Displaying publications 81 - 100 of 144 in total

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  1. Development and anti-microbial potential of topical formulations containing Cocos nucifera Linn
    Sheshala R, Ying LT, Hui LS, Barua A, Dua K
    Antiinflamm Antiallergy Agents Med Chem, 2013;12(3):253-64.
    PMID: 23746224
    In order to achieve better treatment for local wounds and bacterial infections, topical formulations containing Cocos nucifera Linn. were developed. These formulations were evaluated for their physicochemical properties and antimicrobial efficacy against various strains of microorganisms. Semisolid formulations containing 5% w/w of Cocos nucifera Linn. were prepared by employing different dermatological bases and were evaluated for their physical appearance, pH, rheological properties, FTIR-spectroscopic analysis, thermodynamic stability and stability studies. The antimicrobial activity of each prepared formulation was determined using disk-diffusion method against various strains of microorganisms. All the prepared formulations were found to be stable and exhibited suitable physicochemical characteristics including pH, viscosity and spreadability which are necessary for an ideal topical preparation, in addition to strong antimicrobial activity. Carbopol gel base was found to be the most suitable dermatological base for Cocos nucifera Linn. in comparsion to other bases. Cocos nucifera Linn. formulations showed great potential for wounds and local bacterial infections. Moreover, carbopol gel base with its aesthetic appeal was found to be a suitable dermatological base for Cocos nucifera Linn. semisolid formulation as it had demonstrated significant physicochemical properties and greater diffusion when assessed using disk- diffusion method.
    Matched MeSH terms: Drug Stability
  2. Oral fast-release solid dispersion-paradigm shift to nanoparticles
    Wong TW
    Recent Pat Drug Deliv Formul, 2011 Sep;5(3):227-43.
    PMID: 21834774
    Design of oral fast-release solid dispersion of poorly water-soluble drugs has been a great challenge over past decades on issues of drug recrystallization, drug polymorphism, formulation limited to low drug-to-carrier ratio and drug particle aggregation in matrix. The complexity in solid dispersion design is envisaged to be resolvable by the use of nanoparticulate system as solid dosage form. This manuscript reviews several patented processing approaches of nanoparticulate solid dispersion that have been reported recently. Through drug nanoencapsulation, a higher content of drug may be delivered with less aggregation via placing the same drug mass in a greater number of tinier carriers. Nanoencapsulation, by its own process of formation, brings about submicron particles. Keeping drug in these nanoparticles, a remarkable rise in specific surface area of drug is realized for dissolution. The augmentation of drug dissolution can be sufficiently high to the extent that the influences of polymorphism and crystallization phenomenon on drug dissolution in a solid dispersion may be negligible.
    Matched MeSH terms: Drug Stability
  3. Method development and validation of repaglinide in human plasma by HPLC and its application in pharmacokinetic studies
    Ruzilawati AB, Wahab MS, Imran A, Ismail Z, Gan SH
    J Pharm Biomed Anal, 2007 Apr 11;43(5):1831-5.
    PMID: 17240100
    In this study, the development and validation of a high-performance liquid chromatography (HPLC) assay for determination of repaglinide concentration in human plasma for pharmacokinetic studies is described. Plasma samples containing repaglinide and an internal standard, indomethacin were extracted with ethylacetate at pH 7.4. The recovery of repaglinide was 92%+/-55.31. Chromatographic separations were performed on Purospher STAR C-18 analytical column (4.8 mm x 150 mm; 5 microm particle size). The mobile phase composed of acetonitrile-ammonium formate (pH 2.7; 0.01 M) (60:40, v/v). The flow rate was 1 ml/min. The retention time for repaglinide and indomethacin were approximately 6.2 and 5.3 min, respectively. Calibration curves of repaglinide were linear in the concentration range of 20-200 ng/ml in plasma. The limits of detection and quantification were 10 ng/ml and 20 ng/ml, respectively. The inter-day precision was from 5.21 to 11.84% and the intra-day precision ranged from 3.90 to 6.67%. The inter-day accuracy ranged 89.95 to 105.75% and intra-day accuracy ranged from 92.37 to 104.66%. This method was applied to determine repaglinide concentration in human plasma samples for a pharmacokinetic study.
