Preparation and comparison of binary and ternary inclusion complexes of aripiprazole using L-arginine/lysine and MßCD/HPßCD by using different molar ratios.

Aripiprazole (ARI), an antipsychotic having low solubility and stability. To overcome this, formation of binary and ternary using inclusion complexes of Methyl-ß-cyclodextrin (MßCD) /Hydroxy propyl beta cyclodextrin (HPßCD) and L-Arginine (ARG)/ Lysine (LYS) are analyzed by dissolution testing and phase stability study along with their complexation efficacy and solubility constants made by physical mixing. Inclusion complexes with ARG were better than LYS and prepared by solvent evaporation and lyophilization method as well. They are characterized by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (AT-FTIR), X-ray powder diffractometry (XRD), Differential Scanning Calorimetry (DSC), Scanning electron microscopy (SEM) and Thermal gravimetric analysis (TGA). The bond shifting in AT-FTIR confirmed the molecular interactions between host and guest molecules. The SEM images also confirmed a complete change of drug morphology in case of ternary inclusion complexes prepared by lyophilization method for both the polymers. ARI: MßCD: ARG when used in the specific molar ratio of 1:1:0.27 by prepared by lyophilization method has 18 times best solubility while ARI:HPßCD:ARG was 7 times best solubility than pure drug making MßCD a better choice than HPßCD. Change in the molar ratio will cause loss of stability or solubility. Solvent evaporation gave significant level of solubility but less stability.

Binary and ternary complex formation and characterization of artemisinin with sulfobutyl ether ß-cyclodextrin and oleic acid.

Drug-resistant malaria is a global risk to the modern world. Artremisinin (ART) is one of the drugs of choice against drug-resistant (malaria) which is practically insoluble in water. The objective of our study was to improve the solubility of artemisinin (ART) via development of binary complexes of ART with sulfobutylether ß-cyclodextrins (SBE7 ß-CD), sulfobutylether ß-cyclodextrins (SBE7 ß-CD) and oleic acid (ternary complexes). These are prepared in various drugs to excipients ratios by physical mixing (PM) and solvent evaporation (SE) methods. Characterizations were achieved by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and attenuated total reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy. The aqueous-solubility in binary complexes was 12-folds enhanced than ternary complexes. Dissolution of binary and ternary complexes of artemisinin in simulated gastric fluid (pH 1.6) was found highest and 35 times higher for ternary SECx. The crystallinity of artemisinin was decreased in physical mixtures (PMs) while SECx exhibited displaced angles. The attenuated-intensity of SECx showed least peak numbers with more displaced-angles. SEM images of PMs and SECx showed reduced particle size in binary and ternary systems as compared to pure drug-particles. ATR-FTIR spectra of binary and ternary complexes revealed bonding interactions among artemisinin, SBE7 ß-CD and oleic acid.

An evaluation of spectral and statistical parameters of ion pair complexation of Zafirlukast using chromogenic dyes in solid dispersion-based formulations.

The purpose of present work was to develop a novel analytical method for orally given leukotriene antagonist Zafirlukast (ZST), present in Meglumine and Eudragit EEPO based solid dispersion formulation. Four simple, extraction-free, fast, and economical methods based on charge transfer complexation among nitrogen of ZST with sulfonyl group comprising chromogenic mediator bromophenol blue (BPB-Method B), bromothymol blue (BTB-Method C) and bromocresol green (BCG-Method D). The first method (A) is based on the analysis using 0.1 M HCl as a solvent at λmax 242 nm while chromogenic methods yield color complex at λmax 415 nm (BPB-Method B), λmax 420 nm (BTB-Method C) and λmax 435 nm (BCG-Method D). The Beer's Law stayed linear in the concentration ranges of 1-10, 10-75, 5-40 and 15-100 µg/ml for methods A, B, C and D, respectively. The spectral and thermodynamic characterization of each method was carried out by the application of Molar Absorptivity, LOD, LOQ, Association Constant and Gibbs free energy (ΔGo). The methods were statistically optimized and evaluated by F-Distribution Value, P-Value, Shapiro-Wilk P-Value, regression analysis, Q-Q plot, prediction interval, residual histogram and plots. Various experimental conditions affecting the complexation and stability of chromogenic complexes are cautiously studied including optimal temperature, chromogenic agent volume, color stability, recovery, precision and accuracy. All the measurements were executed under ICH guidelines. It can be established that proposed would be an appropriate prospective analytical approach for estimation of ZST in pure bulk, solid dispersions and dosage forms.

