Ternary system of dihydroartemisinin with hydroxypropyl-β-cyclodextrin and lecithin: Simultaneous enhancement of drug solubility and stability in aqueous solutions

Enhanced ophthalmic bioavailability and stability of atropine sulfate via sustained release particles using polystyrene sulfonate resin

Atropine sulfate (ATS) eye drops at low concentrations constitute a limited selection for myopia treatment, with challenges such as low ophthalmic bioavailability and inadequate stability. This study proposes a novel strategy by synthesizing ophthalmic sodium polystyrene sulfonate resin (SPSR) characterized by a spherical shape and uniform size for cationic exchange with ATS. The formulation of ATS@SPSR suspension eye drops incorporates xanthan gum and hydroxypropyl methylcellulose (HPMC) as suspending agents. In vitro studies demonstrated that ATS@SPSR suspension eye drops exhibited sustained release characteristics, and tropic acid, its degradation product, remained undetected for 30 days at 40 °C. The ATS levels in the tear fluids and aqueous humor of New Zealand rabbits indicated a significant increase in mean residence time (MRT) and area under the drug concentration-time curve (AUC0-12h) for ATS@SPSR suspension eye drops compared to conventional ATS eye drops. Moreover, safety assessment confirmed the non-irritating nature of ATS@SPSR suspension eye drops in rabbit eyes. In conclusion, the cation-responsive sustained-release ATS@SPSR suspension eye drops enhanced the bioavailability and stability of ATS, offering a promising avenue for myopia treatment.

Enhanced dissolution rates of glibenclamide through solid dispersions on microcrystalline cellulose and mannitol, combined with phosphatidylcholine

OBJECTIVE

This study aimed to investigate the impact of physical solid dispersions of spray-dried glibenclamide (SG) on the surface of microcrystalline cellulose (MC) and mannitol (M) surfaces, as well as their combination with phosphatidylcholine (P), on enhancing the dissolution rate of glibenclamide (G).

METHODS

Solid dispersions were prepared using varying proportions of 1:1, 1:4, and 1:10 for SG on the surface of MC (SGA) and M (SGM), and then combined with P, in a proportion of 1:4:0.02 using spray drying. The particle size, specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and dissolution rate of SGA and SGM were characterized.

RESULTS

SEM analysis revealed successful adhesion of SG onto the surface of the carrier surfaces. XRD showed reduced crystalline characteristic peaks for SGA, while SGM exhibited a sharp peaks pattern. Both SGA and SGM demonstrated higher dissolution rates compared to SG and G alone. Furthermore, the dissolution rates of the solid dispersions of SG, MC and P (SGAP), and SG, M, and P (SGMP) were sequentially higher than that of SGA and SGM.

CONCLUSIONS

The study suggests that physical solid dispersions of SG on MC and M, along with their combination with P, can effectively enhance the dissolution rate of G. These findings may be valuable in developing of oral solid drug dosage forms utilizing SGA, SGM, SGAP, and SGMP.

Formulation of multicomponent inclusion complex of cyclodextrin-amino acid with Chrysin: Physicochemical characterization, cell viability and apoptosis assessment in human primary glioblastoma cell line

Chrysin (CR) is a water-insoluble drug reported for different therapeutic effects. The microwave irradiation method was used in this study to create a multicomponent inclusion complex (CR-MC) containing CR (drug) and carrier hydroxyl propyl beta cyclodextrin (HP β CD) and L-arginine (LA). The prepared inclusion complex (CR-MC) was evaluated for dissolution study and results were compared with chrysin physical mixture (CR-PM). Further, the samples were assessed for infra-red (IR), nuclear magnetic resonance (NMR), differential scanning calorimeter (DSC), scanning electron microscope (SEM) and molecular docking. Finally, the cell viability, reactive oxygen species and flow cytometer studies were also assessed to check the potential of the prepared inclusion complex on the human primary glioblastoma cell line (U87-MG cell). The phase solubility findings revealed a stability constant (773 mol L-1) as well as a complexation efficiency of 0.027. The dissolution study displayed a significant increase in CR release from CR-MC (99.03 ± 0.39%) > CR-PM (70.58 ± 1.16%) > pure CR (35.29 ± 1.55%). NMR and IR spectral data revealed no interaction between CR and carriers. SEM and DSC study results revealed the conversion into amorphous form. The molecular docking results illustrated a high docking score, which supports the findings of complex formation. The cell viability, reactive oxygen species, and flow cytometry studies results showed enhanced activity from CR-MC against the tested human primary glioblastoma cell line. From the results it has been observed that chrysin solubility significantly increased after complexation and there in vitro activity also enhanced against cancer cell line.

Cyclodextrins and Their Derivatives as Drug Stability Modifiers

Cyclodextrins (CDs) are cyclic oligosaccharides that contain a relatively hydrophobic central cavity and a hydrophilic outer surface. They are widely used to form non-covalent inclusion complexes with many substances. Although such inclusion complexes typically exhibit higher aqueous solubility and chemical stability than pure drugs, it has been shown that CDs can promote the degradation of some drugs. This property of stabilizing certain drugs while destabilizing others can be explained by the type of CD used and the structure of the inclusion complex formed. In addition, the ability to form complexes of CDs can be improved through the addition of suitable auxiliary substances, forming multicomponent complexes. Therefore, it is important to evaluate the effect that binary and multicomponent complexes have on the chemical and physical stability of complexed drugs. The objective of this review is to summarize the studies on the stabilizing and destabilizing effects of complexes with CDs on drugs that exhibit stability problems.

