Objective: This study was conducted to determine the prevalence of hazardous, harmful and dependent drinking among hostel-dwelling students on the main campus of the University of the Free State (UFS), and the influence of sex and academic year on the habit.
Method: A quarter of all hostel-dwelling students of UFS were selected by systematic random sampling. Willing participants completed a questionnaire comprising a demographic section and the Alcohol Use Disorders Identification Test (AUDIT).
Malaria, one of the three most important life-threatening infectious diseases, is recommended to be treated with ACT (artemisinin combination therapy) against which Plasmodium falciparum already displayed resistance. Two artemisinin-4-amino-quinoline hybrid-dimers (1 and 2), previously synthesized, possessed low nanomolar in vitro antiplasmodial activity, while poorly toxic against mammalian cells. They are here investigated to ascertain whether this antimalarial activity would be carried on in vivo against Plasmodium vinckei.
View Article and Find Full Text PDFSeries of bisquinolines 4-15 and bispyrrolo[1,2a]quinoxalines 16-20 containing various polyamine linkers were synthesized. The aqueous solubility and distribution coefficient were experimentally determined. The compounds were screened for antimalarial activity alongside chloroquine against D10 and Dd2 strains of Plasmodium falciparum.
View Article and Find Full Text PDFIn this study, a series of 11 10-aminoethylether derivatives of artemisinin were synthesised and their antimalarial activity against both the chloroquine sensitive (D10) and resistant (Dd2) strains of Plasmodium falciparum was determined. The compounds were prepared by introducing aliphatic, alicyclic and aromatic amine groups with linkers of various chain lengths through an ethyl ether bridge at C-10 of artemisinin using conventional and microwave assisted syntheses, and their structures were confirmed by NMR and HRMS. All derivatives proved to be active against both strains of the parasite.
View Article and Find Full Text PDFArzneimittelforschung
August 2011
New 4-aminoquinoline-derived esters containing the redox-active ferrocene group brought in by either ferrocenyformic or 4-ferrocenylbutanoic acids were synthesized and tested in vitro for their antiplasmodial activity. The results revealed that only esters derived from ferrocenylformic acid were active against both chloroquine (CQ)-resistant Dd2 and CQ-sensitive D10 strains of Plasmodium falciparum. However, none of these showed higher actvity than CQ against the sensitive strain.
View Article and Find Full Text PDFThe aim of this study was to synthesize a series of mono-, di- and trisubstituted derivatives of the human African trypanosomiasis drug eflornithine (alpha-difluoromethylornithine, DMFO, CAS 70052-12-9) to determine their partition coefficients, and to assess whether they deliver the parent drug in the plasma. If increased plasma concentrations of eflornithine could be achieved in this way, an oral dosage form would be possible. The derivatives, nine in total, were successfully synthesized by multi-step derivatisation of eflornithine on either its alpha-carboxylic or/and alpha-amino or/and delta-amino groups by either esterification or/and amidation or/and carbamylation, and their structures confirmed by NMR and MS spectroscopy.
View Article and Find Full Text PDFDihydroartemisinin (DHA) was coupled to different aminoquinoline moieties forming hybrids 9-14, which were then treated with oxalic acid to form oxalate salts (9a-14a). Compounds 9a, 10a, 12, 12a, and 14a showed comparable potency in vitro to that of chloroquine (CQ) against the chloroquine sensitive (CQS) strain, and were found to be more potent against the chloroquine resistant CQR strain. Hybrids 12 and its oxalate salt 12a were the most active against CQR strain, being 9- and 7-fold more active than CQ, respectively (17.
View Article and Find Full Text PDFObjectives: The aim of this study was to synthesize a series of ethylene glycol ether derivatives of the antimalarial drug artemisinin, determine their values for selected physicochemical properties and evaluate their antimalarial activity in vitro against Plasmodium falciparum strains.
Methods: The ethers were synthesized in a one-step process by coupling ethylene glycol moieties of various chain lengths to carbon C-10 of artemisinin. The aqueous solubility and log D values were determined in phosphate buffered saline (pH 7.