Improved solubility and stability of aripiprazole in binary and ternary inclusion complexes using methyl-ß-cyclodextrin and L-arginine.

The aim of this study was to improve the solubility of aripiprazole (ARP) by fabricating binary and ternary inclusion complexes with methyl-ß-cyclodextrin (MßCD) and L-Arginine (LA). Physical mixing and lyophilization were used in the following molar ratios: 1:1, 1:2.5, 1:4, 1:9, 1:1:1, 1:1:0.27, 1:4:1, 1:9:1, 1:3.6:3.6. The developed formulations were analyzed by solubility and dissolution. They were characterized by FTIR, XRD, DSC, SEM and TGA. Ternary formulations prepared by the lyophilization method showed improved dissolution rates in simulated gastric fluid (SGF). The results showcased that the addition of MßCD and LA in inclusion complexes enhanced the solubility and decreased crystallinity. The amorphous nature of Aripiprazole in lyophilization was confirmed by XRD diffractograms. Drug release was dominated by the first-order kinetics (R2 = 0.9932) with the Fickian type of diffusion mechanism (n<0.450). LY18, LY19, LY20 and LY21 have the highest solubility (30, 35, 43 and 48 times higher than the pure drug respectively). Furthermore, it was observed that the method of preparation, as well as a specific drug to polymer and amino acid ratio, are critical for achieving high drug solubility and stability. These complexes appeared to be a promising product for the development of new drug delivery systems.

Ploxomer and ß-cyclodextrin; promising tools to improve solubility of dapoxetine through binary and ternary solid dispersion techniques.

Present study was aimed to formulate solid dispersions (SD) of Dapoxetine (DAPO), a drug with low water solubility with the help of PVP-30, Ploxomer-180 (P-180) and ß-cyclodextrin (CD) by physical mixing to enhance the water solubility and dissolution of drug. Binary and Ternary solid dispersions were prepared with different ratios of drug and polymer and were further evaluated the effects of polymer at individual level as well as when used in combination. The solid dispersions were whitish in color, irregular in shape and have some rough surface when illustrated under SEM. Percentage yield of SDs ranged from 81-95% described the method was structured and significant. Solubility studies were carried out in 0.1N Hcl solution and was observed a remarkable increase in solubility of BSD 8, BSD 12 and TSD 6. Furthermore, the formulations were characterized by FTIR and PXRD. P-180 found an exceptional solubility promoter when used alone and in combination with CD as well. A remarkable enhance in Solubility and dissolution of DAPO was investigated in formulation prepared with ternary SD of Pol-180 and CD.

The integrin facilitated internalization of fibronectin-functionalized camptothecin-loaded DNA-nanofibers for high-efficiency anticancer effects.

Camptothecin (CMPT) in a free form is extremely cytotoxic as well as hydrophobic drug, and is considered to be highly contagious for systemic administration. The fibronectin (FN)-functionalized DNA-based nanocarrier has been designed to load CMPT and target integrin (αvß3) receptors which are highly expressed on the A549 cancer cells. Here, we report DNA nanocarrier in the form of DNA-nanofibers (DNA-NFs) capable of loading CMPT via strand intercalation in the GC (base pairs)-rich regions of the DNA duplex. Hence, our keen purpose was to explore the potential of DNA-NFs to load CMPT and assess the improvements of the outcomes in terms of enhanced therapeutic effects to integrin-rich A549 cancer cells with reduced cytotoxic effects to integrin-lacking HEK293 cells. DNA-NFs were formulated as a polymer of DNA triangles. DNA triangles arranged in a programmed way through the complementary overhangs present at the vertices. DNA triangles were primarily obtained through the annealing of the freshly circularized scaffold strands with the three distinct staple strands of specific sequences. The polymerized triangular tiles instead of forming two-dimensional nanosheets underwent self-coiling to give rise to DNA-NF-shaped structures. Flow cytometry and MTT assays were performed to observe cytotoxic and apoptotic effects on integrin-rich A549 cancer cells compared with the integrin-deficient HEK293 cells. AFM, native-page, and confocal experiments confirmed the polymerization of DNA triangles and the morphology of the resulting nanostructures. AFM and confocal images revealed the length of DNA-NFs to be 3-6 µm and the width from 70 to 110 nm. CMPT loading (via strands intercalation) in GC-rich regions of DNA-NFs and the FN functionalization (TAMRA tagged; red fluorescence) via amide chemistry using amino-modified strands of DNA-NFs were confirmed through the UV-shift analysis (> 10 nm shift) and confocal imaging. Blank DNA-NFs were found to be highly biocompatible in 2-640 µM concentrations. MTT assay and flow cytometry experiments revealed that CMPT-loaded DNA-NFs showed a dose-dependent decrease in the cell viability to integrin-rich A549 cancer cells compared with the integrin-deficient HEK293 cells. Conclusively, FN-functionalized, CMPT-loaded DNA-NFs effectively destroyed integrin-rich A549 cancer cells in a targeted manner compared with integrin-deficient HEK293 cells. Grapical abstract.

