Factors Affecting the Acoustic In Vitro Release of Calcein from PEGylated Liposomes

2019 ◽  
Vol 19 (11) ◽  
pp. 6899-6906 ◽  
Author(s):  
Salma E. Ahmed ◽  
Hesham G. Moussa ◽  
Ana M. Martins ◽  
Yassmine Abbas ◽  
Mohammad H. Al-Sayah ◽  
...  

Typical methods used in cancer treatment, including chemotherapy, are debilitating because of the various adverse side effects experienced by cancer patients. The free drug injected into the patient at given doses affects both healthy and cancerous cells. Therefore, novel methods are being researched to ensure the selectivity of the treatment. The purpose of this study is to test the release of a model fluorescent drug, calcein, from echogenic stealth liposomes, triggered by lowfrequency pulsed ultrasound. Several experimental parameters related to the ultrasound (US) and the investigated liposomes were varied in order to examine their effect on the acoustic release. Upon analysis of experimental results, the study concluded that release can be maximized by optimizing the sonication frequency, power density, and US pulse duration. When a non-isothermal chamber is used to conduct the experiments, it is important to have longer ‘Off’ than ‘On’ US periods in order to avoid overheating the liposomes. Applying such pulsation pattern can also be utilized to achieve slower release rates, which safely meet the desired drug levels at the end of the session. Our study also concluded that optimizing the liposome concentration is vital to delivering desired drug doses. Additionally, the type of lipids used in the synthesis should be carefully selected to produce stable yet acoustically sensitive liposomes capable of releasing at desired rates.

2019 ◽  
Vol 9 (1) ◽  
pp. 76-85 ◽  
Author(s):  
R. Nithya ◽  
K. Siram ◽  
R. Hariprasad ◽  
H. Rahman

Background: Paclitaxel (PTX) is a potent anticancer drug which is highly effective against several cancers. Solid lipid nanoparticles (SLNs) loaded with anticancer drugs can enhance its toxicity against tumor cells at low concentrations. Objective: To develop and characterize SLNs of PTX (PSLN) to enhance its toxicity against cancerous cells. Method: The solubility of PTX was screened in various lipids. Solid lipid nanoparticles of PTX (PSLN) were developed by hot homogenization method using Cutina HR and Gelucire 44/14 as lipid carriers and Solutol HS 15 as a surfactant. PSLNs were characterized for size, morphology, zeta potential, entrapment efficiency, physical state of the drug and in vitro release profile in 7.4 pH phosphate buffer saline (PBS). The ability of PTX to enhance toxicity towards cancerous cells was tested by performing cytoxicity assay in MCF7 cell line. Results: Solubility studies of PTX in lipids indicated better solubility when Cutina HR and Gelucire 44/14 were used. PSLNs were found to possess a neutral zeta potential with a size range of 155.4 ± 10.7 nm to 641.9 ± 4.2 nm. In vitro release studies showed a sustained release profile for PSLN over a period of 48 hours. SLNs loaded with PTX were found to be more toxic in killing MCF7 cells at a lower concentration than the free PTX.


Author(s):  
Elena Bezuglaya ◽  
Hanna Ivashchenko ◽  
Nikolay Lyapunov ◽  
Igor Zinchenko ◽  
Anna Liapunova ◽  
...  

The aim of our study was to identify factors affecting the in vitro release of diclofenac sodium (DS) from hypromellose-based gels (HPMC). Materials and methods. Gels with HPMC and liquids without HPMC were studied by viscosity-rotating viscometer method and spin probe electron paramagnetic resonance spectroscopy. Rheograms were used to determine the flow behavior and the apparent viscosity, and the EPR spectra were used to determine the rotational correlation time (τ–1) of the dissolved spin probes. The in vitro release tests were performed using vertical diffusion cells according to a validated procedure. The assay of DS and isopropyl alcohol (IPA) in the receptor medium was performed by high performance liquid chromatography (HPLC) and gas chromatography (GC) according to validated procedures, and the water content was determined using semi-micro method. Results. The apparent viscosity of the gels increased with increasing HPMC content and depended on the HPMC grade. The high apparent viscosity of the gels did not affect the values of τ–1 of the dissolved spin probes. In viscous gels and Newtonian fluids, the composition of which corresponded to the dispersion medium of gels, the values of τ–1 were identical and were in the range of rapid rotation, which is a prerequisite for similar and rapid release of the dissolved substances from gels and liquids. It was shown that the HPMC-based gel and Newtonian liquid without HPMC in terms of in vitro release parameters DS and IPA were equivalent. During in vitro testing the release of dissolved DS increased with increasing its concentration in the gel and depended on the dispersed state of DS. When the content of IPA was changed from 45.0 % to 22.5 %, the water absorption by the gel and the release of IPA decreased, and the release of DS increased, which was due to the decrease in the solubility of DS in the gel. Conclusions. HPMC, which provided high apparent viscosity of the gels, did not affect the value of τ–1 of the dissolved spin probes and the in vitro release of DS from the gels. The gel and Newtonian liquid were equivalent in terms of in vitro release of DS and IPA. The release of DS altered proportionally with the concentration of DS and depended on its dispersed state. As the content of IPA decreased, the release of IPA decreased, but the release of DS increased because of the decrease in the solubility of the DS in the gel


Author(s):  
Bandaru Lakshmi Narayana Rao ◽  
S. Parimala Krishnan ◽  
Challa Balashekar Reddy

Aims: The aim of the present study was to develop and optimize a Stealth Liposomal Drug Delivery System of microtubule inhibitor using Box–Behnken Design and Desirability function. Study Design: Development and Optimization of Stealth Liposomes. Place and Duration of Study: The study was carried out in the Department of Pharmacy, Annamalai University, between September 2020 and May 2021. Methodology: Stealth Liposomes were prepared by the thin-film hydration method (TFH). The formulation was optimized using Box – Behnken design to study the effect of independent variables, Amount of Egg Phosphatidylcholine (X1), Amount of Cholesterol (X2), and Amount of DSPE-PEG 2000(X3) on dependent variables Entrapment Efficiency (Y1) and In-vitro drug release (Y2). Results: Entrapment efficiency of the Stealth Liposomes ranges from 56.35 to 84.25%and in-vitro release ranges from 62.38 to 94.26%. The optimized formulation was found using the desirability function to get maximum entrapment with maximum drug release. The optimized formulation showed entrapment efficiency of 80.46% and in-vitro release of 90.11%. Conclusion: Stealth Liposomal Drug Delivery System for microtubule inhibitor was successfully developed and optimized using desirability function in Design Expert software by a three-factor, three level Box – Behnken design.


2003 ◽  
Vol 20 (5) ◽  
pp. 569-579 ◽  
Author(s):  
S.-A. Seo ◽  
G. Khang ◽  
J. M. Rhee ◽  
J. Kim ◽  
H. B. Lee

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.


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