The purpose of this study was to synthesize a series of delta-amide derivatives of the antitrypanosomal drug eflornithine (2,5-diamino-2-(difluoromethyl)pentanoic acid hydrochloride, DMFO, CAS 70052-12-9), to determine their physicochemical properties and to assess whether they convert to eflornithine in vivo and if so, whether higher systemic exposure to eflornithine could be achieved by increase intestinal absorption, suggesting an oral treatment to be possible. The derivatives were synthesized by amidation of eflornithine on its delta-amino group using acyl chlorides. The partition coefficients (log D, pH = 7.
View Article and Find Full Text PDFArzneimittelforschung
December 2010
Series of 4-aminoquinolines bearing an amino side chain linked to the ferrocene moiety through an amide bond were synthesized and evaluated for their antimalarial activity against both chloroquine-sensitive (D10, CQ-S) and chloroquine-resistant (Dd2, CQ-R) strains of Plasmodium falciparum. They were also tested for cytotoxicity against Chinese Hamster Ovarian (CHO) cells. Amide 12 featuring propyl side chain linked to the ferrocene ring was the most active of all tested compounds.
View Article and Find Full Text PDFIn continuation of studies focusing on the transdermal delivery of antiretroviral (ARV) drugs, the skin permeation ability of synthesized homologous series of both oligomeric and polymeric ethylene glycol (PEG) carbonates of zidovudine (3'-azido-3'-deoxythymidine, AZT, CAS 30516-87-1) and stavudine (2',3'-dideoxy-2',3'-didehydrothymine, d4T, CAS 3056-17-5) was evaluated in vitro through excised human skin in phosphate buffered solution (PBS) (0.01 M, pH 7.4) at 37 degrees C by using Franz cell diffusion methodology.
View Article and Find Full Text PDFThe aim of this study was to investigate the effects of different ester groups in position 5' of stavudine on the transdermal penetration with and without the use of Pheroid™ as the delivery system. Six esters were prepared by reaction of stavudine with six different acid chlorides at room temperature. Female human abdominal skin was used for in vitro penetration in Franz diffusion cells.
View Article and Find Full Text PDFNovel artemisinin-quinoline hybrid-dimers were synthesized from dihydroartemisinin and different aminoquinolines at elevated temperatures (90-110°C). All compounds were obtained as the β-isomers and were tested against both chloroquine sensitive and resistant strains of Plasmodium falciparum. Hybrid-dimer 8 showed the highest antiplasmodial activity, inheriting the optimum chain length of three carbon atoms.
View Article and Find Full Text PDFObjectives: The aim of this study was to synthesise and determine the transdermal penetration of cytarabine alkylamide derivatives and assess the correlation of flux with physicochemical properties.
Methods: The alkylamide derivatives of cytarabine were synthesised by acylation at the N4-amino group by the mixed anhydride method. The in-vitro permeation studies were performed using the Franz diffusion cell methodology.
Background: Cytarabine is a deoxycytidine analogue commonly used in the treatment of hematological malignant diseases. Its clinical utility, however, is severely limited by its short plasma half-life because of the catabolic action of nucleoside deaminases.
Method: In this study, N(4)-carbamate derivatives of cytarabine (1) were synthesized and evaluated for transdermal penetration because this mode of administration may circumvent its limitations.
The purpose of this study was to synthesize and determine the in vitro transdermal penetration of cytarabine and its 5'-alkyl esters and to establish a correlation, if any, with selected physicochemical properties. The n-alkyl esters were synthesized by acylation of cytarabine (1) at its pharmacophoric 5'-OH. The transdermal flux values of (1) and its esters were determined in vitro using Franz diffusion cell methodology.
View Article and Find Full Text PDFThe objective of this study was to determine the in vitro transdermal permeation through the human stratum corneum (SC) of the antiretroviral (ARV) drug lamivudine (3TC) (1) and its synthesised methoxypoly(ethylene glycol) (MPEG) carbamates and carbonates in phosphate buffer solution and with the use of Pheroid as delivery system and to establish a relationship, if any, with selected physicochemical properties. The synthesis and in vitro human skin permeation flux of three N4-methoxypoly(ethylene glycol) carbamates (3)-(5) and three 6'-O-methoxypoly(ethylene glycol) carbonates (6)-(8) of lamivudine are reported. The derivatives were synthesised in a two-step process by coupling activated MPEG oligomers of various chain lengths to either the 4-amino or 6'-hydroxy group of lamivudine.