    Matched MeSH terms: Drug Stability
  4. Fulltext Effect of compositions in nanostructured lipid carriers (NLC) on skin hydration and occlusion
    Loo Ch, Basri M, Ismail R, Lau H, Tejo B, Kanthimathi M, et al.
    Int J Nanomedicine, 2013;8:13-22.
    PMID: 23293516 DOI: 10.2147/IJN.S35648
    To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC), skin hydration, and transepidermal water loss.
    Matched MeSH terms: Drug Stability
  5. Aging and microwave effects on alginate/chitosan matrices
    Wong TW, Chan LW, Kho SB, Heng PW
    J Control Release, 2005 Jun 2;104(3):461-75.
    PMID: 15911046
    The influence of microwave irradiation on the drug release properties of freshly prepared and aged alginate, alginate-chitosan and chitosan beads was investigated. The beads were prepared by extrusion method with sulphathiazole as a model drug. The dried beads were subjected to microwave irradiation at 80 W for 10 min, 20 min or three consecutive cycles of 10 and 20 min, respectively. The profiles of drug dissolution, drug content, drug stability, drug polymorphism, drug-polymer interaction, polymer crosslinkage and complexation were determined by dissolution testing, drug content assay, differential scanning calorimetry and Fourier transform infra-red spectroscopy. The chemical stability of drug embedded in beads was unaffected by microwave conditions and length of storage time. The release property of drug was mainly governed by the extent of polymer interaction in beads. The aged alginate beads required intermittent cycles of microwave irradiation to induce drug release retarding effect in contrast to their freshly prepared samples. Unlike the alginate beads, the level of polymer interaction was higher in aged alginate-chitosan beads than the corresponding fresh beads. The drug release retarding property of aged alginate-chitosan beads could be significantly enhanced through subjecting the beads to microwave irradiation for 10 min. No further change in drug release from these beads was observed beyond 30 min of microwave irradiation. Unlike beads containing alginate, the rate and extent of drug released from the aged chitosan beads were higher upon treatment by microwave in spite of the higher degree of polymer interaction shown by the latter on prolonged storage. The observation suggested that the response of polymer matrix to microwave irradiation in induction of drug release retarding property was largely affected by the molecular arrangement of the polymer chains.
    Matched MeSH terms: Drug Stability
  6. Blood-brain barrier permeable anticholinesterase aurones: synthesis, structure-activity relationship, and drug-like properties
    Liew KF, Chan KL, Lee CY
    Eur J Med Chem, 2015 Apr 13;94:195-210.
    PMID: 25768702 DOI: 10.1016/j.ejmech.2015.02.055
    A series of novel aurones bearing amine and carbamate functionalities at various positions (rings A and/or B) of the scaffold was synthesized and evaluated for their acetylcholinesterase and butyrylcholinesterase inhibitory activities. Structure-activity relationship study disclosed several potent submicromolar acetylcholinesterase inhibitors (AChEIs) particularly aurones bearing piperidine and pyrrolidine moieties at ring A or ring B. Bulky groups particularly methoxyls, and carbamate to a lesser extent, at either rings were also prominently featured in these AChEI aurones as exemplified by the trimethoxyaurone 4-3. The active aurones exhibited a lower butyrylcholinesterase inhibition. A 3'-chloroaurone 6-3 originally designed to improve the metabolic stability of the scaffold was the most potent of the series. Molecular docking simulations showed these AChEI aurones to adopt favourable binding modes within the active site gorge of the Torpedo californica AChE (TcAChE) including an unusual chlorine-π interaction by the chlorine of 6-3 to establish additional bondings to hydrophobic residues of TcAChE. Evaluation of the potent aurones for their blood-brain barrier (BBB) permeability and metabolic stability using PAMPA-BBB assay and in vitro rat liver microsomes (RLM) identified 4-3 as an aurone with an optimal combination of high passive BBB permeability and moderate CYP450 metabolic stability. LC-MS identification of a mono-hydroxylated metabolite found in the RLM incubation of 4-3 provided an impetus for further improvement of the compound. Thus, 4-3, discovered within this present series is a promising, drug-like lead for the development of the aurones as potential multipotent agents for Alzheimer's disease.
    Matched MeSH terms: Drug Stability
  7. The wound healing properties of Channa striatus-cetrimide cream-- tensile strength measurement
    Baie SH, Sheikh KA
    J Ethnopharmacol, 2000 Jul;71(1-2):93-100.