RP-HPLC Method for the Determination and Quantification of Artesunate.

A simple, rapid and cost-effective reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed for the quantification of artesunate. C18 Promosil (ODS, 150 × 4.6 mm, 5 µm) column was used as stationary phase to separate the drug. Mobile phase comprised of ethanol: water (65:35) having pH 4.5 was run isocratically at a flow rate of 1 mL/min at 27°C. The method was validated according to ICH guidelines for linearity, precision, accuracy, robustness, specificity, limit of detection (LOD) and limit of quantification (LOQ). The method was found accurate, precise and robust with an average retention time of 4.509 min and 0.5357 %RSD. Good linearity was observed in the concentration range of 2-10 mg/ml with regression coefficient R2 value of 0.9995 and slope value of 369,928. Conclusively, as per ICH norms, the developed method was successfully validated and used for the quantification of artesunate in fast dissolving tablets (FDTs).

Synthesis of Ligand Functionalized ErbB-3 Targeted Novel DNA Nano-Threads Loaded with the Low Dose of Doxorubicin for Efficient In Vitro Evaluation of the Resistant Anti-Cancer Activity.

PURPOSE: Doxorubicin (Dox) being a hydrophobic drug needs a unique carrier for the effective encapsulation with uniformity in the aqueous dispersion, cell culture media and the biological-fluids that may efficiently target its release at the tumor site. METHODS: Circular DNA-nanotechnology was employed to synthesize DNA Nano-threads (DNA-NTs) by polymerization of triangular DNA-tiles. It involved circularizing a linear single-stranded scaffold strand to make sturdier and rigid triangles. DNA-NTs were characterized by the AFM and Native-PAGE tests. Dox binding and loading to the Neuregulin1 (NRG1) functionalized DNA based nano-threads (NF-DBNs) was estimated by the UV-shift analysis. The biocompatibility of the blank NRG-1/DNA-NTs and enhanced cytotoxicity of the NF-DBNs was assessed by the MTT assay. Cell proliferation/apoptosis was analyzed through the Flow-cytometry experiment. Cell-surface binding and the cell-internalization of the NF-DBNs was captured by the double-photon confocal microscopy (DPCM). RESULTS: The AFM images revealed uniform DNA-NTs with the diameter 30 to 80 nm and length 400 to 800 nm. PAGE native gel was used for the further confirmation of the successful assembly of the strands to synthesize DNA-NTs that gave one sharp band with the decreased electrophoretic mobility down the gel. MTT assay showed that blank DNA-NTs were biocompatible to the cells with less cytotoxicity even at elevated concentrations with most of the cells (94%) remaining alive compared to the dose-dependent enhanced cytotoxicity of NF-DBNs further evidenced by the Flow-cytometry analysis. CONCLUSION: Uniform and stiffer DNA-NTs for the potential applications in targeted drug delivery was achieved through circular DNA scaffolding.

Synthetic NRG-1 functionalized DNA nanospindels towards HER2/neu targets for in vitro anti-cancer activity assessment against breast cancer MCF-7 cells.

