Three Essays On Applications Of Intrahousehold Resource Allocation Models

This dissertation consists of three chapters on the topic of intrahousehold resource allocation models. The first chapter tests the unitary and general collective models of intrahousehold resource allocation for various household compositions. I find that, for the quasiquadratic Engel curve specification, the overall results support the previous findings in the literature that the unitary model fails to explain how resources are allocated for all household types. However, when using the QUAIDS specification, the results can reject the unitary model only for smaller-sized households. The general collective model, on the other hand, cannot be rejected in either quasi-quadratic or QUAIDS and not in any of the household compositions. Overall, the results support the general collective model of household behavior rather than the unitary model. The second chapter derives and tests restrictions imposed by the collective model for households with more than two decision-makers in the absence of price variation. It extends the two-decision-maker model in chapter one to derive the testable restrictions for households with multiple decision makers using unconditional demand systems. Moreover, for comparison, a particular type of demand system that is conditional on distribution factors is also estimated as an alternative way to test the collective model. The results show that neither unconditional nor conditional demand systems can reject Pareto efficiency. Therefore, both approaches provide consistent outcomes supporting the hypothesis that the multiple-decision-maker households in Thailand behave in the Pareto efficient manner predicted by the collective model. Finally, my third chapter attempts to examine how one can exploit household-level consumption data to recover information about individual household members for situations with iv no price variation. By combining consumption data from single and couple households, I am able to estimate the resource shares and indifference scales (a variation of the standard equivalence scales in the collective settings) for each household member via a system of Engel curves. The results show that, in Thailand, wives are likely to have higher resource shares than husbands in the married-couple households, while wives with higher education have the ability to extract more household resources. However, resource shares for wives are smaller for older-married compared to younger-married couples. Moreover, if a female were to live alone, she would need approximately three-quarters of the couple‟s income to reach the same indifference curve, and hence the same standard of living, that she would attain as a wife in the married-couple household

Lipid-based nanocarriers to enhance skin permeation and antioxidant activity of Centella asiatica extract

The purpose of this study was to evaluate the use of different formulations, including solution, gel, liposome and niosome for in vitro skin permeation and antioxidant activity of Centella asiatica (CA) extract. The liposomes and niosomes loaded with CA were characterized to observe the physicochemical properties i.e., particle size, zeta potential, percentage of entrapment efficiency (%EE) and percentage of loading efficiency (%LE). In vitro skin permeation studies revealed that liposome formulations had a superior enhancing effect on skin permeation compared to niosome, gel and solution formulation. Upon applied niosome formulations for the delivery of CA extract at 24 hours (h), the antioxidant activity was higher than liposome, gel and solution formulation, as evidenced by the increased in percent inhibition using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. However, there was no significant difference in antioxidant activity between niosome and liposome formulations. Accordingly, both the liposome and noisome formulations are promising approaches for transdermal delivery of CA extract for promoting successful antioxidant activity

Lipid-based nanocarriers to enhance skin permeation and antioxidant activity of Centella asiatica extract

The purpose of this study was to evaluate the use of different formulations, including solution, gel, liposome and niosome for in vitro skin permeation and antioxidant activity of Centella asiatica (CA) extract. The liposomes and niosomes loaded with CA were characterized to observe the physicochemical properties i.e., particle size, zeta potential, percentage of entrapment efficiency (%EE) and percentage of loading efficiency (%LE). In vitro skin permeation studies revealed that liposome formulations had a superior enhancing effect on skin permeation compared to niosome, gel and solution formulation. Upon applied niosome formulations for the delivery of CA extract at 24 hours (h), the antioxidant activity was higher than liposome, gel and solution formulation, as evidenced by the increased in percent inhibition using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. However, there was no significant difference in antioxidant activity between niosome and liposome formulations. Accordingly, both the liposome and noisome formulations are promising approaches for transdermal delivery of CA extract for promoting successful antioxidant activity

A combined approach of hollow microneedles and nanocarriers for skin immunization with plasmid DNA encoding ovalbumin

Boonnada Pamornpathomkul,1 Adisak Wongkajornsilp,2 Wanida Laiwattanapaisal,3 Theerasak Rojanarata,1 Praneet Opanasopit,1 Tanasait Ngawhirunpat1 1Department of Pharmaceutical Technology, Faculty of Pharmacy, Pharmaceutical Development of Green Innovations Group, Silpakorn University, Nakhon Pathom, 2Department of Pharmacology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 3Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand Abstract: The aim of this study was to investigate the use of different types of microneedles (MNs) and nanocarriers for in vitro skin permeation and in vivo immunization of plasmid DNA encoding ovalbumin (pOVA). In vitro skin permeation studies indicated that hollow MNs had a superior enhancing effect on skin permeation compared with solid MN patches, electroporation (EP) patches, the combination of MN and EP patches, and untreated skin. Upon using hollow MNs combined with nanocarriers for pOVA delivery, the skin permeation was higher than for the delivery of naked pOVA, as evidenced by the increased amount of pOVA in Franz diffusion cells and immunoglobulin G (IgG) antibody responses. When the hollow MNs were used for the delivery of nanocarrier:pOVA complexes into the skin of mice, they induced a stronger IgG immune response than conventional subcutaneous (SC) injections. In addition, immunization of mice with the hollow MNs did not induce signs of skin infection or pinpoint bleeding. Accordingly, the hollow MNs combined with a nanocarrier delivery system is a promising approach for delivering pOVA complexes to the skin for promoting successful immunization. Keywords: hollow microneedle, solid microneedle, electroporation, plasmid DNA encoding ovalbumin, skin immunization, nanocarrie