    PMID: 10904151
    Channa striatus, a fresh water snakehead fish, is reported to enhance dermal wound healing. Biochemical components such as amino acids and fatty acids are important for the synthesis of collagen fibers during wound healing. Arachidonic acid, a precursor of prostaglandin plays a vital role in healing the wounds. Haruan (C. striatus) contains all the essential amino acids for wound healing particularly glycine as well as high contents of arachidonic acid and polyunsaturated fatty acids that can promote prostaglandin synthesis. In the present work we have studied the wound healing effect of C. striatus in Sprague-Dawley rats. Cream formulations having different haruan fish extract concentrations as the active ingredient were prepared and stabilized, and they were applied to the wounds. The healing of wounds was characterized by an increase in the tensile strength of the skin, determined on the 7th post-operative day in each case. Haruan treatment of wounds promotes remodeling of collagen, by the synthesis of inter- and intra-molecular protein crosslinking and thus produces a marked increase (P<0.05) in tensile strength as compared to the cetrimide treated group. On the basis of our experiment we conclude that C. striatus helps in wound healing as indicated by the increase in tensile strength. We hypothesise that this effect may be due to its high content of arachidonic acid, glycine and polyunsaturated fatty acids. The mechanism of wound healing will be investigated in future studies.
    Matched MeSH terms: Drug Stability
  8. Immobilization of aminoacylase by encapsulation in poly-L-lysine-stabilized calcium alginate beads
    Lee KH, Lee PM, Siaw YS
    J Chem Technol Biotechnol, 1993;57(1):27-32.
    PMID: 7763683
    Aminoacylase I (EC 3.5.1.14) encapsulated in calcium alginate beads stabilized with poly-L-lysine was used for the production of L-phenylalanine by the hydrolysis of a racemic mixture of N-acetyl-DL-phenylalanine. The immobilized aminoacylase was studied with respect to operational stability, thermal stability, effects of pH and temperature and kinetic constants. The leakage of enzyme from the stabilized beads was eliminated. The immobilized enzyme retained high biological activity. The Km and Vmax values for the stabilized beads were 11.11 mmol dm-3 and 0.076 mumol min-1 respectively. The optimum pH and temperature for the hydrolysis were 6.5 and 55 degrees C respectively. Scanning electron micrographs revealed crosslinked structures on the surface of the beads. The operational performances of the beads in a batch reaction and a packed-bed bioreactor for continuous reaction were investigated. With batch reaction, only about 5% of enzyme activity was lost within ten reaction cycles and there was no significant loss of activity over 600 h of continuous operation after equilibrium was reached, and a conversion yield of about 80% was obtained.
    Matched MeSH terms: Drug Stability
  9. Fulltext Pharmacokinetics and Biodistribution of Thymoquinone-loaded Nanostructured Lipid Carrier After Oral and Intravenous Administration into Rats
    Zakarial Ansar FH, Latifah SY, Wan Kamal WHB, Khong KC, Ng Y, Foong JN, et al.
    Int J Nanomedicine, 2020;15:7703-7717.
    PMID: 33116496 DOI: 10.2147/IJN.S262395
    Background: Thymoquinone (TQ), an active compound isolated from Nigella sativa, has been proven to exhibit various biological properties such as antioxidant. Although oral delivery of TQ is valuable, it is limited by poor oral bioavailability and low solubility. Recently, TQ-loaded nanostructured lipid carrier (TQ-NLC) was formulated with the aim of overcoming the limitations. TQ-NLC was successfully synthesized by the high-pressure homogenization method with remarkable physiochemical properties whereby the particle size is less than 100 nm, improved encapsulation efficiency and is stable up to 24 months of storage. Nevertheless, the pharmacokinetics and biodistribution of TQ-NLC have not been studied. This study determined the bioavailability of oral and intravenous administration of thymoquinone-loaded nanostructured lipid carrier (TQ-NLC) in rats and its distribution to organs.

    Materials and Methods: TQ-NLC was radiolabeled with technetium-99m before the administration to the rats. The biodistribution and pharmacokinetics parameters were then evaluated at various time points. The rats were imaged at time intervals and the percentage of the injected dose/gram (%ID/g) in blood and each organ was analyzed.

