Manufacture and Applications of Gelatin Nanoparticles: A Practical Approach
Andreia Ascenso, Sandra Simões, Helena Ribeiro in Carrier-Mediated Dermal Delivery, 2017
In order to evaluate the formulation stability after dryness, an aliquot of the nanosuspension was dried at room temperature in an Eppendorf 5301 concentrator (Hamburg, Germany). After this procedure, the material clotted becoming insoluble. To solve this problem, glucose and sucrose were chosen as stabilizers at different concentrations [46] and added to 100 gL of the suspension. After dryness, the material was resuspended and analyzed regarding its size and polydispersity index.
Poly(Alkyl Cyanoacrylate) Nanoparticles for Delivery of Anti-Cancer Drugs
Mansoor M. Amiji in Nanotechnology for Cancer Therapy, 2006
The type of degradation (bulk or surface degradation) of polymethyl-, polyethyl-, and poly(isohexyl cyanoacrylate) nanoparticles was determined using photon correlation spectroscopic measurements.48 In the case of surface degradation, the particle size should show an immediate increase while the polydispersity index remaining constant. If bulk degradation dominates, a lag period should occur, preceding the decrease in mean size due to disintegration of the particles. This process of disintegration would lead to a more heterogeneous distribution of particle sizes and consequently to an increase in the polydispersity index. Incubation of polyethyl cyanoacrylate nanoparticles with in 10−4 N NaOH led to an immediate, continuous decrease in particle size, as well as an unchanged polydispersity index indicating the predominant surface degradation. Incubation of PIHCA nanoparticles in 10−4 N NaOH led to no detectable size decrease; polydispersity was also unchanged, indicating the degradation by surface erosion at a much slower rate than poly(ethyl cyanoacrylate) nanoparticles. Coating the particles with poloxamers did not accelerate the particle degradation. At low electrolyte concentration, the size and dispersity of PIHCA nanoparticles remained unchanged during incubation in 10−4 N NaOH. At high ionic strength, the size increase of nanoparticles as a result of flocculation was larger than the size decrease due to degradation. In vitro degradation was also determined by turbidimetric measurements.55 Poly(-methyl cyanoacrylate) and poly(ethyl cyanoacrylate) nanoparticles underwent the fastest degradation. A high electrolyte concentration in the medium led to the formation of larger aggregates accompanied by an increase in absorption of dispersion. The slowly degrading polymers PIBCA and PIHCA probably release a low concentration of degradation products over a prolonged period of time, indicating their low toxicity.
Nanosuspensions as Nanomedicine: Current Status and Future Prospects
Debarshi Kar Mahapatra, Sanjay Kumar Bharti in Medicinal Chemistry with Pharmaceutical Product Development, 2019
Mean particle size and polydispersity index (PI) is an essential characteristic parameter of nanosuspensions since it affects the saturation solubility, dissolution velocity, physical stability, and biological performance. It is determined by photon correlation spectroscopy (PCS). The mean particle diameter of nanosuspension can be determined rapidly and accurately using PCS. The wide particle size distribution, also known as polydispersity index can also be measured using PCS. The PI for nanosuspension should be as low as possible for long-term stability of the formulation. The PI value of 0.1–0.25 indicates a fairly narrow size distribution whereas a PI value greater than 0.5 indicates a very broad distribution. The measuring range of PCS is limited to approximately 3 nm–3 μm. Therefore, additionally laser diffractometry (LD) is used to detect any content of particles in the micrometer range or aggregates of drug nanoparticles. Laser diffractometry yields a volume size distribution and can be used to measure particles ranging from 0.05–80 μm and in certain instruments particle sizes up to 2000 μm can be measured. The typical LD characterization includes determination of diameter 50% LD [50] and diameter 99% LD [99] values, which indicate that either 50 or 99% of the particles are below the indicated size. Nanosuspensions meant for parenteral or pulmonary delivery should be analyzed by LD to minimize the risk of capillary blockade or emboli formation associated with particles having the size greater than 5–6 μm. Data obtained from these two techniques are not the same because LD data are volume based and the PCS mean diameter is the light intensity weighted size. The nanosuspensions can be suitably diluted with deionized water before carrying out PCS or LD analysis [22, 24]. Coulter counter technique is much more efficient technique than LD for particle size analysis as it helps in accurate quantification of microparticulate drug content. It is used in case of intravenous administration of nanosuspension and gives an absolute number of particles per volume unit for the different size of classes [22].
Scalable flibanserin nanocrystal-based novel sublingual platform for female hypoactive sexual desire disorder: engineering, optimization adopting the desirability function approach and in vivo pharmacokinetic study
Published in Drug Delivery, 2021
Marianne J. Naguib, Amal I. A. Makhlouf
Polydispersity index is a measure of the homogeneity of particle size within the dispersed system. The smaller the dispersity index, the more uniform the system (Salah et al., 2018). The PDI of the prepared FLB-nanocrystals ranged from 0.42 ± 0.01 to 0.86 ± 0.16 (Table 2). The results came in harmony with previous research involving the preparation of nanocrystals by sono-precipitation method and got similar PDI values (Kassem et al., 2017). Similarly, Xia et al., tried to formulate nitrendipine nanocrystals using the sonication method and reported that increasing drug concentration and greater supersaturation resulted in higher crystal growth and agglomeration rate, leading to larger initial crystals with an increase in the PDI value (Xia et al., 2010). However, the ANOVA test revealed that there was a non-significant difference in PDI values between formulations (p > 0.05).
Optimized piperine–phospholipid complex with enhanced bioavailability and hepatoprotective activity
Published in Pharmaceutical Development and Technology, 2021
Sayan Biswas, Pulok K. Mukherjee, Amit Kar, Subhadip Bannerjee, Rawiwan Charoensub, Thidarat Duangyod
The mean particle diameter of the complex was found to be 205.85 ± 12 nm as observed in Figure 3(C) and the polydispersity index was calculated as 0.32 ± 0.06. The low polydispersity index (value less than 0.5) indicates a narrow range of particle size distribution. The smaller particle size enables the drug–phospholipid complex to permeate through physiological barriers effectively (Bhattacharyya et al. 2014). Another important parameter Zeta potential provides a measure of degree stability of colloidal dispersions of PPC. Zeta potential values greater than ±30 mV partially indicates the physical stability of colloidal dispersion (Allam et al. 2015). Zeta potential value of −63 ± 2.12 mV of the complex in solution form confirms its stability.
Chitosan-coated liposome-containing carbamazepine and coenzyme Q10: design, optimization and evaluation
Published in Journal of Liposome Research, 2021
The polydispersity index measured by the dynamic light scattering gives information about particle size distribution. It is important that the this value is sufficiently low so that it does not cause aggregation to occur in the formulation over time and thus to decrease the stability. Table 6 demonstrates that total liposomal formulations have PDIs of 0.12 to 0.14, which means that liposomal suspensions have a suitable size distribution and a constricted dispersity. These results show that the process of coating liposomes with chitosan changed the particle size and zeta potential value of the liposomes, but did not influence the homogeneity of the size of liposomes designed. Nevertheless, all formulations were in the nanometre size range.