Fabrication of controlled-release polymeric microneedles containing progesterone-loaded self-microemulsions for transdermal delivery.

Progesterone (PG) has been approved for hormone replacement therapy to mitigate the risk of endometrial carcinoma. However, there has been a lack of success in oral PG due to its rapid degradation. Transdermal PG has advantages but lacks efficacy due to its poor solubility (Log p = 3.9). Therefore, this study aimed to evaluate how combining self-microemulsifying drug delivery systems (SMEDDS) and polymeric microneedles (MNs) could improve the transdermal delivery of PG in a controlled-release manner. Among PG-SMEDDS, PG-SME5 was selected for its desirable properties and stability. The two-layer polymeric MNs formulation incorporating PG-SME5 (PG-SMEDDS-tMNs) was formulated from aqueous blends of polymers as a first layer and 20% PCL as a second layer. It successfully penetrated neonatal porcine skin with the dissolution of the first layer observed within 15 min after application. In vitro skin permeation revealed that the percentage of PG which permeated the skin over 82 h using PG-SMEDDS-tMNs was higher than a PG-suspension and PG-SMEDDS. The Higuchi kinetic showed controlled release over 15 days of PG from PG-SMEDDS-tMNs. These studies suggested that incorporating PG-SMEDDS into controlled-release two-layer polymeric MNs could be a promising approach for improving the transdermal delivery of PG.

Antibody-decorated chitosan-iodoacetamide-coated nanocarriers for the potential delivery of doxorubicin to breast cancer cells.

Using an active targeting approach of chemotherapeutics-loaded nanocarriers (NCs) with monoclonal antibodies is a potential strategy to improve the specificity of the delivery systems and reduce adverse reactions of chemotherapeutic drugs. Specific targeting of the human epidermal growth factor receptor-2 (HER-2), expressed excessively in HER-2-positive breast cancer cells, can be achieved by conjugating NCs with an anti-HER-2 monoclonal antibody. We constructed trastuzumab-conjugated chitosan iodoacetamide-coated NCs containing doxorubicin (Tras-Dox-CHI-IA-NCs) as a tumor-targeted drug delivery system, during the study. Chitosan-iodoacetamide (CHI-IA) was synthesized and utilized to prepare trastuzumab-conjugated NCs (Tras-NCs). The morphology, physicochemical properties, drug loading, drug release, and biological activities of the NCs were elucidated. The Tras-NCs were spherical, with a particle size of approximately 76 nm, and had a positive zeta potential; after incorporating the drug, the size of the Tras-NC increased. A prolonged, 24-h drug release from the NCs was achieved. The Tras-NCs exhibited high cellular accumulation and significantly higher antitumor activity against HER-2-positive breast cancer cells than the unconjugated NCs and the drug solution. Therefore, Tras-Dox-CHI-IA-NCs could be a promising nanocarrier for HER-2-positive breast cancer.

Dual-Targeted Therapy in HER2-Overexpressing Breast Cancer with Trastuzumab and Novel Cholesterol-Based Nioplexes Silencing Mcl-1.

The challenge in HER2-overexpressing breast cancer therapy lies in creating an effective target therapy to overcome treatment resistance. Monoclonal antibodies and target gene silencing by siRNA are two potential strategies that have been widely developed for treating HER2-positive breast cancer. The siRNA delivery system is a crucial factor that influences siRNA therapy's success. In this study, lipid-based nanoparticles (cationic niosomes) composed of different cholesterol-based cationic lipids were formulated and characterized for delivering siRNA into HER2-overexpressing breast cancer cells. Niosomes containing a trimethylammonium headgroup showed the highest siRNA delivery efficiency with low toxicity. The myeloid cell leukemia-1 (Mcl-1) siRNA nioplex treatment significantly decreased mRNA expression and breast cancer cell growth. Dual-targeted therapy, consisting of treatment with an Mcl-1 siRNA nioplex and trastuzumab (TZ) solution, noticeably promoted cell-growth inhibition and apoptosis. The synergistic effect of dual therapy was also demonstrated by computer modeling software (CompuSyn version 1.0). These findings suggest that the developed cationic niosomes were effective nanocarriers for siRNA delivery in breast cancer cells. Furthermore, the Mcl-1 nioplex/TZ dual treatment establishes a synergistic outcome that may have the potential to treat HER2-overexpressing breast cancer.