Transdermal delivery of fluorescein isothiocyanate-dextrans using the combination of microneedles and low-frequency sonophoresis

AbstractThis study aimed to evaluate the patient-friendly methods that are used in the delivery of hydrophilic macromolecules into deep skin layers, in particular, the combination of microneedles patch (MNs patch) and low-frequency sonophoresis (SN). The hydrophilic macromolecule drug fluorescein isothiocyanate (FITC)-dextrans (FD-4: MW 4.4 kDa) was used as the model drug in our experimental design. In this study, excised porcine skin was used to investigate and optimize the key parameters that determine effective MNs- and SN-facilitated FD-4 delivery. In vitro skin permeation experiments revealed that the combination of MNs patch with SN had a superior enhancing effect of skin permeation for FD-4 compared to MNs alone, SN alone or untreated skin, respectively. The optimal parameters for the combination of MNs and SN included the following: 10 N insertion force of MNs, 4 W/cm2 SN intensity, 6 mm radiation diameter of the SN probe, 2 min application time, and the continuous mode duty cycle of SN. In addition, vertical sections of skin, clearly observed under a confocal microscope, confirmed that the combination of MNs and SN enhanced permeation of FD-4 into the deep skin layers. These studies suggest that the combination of MNs and SN techniques could have great potential in the delivery of hydrophilic macromolecules into deep skin

Role of the charge, carbon chain length, and content of surfactant on the skin penetration of meloxicam-loaded liposomes

Sureewan Duangjit,1,2 Boonnada Pamornpathomkul,1 Praneet Opanasopit,1 Theerasak Rojanarata,1 Yasuko Obata,2 Kozo Takayama,2 Tanasait Ngawhirunpat11Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand; 2Department of Pharmaceutics, Hoshi University, Shinagawa-ku, Tokyo, JapanAbstract: The objective of this study was to investigate the influence of surfactant charge, surfactant carbon chain length, and surfactant content on the physicochemical characteristics (ie, vesicle size, zeta potential, elasticity, and entrapment efficiency), morphology, stability, and in vitro skin permeability of meloxicam (MX)-loaded liposome. Moreover, the mechanism for the liposome-enhanced skin permeation of MX was determined by Fourier transform infrared spectroscopy and differential scanning calorimetry. The model formulation used in this study was obtained using a response surface method incorporating multivariate spline interpolation (RSM-S). Liposome formulations with varying surfactant charge (anionic, neutral, and cationic), surfactant carbon chain length (C4, C12, and C16), and surfactant content (10%, 20%, and 29%) were prepared. The formulation comprising 29% cationic surfactant with a C16 chain length was found to be the optimal liposome for the transdermal delivery of MX. The skin permeation flux of the optimal formulation was 2.69-fold higher than that of a conventional liposome formulation. Our study revealed that surfactants affected the physicochemical characteristics, stability, and skin permeability of MX-loaded liposomes. These findings provide important fundamental information for the development of liposomes as transdermal drug delivery systems.Keywords: optimal liposome, optimization, transdermal drug delivery, surfactant charge, surfactant carbon chain length, surfactant conten

Facile, sensitive and reagent-saving smartphone-based digital image colorimetric assay of captopril tablets enabled by long-pathlength RGB acquisition

A new assay of captopril (CTP) tablets was developed based on digital image colorimetry using Ellman’s reagent. For the first time, a facile technique of increasing the analytical path was applied in this work to enhance the sensitivity. For this purpose, the reaction solutions were photographed using a smartphone while they were contained in two 1-cm pathlength cuvettes which were placed side by side. The Red-Green-Blue (RGB) in term of [B/(R+G+B)] was used to plot a standard curve. Compared to using a single cuvette, double cuvettes resulted in more precise analytical signals and better linearity (r2 of 0.9992). Additionally, CTP could be analyzed at low concentrations (2.5–25 µM) with LOD of 0.70 µM and LOQ of 2.13 µM, thus lowering the reagent consumption. The assay was proven to be valid, and it was greener, faster, and more affordable than the pharmacopeial chromatographic method, thereby suitable for pharmaceutical quality control