    Results: Oral administration of TQ-NLC exhibited greater relative bioavailability compared to intravenous administration. It is postulated that the movement of TQ-NLC through the intestinal lymphatic system bypasses the first metabolism and therefore enhances the relative bioavailability. However, oral administration has a slower absorption rate compared to intravenous administration where the AUC0-∞ was 4.539 times lower than the latter.

    Conclusion: TQ-NLC had better absorption when administered intravenously compared to oral administration. However, oral administration showed greater bioavailability compared to the intravenous route. This study provides the pharmacokinetics and biodistribution profile of TQ-NLC in vivo which is useful to assist researchers in clinical use.

    Matched MeSH terms: Drug Stability
  10. Solvent-free lipase-catalyzed synthesis of a novel hydroxyl-fatty acid derivative of kojic acid
    El-Boulifi N, Ashari SE, Serrano M, Aracil J, Martínez M
    Enzyme Microb Technol, 2014 Feb 5;55:128-32.
    PMID: 24411455 DOI: 10.1016/j.enzmictec.2013.10.009
    The aim of this work was the synthesis of a novel hydroxyl-fatty acid derivative of kojic acid rich in kojic acid monoricinoleate (KMR) which can be widely used in the cosmetic and food industry. The synthesis of KMR was carried out by lipase-catalysed esterification of ricinoleic and kojic acids in solvent-free system. Three immobilized lipases were tested and the best KMR yields were attained with Lipozyme TL IM and Novozym 435. Since Lipozyme TL IM is the cheapest, it was selected to optimize the reaction conditions. The optimal reaction conditions were 80 °C for the temperature, 1:1 for the alcohol/acid molar ratio, 600 rpm for stirring speed and 7.8% for the catalyst concentration. Under these conditions, the reaction was scaled up in a 5×10⁻³ m³ stirred tank reactor. ¹H-¹³C HMBC-NMR showed that the primary hydroxyl group of kojic acid was regioselectively esterified. The KMR has more lipophilicity than kojic acid and showed antioxidant activity that improves the oxidation stability of biodiesel.
    Matched MeSH terms: Drug Stability
  11. Significance of lipid matrix aging on in vitro release and in vivo bioavailability
    Choy YW, Khan N, Yuen KH
    Int J Pharm, 2005 Aug 11;299(1-2):55-64.
    PMID: 15955645
    A polyglycolised glyceride carrier, Gelucire 50/13, was incorporated with paracetamol as a model drug, filled into hard gelatin capsules and stored at three different temperatures for various lengths of time. The resultant solidified matrix within the capsule was subjected to thermal analysis using differential scanning calorimetry (DSC) to ascertain its supramolecular structure. Polymorphic transformations towards more stable gelucire forms were observed upon aging the matrices, with samples stored at a temperature near the melting range of the lower temperature gelucire melting fraction showing the most profound changes. The increase in the rate of drug release from aged samples could be correlated to the alterations to the supramolecular structure of the gelucire. Accelerated drug release from aged samples could also be seen from in vivo studies using healthy human volunteers, although the extent of absorption was not affected. Therefore, even though the sustainability of release may be compromised by aging the gelucire matrices, the bioavailability of the incorporated drug is unlikely to be affected.
    Matched MeSH terms: Drug Stability
  12. Correlating gastric emptying of amphotericin B and paracetamol solid lipid nanoparticles with changes in particle surface chemistry
    Amekyeh H, Billa N, Roberts C
    Int J Pharm, 2017 Jan 30;517(1-2):42-49.
    PMID: 27923696 DOI: 10.1016/j.ijpharm.2016.12.001
    Oral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery.
    Matched MeSH terms: Drug Stability
  13. Cross-linked chitosan/sepiolite composite for the adsorption of methylene blue and reactive orange 16
    Marrakchi F, Khanday WA, Asif M, Hameed BH
    Int J Biol Macromol, 2016 Dec;93(Pt A):1231-1239.