Rapid Microwave-Assisted Synthesis of pH-Sensitive Carbon-Based Nanoparticles for the Controlled Release of Doxorubicin to Cancer Cells.

Carbon-based nanoparticles (CNPs) are a new type of interesting nanomaterials applied in various pharmaceutical fields due to their outstanding biocompatible properties. Novel pH-sensitive CNPs were rapidly synthesized within 1 min by microwave-assisted technique for doxorubicin (DOX) delivery into five cancer cell lines, including breast cancer (BT-474 and MDA-MB-231 cell lines), colon cancer (HCT and HT29 cell lines), and cervical cancer (HeLa cell lines). CNPs and DOX-loaded CNPs (CNPs-DOX) had nano-size of 11.66 ± 2.32 nm and 43.24 ± 13.25 nm, respectively. DOX could be self-assembled with CNPs in phosphate buffer solution at pH 7.4 through electrostatic interaction, exhibiting high loading efficiency at 85.82%. The release of DOX from CNPs-DOX at pH 5.0, often observed in the tumor, was nearly two times greater than the release at physiological condition pH 7.4. Furthermore, the anticancer activity of CNPs-DOX was significantly enhanced compared to free DOX in five cancer cell lines. CNPs-DOX could induce cell death through apoptosis induction in MDA-MB-231 cells. The findings revealed that CNPs-DOX exhibited a promising pH-sensitive nano-system as a drug delivery carrier for cancer treatment.

Chitosan capped-gold nanoparticles as skin penetration enhancer for small molecules: A study in porcine skin.

Skin is considered one of the most convenient sites for drug administration. The present study evaluated the effect of gold nanoparticles stabilized by chitosan (CS-AuNPs) and citrate ions (Ci-AuNPs) on skin permeation of sodium fluorescein (NaFI) and rhodamine b base (RhB) as small model hydrophilic and lipophilic permeants, respectively. CS-AuNPs and Ci-AuNPs were characterized by transmitted electron microscopy (TEM) and dynamic light scattering (DLS). Skin permeation was investigated using porcine skin with diffusion cells and confocal laser scanning microscopy (CLSM). The CS-AuNPs and Ci-AuNPs were spherical-shaped nanosized particles (38.4 ± 0.7 and 32.2 ± 0.7 nm, respectively). The zeta potential of CS-AuNPs was positive (+30.7 ± 1.2 mV) whereas that of Ci-AuNPs was negative (-60.2 ± 0.4 mV). The skin permeation study revealed that CS-AuNPs could enhance the permeation of NaFI with enhancement ratio (ER) of 38.2 ± 7.5, and the effect was superior to that of Ci-AuNPs. CLSM visualization suggested that skin permeation was enhanced by improving the delivery through the transepidermal pathway. However, the permeability of RhB, a lipophilic molecule, was not significantly affected by CS-AuNPs and Ci-AuNPs. Moreover, CS-AuNPs had no cytotoxic toward human skin fibroblast cells. Therefore, CS-AuNPs are a promising skin permeation enhancer of small polar compounds.

Fabrication of polyvinyl pyrrolidone-K90/Eudragit RL100-based dissolving microneedle patches loaded with alpha-arbutin and resveratrol for skin depigmentation.