DNA based nano-carriers synthesized from short circular scaffolds (circular DNA nanotechnology) attains stiffer topology for ligand functionalization (neuregulin-1/NRG-1 ligand) and biological applications (targeted drug delivery). Daunorubicin (DR) is a hydrophobic chemical that requires robust vectors to efficiently encapsulate and avoid its free dispersion in water, biological media and cell culture. Here we design DNA nanospindels (DNA-NS) to efficiently load DR and target the (highly expressed) HER2/neu receptors on the plasma membrane of drug-resistant MCF-7 (breast cancer) cells. DNA-NS were synthesized by polymerizing the DNA-triangles (utilizing 84-nt short circular scaffold strand) into larger DNA nano-ribbons characterized by the native-PAGE testing. AFM results revealed the spinning of DNA nanoribbons on its (own) axis because of the intrinsic curvature of the DNA double helix resulting in the formation of the firm and twisted DNA-NS with the diameter (50-70 nm) and length (0.5-4 µm). DA loading onto DNA-NS was confirmed by the UV shift analysis. The MTT results with the blank DNA-NS evidenced its biocompatibility (remained value of 93%) compared to the decreased viability of the MCF-7 cells after treatment with DNA-NS (DR loaded). These findings were further supported by the analysis of cell proliferation/apoptosis through flow cytometry showing 64% apoptosis after treating with the DR loaded DNA-NS. Hence, through the short circular DNA nanotechnology, we have achieved a stiffer, uniform, and biocompatible DNA-NS for applications in the targeted therapy.

Hematopoietic effects of Azadirachta indica methanolic extract in cyclophosphamide mediated myelosuppressed albino rat.

Myelosuppression or bone marrow suppression is one of the most common side effects caused by anti-cancer drugs. Certain nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics and viruses like B19 virus can also cause bone marrow suppression resulting in serious consequences like leukopenia, anemia and thrombocytopenia. Currently, it is mainly treated by Filgrastim, use of which is not without side effects. Certain natural drugs can be a safer alternative to treat myelosuppression. Azadirachta indica, commonly known as Neem, is an important medicinal plant of subcontinent. Keeping in view the traditional uses of Neem, present study aims to investigate its potential role in reversing myelosuppression. Albino rats were used to determine hematopoietic activity of Neem leaves after inducing myelosuppression by cyclophosphamide given subcutaneously. Filgrastim was used as reference standard to compare the antimyelosuppressant activity of the drug. The drug was evaluated in three doses i.e. 50mg/kg, 100mg/kg and 200mg/kg body weight, while blood samples were drawn on 0, 1st, 7th, 14th and 21st day. The drug was found to be effective in reversing bone marrow suppression in all three doses based on the hematological parameters (mean WBC, RBC, platelets, Hb, Hct etc.) which improved significantly. The results suggest that the drug can be used as antimyelosuppressant after establishing its safety and identifying its active constituents with their mechanism of action.

Insight on the fractionations and structural characterizations of innovative antidiarrheal compounds screened from leaves of Psidium guajava of local origin in Pakistan.

Numerous ailments have been effectively treated with natural plants for long time all over the world. Plants provided a back bone for the exploration of novel medicinal compounds. Therefore, chief focus of our study was to isolate the biologically active compounds from the plant source and evaluate their antidiarrheal potentials, as diarrhea is still the most dominant disease in developing countries. The isolation and structure elucidation of two new compounds were identified from methanolic and chloroform extracts of Psidium guajava (guava) leaves. Extracts of plants were acquired by successive maceration from dried powder. Castor oil induced diarrheal-model was used to evaluate the antidiarrheal activity and therapeutic response was endorsed to the suppression of normal and wet stools in Spraug Dawley rats. Through the series of fractionations, compound-A was obtained from methanolic extract and named 3-(4-amino 1,3,8-tri-OH 5,6-di-CH3 7-propyl 1,2,3,4,4a,5,8,8a-octahydronaphthalen 2-yl) propanoic3-(4-NH3 7-butyl 1,3,8-tri-OH 5,6-di-CH3 1,2,3,4,4a,5,8,8a-octahydronaphthalen 2-yl)propanoic anhydride. Compound-B was entitled 5-(3-hydroxy-1,4-di-CH3-1,2,3,4,4a,5,8,8a-octahydronaphthalen-2-yl)pent-3-enoic acid was acquired from the chloroform extract. The structure elucidations of both compounds were interpreted through spectroscopic data, including EI-MS, FTIR, 1HNMR and 13C-NMR. The significant antidiarrheal activities were determined with crude extracts and isolated compounds. In inference, present study revealed that substantial antidiarrheal feature of guava is confined to the identified compounds.