Fe-MnO2 nanosheets loading dihydroartemisinin for ferroptosis and immunotherapy

Ferroptosis has emerged as a therapeutic tactic to trigger cancer cell death driven by abnormal accumulation of reactive oxygen species (ROS). However, a single ferroptosis treatment modality is often limited. In this work, a combination therapy of ferroptosis and immunotherapy for cancer was proposed. Specifically, a versatile nanodrug was designed for the multiple treatment of hepatocellular carcinoma (HCC) by loading dihydroartemisinin (DHA) on Fe³⁺-doped MnO₂ nanosheets (Fe-MnO₂/DHA). Firstly, Fe-MnO₂/DHA was degraded by glutathione (GSH) in the tumor microenvironment (TME) to release Fe²⁺, Mn²⁺ and DHA, leading to aberrant ROS accumulation due to Fenton/Fenton-like reaction. Secondly, breakage of endoperoxide bridge from DHA was caused by Fe²⁺ to further induce oxidative stress. Thirdly, the depleted GSH promoted the inactivation of glutathione peroxidase 4 (GPX4), resulting in lipid peroxide (LPO) accumulation. The resulting LPO and ROS could induce ferroptosis and apoptosis of liver cancer cells. Furthermore, Fe-MnO₂/DHA mediated three-pronged stimulation of oxidative stress, resulting in high levels of targeted immunogenic cell death (ICD). It could enhance the infiltration of CD4⁺ T and CD8⁺ T cells, and promote macrophage polarization. DHA also acted as an immunomodulator to inhibit regulatory T cells (Tregs) for systemic antitumor. Overall, Fe-MnO₂/DHA presents a multi-modal therapy for HCC driven by ferroptosis, apoptosis and immune activation, significantly advancing synergistic cancer treatment.

Voriconazole Eye Drops: Enhanced Solubility and Stability through Ternary Voriconazole/Sulfobutyl Ether β-Cyclodextrin/Polyvinyl Alcohol Complexes

Voriconazole (VCZ) is a broad-spectrum antifungal agent used to treat ocular fungal keratitis. However, VCZ has low aqueous solubility and chemical instability in aqueous solutions. This study aimed to develop VCZ eye drop formulations using cyclodextrin (CD) and water-soluble polymers, forming CD complex aggregates to improve the aqueous solubility and chemical stability of VCZ. The VCZ solubility was greatly enhanced using sulfobutyl ether β-cyclodextrin (SBEβCD). The addition of polyvinyl alcohol (PVA) showed a synergistic effect on VCZ/SBEβCD solubilization and a stabilization effect on the VCZ/SBEβCD complex. The formation of binary VCZ/SBEβCD and ternary VCZ/SBEβCD/PVA complexes was confirmed by spectroscopic techniques and in silico studies. The 0.5% w/v VCZ eye drop formulations were developed consisting of 6% w/v SBEβCD and different types and concentrations of PVA. The VCZ/SBEβCD systems containing high-molecular-weight PVA prepared under freeze-thaw conditions (PVA-H hydrogel) provided high mucoadhesion, sustained release, good ex vivo permeability through the porcine cornea and no sign of irritation. Additionally, PVA-H hydrogel was effective against the filamentous fungi tested. The stability study revealed that our VCZ eye drops provide a shelf-life of more than 2.5 years at room temperature, while a shelf-life of only 3.5 months was observed for the extemporaneous Vfend^® eye drops.

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

The goal of the study was the discrimination of β-cyclodextrin (β-CD)/hazelnut (Corylus avellana L.) oil/antioxidant ternary complexes through Fourier-transform infrared spectroscopy coupled with principal component analysis (FTIR-PCA). These innovative complexes combine the characteristics of the three components and improve the properties of the resulting material such as the onsite protection against oxidative degradation of hazelnut oil unsaturated fatty acid glycerides. Also, the apparent water solubility and bioaccessibility of the hazelnut oil components and antioxidants can be increased, as well as the controlled release of bioactive compounds (fatty acid glycerides and antioxidant flavonoids, namely hesperidin, naringin, rutin, and silymarin). The appropriate method for obtaining the ternary complexes was kneading the components at various molar ratios (1:1:1 and 3:1:1 for β-CD hydrate:hazelnut oil (average molar mass of 900 g/mol):flavonoid). The recovering yields of the ternary complexes were in the range of 51.5-85.3% and were generally higher for the 3:1:1 samples. The thermal stability was evaluated by thermogravimetry and differential scanning calorimetry. Discrimination of the ternary complexes was easily performed through the FTIR-PCA coupled method, especially based on the stretching vibrations of CO groups in flavonoids and/or CO/CC groups in the ternary complexes at 1014.6 (± 3.8) and 1023.2 (± 1.1) cm^-1 along the second PCA component (PC₂), respectively. The wavenumbers were more appropriate for discrimination than the corresponding intensities of the specific FTIR bands. On the other hand, ternary complexes were clearly distinguishable from the starting β-CD hydrate along the first component (PC₁) by all FTIR band intensities and along PC₂ by the wavenumber of the asymmetric stretching vibrations of the CH groups at 2922.9 (± 0.4) cm^-1 for ternary complexes and 2924.8 (± 1.4) cm^-1 for β-CD hydrate. The first two PCA components explain 70.38% from the variance of the FTIR data (from a total number of 26 variables). Other valuable classifications were obtained for the antioxidant flavonoids, with a high similarity for hesperidin and naringin, according to FTIR-PCA, as well as for ternary complexes depending on molar ratios. The FTIR-PCA coupled technique is a fast, nondestructive and cheap method for the evaluation of quality and similarity/characteristics of these new types of cyclodextrin-based ternary complexes having enhanced properties and stability.