    PMID: 27663552 DOI: 10.1016/j.ijbiomac.2016.09.069
    Cross-linked chitosan/sepiolite composite was prepared from sepiolite clay and chitosan, and was cross-linked using epichlorohydrin. Among the various weight ratio percentage of chitosan and sepiolite clay composites, CS50SP50 was selected as the best adsorbent for both methylene blue (MB) and reactive orange 16 (RO 16). At an optimum adsorbent dosage of 0.2g/100mL, the effects of initial dye concentration (25-400mg/L) and pH (3-11) on MB and RO 16 adsorption onto CS50SP50 composite were studied. Monolayer adsorption capacities of CS50SP50 composite for MB and RO 16 were 40.986mg/g and 190.965mg/g, respectively at 30°C. Freundlich, Langmuir and Temkin isotherms applied on the adsorption data for both the dyes reveal that data fitted best for Freundlich model. For both the dyes pseudo-second-order kinetics were found to describe the adsorption process better than pseudo-first-order kinetics. The adsorption capacity of CS50SP50 composite for both the dyes was found better compared to previous studies thus making it potentially low-cost adsorbent for removal of both cationic and reactive dyes.
    Matched MeSH terms: Drug Stability
  14. Pharmacokinetic and anti-colon cancer properties of curcumin-containing chitosan-pectinate composite nanoparticles
    Alkhader E, Roberts CJ, Rosli R, Yuen KH, Seow EK, Lee YZ, et al.
    J Biomater Sci Polym Ed, 2018 12;29(18):2281-2298.
    PMID: 30376409 DOI: 10.1080/09205063.2018.1541500
    Curcumin, the active ingredient of the rhizome curcuma longa has been extensively studied as an anticancer agent for various types of tumours. However, its efficacy as an anticancer agent is restricted due to poor absorption from the gastrointestinal tract, rapid metabolism and degradation in acidic medium. In the present study, we encapsulated curcumin in chitosan-pectinate nanoparticulate system (CUR-CS-PEC-NPs) for deployment of curcumin to the colon, whereby curcumin is protected against degradative effects in the upper digestive tract, and hence, maintaining its anticancer properties until colon arrival. The CUR-CS-PEC-NPs was taken up by HT-29 colorectal cancer cells which ultimately resulted in a significant reduction in cancer cell propagation. The anti-proliferative effect of the encapsulated curcumin was similar to that of free curcumin at equivalent doses which confirms that the encapsulation process did not impede the anticancer activity of curcumin. The oral bioavailability (Cmax, and AUC) of curcumin in CUR-CS-PEC-NPs was enhanced significantly by 4-folds after 6 hours of treatment compared to free curcumin. Furthermore, the clearance of curcumin from the CUR-CS-PEC-NPs was lower compared to free curcumin. These findings point to the potential application of the CUR-CS-PEC-NPs in the oral delivery of curcumin in the treatment of colon cancer.
    Matched MeSH terms: Drug Stability
  15. Effects of formulation development methods on the stability of model protein pharmaceuticals embedded in solid lipid matrices
    Tabbassum M, Zeeshan F
    Pharm Dev Technol, 2019 Jun;24(5):649-662.
    PMID: 30474456 DOI: 10.1080/10837450.2018.1551902
    This study was conducted to investigate the influence of formulation development methods on the stability (secondary structure, aggregation, and biological activity) of protein drugs embedded in lipid matrices. Catalase, horseradish peroxidase, and α-chymotrypsin were employed as model proteins, while Precirol® AT05 (glyceryl palmitostearate) was used as lipid matrix. Protein-loaded lipid matrices were prepared using melting and mixing and wet granulation methods. Attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, size exclusion chromatography (SEC) and biological activity analyses were performed. ATR FT-IR analysis indicated significant interference of the lipid with the protein amide-I band, which was eliminated using spectral subtraction. Wet granulation method induced more changes in protein secondary structure compared to melting and mixing method. SEC analysis gave evidence of protein aggregation for catalase upon adopting the wet granulation method. The biological activity of catalase was found to reduce significantly than other two proteins upon using wet granulation method, which might be ascribed to both secondary structure alterations and the formation of aggregates. Horseradish peroxidase and α-chymotrypsin did not form any soluble aggregates. In conclusion, melting and mixing method emerged as a better incorporation method compared to wet granulation because of better stability shown by the formulated proteins.
    Matched MeSH terms: Drug Stability
  16. Biocompatible disulphide cross-linked sodium alginate derivative nanoparticles for oral colon-targeted drug delivery
    Ayub AD, Chiu HI, Mat Yusuf SNA, Abd Kadir E, Ngalim SH, Lim V
    Artif Cells Nanomed Biotechnol, 2019 Dec;47(1):353-369.