Design, synthesis and evaluation of DNA nano-cubes as a core material protected by the alginate coating for oral administration of anti-diabetic drug.

Poor control towards glycemic levels among diabetic patients may lead to severe micro/macro-vascular and neuropathic complexities. Proper functioning of alpha-beta cells of pancreases is required to attain long term glycemic control among type 2 diabetics. The recent developments to manage diabetes are focused on controlling the insulin-glucagon secretions from the pancreases. DPP-4 inhibitors class of drugs after elevating GLP-1/GIP (incretins) levels in the blood, not only raise the insulin levels but also suppress the glucagon level. Vildagliptin (VI) is a potent DPP-4 inhibitor with least adverse events compared to other DPP-4 inhibitors. We encapsulated VI into 3D nanocube that gets bind to the DNA due to secondary amine in its chemical structure. DNA-nanocube being negatively charged was incubated with the PLL to attain positive surface. Ultimately VI loaded nanocubes were coated with the negatively charged Na-alginate via electrostatic attraction method to get stable spherical nanospheres for oral delivery of VI. Nanospheres were evaluated physically through native PAGE analysis, DSC, TGA, dissolution testing, XRD and FTIR. We attained uniformed and spherical nanospheres with stable topology, nanoscale size precision (40-150 nm in diameter), Entrapment efficiency (up to 90%), prolonged drug release (13 ± 4 h) at basic pH, and superior oral antidiabetic effects with improved GLP1 and glycemic levels. The formulated nanospheres attained size uniformity and better therapeutic outcomes in terms of reduced adverse events and better control of glycemic levels than previously reported methods with decreased dosage frequency tested in Db/Db mice.

DNA scaffold nanoparticles coated with HPMC/EC for oral delivery.

The control of the glycemic level among diabetes/T2 patients is very important for their long term survival and avoiding further complexities including micro/macrovascular diseases as well as diabetic neuropathy. Vildagliptin (VD) is a drug that has addressed these issues successfully with the desired safety portfolio. We used DNA-nanocubes for initial nano-encapsulation of VD followed by HPMC/EC coating. The results revealed the stable, smooth, spherical and nano-sized nanoparticles with improved size uniformity (from 100 to 400 nm in diameter) and encapsulation-efficiency (E.E.%) than previously reported (500-2000 nm) with the chemical compatibility evident in ATR/FTIR and DSC results. Animal experiments results revealed the improvement of incretin level in the serums due to potent DPP-4 inhibition compared to the free-VD/solution with better maintenance of glycemic levels after feeding. The safety of these HPMC/EC-DNA-VD nanoparticles was assessed through the histological-examination after completion of the treatment turn. The solvent evaporation technique provided the better coating of HPMC around DNA-core with gastro-resistant and effervescent property due to presence of NaHCO3 (0.01%) in the formulations that caused delayed delivery of VD as well as nanoparticles to the intestine, increasing the availability time of the drug and nanospheres at the target sites (intestine and blood) where DPP-4 enzyme is most abundant (to degrade the GLP-1 and GIP causing loss of control of the postprandial glycemic levels. So the availability of sustained release nanospheres near the target sites and prolonged DPP-4 inhibition improved the outcomes of the therapy.

Enhancement of solubility and dissolution profile of artesunate by employing solid dispersion approach: An in-vitro evaluation.

Current study was designed with an aim to improve the solubility and dissolution profile of artesunate by preparing solid dispersions through solvent evaporation and freeze-drying techniques using polyethylene glycol 4000 (PEG4000) as solubility enhancer. Developed formulations were characterized for FTIR, XRD, TGA and SEM. Maximum increase in solubility was attained by freeze-dried solid dispersions (FD F444) i.e. 2.99 folds and 2.66 folds by solvent evaporation solid dispersion (SE F44) as compare to pure drug. Amorphous nature of artesunate in solid dispersions was confirmed from XRD diffractographs. Surface morphology indicated the existence of rough surface in freeze- dried solid dispersions (FDDs) and smooth surface in solvent evaporation solid dispersions (SEDs). Rapid dissolution rates were exhibited by fast dissolving tablets of optimized formulations. Moreover, the release of the drug was dominated by the first order kinetics (R2 = 0.9932) with the Fickian type of diffusion mechanism (n<0.450).