Formulation of Multicomponent Chrysin-Hydroxy Propyl β Cyclodextrin-Poloxamer Inclusion Complex Using Spray Dry Method: Physicochemical Characterization to Cell Viability Assessment

The work aimed to enhance chrysin (CHR) water solubility, dissolution, and in vitro antibacterial as well as cell viability. Chrysin binary, as well as ternary inclusion complex, were prepared using the spray drying method. The influence of an auxiliary component (poloxamer; PLX) was also assessed after being incorporated into the chrysin HP βCD complex (CHR-BC) and formed as a chrysin ternary complex (CHR-TC). The phase solubility investigation was carried out in order to assess the complexation efficiency and stability constant. The samples were assessed for the dissolution test, physicochemical evaluation, antibacterial activity, and cell viability tests were also assessed. The results of the phase solubility investigation showed that the stability constant for the binary system (268 M^-1) was lower than the ternary system (720 M^-1). The complex stability was validated by the greater stability constant value. The dissolution results showed that pure CHR had a limited release of 32.55 ± 1.7% in 60 min, while prepared CHR-TC and CHR-BC both demonstrated maximum CHR releases of 99.03 ± 2.34% and 71.95 ±2.1%, respectively. The dissolution study's findings revealed that the release of CHR was much improved over that of pure CHR. A study using a scanning electron microscope showed that CHR-TC contains more agglomerated and amorphous components. The higher conversion of crystalline CHR into an amorphous form is responsible for the structural alterations that are observed. After complexation, the distinctive peaks of pure CHR changed due to the complexation with HP βCD and PLX. The antimicrobial and cell viability results revealed improved antimicrobial activity as well as a lower IC50 value than pure CHR against the tested anticancer cell line (MCF7).

Voriconazole-Cyclodextrin Supramolecular Ternary Complex-Loaded Ocular Films for Management of Fungal Keratitis

Fungal keratitis is one of the leading causes of ophthalmic mycosis affecting the vision due to corneal scarring. Voriconazole (VRC) is the most preferred azole antifungal agent for treating ocular mycotic infections. Ocular drug delivery is challenging due to the shorter corneal residence time of the formulation requiring frequent administration, leading to poor patient compliance. The present study aimed at improving the solubility, transcorneal permeation, and efficacy of voriconazole via the formation of cyclodextrin-based ternary complexes and incorporation of the complex into mucoadhesive films. A phase solubility study suggested a ∼14-fold improvement in VRC solubility, whereas physicochemical characterization confirmed the inclusion of VRC in the cyclodextrin inner cavity. In silico docking studies were performed to predict the docking conformation and stability of the inclusion complex. Complex-loaded films showed sustained release of voriconazole from the films and improved transcorneal permeation by ∼4-fold with an improved flux of 8.36 μg/(cm² h) for ternary complex-loaded films compared to 1.86 μg/(cm² h) for the pure VRC film. The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and hen's egg-chorioallantoic membrane test (HET-CAM) assays confirmed that the complexes and ocular films were nonirritant and safe for ocular administration. The antifungal study performed using Aspergillus fumigatus and Fusarium oxysporum suggested improved antifungal activity compared to the pure drug film. In conclusion, the supramolecular cyclodextrin ternary complex proved to be a promising strategy for enhancing the solubility and permeability and augmenting the antifungal activity of voriconazole in the management of fungal keratitis.

Hydroxypropyl-β-cyclodextrin as an effective carrier of curcumin - piperine nutraceutical system with improved enzyme inhibition properties

The nutraceutical system of curcumin-piperine in 2-hydroxypropyl-β-cyclodextrin was prepared by using the kneading technique. Interactions between the components of the system were defined by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR). Application of hydroxypropyl-β-cyclodextrin as a carrier-solubiliser improved solubility of the curcumin-piperine system, its permeability through biological membranes (gastrointestinal tract, blood-brain barrier) as well as the antioxidant, antimicrobial and enzyme inhibitory activities against acetylcholinesterase and butyrylcholinesterase.