View Article and Find Full Text PDFThe title compound, C(17)H(27)BrO(5), DEB, is a derivative of artemisinin which is used in malara therapy. The OR-group at C12 is cis to the CH(3)-group at C11 and axially oriented on ring D which has a chair conformation. The crystal packing is stabilized by several weak inter-molecular C-H⋯O inter-actions, which combine to form a C-H-O bonded network parallel to (001).
View Article and Find Full Text PDFThe objective of this study was to synthesize derivatives of the anti-HIV drug stavudine (d4T) with more favourable physicochemical properties for transdermal delivery in an effort to increase transdermal penetration of stavudine and thus reduce the severe side effects associated with the dose-dependent oral therapy. The synthesis, hydrolytic stability, and in vitro human skin permeation flux of a series of novel methoxypoly(ethylene glycol) (MPEG) carbonates of stavudine are reported. The carbonates were synthesized in a two-step process by coupling the MPEG promoiety of various chain lengths to C-5' of d4T.
View Article and Find Full Text PDFObjectives: The aim of this study was to synthesise a series of novel methoxypoly(ethylene glycol) carbonate prodrugs of the antiretroviral drug zidovudine (azidothymidine, AZT) in an attempt to enhance the physicochemical properties for transdermal delivery, which may reduce the severe side-effects and toxicity associated with high oral doses of AZT.
Methods: Methoxypoly(ethylene glycol) carbonates of AZT were synthesised in two steps: activation of the relevant methoxypoly(ethylene glycol) with p-nitrophenyl chloroformate, followed by reaction with AZT. Analysis of the hydrolytic stability in phosphate buffer at pH 5.
A series of N,N-bis(trifluoromethylquinolin-4-yl)- and N,N-bis[2,8-bis(trifluoromethyl)quinolin-4-yl] diamino alkane and piperazine derivatives were synthesised by employing a simple and rapid displacement reaction of the 4-chloro group on the 2-trifluoromethyl- and 2,8-bis(trifluoromethyl)-quinoline by diaminoalkane or piperazine groups. Results of in vitro antimalarial activity evaluations of these compounds against the chloroquine-sensitive (D10) and chloroquine-resistant (K1) strains of Plasmodium falciparum indicate that compounds with trifluoromethyl groups in both the 2 and 8 positions coupled with diaminoalkyl bridging chains of 2 to 6 carbon atoms exhibit a slightly higher activity than compound with only a trifluoromethyl group at position 2, and those with a piperazine bridge. These compounds exhibit higher activity in the chloroquine-resistant than in the chloroquine-sensitive strains of the Plasmodium.
View Article and Find Full Text PDFFive novel epoxide derivatives of cytochalasin B were synthesized. Reaction of cytochalasin B with t-BHP and BuLi led to selective epoxidation of the C-21/22 double bond to give a single monoepoxide, while reaction with m-CPBA yielded two diepoxides. Reaction of the monoepoxide with m-CPBA yielded two triepoxides.
View Article and Find Full Text PDFThe objective of this study was to determine the in vitro transdermal permeation through human epidermis of zalcitabine, lamivudine and the synthesised N-acyl lamivudine esters, with and without the use of Pheroid as delivery system and to establish a correlation, if any, with selected physicochemical properties. Six N-acyl lamivudine esters were prepared by acylation of lamivudine with six different acid chlorides. The experimental aqueous solubility, log D and in vitro transdermal flux values were determined for these compounds.
View Article and Find Full Text PDFThe primary aim of this study was to determine the transdermal penetration of acetylsalicylic acid and some of its derivatives, to establish a correlation, if any, with selected physicochemical properties and to determine if transdermal application of acetylsalicylic acid and its derivatives will give therapeutic drug concentrations with respect to transdermal flux. Ten derivatives of acetylsalicylic acid were prepared by esterification of acetylsalicyloyl chloride with ten different alcohols. The experimental aqueous solubility, logD and transdermal flux values were determined for acetylsalicylic acid and its derivatives at pH 4.
View Article and Find Full Text PDFThe glucoside and mannoside derivatives of the NSAIDs flurbiprofen, ibuprofen, ketoprofen and naproxen were synthesised and their penetration through human skin was determined. Experimental transdermal flux data showed that the parent NSAIDs penetrated human skin to a much higher extent than the glycosides.
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