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Liquisolid technique as a tool for enhancement of poorly water-soluble drugs and evaluation of their physicochemical properties

Liquisolid technique as a tool for enhancement of poorly water-soluble drugs and evaluation of their physicochemical properties

The potential of liquisolid systems to improve the dissolution properties of a water-insoluble agent (indomethacin) was investigated. In this study, different formulations of liquisolid tablets using different co-solvents (non-volatile solvents) were prepared and the effect of aging on the dissolution behaviour of indomethacin liquisolid compacts was investigated. To evaluate any interaction between indomethacin and the other components in liquisolid formulations, X-ray powder diffraction (XPD) and differential scanning calorimetry (DSC) were used. Dissolution test was carried out at two different pH, 1.2 and 7.2, to simulate the stomach or intestine fluid, respectively. The results showed that liquisolid formulations exhibited significantly higher drug dissolution rates at pH 1.2 and 7.2 compared to compacts prepared by the direct compression technique. The enhanced rate of indomethacin dissolution from liquisolid tablets was probably due to an increase in wetting properties and surface area of drug particles available for dissolution. In order to investigate the effect of aging on the hardness and dissolution rate of liquisolid compacts, the formulations were stored at 25 °C/75% relative humidity for a period of 12 months. The results showed that aging had no significant effect on dissolution profiles of liquisolid tablets. Liquisolid compacts containing propylene glycol as vehicle produced higher dissolution rates in comparison with liquisolid compacts containing PEG 400 or Tween 80 of the same concentration. The DSC and XPD results showed no changes in crystallinity of the drug and interaction between indomethacin and excipients (Avicel and silica) during the process.

Open access
Modulation of brain glutamate dehydrogenase as a tool for controlling seizures

Abstract

Glutamate (Glu) is a major excitatory neurotransmitter involved in epilepsy. Glu is synthesized by glutamate dehydrogenase (GDH, E.C. 1.4.1.3) and dysfunction of the enzymatic activity of GDH is associated with brain pathologies. The main goal of this work is to establish the role of GDH in the effects of antiepileptic drugs (AEDs) such as valproate (VALP), diazepam (DIAZ) and diphenylhydantoin (DPH) and its repercussions on oxygen consumption. Oxidative deamination of Glu and reductive amination of aketoglutarate (αK) in mice brain were investigated. Our results show that AEDs decrease GDH activity and oxygen consumption in vitro. In ex vivo experiments, AEDs increased GDH activity but decreased oxygen consumption during Glu oxidative deamination. VALP and DPH reversed the increase in reductive amination of αK caused by the chemoconvulsant pentylenetetrazol. These results suggest that AEDs act by modulating brain GDH activity, which in turn decreased oxygen consumption. GDH represents an important regulation point of neuronal excitability, and modulation of its activity represents a potential target for metabolic treatment of epilepsy and for the development of new AEDs.

Open access
Elicitation – a tool to improve secondary metabolites production in Melissa Officinalis L. Suspension cultures / Elicitácia ako nástroj na zlepšenie produkcie sekundárnych metabolitov v suspenzných kultúrach Melissa Officinalis L.

Abstract

Our recent study is focussed on the investigation of the influence of biotic (Botrytis cinerea, methyl jasmonate) and abiotic (cadmium and cobalt chloride) elicitors on Melissa officinalis L. (lemon balm) suspension cultures production properties. The plant material was treated with different concentrations of methyl jasmonate (10 and 100 μmol.l−1), with a phytopathogenic fungus hydrolyzate (Botrytis cinerea, 1 and 2 ml with glucose equivalent 24 μg.ml−1), cadmium and cobalt (II) chloride (both at concentrations 100 μmol.l−1 and 1 μmol.l−1). Elicited suspension cultures were harvested after 24, 48 and 72 h of elicitor treatment. The elicitation effect was evaluated based on hydroxycinnamic acid derivatives content expressed as rosmarinic acid in dose- and time-dependent manners. The Botrytis cinerea hydrolyzate exhibited the best effect on Melissa officinalis L. suspension cultures production properties among biotic elicitors (glucose equivalent 24 mg.ml−1, 1 ml, after 72 h of treatment). The hydroxycinnamic acid derivatives content increased in triplicate compared to non-elicited samples. Methyl jasmonate affected the suspension cultures production properties moderately at concentration 10 μmol.l−1. Chlorides salts of cobalt and cadmium stimulated phenolic compounds production effectively at concentrations 100 μmol.l−1. The presence of cobalt and cadmium ions in suspension cultures growth media increased the hydroxycinnamic acid derivatives content twofold and quadruple, respectively.