Development of a stable oral pediatric solution of hydrochlorothiazide by the combined use of cyclodextrins and hydrophilic polymers

Hydrochlorothiazide (HCT) is widely used in pediatrics for hypertension management. Due to the lack of pediatric commercial forms, community or hospital pharmacies generally prepare HCT extemporaneous pediatric suspensions by dispersing in water a portion of a crushed tablet or the drug powder; however, any dose or stability control is usually done on these preparations. Obtaining stable HCT solutions is very challenging, due to its low water-solubility and pH-dependent degradation. The aim of this work was to develop a stable 2 mg/mL-HCT oral pediatric solution without using co-solvents. Combined use of cyclodextrins (CD) and hydrophilic polymers was exploited to improve poor HCT solubility and stability. HPβCD and SBEβCD were selected, considering their safe toxicological profiles, while PVP resulted the best among the tested polymers. Low PVP concentrations (0.2-1.0%) improved the solubilizing efficiency of both CDs, allowing to reach the prefixed HCT concentration. Different CD-PVP concentrations were used to prepare several 2 mg/mL-HCT solutions in pH 5.5 buffer. The best stability was shown by solutions containing the highest SBEβCD concentration (25 mM), which allowed a 3-months stability at 4 °C. In vivo studies on rats showed that such formulation allowed a more pronounced and more reproducible diuretic effect than the corresponding HCT suspension.

Combination Therapies of Artemisinin and its Derivatives as a Viable Approach for Future Cancer Treatment

BACKGROUND

Many anticancer drugs have been developed for clinical usage till now, but the major problem is the development of drug-resistance over a period of time in the treatment of cancer. Anticancer drugs produce huge adverse effects, ultimately leading to death of the patient. Researchers have been focusing on the development of novel molecules with higher efficacy and lower toxicity; the anti-malarial drug artemisinin and its derivatives have exhibited cytotoxic effects.

METHODS

We have done extensive literature search for artemisinin for its new role as anti-cancer agent for future treatment. Last two decades papers were referred for deep understanding to strengthen its role.

RESULT

Literature shows changes at 9, 10 position in the artemisinin structure produces anticancer activity. Artemisinin shows anticancer activity in leukemia, hepatocellular carcinoma, colorectal and breast cancer cell lines. Artemisinin and its derivatives have been studied as combination therapy with several synthetic compounds, RNA interfaces, recombinant proteins and antibodies etc., for synergizing the effect of these drugs. They produce an anticancer effect by causing cell cycle arrest, regulating signaling in apoptosis, angiogenesis and cytotoxicity activity on the steroid receptors. Many novel formulations of artemisinin are being developed in the form of carbon nanotubes, polymer-coated drug particles, etc., for delivering artemisinin, since it has poor water/ oil solubility and is chemically unstable.

CONCLUSION

We have summarize the combination therapies of artemisinin and its derivatives with other anticancer drugs and also focussed on recent developments of different drug delivery systems in the last 10 years. Various reports and clinical trials of artemisinin type drugs indicated selective cytotoxicity along with minimal toxicity thus projecting them as promising anti-cancer agents in future cancer therapies.

Binary and ternary complexes of norfloxacin to improve the solubility of the active pharmaceutical ingredient

AIM

Binary and ternary complexes with hydroxypropyl-β-cyclodextrin (HPβCD), using glutamic acid (GA), proline or lysine as the third component, were developed to increase the solubility and the dissolution rate of norfloxacin (NOR).

METHODS/RESULTS

Complexation was evaluated by phase solubility studies, obtaining the highest NOR solubility with GA and HPβCD. Thermal analysis suggested that different kinds of interactions occur among NOR, HPβCD and each amino acid, and when the systems were prepared by kneading or by means of freeze-drying technique. Dissolution studies, performed on simulated gastric fluid and subsequent simulated intestinal fluid, showed the highest rate of NOR from NOR-HPβCD-GA.

CONCLUSION

NOR:HPβCD:GA was the best approach for improving the bioavailability of NOR.

Development Insights of Surface Modified Lipid Nanoemulsions of Dihydroartemisinin for Malaria Chemotherapy: Characterization, and in vivo Antimalarial Evaluation

BACKGROUND

The use of dihydroartemisinin (DHA) for effective malaria treatment is challenged by its poor aqueous solubility and inadequate bioavailability leading to treatment failures and emergence of resistant strains. A review of some novel drug delivery systems developed to address these challenges and their patents revealed that no study has reported the application of surface modified lipid nanoemulsions for improved antimalarial activity of DHA.

OBJECTIVE

The main thrust of this study is to develop oral dihydroartemisinin formulations solubilized in surface modified lipid nanoemulsions, characterize, and evaluate their activity against murine malaria.

METHOD

Lipid nanoemulsions containing dihydroartemisinin were formulated by high pressure homogenization using soybean oil, and polyethylene glycol 4000 was employed for surface modification. The formulations were characterized for droplet size, surface charge, pH, fouriertransform infrared spectroscopy, and surface morphology, viscosity and drug content efficiency. In vitro haemolytic study as a function of cytotoxicity using red blood cells as well as in vivo anti-malarial study using murine malaria model was also investigated.

RESULTS

Nanoemulsions recorded droplet sizes ranging from 26 - 56 nm, and zeta potential in the range of -28 to -35 mV. The formulations were slightly acidic (pH 4.4 - 5.8) with the drug molecularly dispersed as seen using infrared spectroscopy. The formulations showed non- Newtonian flow with significant drug content efficiency in the range of 77-96%. The formulations did not induce haemolysis of cells and showed good clearance of parasitaemia.