Alpha-arbutin (AA) and resveratrol (Res) are widely used in skin-lightening products. However, current topical formulations have minimal skin-lightening effects due to the low absorption and poor solubility of these active compounds. This study investigated the efficacy and safety of using dissolving microneedle (DMN) patches to improve the delivery of AA and Res for skin depigmentation. The DMN patches (F0-F3) fabricated from polyvinyl pyrrolidone-K90 (PVP-K90)/Eudragit RL100 blends successfully penetrated excised porcine skin and showed sufficient mechanical strength to resist compression forces. Loading DMNs with 10% AA and 2% Res at a ratio of 5 : 1 (F3) resulted in a synergistic interaction between the drugs with desirable dissolving ability, drug loading, and stability. Furthermore, both in vitro and in vivo studies revealed that the use of F3 DMN patches successfully enhanced the intradermal delivery of AA and Res over a 24 h period, with the delivered amount being higher (∼2.6 times) than that provided by a cream formulation (P < 0.05). After removing the DMN patches, the mice's skin was spontaneously and completely resealed within 12 h. In clinical studies, F3 DMN patches slightly decreased the melanin index of the participants without causing skin irritation or erythema at any time during the 24 h period when the patches were applied (P < 0.05). Moreover, application of the patches for 24 h was not found to affect skin hydration, transepidermal water loss, or skin elasticity. Therefore, AA/Res-loaded DMN patches could offer a promising approach for the effective local delivery of cosmetic agents for skin depigmentation.

Mussel-inspired poly(hydroxyethyl acrylate-co-itaconic acid)-catechol/hyaluronic acid drug-in-adhesive patches for transdermal delivery of ketoprofen.

This research aimed to create new hydrophilic drug-in-adhesive patches for transdermal drug delivery. Poly(hydroxyethyl acrylate-co-itaconic acid)-catechol (PHI-cat) and hyaluronic acid (HA) were used as main components in the pressure-sensitive adhesive. Citric acid and aluminium hydroxide were exploited as crosslinking agents and ketoprofen was employed as a model delivering compound. The adhesive performance, physicochemical properties, drug-polymer interaction, drug crystallization, drug content, drug permeation through the skin, and coordination polymer network of the patches were investigated. In addition, skin irritation and adhesion potential in human subjects were assessed. Due to the ability of catechol groups to form interaction with the skin tissue, the patches containing PHI-cat and HA offered a considerably greater adhesion ability to human skin compared with the patches without catechol and commercial patches. Furthermore, the patches had good physical and chemical stability. Therefore, these catechol-functionalized patches may be potential transdermal drug delivery systems with excellent adhesive properties for the delivery of a drug through the skin.

Bioinspired ketoprofen-incorporated polyvinylpyrrolidone/polyallylamine/ polydopamine hydrophilic pressure-sensitive adhesives patches with improved adhesive performance for transdermal drug delivery.

Inspired by the natural mussel adhesive mechanism, three different materials-polydopamine (PDA), polyvinylpyrrolidone (PVP), and polyallylamine (PAM)-were used to make innovative pressure-sensitive adhesives (PSAs) for transdermal delivery of ketoprofen. PDA was synthesized under alkaline conditions using a self-polymerization reaction and was exploited as a cross-linking agent due to its biocompatibility. The adhesive performance, physicochemical properties, drug content, and drug permeation through the skin were examined. Moreover, in vivo skin irritation and skin adhesion performance were investigated. PVP/PAM/PDA PSAs showed a significantly higher adhesion to human skin compared with commercial patches owing to the interaction between the catechol groups presented on the patches and the skin. In addition, the patches were stable for six months. Consequently, the PVP/PAM/PDA patches exhibited outstanding tissue adhesiveness, enabling universal tissue adherence while causing no skin tissue irritation or inflammatory reaction.

Formulation and Optimal Design of Dioscorea bulbifera and Honey-Loaded Gantrez®/Xyloglucan Hydrogel as Wound Healing Patches.