Vildagliptin loaded triangular DNA nanospheres coated with eudragit for oral delivery and better glycemic control in type 2 diabetes mellitus.

Diabetes mellitus type 2 is a multidimensional disease associated with poor glycemic control through compromised sensitivity of pancreatic islet α and ß cells against glucose and dwindled secretion of insulin which is linked with the quantity of incretin hormones that are abridged by dipeptidyl peptidase-4 (DPP-4) in diseased condition. Vildagliptin (VG) inhibits DPP-4 therefore regulates the incretins that conversely maintains glycemic control. The safe reach and absorption of VG from intestine was dubious. Therefore we used Electrostatic Attraction Method to develop drug loaded DNA nanotechnology triangles coated by Eudragit (Eud) to make stable nanospheres of Vildagliptin (VG). We further analyzed the formulated nanospheres by AFM, XRD, DSC, SEM, TGA, ATR-FTIR and native PAGE. Additionally the efficacy of formulated nanospheres for drug release and glycemic control was assessed in Db/Db mouse. Our results showed that formulated nanospheres are smooth, spherical, stable and uniform in size ranging from 500 to 2000 nm with drug entrapment efficiency up to 95 ± 2% and extended drug release up to 15 ± 2 h. FTIR and DSC results confirmed the absence of VG-DNA-Eud interaction and XRD studies revealed a change in the crystalline status of the VG in nanospheres. Ex-vivo studies indicate that Eud-DNA-VG nanospheres effectively bypasses the acidic pH of the stomach and enhances glycemic control in Db/Db mouse without any risk of pancreatitis or pancreatic cancer. To the best of our knowledge, this is the first study conclusively reporting that VG loaded DNA Nano-architects coated with Eudragit are stable, safe and may improve therapeutic outcomes after oral delivery.

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.

Improved physicochemical characteristics of artemisinin using succinic acid.

Artemisinin (ARMN) is a potent antimalarial drug, which is effective against multidrug resistant strains of Plasmodium falciparum and produces rapid recovery even in patients with cerebral malaria. Being poorly soluble in water, artemisinin is incompletely absorbed after oral intake due to poor dissolution characteristics in the intestinal fluids. To enhance these properties, solid dispersions of artemisinin with succinic acid (SUC) were prepared using drug-carrier ratios 1 : 1, 1 : 4, 1 : 6, 1 : 8 and 1 : 10 by solvent evaporation and freeze drying methods. These solid dispersions were characterized by differential scanning calorimetery (DSC), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction patterns (XRD), phase solubility and dissolution kinetics evaluated by applying zero order, first order, Higuchi, and Korsmeyer-Peppas models. Physical mixtures produced significantly higher aqueous solubility and rate of dissolution as compared to artemisinin alone. The dissolution profiles of all formulations followed Higuchi model and exhibited diffusion-controlled release of drug. Solvent evaporation method (SLVPs) exhibited improved solubility and freeze dried solid dispersions (FDSDs) produced highest solubility but stability constant was opposite. ARMN and SUC both were found completely crystalline as shown by their XRD patterns. Physical mixtures (PMs) showed reduced intensity in their XRD patterns while solid dispersions by SLVPs exhibited twice reduced intensity and much displaced angles, whereas FDSDs showed synergistic effects in some of ARMN and SUC peaks. DSC thermograms of FDSDs at drug-carrier ratios 1 : 1-1 : 4 showed lower melting temperature and enthalpy change (deltaH) values than respective SLVPs, whereas at higher ratios, a reverse was true. SLVPs showed displaced methyl stretching bands at lower drug-carrier ratios and exhibited O-H stretching characteristic bands of SUC at higher drug-carrier ratios. In addition, carbonyl group and C-O stretching vibrations characteristic of SUC (1307 cm(-1)) appeared prominently compared to PMs, whereas C-O stretching characteristic bands of ARMN disappeared at higher ratios. FDSDs exhibited distinct nature of bonding compared to respective SLVPs and PMs.