CONCLUSION

Surface-modified lipid nanoemulsion is a perfect carrier system for improving the anti-malarial activity of dihydroartemisinin.

Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation

The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and ¹H nuclear magnetic resonance spectroscopy (¹H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was confirmed by DSC, FT-IR and ¹H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 µm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.

Multicomponent cyclodextrin system for improvement of solubility and dissolution rate of poorly water soluble drug

The purpose of the present study was to investigate the interaction of Cinnarizine (CIN) with Hydroxypropyl-β-Cyclodextrin (HPβCD) in the presence of Hydroxy Acids (HA). Various binary and ternary systems of CIN with HPβCD and HA were prepared by kneading and coevaporation methods. For the ternary systems, HA were tried in three different concentrations. The interaction in solution phase was studied in detail by the phase solubility method, and the solid phase interactions were characterized by Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), X-Ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) and Proton Nuclear Magnetic Resonance (1H-NMR). Phase solubility revealed the positive effect of HA on the complexation of CIN with HPβCD. Solid phase characterization confirmed the formation of inclusion complex in the ternary systems. Solubility and dissolution studies illustrated that out of three different concentrations tried, HA were most effective at the 1 M concentration level. Ternary systems were very effective in improving the solubility as well as dissolution profile of CIN than the CIN-HPβCD binary systems. FTIR, 1H-NMR and Molecular docking studies gave some insight at molecular level that actually which part of CIN was interacting with the HPβCD. Molecular docking and free energy calculation even enlighten the role of tartaric acid in increasing solubility of CIN in the ternary system.

β-Cyclodextrin-based inclusion complexes and nanocomposites of rivaroxaban for solubility enhancement

Rivaroxaban (RIV) is an oral anticoagulant used in the prevention of venous thromboembolism in adult patients after total hip replacement or total knee replacement surgery. It is practically insoluble in water and buffer systems (pH 3-9). The present study was aimed to investigate the β-CD-based inclusion complexes and nanocomposites of rivaroxaban (RIV) for solubility and dissolution enhancement. A novel solubility enhancement approach of inclusion complexation of RIV with β-CD using spray drying method combined with high pressure homogenization as a particle engineering method was used. Change in crystallinity of RIV nanocomposites was assessed by DSC and PXRD. The interaction of drug with β-CD was projected through ¹H-NMR and FT-IR studies. Saturation solubility and in vitro dissolution study revealed a dramatic increase in solubility and dissolution of RIV, respectively. Thus, spray-dried β-CD-based nanocomposites could be an innovative approach for solubility and dissolution enhancement of RIV.

Degradation kinetics study of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) by a validated stability-indicating RP-HPLC method

The chemical stability of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG), a therapeutic agent for neutropenia, was investigated using a validated stability-indicating reversed phase high-performance liquid chromatographic (RP-HPLC) method. The forced degradation of PLAG was carried out under the stress conditions of hydrolysis (alkaline, acidic and various pH buffers), oxidation, photolysis and heat. A simple, sensitive, specific, robust, precise and accurate RP-HPLC method was developed and validated for evaluating the degradation kinetics of PLAG. The chromatographic validation of various parameters, such as system suitability, detection limit, quantification limit, linearity, accuracy, precision, specificity, robustness and stability, was achieved. The method was validated for linearity, accuracy and precision over the concentration range of 0.7813-100μg/mL (r²=0.9999). The proposed method provided excellent stability study of PLAG indicated by the resolution of degradation products from the drug. Degradation of PLAG provided first order kinetics under all experimental conditions. PLAG was catalysed more rapidly in alkaline and acidic conditions than in neutral conditions. PLAG was relatively stable in photolytic and oxidative conditions compared to hydrolysis and thermal conditions, although this drug was not also stable in these conditions. Exposed to high temperature, PLAG was more rapidly catalysed. The activation energy evaluated from the Arrhenius plot was about 110kJ/mol in the thermal conditions. Additionally, PLAG with a t_1/2 of about 400h was very stable at room temperature. Therefore, PLAG was considerably influenced by alkaline and acidic hydrolysis, and thermal degradation.

Design of Drug Delivery Systems Containing Artemisinin and Its Derivatives

Artemisinin and its derivatives have been reported to be experimentally effective for the treatment of highly aggressive cancers without developing drug resistance, they are useful for the treatment of malaria, other protozoal infections and they exhibit antiviral activity. However, they are limited pharmacologically by their poor bioavailability, short half-life in vivo, poor water solubility and long term usage results in toxicity. They are also expensive for the treatment of malaria when compared to other antimalarials. In order to enhance their therapeutic efficacy, they are incorporated onto different drug delivery systems, thus yielding improved biological outcomes. This review article is focused on the currently synthesized derivatives of artemisinin and different delivery systems used for the incorporation of artemisinin and its derivatives.