Open access
Simultaneous quantitative analysis of olmesartan, amlodipine and hydrochlorothiazide in their combined dosage form utilizing classical and alternating least squares based chemometric methods

experimental study, Chemometr. Intell. Lab. Syst . 56 (2001) 73–81; DOI: 10.1016/S0169-7439(01)00110-1. 26. J. Jaumot, R. Gargallo, A. de Juan and R. Tauler, A graphical user-friendly interface for MCR-ALS: a new tool for multivariate curve resolution in MATLAB, Chemometr. Intell. Lab. Syst . 76 (2005) 101–110; DOI: 10.1016/j.chemolab.2004.12.007. 27. A. C. Olivieri, H. C. Goicoechea and F. A. Iñón, MVC1: an integrated MatLab toolbox for first-order multivariate calibration, Chemometr. Intell. Lab. Syst . 73 (2004) 189–197; DOI: 10.1016/j.chemolab.2004

Open access
Transdermal patches: Design and current approaches to painless drug delivery

delivery system, Int. J. Pharm. Pharm. Sci . 3 (2011) 26–34. 25. S. Rani, K. Saroha, N. Syan and P. Mathur, Transdermal patches a successful tool in transdermal drug delivery system: An overview, Der Pharm. Sinica 2 (2011) 17–29. 26. B. Berner and V. A. John, Pharmacokinetic characterization of transdermal delivery system, J. Clin. Pharmacol . 26 (1994) 121–134. 27. S. Mutalik and N. Udupa, Pharmacological evaluation of membrane-moderated transdermal system of glipizide, Clin. Exp. Pharmacol. Physiol . 33 (2006) 17-26. 28. C. L. Stevenson, J. T. Jr

Open access
Development and validation of novel self-report questionnaire about the assessment of adolescents’ relation to medicines use and risk

Abstract

Adolescents have a lack of experience, knowledge of medicines, which often leads to incorrect use of medicines. Slovak adolescents' attitude towards the use and risk of medicines is not known, and therefore, we prepared a questionnaire and then we evaluated the face, content (CVR i <1) and construct validity and reliability (Cronbach’s α = 0.85). The questionnaire is an appropriate tool to assess the quality of knowledge and experience of adolescents with drugs and the data could, on the introduction of measures, contribute to the rational use of medicines by adolescents in Slovakia.

Open access
Challenges relating to comparison of flavonoid glycosides dissolution profiles from Sutherlandia frutescens products

Abstract

Unlike the case of conventional drug formulations, dissolution tests have hitherto not been required for herbal medicinal products commercially available in South Africa. This study investigated dissolution of the South African Sutherlandia frutescens using selected flavonoid glycosides as marker compounds. Dissolution of markers was assessed in three dissolution media at pH 1.2, 4.5 and 6.8, and samples were analysed using a validated HPLC method. The dissolution profile of each marker varied for the different materials investigated. All three media utilised showed differences in flavonoid glycoside dissolution between the S. frutescens products evaluated, with f2 values < 50 for comparison of flavonoid dissolution from any two of the materials. Dissolution of S. frutescens materials could thus be characterised using the markers in all the media tested. This tool may be employed in the future for comparison of orally administered S. frutescens products, provided between- batch variability is evaluated and found less than between-sample variability.

Open access
Distinguishing Smilax glabra and Smilax china rhizomes by flow-injection mass spectrometry combined with principal component analysis

Abstract

Flow-injection mass spectrometry (FIMS) coupled with a chemometric method is proposed in this study to profile and distinguish between rhizomes of Smilax glabra (S. glabra) and Smilax china (S. china). The proposed method employed an electrospray-time-of-flight MS. The MS fingerprints were analyzed using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) with the aid of SIMCA software. Findings showed that the two kinds of samples perfectly fell into their own classes. Further predictive study showed desirable predictability and the tested samples were successfully and reliably identified. The study demonstrated that the proposed method could serve as a powerful tool for distinguishing between S. glabra and S. china.

Open access
Therapeutic drug monitoring of atypical antipsychotic drugs

Abstract

Schizophrenia is a severe psychiatric disorder often associated with cognitive impairment and affective, mainly depressive, symptoms. Antipsychotic medication is the primary intervention for stabilization of acute psychotic episodes and prevention of recurrences and relapses in patients with schizophrenia. Typical antipsychotics, the older class of antipsychotic agents, are currently used much less frequently than newer atypical antipsychotics. Therapeutic drug monitoring (TDM) of antipsychotic drugs is the specific method of clinical pharmacology, which involves measurement of drug serum concentrations followed by interpretation and good cooperation with the clinician. TDM is a powerful tool that allows tailor-made treatment for the specific needs of individual patients. It can help in monitoring adherence, dose adjustment, minimizing the risk of toxicity and in cost-effectiveness in the treatment of psychiatric disorders. The review provides complex knowledge indispensable to clinical pharmacologists, pharmacists and clinicians for interpretation of TDM results.

Open access
Clinical testing of antiretroviral drugs as future prevention against vaginal and rectal transmission of HIV infection – a review of currently available results

Abstract

The original purpose of vaginally applied microbicides was to slow down the HIV epidemic among the population until an effective vaccination was developed. Nowadays, antiretrovirals applied in the form of gels or vaginal rings are considered most prominent in this field and are tested via vaginal or, rarely, rectal applications in numerous clinical studies (9 different antiretroviral drugs in 33 clinical studies, especially in Africa). Only tenofovir (1 % gel) and dapivirine (25 mg in vaginal ring) progressed into the phase III clinical testing. Their efficiency depended on the user´s strict adherence to the application regimen (for tenofovir 54 %, for dapivirine 61 % in participants over 25 years of age). Despite this, they are expected to be important and effective tools of preventive medicine in the near future. This review summarizes the results obtained during long-term clinical testing (2005–2018) of antiretroviral drugs against vaginal and rectal transmission of HIV infection.

Open access