Hydrogel patches are some of the most effective dressings for wound healing. In this study, the Gantrez® S-97 (Gan)/xyloglucan (XG) hydrogel patches were formulated by using a full central composite design (CCD). The optimized hydrogel patches consisted of 17.78% w/w of Gan and 0.1% w/w of XG. Honey and D. bulbifera extract were loaded in the Gan/XG hydrogel patches. The physical properties of the hydrogel patches, including water content, water absorption, rate of water vapor transmission, and mechanical properties, were examined. The D. bulbifera extract/honey-loaded patch exhibited a higher value of water absorption, tensile strength, and elongation than the honey-loaded patch and the unloaded patch, respectively. The biological activities of the patches were also investigated. All hydrogel patches protected wounds from external bacterial infection. The D. bulbifera extract/honey-loaded patch exhibited stronger antioxidant activity than the honey-loaded patch and the unloaded patch. Besides, all the hydrogel patches with concentrations of 0.5-2.5 mg/mL showed that they were nontoxic to fibroblast cells. The combination of D. bulbifera extract and honey in the patch affected fibroblast proliferation. In addition, all Gan/XG hydrogel patches significantly induced recovery of the scratch area. Therefore, the Gan/XG hydrogel patches could be candidates as wound dressings.

Maleimide-functionalized carboxymethyl cellulose: A novel mucoadhesive polymer for transmucosal drug delivery.

The objective of this research was to develop a novel mucoadhesive polymer for drug delivery applications based on N-(2-aminoethyl) maleimide-functionalized carboxymethyl cellulose in which the weight ratios of the materials were tuned to explore the condition providing the highest maleimide content on the polymer. The polymers were synthesized from N-(2-aminoethyl) maleimide that was conjugated to carboxymethyl cellulose with their mucoadhesive properties examined by tensile testing, rheology, and flow-through analysis and their biocompatibilities evaluated on the human gingival fibroblast cell line (HGF-1). The anti-inflammatory drug benzydamine was loaded into mucoadhesive-polymer-based tablets and used to demonstrate the application of the synthesized polymer. The polymer exhibited superior mucoadhesive capability compared to carboxymethyl cellulose through the interaction between maleimide moiety and mucin. The functionalized polymer also possessed the ability to control the release of benzydamine with Higuchi's release model and was proven to be a potential candidate in mucoadhesive drug delivery.

Synthesis of Polyethylene Glycol Diacrylate/Acrylic Acid Nanoparticles as Nanocarriers for the Controlled Delivery of Doxorubicin to Colorectal Cancer Cells.

Doxorubicin (Dox) is known for its potential to deliver desirable anticancer effects against various types of cancer including colorectal cancer. However, the adverse effects are serious. This study aimed to synthesize polyethylene glycol diacrylate (PEGDA)/acrylic acid (AA)-based nanoparticles (PEGDA/AA NPs) for Dox delivery to colorectal cancer cells. The NPs were synthesized using free-radical polymerization reaction using the monomers PEGDA and AA with their physical properties, drug loading and release, biocompatibility, and anticancer effect evaluated. The NPs were spherical with a size of around 230 nm, with a 48% Dox loading efficiency and with loading capacity of 150 µg/mg. Intriguingly, the NPs had the ability to prolong the release of Dox in vitro over 24 h and were non-toxic to intestinal epithelial cells. Dox-loaded PEGDA/AA NPs (Dox-NPs) were able to effectively kill the colorectal cancer cell line (HT-29) with the Dox-NPs accumulating inside the cell and killing the cell through the apoptosis pathway. Overall, the synthesized PEGDA/AA NPs exhibit considerable potential as a drug delivery carrier for colon cancer-directed, staged-release therapy.

Smartphone-based technique for the determination of a titration equivalence point from an RGB linear-segment curve with an example application to miniaturized titration of sodium chloride injections.

