibition as compared with neat drug (TPT). Thus, the investigation summarized an innovative simple tool for developing stable TPT NPs for effective delivery for treating solid tumors.

The dual drug loaded poly(dl-lactic-co-glycolic acid) (PLGA(1)) nanoparticles (TOP-TAM NPs(2)) concurrently delivering topotecan hydrochloride (TOP(3)) and tamoxifen citrate (TAM(4)) were developed to achieve synergism for the treatment of breast cancer by enhancing the permeation of TOP through the gut and the cells present in the breast. TAM acted as P-glycoprotein (P-gp(5)) inhibitor, reduced the side effects of individual drugs by reducing the dose. The NPs were prepared by double emulsion (w/o/w) method. The optimized TOP-TAM NPs were found to have smooth and spherical morphology by using SEM(6) and TEM(7) technique. Similarly size of nanoparticles was found to be 151.2 ± 1.6 nm with 0.147 ± 0.03 polydispersity index (PDI(8)). The percentage entrapment efficiency of 95.17 ± 3.57 and 57.77 ± 2.2 was found for TAM and TOP respectively. The lyophillized nanoparticles under DSC(9) showed amorphous nature of both TOP and TAM. In an in vitro release study the release of drugs from TOP-TAM NPs was found to follow the Higuchi pattern. The ex vivo gut permeation study revealed that the TAM enhanced the permeation of TOP and increased its bioavailability by 1.9 folds. The permeation and activity of combination of drugs were further confirmed by carrying out cell line studies on MCF-7 cells., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Nanomedicine combination therapy, a strategy to delivery multiple drugs via a single nanosystem has opened new avenues to treat cancer and prevent side effects and overcome chemoresistance. The present work utilizes a chemotherapeutic agent topotecan hydrochlorideand a natural chemosensitizer (thymoquinone, TQ) incorporated into poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) to target tumor. The objective of the present work is to develop a reversed phase HPLC method for simultaneous estimation of TQ along with the pH dependent lactone and carboxylate forms of topotecan and validate its applicability. Chromatographic separation was obtained on Agilent 1200 Infinity series C18 analytical column using gradient elution with acetonitrile and 1% triethylamine acetate (TEAA) buffer (pH 5.5) as mobile phase and a flow rate of 0.8 mL/min. Analytical detection was done at 253 nm. Validation was performed as per ICH guidelines and characterization and stability of the optimized nanoparticles were evaluated. The retention time of 5.93, 8.73, and 19.76 min was obtained for lactone, carboxylate and TQ, respectively. Linearity response was established in the range of 5‒45 µg/mL. The limits of detection and quantification were found to be 15 and 50 ng/mL for lactone, 18 and 59 ng/mL for carboxylate, and 5 and 18 ng/mL for TQ, respectively. The method was validated in terms of robustness, precision, accuracy, specificity and percent loading, entrapment efficiency, and in vitro drug release. The stability of the nanoparticles was determined using the above validated method. The method was successfully validated and applied for routine analyses indicating its use as a suitable analytical tool to determine efficiency of the proposed therapy. [ABSTRACT FROM AUTHOR]

Poor and suboptimal therapeutic outcomes with single anticancer drugs have led to a keen interest in combination chemotherapy. Co-delivery of potent anticancer agents with high efficacy and least off-target site effects is highly desirable but often requires focussed formulatory approaches. The unique physiochemical properties of the chosen drugs further add to the challenge. The current work is an attempt to co-deliver topotecan (hydrophilic moiety) and thymoquinone (lipophilic moiety) from a nanomatrix eliciting a suitable release profile. Topotecan- thymoquinone loaded PLGA nanomatrix (TP-TY NPs) were formulated by a modified double emulsion solvent evaporation method where topotecan is solubilized in the inner aqueous phase while thymoquinone is incorporated into the organic phase of the double emulsion. Independent and dependent variables were optimized using central composite design (CCD) to obtain TP-TY NPs which were then characterized in terms of zeta potential, surface morphology, residual PVA content, injectability, syringeability, and reconstitution time. The nature of entrapped drugs was confirmed by DSC and XRD analyses and drug release pattern was studied. CCD indicated quadratic as the best fit model. The optimized formulation had particle size of 240.7 ± 8.3 nm and percent entrapment and loading of 62.6 ± 2.6 and 6.52 ± 0.25 respectively for thymoquinone and 42.3 ± 1.2% and 3.6 ± 0.26 for topotecan respectively. The particles had a spherical shape, residual PVA content of 6.22% and negative zeta potential of − 1.16 mV indicating the stability of the nanoparticles. DSC and XRD confirmed the transformation of drug from its crystalline to amorphous form when entrapped in the PLGA nanomatrix. The lyophilized particles reconstituted within 30 s and suspension thus obtained conformed to the standard tests of syringeability and injectability. TP-TY NPs revealed a sustained release pattern of both the drugs with a minimal burst release and a total percentage release > 90% in 96 h. Finally, the short term accelerated stability analysis showed no significant changes with a minimal variation in the release pattern. Conclusively, the CCD supported successful formulation of nanomatrix aimed at co-delivery of topotecan and thymoquinone. [ABSTRACT FROM AUTHOR]