Improvement of solubility, dissolution and stability profile of artemether solid dispersions and self emulsified solid dispersions by solvent evaporation method

The purpose of this study was to investigate changes in the water solubility of artemether; a poorly soluble drug used for the treatment of malaria. Different solid dispersions (SDs) of artemether were prepared using artemether and polyethylene glycol 6000 at ratio 12:88 (Group 1), self-emulsified solid dispersions (SESDs) containing artemether, polyethylene glycol 6000, cremophor-A-25, olive oil, hydroxypropylmethylcellulose and transcutol in the ratio 12:75:5:4:2:2, respectively (Group 2). SESDs were also prepared by substituting cremophor-A-25 in Group 2 with poloxamer 188 (noted as Group 3). Each of these preparations was formulated using physical mixing and the solvent evaporation method. Aqueous solubility of artemether improved 11-, 95- and 102-fold, while dissolution (in simulated gastric fluid) increased 3-, 13- and 14-fold, for formulation groups 1, 2 and 3, respectively. X-ray diffraction patterns of SDs indicated a decrease in peak intensities at 10° implying reduced artemether crystallinity. Scanning electron micrographs invariably revealed embedment of artemether by various excipients and a glassy appearance for solvent evaporated mixtures for all three formulation Groups. Our findings indicate improved hydrophilic interactions for drug particles yield greater solubility and dissolution in the following order for artemether formulating methods: solvent evaporation mixtures > physical mixtures > pure artemether.

Preparation and In Vitro/In Vivo Evaluation of Puerarin Solid Self-Microemulsifying Drug Delivery System by Spherical Crystallization Technique

The aim of this work was to establish a method for preparing stable and controllable solid self-microemulsifying drug delivery system (S-SMEDDS) by spherical crystallization technique, which was explored for promoting the dissolution, oral bioavailability, and process efficiency. Solubility test, preparation of liquid self-microemulsifying drug delivery system (L-SMEDDS), and the obtained ternary phase diagrams test have been performed to screen and optimize the composition of LSMEDDS. The optimized formulation was used to prepare puerarin solid self-microemulsifying drug delivery system (Pue-SSMEDDS) by spherical crystallization technique. Droplet size and morphological analysis of the optimal Pue-SSMEDDS were determined to evaluate the final formulation. And the Pue-SSMEDDS was also assessed by flowability study, angle of repose, Carr's index, and flow velocity. Furthermore, the vitro dissolution and pharmacokinetic profile in vivo were analyzed. The study in vitro showed the Pue-SSMEDDS could disperse in the dispersion medium within 60 s and was spherical with the particle size of 19.66 nm and zeta potential of -28.3 mV. It could keep stable at low temperature and seal condition for 3 months. In vivo pharmacokinetic experiments of rats, the mean plasma concentration of self-microemulsion group was much higher than that of conventional tablets and could play a long-lasting efficacy, while there was no significant difference between the LSMEDDS and S-SMEDDS. The results suggested the potential of S-SMEDDS could improve the oral bioavailability of poorly water-soluble drug, such as puerarin.

Self-assembled targeted nanoparticles based on transferrin-modified eight-arm-polyethylene glycol-dihydroartemisinin conjugate

Poor delivery of insoluble anticancer drugs has so far precluded their clinical application. In this study, an efficient tumor targeted-nanoparticle delivery system, transferrin-eight-arm-polyethylene glycol–dihydroartemisinin nanoparticles (TF-8arm-PEG-DHA NPs) for the vehiculation of dihydroartemisinin (DHA) was first prepared and evaluated for its targeting efficiency and cytotoxicity in vitro and in vivo to Lewis lung carcinoma (LLC) cells, which overexpress transferrin receptors (TFRs). The synthesized TF-8arm-PEG–DHA NPs had high solubility (~102 fold of free DHA), relatively high drug loading (~10 wt% DHA), long circulating half-life and moderate particle size (~147 nm). The in vitro cytotoxicity and in vivo tumor growth inhibition studies in LLC-tumor bearing mice confirmed the enhanced efficacy of TF-modified 8arm-PEG-DHA NPs compared to free DHA and non-modified 8arm-PEG-DHA NPs. All these results together supported that the formulation developed in this work exhibited great potential as an effective tumor targeting delivery system for insoluble anticancer drugs.

Improved Aqueous Solubility and Antihypercholesterolemic Activity of Ezetimibe on Formulating with Hydroxypropyl-β-Cyclodextrin and Hydrophilic Auxiliary Substances

The purpose of this study was to improve the aqueous solubility, dissolution, and pharmacodynamic properties of a BCS class II drug, ezetimibe (Eze) by preparing ternary cyclodextrin complex systems. We investigated the potential synergistic effect of two novel hydrophilic auxiliary substances, D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and L-ascorbic acid-2-glucoside (AA2G) on hydroxypropyl-β-cyclodextrin (HPBCD) solubilization of poorly water-soluble hypocholesterolemic drug, Eze. In solution state, the binary and ternary systems were analyzed by phase solubility studies and Job's plot. The solid complexes prepared by freeze-drying were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). The log P values, aqueous solubility, dissolution, and antihypercholesterolemic activity of all systems were studied. The analytical techniques confirmed the formation of inclusion complexes in the binary and ternary systems. HPBCD complexation significantly (p < 0.05) reduced the log P and improved the solubility, dissolution, and hypocholesterolemic properties of Eze, and the addition of ternary component produced further significant improvement (p < 0.05) even compared to binary system. The remarkable reduction in log P and enhancement in solubility, dissolution, and antihypercholesterolemic activity due to the addition of TPGS or AA2G may be attributed to enhanced wetting, dispersibility, and complete amorphization. The use of TPGS or AA2G as ternary hydrophilic auxiliary substances improved the HPBCD solubilization and antihypercholesterolemic activity of Eze.