A smartphone-based technique for determining the titration equivalence point from a linear-segment curve was developed for the first time. In this method, a titrant in an increasing microliter-volume was added to a set of sample aliquots containing an indicator covering both sides of the equivalence point. The solutions were subsequently photographed in one shot, in a dark box using a smartphone camera and an illuminating screen of a tablet or light emitting diode lamps arranged below a white acrylic sheet as a light source. After the colors of the solutions were delineated to Red, Green, and Blue (RGB) values, 1/log G was used to construct a plot in which the equivalence point was located at the intersection of the two lines in the region before and after the equivalence point. The technique was successfully applied to the miniaturized titration of sodium chloride injections, showing the good linear relationship of equivalence points to the sodium chloride concentration in the range of 0.4163-0.9675% w/v (R2 of 0.9998). The assay was accurate (% recovery of 98.92-100.52), precise (% relative standard deviation ≤ 1.20), and unaffected by the use of different types of microplates, smartphones, and RGB analysis tools. Additionally, it required no expensive nor complicated equipment and offered the possibility of performing analysis on a single smartphone device when it was used with a mobile application developed to aid data processing and immediate production of reports of analytical results.

Design and Optimization of 3D-Printed Gastroretentive Floating Devices by Central Composite Design.

This study aimed to optimize the size of capsule-shaped 3D-printed devices (CPD) using an experimental design by the response surface methodology to provide a gastroretentive drug delivery system (GRDDS) with optimal floating time. The CPD was fabricated using a fused deposition modeling (FDM) 3D printer. The central composite design was employed for the optimization of the devices. The morphology of the CPD was observed using a digital microscope and scanning electron microscope (SEM). The in vitro floating time and drug release were evaluated using a USP dissolution apparatus II. Appropriate total floating time (TFT) of the devices (more than 3 h) was obtained with the device's body, cap, and bottom thickness of 1.2, 1.8, and 2.9 mm, respectively. The release kinetics of the drug from the devices fitted well with zero-order kinetics. In conclusion, the optimization of CPD for GRDDS using the experimental design provided the devices with desirable floating time and ideal drug release characteristics.

Development and Evaluation of Novel Water-Based Drug-in-Adhesive Patches for the Transdermal Delivery of Ketoprofen.

The objective of this study was to develop novel water-based drug-in-adhesive pressure-sensitive adhesives (PSAs) patches for the transdermal delivery of ketoprofen, employing poly(N-vinylpyrrolidone-co-acrylic acid) copolymer (PVPAA) and poly(methyl vinyl ether-alt-maleic anhydride) (PMVEMA) as the main components. The polymers were crosslinked with tartaric acid and dihydroxyaluminium aminoacetate using various polymer ratios. Ketoprofen was incorporated into the PVPAA/PMVEMA PSAs during the patch preparation. The physicochemical properties, adhesive properties, drug content, release profile, and skin permeation of the patches were examined. Moreover, the in vivo skin irritation and skin adhesion performance in human volunteers were evaluated. The patches prepared at a weight ratio of PVPAA/PMVEMA of 1:1 presented the highest tacking strength, with desirable peeling characteristics. The ketoprofen-loaded PVPAA/PMVEMA patches exhibited superior adhesive properties, compared to the commercial patches, because the former showed an appropriate crosslinking and hydrating status with the aid of a metal coordination complex. Besides, the permeated flux of ketoprofen through the porcine skin of the ketoprofen-loaded PVPAA/PMVEMA patches (4.77 ± 1.00 µg/cm2/h) was comparable to that of the commercial patch (4.33 ± 0.80 µg/cm2/h). In human studies, the PVPAA/PMVEMA patches exhibited a better skin adhesion performance, compared with the commercial patches, without skin irritation. In addition, the patches were stable for 6 months. Therefore, these novel water-based PSAs may be a potential adhesive for preparing drug-in-adhesive patches.

Feasibility of chitosan-based nanoparticles approach for intranasal immunisation of live attenuated Japanese encephalitis vaccine.