    PMID: 30691309 DOI: 10.1080/21691401.2018.1557672
    The application of layer-by-layer (LbL) approach on nanoparticle surface coating improves the colon-specific drug delivery of insoluble drugs. Here, we aimed to formulate a self-assembled cysteamine-based disulphide cross-linked sodium alginate with LbL self-assembly to improve the delivery of paclitaxel (PCX) to colonic cancer cells. Cysteamine was conjugated to the backbone of oxidized SA to form a core of self-assembled disulphide cross-linked nanospheres. P3DL was selected for PCX loading and fabricated LbL with poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSCMA) resulting from characterization and drug release studies. P3DL-fabricated PCX-loaded nanospheres (P3DL/PAH/PSSCMA) exhibited an encapsulation efficiency of 77.1% with cumulative drug release of 45.1%. Dynamic light scattering analysis was reported at 173.6 ± 2.5 nm with polydispersity index of 0.394 ± 0.105 (zeta potential= -58.5 mV). P3DL/PAH/PSSCMA demonstrated a pH-dependent swelling transition; from pH 1 to 7 (102.2% increase). The size increased by 33.0% in reduction response study after incubating with 10 mM glutathione (day 7). HT-29 cells showed high viabilities (86.7%) after treatment with the fabricated nanospheres at 0.8 µg/mL. Cellular internalization was successful with more than 70.0% nanospheres detected in HT-29 cells. Therefore, this fabricated nanospheres may be considered as potential nanocarriers for colon cancer-targeted chemotherapeutic drug delivery.
    Matched MeSH terms: Drug Stability
  17. A stable hydrocortisone nanosuspension for improved dissolution: Preparation, characterization and in vitro evaluation
    Ali HS, Khan S, York P, Shah SM, Khan J, Hussain Z, et al.
    Pak J Pharm Sci, 2017 Sep;30(5):1635-1643.
    PMID: 29084684
    Drug nanosuspensions have gained tremendous attraction as a platform in drug delivery. In the present work, a nanosuspension was prepared by a wet milling approach in order to increase saturation solubility and dissolution of the water insoluble drug, hydrocortisone. Size of the generated particeles was 290 nm ± 9 nm having a zeta potential of -1.9 mV ± 0.6 mV. Nanosized particles were found to have a rod shape with a narrow particle size distribution (PDI =0.17). Results of differential scanning calorimetry and X-ray diffraction analyses revealed minor modifications of crystallinity of hydrocortisone following the milling process. Solubility of hydrocortisone was enhanced by nanonization to 875µg/ml ±2.5, an almost 2.9-fold compared to the raw hydrocortisone. Moreover, the nanosuspension formulation substabtially enhanced the dissolution rate of hydrocortisone where >97% of the hydrocortisone was dissolved within 10 minutes opposed to 22.3% for the raw 50% for the raw hydrocortisone and the commercial tablet, respectively. The bioavailability study resulted in AUC 0-9h for HC nanosuspensions (31.50±2.50), which is significantly (p<0.05) higher compared to the AUC 0-9h (14.85±3.25) resulted for HC solution. The nanosuspension was physically stable at room temperature for 24 months.
    Matched MeSH terms: Drug Stability
  18. Challenges in pediatric drug use: A pharmacist point of view
    Balan S, Hassali MA, Mak VSL
    Res Social Adm Pharm, 2017 May-Jun;13(3):653-655.
    PMID: 27493130 DOI: 10.1016/j.sapharm.2016.06.014
    The pediatric population is an enormously diverse segment of population varying both in size and age. The diversity caused pharmacists face various challenges primarily related to procuring, provision as well as use of drugs in this group of patients. Pediatric dose calculation is particularly a concern for pharmacists. Another challenge faced by pharmacists is unavailability of suitable formulations for pediatric use. This has also led many pharmacists to prepare extemporaneous liquid preparations, even though stability data on such preparations are scarce. Some extemporaneous preparations contain excipients which are potentially harmful in children. Besides that, inadequate labeling and drug information for pediatric drug use had not only challenged pharmacists in recommending and optimizing drug use in children, but also inadvertently caused many drugs used outside the approved terms of the product license (off-label use). Pharmacists are striving to stay connected to overcome the common and comparable challenges faced in their day to day duties and strive to maximize the safe and effective use of medicines for children.
    Matched MeSH terms: Drug Stability
  19. Stereoselective method development and validation for determination of concentrations of amphetamine-type stimulants and metabolites in human urine using a simultaneous extraction-chiral derivatization approach
    Wan Raihana WA, Gan SH, Tan SC
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Jan 1;879(1):8-16.