Cyclodextrin and Meglumine-Based Microemulsions as a Poorly Water-Soluble Drug Delivery System

Cyclodextrins (CDs) and meglumine (MEG) are pharmaceutical excipients widely used to improve solubility of poorly water-soluble drugs. The purpose of this work was to study the effect of CDs or MEG on the internal microstructure of soya oil-based O/W microemulsions (MEs) and on the modulation of the solubility and release rate of Class II model hydrophobic drugs, sulfamerazine and indomethacin. The pseudoternary phase diagrams revealed that higher proportions of oil phase, as well as the presence of β-cyclodextrin (ßCD), methyl-ßCD, and MEG, favored the incorporation of the drugs. The conductivity studies, particle size, and zeta potential analysis showed that the O/W ME structure remained unaffected and that the ME presented reduced droplet sizes after the incorporation of the ligands. The drug-component interactions were assessed by proton nuclear magnetic resonance studies. The highest incorporations of sulfamerazine (35.6 mg/mL) and indomethacin (73.1 mg/mL) were obtained with the ME with W = 5%, MEG and W = 1.8% ßCD in a phosphate buffer solution of pH 8, respectively. In addition, the ligands in ME significantly enhanced the released amount of the drugs, probably due to a solubilizing effect that facilitates the drug to penetrate the unstirred water layer adjacent to membranes.

Development, characterization and antimalarial efficacy of dihydroartemisinin loaded solid lipid nanoparticles

Effective use of dihydroartemisinin (DHA) is limited by poor water-solubility, poor pharmacokinetic profile and unsatisfactory clinical outcome especially in monotherapy. To reduce such limitations, we reformulated DHA into solid lipid nanoparticles (SLNs) as a nanomedicine drug delivery system. DHA-SLNs were characterized for physical parameters and evaluated for in vitro and in vivo antimalarial efficacy. DHA-SLNs showed desirable particle characteristics including particle size (240.7 nm), particle surface charge (+17.0 mV), drug loadings (13.9 wt %), encapsulation efficacy (62.3%), polydispersity index (0.16) and a spherical appearance. Storage stability up to 90 days and sustained release of drug over 20 h was achieved. Enhanced in vitro (IC50 0.25 ng/ml) and in vivo (97.24% chemosuppression at 2mg/kg/day) antimalarial activity was observed. Enhancement in efficacy was 24% when compared to free DHA. These encouraging results show potential of using the described formulation for DHA drug delivery for clinical application.

FROM THE CLINICAL EDITOR

Malaria still poses a significant problem worldwide. One of the current drugs, artemisinin has been shown to be effective, but has poor water-solubility. The authors here described their formulation of making dihydroartemisinin (DHA) into solid lipid nanoparticles, with subsequent enhancement in efficacy. These results would have massive potential in the clinical setting.

Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs

In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.

A Self-microemulsifying Drug Delivery System (SMEDDS) for a Novel Medicative Compound Against Depression: a Preparation and Bioavailability Study in Rats

AJS is the code name of an untitled novel medicative compound synthesized by the Tasly Holding Group Company (Tianjin, China) based on the structure of cinnamamide, which is one of the Biopharmaceutics Classification System (BCS) class II drugs. The drug has better antidepressant effect, achieved by acting on the 5-hydroxytryptamine receptor. However, the therapeutic effects of the drug are compromised due to its poor water solubility and lower bioavailability. Herein, a self-microemulsifying drug delivery system (SMEDDS) was developed to improve its solubility and oral bioavailability. AJS-SMEDDS formulation was optimized in terms of drug solubility in the excipients, droplet size, stability, and drug precipitation using a pseudo-ternary diagram. The pharmacokinetic study was performed in rats, and the drug concentration in plasma samples was assayed using the high-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS) method. The optimized formulation for SMEDDS has a composition of castor oil 24.5%, Labrasol 28.6%, Cremphor EL 40.8%, and Transcutol HP 2.7% (co-surfactant). No drug precipitation or phase separation was observed from the optimized formulation after 3 months of storing at 25°C. The droplet size of microemulsion formed by the optimized formulation was 26.08 ± 1.68 nm, and the zeta potential was -2.76 mV. The oral bioavailability of AJS-SMEDDS was increased by 3.4- and 35.9-fold, respectively, compared with the solid dispersion and cyclodextrin inclusion; meanwhile, the C max of AJS-SMEDDS was about 2- and 40-fold as great as the two controls, respectively. In summary, the present SMEDDS enhanced oral bioavailability of AJS and was a promising strategy to orally deliver the drug.