Spectrophotometric method for the determination of Gemifloxacin mesylate in pure and tablet dosage form.

A spectrophotometric method for the determination of Gemifloxacin mesylate (GFX) is developed and validated according to ICH guidelines. GFX is a fluoroquinolone that is used in the treatment of pneumonia. The analysis of the pure drug was carried out at its λmax 270 nm. The method was linear from 0.5-5µg/mL, r(2) 0.999 and equation is 0.102-0.000. The % RSD for inter-day (0.969%) and intra-day (0.714%) assuring a good precision and accuracy was close to 100%. Limit of detection and Limit of quantification were 0.197 and 0.599µg/mL, respectively. The validation results and statistical data demonstrate that the method is accurate, sensitive, cost effective and reproducible and has an importance in quality assurance of GFX analysis. The developed method was proved suitable for analysis of GFX in the pure and tablet dosage forms without interference of excepients.

Malaria and artemisinin derivatives: an updated review.

Malaria is the world's most prevalent disease that affects 515-600 million people each year and about 40% of the world's population live at risk for this infection. The prevalence of morbidity and mortality from drug resistant malaria (Plasmodium falciparum) is increasing in most of the developing countries, which is also a global threat because international travel is common now and imported malaria is increasingly a serious problem. Since rapid schizonticidal action of naturally occurring endoperoxides pharmacophore present in artemisinin against drug-resistant malaria has been documented, researchers have focused more on artemisinin analogs than any other antimalarials. In this review, drugs of choice about malaria i.e. artemisinin and its analogus/derivatives (arteether, artemether, artemiside, artemisinin, artemisone, artesunate, dihydroartemisinin) have been discussed in detail e.g. bioavailability, formulation development, stability, combination therapy, additional benefits, drug resistance and toxicity have been reviewed.

Improved physicochemical characteristics of artemisinin-nicotinamide solid dispersions by solvent evaporation and freeze dried methods.

Artemisinin (ARMN) is a drug of choice against drug-resistant malaria especially due to Plasmodium falciparum. Being poorly soluble in water, its solid dispersions with nicotinamide (NA) were prepared at various drug-carrier ratios (1:1, 1:4, 1:6, 1:8, 1:10) by solvent evaporation and freeze drying methods. These solid dispersions were characterized by differential scanning calorimetery (DSC), fourier transform infrared spectroscopy (FTIR), X-ray diffraction patterns (XRD), phase solubility and dissolution studies. Artemisinin and nicotinamide both were found completely crystalline as shown by their XRD patterns. Physical mixtures (PMs) showed decreased intensity in their XRD patterns while solid dispersions by solvent evaporation method (SLVPs) exhibited displaced angles and decreased intensity whereas freeze dried solid dispersions (FDSDs) showed least number of peaks having low intensity and maximum displaced angles. DSC thermograms of drug-carrier ratios at 1:1-1:4 showed lower melting temperature than artemisinin and nicotinamide in all preparations. Endothermic temperature of artemisinin in PMs and SLVPs increased with rise of nicotinamide content upto 1:6 ratio followed by decline. All samples showed crystallization temperature below the artemisinin except drug-carrier ratio 1:6 of PMs while δH value was minimum at this ratio. FDSDs produced lowest endothermic temperature than corresponding PMs and SLVPs. SLVPs exhibited band shifting in both functional and fingerprint region compared to respective PMs as exhibited by their FTIR spectra. FDSDs and SLVPs showed different nature of bonding among artemisinin and nicotinamide. FDSDs produced strongest CONH(2) bonding followed by SLVPs and PMs respectively. PMs produced significantly higher aqueous solubility and rate of dissolution as compared to artemisinin alone. SLVPs exhibited improved solubility and dissolution profile corresponding to PMs. FDSDs showed highest release rate and aqueous solubility followed by SLVPs and PMs at all ratios. PMs and SLVPs showed their highest dissolution profile at 1:6 drug-carrier ratio followed by gradual decrease while FDSDs progressed in dissolution rate with increase of nicotinamide content successively upto maximum at 1:10 ratio.