Intranasal (IN) administration, a non-invasive route, is explored to overcome the limitations of conventional subcutaneous (SC) injection for Japanese encephalitis (JE) immunisation. Mucoadhesive nanoparticles (NPs) are recognised for the benefits they offer via IN delivery, such as extended retention time of the vaccine on the mucosa. The purpose of this study was to evaluate immunisation effect of live attenuated Japanese encephalitis-chimeric virus vaccine (JE-CV)-loaded mucoadhesive NPs based on chitosan (CS) or chitosan maleimide (CM), a novel mucoadhesive polymer, via the IN route to improve the mucosal immunisation against JE. The results revealed that IN immunisation stimulated seroprotection following PRNT50 evaluation. Moreover, compared with SC immunisation, IN immunisation in mice provided a higher sIgA level, leading to improved mucosal immune response. In addition, chitosan-based NPs showed an adjuvant effect on the IN vaccine due to their mucoadhesive and antigen-uptaken properties. CM NPs successfully induced sIgA. In contrast, SC JE-CV immunisation induced negligible mucosal immunity. These immunological advantages revealed that JE-CV-loaded mucoadhesive NPs are a promising approach for IN vaccination as an alternative route for JE protection due to the stimulatory effects on both mucosal and systemic immune responses.

Students' Perspectives and Achievements toward Online Teaching of Medicinal Chemistry Courses at Pharmacy School in Thailand During the COVID-19 Pandemic.

This communication was to share the efforts made in developing the fully online courses in medicinal chemistry during the educational disruption due to the coronavirus disease 2019 (COVID-19) pandemic. In the academic year 2020, the online course was implemented for the first time at the Faculty of Pharmacy, Silpakorn University, Thailand. Various online teaching strategies were integrated, raising the question of whether the developed online courses would deliver similar learning outcomes to the traditional classroom. At the end of each semester, the teaching assessment report was conducted and evaluated in 4 parts: part 1, evaluation of lecturer; part 2, student's self-evaluation; part 3, learning outcome development after studying the course; part 4, appropriateness of class environment and equipment. Overall, student responses toward parts 1-3 in the online class were as satisfactory as those in the previous on-site class. Lower scores toward part 4 were observed in the online class. In addition, student performance in terms of grade distributions between the on-site and online classes was different. On-site students earned the highest proportion of A grades, whereas online students earned a higher proportion of B+'s to F's. While the pandemic persists and the need for online courses remains, we hope that this communication will provide some educational insight and strategies to help in the ongoing efforts to adapt and establish more successful online courses.

Influence of nanofiber alignment on the release of a water-soluble drug from cellulose acetate nanofibers.

Cellulose acetate nanofibers with different degrees of alignment (randomly aligned (RA), partially aligned (PA), and highly aligned (HA)) were produced using an electrospinning technique. The different degrees of alignment were obtained by adjusting the rotation speed of the collector. Alpha-arbutin (3% w/w) employed as a model water-soluble compound was incorporated into the nanofibers during the fabrication process. The drug release characteristics were investigated using the nanofiber mats with the same size and weight. The prepared nanofibers with different degrees of alignment showed similar physical characteristics, including the fiber diameter, drug loading efficiency and capacity, and molecular form of the drug in the fibers. Interestingly, alpha-arbutin was released from HA nanofibers at a significantly faster rate than the PA and RA nanofibers. Eighty percent of the drug was released into the medium in 1.7, 4.2, and 9.4 min for HA, PA, and RA nanofibers, respectively. The orientation of nanofibers played a crucial role in governing the drug release, probably by creating network meshes with different degrees of entanglement, affecting the diffusion of drug to the external medium. Consequently, this approach can be used as a simple means of achieving immediate-release or fast-acting characteristics of cellulose-based formulations containing a water-soluble drug.

Rapid synthesis of chitosan-capped gold nanoparticles for analytical application and facile recovery of gold from laboratory waste.