Preparation and Characterization of Solid Dispersions of Artemether by Freeze-Dried Method

Solid dispersions of artemether and polyethylene glycol 6000 (PEG6000) were prepared in ratio 12 : 88 (group-1). Self-emulsified solid dispersions of artemether were prepared by using polyethylene glycol 6000, Cremophor-A25, olive oil, Transcutol, and hydroxypropyl methylcellulose (HPMC) in ratio 12 : 75 : 5 : 4 : 2 : 2, respectively (group-2). In third group, only Cremophor-A25 was replaced with Poloxamer 188 compared to group-2. The solid dispersions and self-emulsified solid dispersions were prepared by physical and freeze dried methods, respectively. All samples were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimeter, scanning electron microscopy, and solubility, dissolution, and stability studies. X-ray diffraction pattern revealed artemether complete crystalline, whereas physical mixture and freeze-dried mixture of all three groups showed reduced peak intensities. In attenuated total reflectance Fourier transform infrared spectroscopy spectra, C–H stretching vibrations of artemether were masked in all prepared samples, while C–H stretching vibrations were representative of polyethylene glycol 6000, Cremophor-A25, and Poloxamer 188. Differential scanning calorimetry showed decreased melting endotherm and increased enthalpy change (ΔH) in both physical mixture and freeze-dried mixtures of all groups. Scanning electron microscopy of freeze-dried mixtures of all samples showed glassy appearance, size reduction, and embedment, while their physical mixture showed size reduction and embedment of artemether by excipients. In group-1, solubility was improved up to 15 times, whereas group-2 showed up to 121 times increase but, in group-3, when Poloxamer 188 was used instead of Cremophor-A25, solubility of freeze-dried mixtures was increased up to 135 times. In fasted state simulated gastric fluid at pH 1.6, the dissolution of physical mixture was increased up to 12 times and freeze-dried mixtures up to 15 times. The stability of artemether was substantially enhanced in freeze-dried mixtures by using polyethylene glycol 6000, Cremophor-A25, and Poloxamer 188 of self-emulsified solid dispersions of artemether in Hank's balanced salt solution at pH 7.4.

Solubility and release modulation effect of sulfamerazine ternary complexes with cyclodextrins and meglumine

This study investigated the effect on solubility and release of ternary complexes of sulfamerazine (SMR) with β-(βCD), methyl-(MβCD) and hydroxypropyl-β-cyclodextrin (HPβCD) using meglumine (MEG) as the ternary component. The combination of MEG with MβCD resulted the best approach, with an increased effect (29-fold) of the aqueous solubility of SMR. The mode of inclusion was supported by 2D NMR, which indicated that real ternary complexes were formed between SMR, MEG and MβCD or HPβCD. Solid state analysis was performed using Fourier-transform infrared spectroscopy (FT IR), differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD), which demonstrated that different interactions occurred among SMR, MEG and MβCD or HPβCD in the ternary lyophilized systems. The ternary complexes with βCD and MβCD produced an additional retention effect on the release of SMR compared to the corresponding binary complexes, implying that they were clearly superior in terms of solubility and release modulation.

The difficulties for a photolabile drug in topical formulations: the case of diclofenac

Topical commercial formulations containing diclofenac (DC) were submitted to photostability tests, according to the international rules, showing a clear degradation of the drug. The degradation process was monitored by applying the multivariate curve resolution technique to the UV spectral data from samples exposed to stressing irradiation. This method was able to estimate the number of components evolved as well as to draw their spectra and concentration profiles. Three photoproducts (PhPs) were resolved by the analysis of photodegradation kinetics, according to two consecutive reactions with a mechanism postulated as DC>PhP₁>PhP₂ and PhP₃. Photodegradation rate of DC in gel was found to be very fast, with a residual content of 90% only after 3.90 min under a radiant exposure of 450 Wm(-2). Because of a very slow skin uptake of DC, a prolonged time of exposure to light could lead to a significant decrease of drug available or the uptake of undesired photoproducts. New gel formulations were designed to increase the photostability of DC by incorporating chemical light-absorbers or entrapping the drug into cyclodextrin. Drug photostability resulted increased significantly in comparison with that of the commercial formulations. The gel containing the light-absorbers such as octisilate, octyl methoxycinnamate and a combination thereof showed a residual DC of 90% up to 12.22 min, 13.75 min and 15.71 min, respectively, under the same irradiation power. The best results were obtained by incorporating the drug in β-cyclodextrin with a degradation of 10% after 25.01 min of light exposure.

Photostability of barnidipine in combined cyclodextrin-in-liposome matrices

Background: The improvement of barnidipine photostability was investigated in cyclodextrin or liposome matrices and in appropriate combinations of these matrices. These supramolecular systems allowed the preparation of liquid formulations, as an alternative to the current solid commercial specialties. Materials & methods: Photodegradation stressing tests were performed according to the ICH rules and monitored by derivative spectrophotometry. Optimization was evaluated in terms of drug-inclusion efficiency. Results: The photodegradation rate of barnidipine in ethanol proved rapid (residual percentage of 29.81%) after a radiation exposure of 225 kJ/m2. The residual concentrations detected for liposome and cyclodextrin complexes were 42.90 and 72.03%, respectively. The best results were obtained when the drug–cyclodextrin complex was in turn entrapped in liposomes (residual percentage of 90.78%). Conclusion: The stability of the drug-in-cyclodextrin-in-liposome system increased significantly with a value close to that of solid formulations whose residual percentage was 96.03%.