    PMID: 21147046 DOI: 10.1016/j.jchromb.2010.10.037
    Amphetamine-type stimulants (ATS) are a group of chiral amine drugs which are commonly abused for their sympathomimetic and stimulant properties. ATS are extensively metabolised by hepatic cytochrome P450 enzymes. As metabolism of ATS has been shown to be highly stereospecific, stereoselective analytical methods are essential for the quantitative determination of ATS concentrations for both in vivo and in vitro studies of ATS metabolism. This paper describes a new stereoselective method for the simultaneous determination of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), 4-hydroxy-3-methoxyamphetamine (HMA), 3,4-hydroxymethamphetamine (HHMA) and 3,4-hydroxyamphetamine (HHA) in human urine samples validated according to the United States Food and Drug Administration guidelines. In this method, analytes are simultaneously extracted and derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-MTPCl) as the chiral derivatization reagent. Following this, the analytes were subjected to a second derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) which targets the hydroxyl groups present in HMMA, HMA, HHMA and HHA. The derivatized analytes were separated and quantified using gas chromatography-mass spectrometry (GC-MS). The method was evaluated according to the established guidelines for specificity, linearity, precision, accuracy, recovery and stability using a five-day protocol. Intra-day precision ranged from 0.89 to 11.23% RSD whereas inter-day precision was between 1.03 and 12.95% RSD. Accuracy values for the analytes ranged from -5.29% to 13.75%. Limits of quantitation were 10 μg/L for AM, MA, MDMA, HMA and HMMA and 2μg/L for MDA, HMA and HHA. Recoveries and stability values were also within accepted values. The method was applied to authentic ATS-positive samples.
    Matched MeSH terms: Drug Stability
  20. Validation of high performance liquid chromatography-electrochemical detection methods with simultaneous extraction procedure for the determination of artesunate, dihydroartemisinin, amodiaquine and desethylamodiaquine in human plasma for application in clinical pharmacological studies of artesunate-amodiaquine drug combination
    Lai CS, Nair NK, Muniandy A, Mansor SM, Olliaro PL, Navaratnam V
    J Chromatogr B Analyt Technol Biomed Life Sci, 2009 Feb 15;877(5-6):558-62.
    PMID: 19147417 DOI: 10.1016/j.jchromb.2008.12.037
    With the expanded use of the combination of artesunate (AS) and amodiaquine (AQ) for the treatment of falciparum malaria and the abundance of products on the market, comes the need for rapid and reliable bioanalytical methods for the determination of the parent compounds and their metabolites. While the existing methods were developed for the determination of either AS or AQ in biological fluids, the current validated method allows simultaneous extraction and determination of AS and AQ in human plasma. Extraction is carried out on Supelclean LC-18 extraction cartridges where AS, its metabolite dihydroartemisinin (DHA) and the internal standard artemisinin (QHS) are separated from AQ, its metabolite desethylamodiaquine (DeAQ) and the internal standard, an isobutyl analogue of desethylamodiaquine (IB-DeAQ). AS, DHA and QHS are then analysed using Hypersil C4 column with acetonitrile-acetic acid (0.05M adjusted to pH 5.2 with 1.00M NaOH) (42:58, v/v) as mobile phase at flow rate 1.50ml/min. The analytes are detected with an electrochemical detector operating in the reductive mode. Chromatography of AQ, DeAQ and IB-DeAQ is carried out on an Inertsil C4 column with acetonitrile-KH(2)PO(4) (pH 4.0, 0.05M) (11:89, v/v) as mobile phase at flow rate 1.00ml/min. The analytes are detected by an electrochemical detector operating in the oxidative mode. The recoveries of AS, DHA, AQ and DeAQ vary between 79.1% and 104.0% over the concentration range of 50-1400ng/ml plasma. The accuracies of the determination of all the analytes are 96.8-103.9%, while the variation for within-day and day-to-day analysis are <15%. The lower limit of quantification for all the analytes is 20ng/ml and limit of detection is 8ng/ml. The method is sensitive, selective, accurate, reproducible and suited particularly for pharmacokinetic study of AS-AQ drug combination and can also be used to compare the bioavailability of different formulations, including a fixed-dose AS-AQ co-formulation.
    Matched MeSH terms: Drug Stability
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