Chitosan-capped gold nanoparticles (CS-AuNPs) were synthesized via a rapid method by exposing 0.75 mL of 10 mM HAuCl4 and 5 mL of 0.1% w/v chitosan solution to microwave irradiation at 125 °C for 40 s. The resulting red colloidal solution contained monodispersed, spherical, and stable CS-AuNPs with a mean diameter of 17.8 nm and showed the maximum absorption peak at 520 nm. Owing to the positively charged surface, CS-AuNPs were applied to the assay of the polyanionic compound disodium edetate based on the aggregation-induced red-to-blue color change of the particles and the measurement of increased absorbance at 670 nm. The assay was accurate and precise; its results were comparable to those obtained from the titrimetric reference method. Moreover, gold was shown to be easily recovered from CS-AuNPs through alkaline-induced precipitation followed by acid treatment and heating, which provides a facile and efficient means for treatment of laboratory waste.

Three-dimensional (3D)-printed devices composed of hydrophilic cap and hydrophobic body for improving buoyancy and gastric retention of domperidone tablets.

The aim of this study was to produce capsule-shaped floating devices (CFD) using a fused deposition modeling (FDM) three-dimensional (3D) printer, for controlling the release and gastric retention of domperidone (DOM) tablets (Motilium-MⓇ). In order to enhance the buoyancy of the devices, a hollow cap with different wall thicknesses (1.2-1.5 mm) was printed with a hydrophilic (polyvinyl alcohol, PVA) filament. The body of the device was made from a hydrophobic (polylactic acid, PLA) filament. Bodies with aperture sizes (1-2 mm) were produced to investigate how this would affect drug release. Morphology, weight variation, ex vivo and in vivo floating time and drug release characteristics were examined. The results revealed that increasing the cap thickness of the devices (1.2 to 1.3 mm) increased the total floating time (TFT). The maximum TFT (10 h) with floating lag time (FLT) < 5 s was observed from Motilium-MⓇ incorporated CFD3-5 (cap with 1.3-mm wall thickness). Decreasing the size of the holes on the devices led to the sustained release of DOM. The CFD5 (cap with 1.3-mm cap thickness and 1.5-mm hole width) delivered approximately 98% release in 10 h, and the release kinetics fit well with the zero-order kinetics (R2 > 0.95). In vivo floating studies in rabbits showed that the floating time of CFD5 was more than 10 h. These results demonstrated that the CFD was successfully designed to provide gastro-retentive drug delivery with the capacity to float and provide sustained drug release.

Ion pair extraction coupled with digital image colorimetry as a rapid and green platform for pharmaceutical analysis: An example of chlorpromazine hydrochloride tablet assay.

Ion pair extraction coupled with digital image colorimetry has been developed as a promising platform for pharmaceutical analysis. The applicability of the approach was demonstrated through the assay of chlorpromazine hydrochloride tablets. In this method, the colorless, positively charged drug reacted with an anionic methyl orange dye in 1.5 mL microcentrifuge tubes, forming a yellow ion pair complex, which was extracted one time using a green solvent, i.e., ethyl acetate. Without the isolation or transfer of the liquid phase for dilution or measurement in a cuvette, a set of multiple tubes consisting of standards and samples were placed in a radial alignment above the white-light-illuminating screen of an iPad in a closed dark box and an image was taken in a single shot from the top of the box using an iPhone camera. The intensities of the yellow color of the extracts were transformed into red-green-blue (RGB) pixels using a mobile application, and the B values divided by the total of R + B + G were used as the analytical signals, which were plotted against the drug concentration to construct a standard curve. The proposed method showed good linearity (R2 = 0.9998) over the concentration range of 2.5-50 µg mL-1 with a limit of quantitation of 2.30 µg mL-1. The proposed method was accurate, precise, and free from interferences by excipients used in tablets, thus yielding assay results with no significant difference from those analyzed using the United States Pharmacopeia 42 reference method. Moreover, the proposed method is exceptional because it can be rapidly and easily used, requires relatively inexpensive instrumentation, can be safely utilized by analysts, and is environmentally friendly. Therefore, the proposed assay platform has considerable potential for application to routine quality control and analysis of drug formulations in the pharmaceutical industry.