An International Quarterly Research Journal


                                                                ISSN : 0971 - 9822

Vol   16,  No   1 ,  January-March,   2012

Asian Chemistry Letters                                                                                                                Vol. 16, No. 1 (2012)1-8

Incorporation and delivery of bioactive molecules from smart carbon nano-devices

Li Jiana, Tapas Ranjan Nayaka, Gary Wiratama Chandraa, Sundara Ramaprabhub,
Sandeep Kumar Vashistc, Fwu-Shan Sheuc and Giorgia Pastorina,c,d*
aNational University of Singapore, Singapore 117543.
aDepartment of Physics, Indian Institute of Technology Madras, Chennai (India) 600036.
aNUSNNI-NanoCore, National University of Singapore, Singapore 117580
dNUS Graduate School for Integrative Sciences and Engineering, Singapore 117456.


Among the drug delivery systems used for cancer therapy, carbon nanotubes (CNTs) have suggested interesting applications on the basis of their abilities to enter cells in a non-invasive way and their versatility in terms of functionalization at their external surface for drug incorporation, imaging and targeting purposes. More recently, the discovery that their hollow inner space can accommodate bioactive agents has opened new possibilities for encapsulation of anticancer agents and for protection from the surrounding environment.
In this study, we report on a "carbon nanotube bottle" structure as a smart nanodevice for delivery of cisplatin, a FDA-approved anticancer drug. For this purpose, CNTs were chemically modified and further sealed with functionalized gold nanoparticles after the loading of the bioactive agent inside.  In this investigation, we observed that the caps did not avoid the incorporation of drug in the inner space of CNTs; conversely, higher drug loading was obtained inside the CNTs in comparison with previous works



Asian Chemistry Letters                                                                                                               Vol. 16, No. 1 (2011)9-22

Transdermal delivery of active compounds for the treatment of erectile dysfunction

Ismail Tuncer Degim and Sibel Ilbasmis-Tamer
                                       Gazi University Faculty of Pharmacy, Ankara, TURKEY   


Erectil dysfunctions start with difficulties in erection and then gradually becomes a real problem by years. Many treatments and helping remedies include some painful and undesired applications are still used. In recent years there are some transdermal drug formulations appear in the shelfs which were very attractive for the patients having erectil  dysfunctions especially if they rae at the beginning. Therefore current  knowledge and informative examplees were given which leads readers to  understand how transdermal applications of these formulations can help and how molcules pass through skin layers and finally the possibility of  success and reasons for failure after application of these formulations discussed in this review.



Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)23-30


Development and Validation of an RP-LC Method for the Determination of

Granisetron in Dosage Forms

Mehmet Gumustas1,2, Sibel A Ozkan1*
1Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06100, Ankara – Turkey;
2Hitit University, Science and Literature Faculty, Department of Chemistry, 19040, Corum – Turkey


Granisetron (GRA) is a serotonin 5-HT3 receptor antagonist used as an anti-emetic to treat nausea and vomiting following chemotherapy. A specific, sensitive, simple and rapid LC-UV method has been developed for the determination of GRA. In the proposed method, a reversed-phase column (X-Select RP-18 (250 × 4.6 mm ID × 5m) with the mobile phase assayed were methanol:water (45:55; v/v), containing 15 mM phosphoric acid. The pH of the mobile phase was adjusted at 2.50 by addition of sodium hydroxide. 1.0 ml/min flow rate was used to separation with a detection wavelength of 215 nm. The chromatographic separation was performed at 25oC column temperature. Hydrochlorothiazide (HCT) was selected as the internal standard (IS). Using these conditions, the retention times were obtained as 3.30 min for HCT, 4.19 min for GRA. The assay was linear in the concentration range of 0.25-15 mg mL–1. It was successfully applied to the analysis of GRA in pharmaceutical dosage forms. The present RP-LC study purposes a rapid, simple, sufficiently precise and accurate method for the determination of GRA in raw material and pharmaceutical formulations. The proposed method allows a number of cost and time saving benefits. In order to demonstrate the validity and applicability of the proposed RP-LC method, recovery tests were also carried out. High percentage recovery shows that the method is free from the interferences of the commonly used excipients and additives in the formulations of drugs. © Anita Publications.
Keywords: Granisetron, RP-LC, Determination, Dosage form, Validation


Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)31-36


The Promising Emulsion Formulations of Ostrich Oil produced from Pre-fleshing

wastes of Ostrich Skin

Hüseyin A Karavanaaa1, Sinem Y Karavana2, Sakine Tuncay2, Ahmet Aslan1, Özgen Özer2*
1Ege University, Faculty of Engineering, Department of Leather Engineering, 35100, Bornova, Izmir-Turkey
2Ege University, Faculty of Pharmacy, Department of Pharmaceutical Technology, 35100, Bornova, Izmir-Turkey


Ostrich oil is derived from the ostrich skin and has been reported to have anti-inflammatory properties as well as its cosmetic and dermal effects. Emulsion formulations were prepared with ostrich oil obtained from pre-fleshing waste of ostrich skin. The anti-inflammatory effect of the formulation was investigated by determining oedema inhibition. The effect of formulation on skin was determined by skin irritation and pigmentation tests. The anti-inflammatory effect of the emulsion formulation was found similar with commercial product. No significant change found between erythema and melanin values of formulations and control groups. It was concluded that ostrich oil obtained from pre-fleshing waste was suitable oil phase for emulsion formulations and has no side effect on skin. Using pre-fleshing waste for producing ostrich oil could provide economic and ecological benefits.



Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)37-50

Nanotechnology in theranostics (diagnosis, thgeraphy), imaging, drug design and targeting

Lütfi Genç
Anadolu University, Faculty of Pharmacy, Pharmaceutical Technology Department, 26470 Eskiehir-TURKEY


Nanotechnology is able  to provide nanoparticulate drug delivery systems (NPDDSs) for treatment of diseases. In recent years, the scope has been widened to incorporate many disciplines in the drug delivery research covering physics, polymer sciences, material sciences, engineering, genetics, biotechnology, pharmaceutical technology and moleculer pharmaceutics. NPDDSs are a challenging area pulsating changes happening almost every day. This is an attempt to cover the recent trends and emerging technologies in the area of NPDDSs. This review covers a complete overview of the NPDDSs namely nanosuspensions, nano-microemulsions, polymer-based nanoparticles, nanofibers, nanocrystals, nanoparticles, nanosphers, nanocapsules, lipid-based nanoparticles, quantum dots and carbon nanotubes and will assist the readers in understanding the diverse types of NPDDSs available or under development, as well as highlight their applications in the future development of nanomedicines.
Keywors: Nanotechnology, drug delivery systems, theranostics, imaging, targeting.


Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)51-66

Multiple emulsions as drug delivery systems

Jacqueline M Morais and Orlando D H Santos*
Department of Pharmaceutical Sciences
 School of Pharmacy, University of Ouro Preto, Ouro Preto, MG, Brazil


Multiple emulsions have potential applications as pharmaceutical and dermatologic-cosmetic delivery vehicles due to their ability to entrap and slowly release different agents. Emulsions may be utilized to overcome major formulation challenges such as solubilization of poorly aqueous-soluble drugs and/or protection of drugs susceptible to hydrolysis. In addition, they can be used for the purposes of drug targeting and/or reduction of toxic effects to sensitive tissues. Limitations on multiple emulsion applications are mainly due to difficulties in characterizing and elucidating parameters related to emulsion stability, emulsification process (especially one-step method) and marker release mechanism. The use of multiple emulsions as drug carrier depends on the formulation feasibility i.e. use of oils and emulsifiers able to guarantee short and long-term stability and no toxicity. This review provides an overview of the physicochemical properties, methods of preparation and stability of multiple emulsion formulations.©Anita Publications. All rights reserved
Keywords: multiple emulsions, emulsification processes, drug delivery systems


Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)67-78

Transdermal films of metoclopramide hydrochloride with terpenes as penetration enhancers: Design, characterization, in vitroevaluation and ATR-FTIR spectroscopic investigation on excised pig skin

Betül Aktar1, M Sedef Erdal1, Olcay Sairli2, Sevgi Güngör1, YildizÖzsoy1
Istanbul University, Faculty of Pharmacy, 1Department of Pharmaceutical Technology
2Department of Analytical Chemistry, 34116, Universite, Istanbul, Turkey


The aim of this study was to develop novel transdermal films of metoclopramide hydrochloride (MTC) with sodium alginate as matrix agent to investigate the influence of various terpenes on in vitro release of MTC from transdermal films. ATR-FTIR studies on excised pig skin were performed in order to evaluate the effect of terpenes (nerolidol, eucalyptol, dl-limonene or terpinolene) on barrier function of skin. Transdermal filmsof MTC prepared using sodium alginate as matrix agent had the good physicochemical and adhesive properties. In vitrorelease data indicated that MTC had highest drug release ratefrom the films containing terpinolene as permeation enhancer. On the other hand, the mixtures containing limonene as terpene, produced greater decrease in peak heights and areas of asymmetric and symmetric stretching vibrations in comparison to the untreated skin, suggesting an overall extraction of the stratum corneum lipids. Future studies will be focusing on in vitro/in vivopermeation studies to optimize permeation of drug from the formulations.
Keywors: Metoclopramide hydrochloride, sodium alginate, transdermal film, terpenes, ATR-FTIR.


Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)79-86

b-elimination and its implications in the chemical stability of protein pharmaceuticals

Vineet Kumar* and Shubhadra N Singh
*Pharmaceutics, 100 Research Drive, Abbott Bioresearch Center, Worcester-01605, MA, USA


Chemical instability in protein formulations occurs by various routes. Although a lot of work has been done towards the understanding of the more common pathways of chemical degradation including oxidation and deamidation, the efforts towards the understanding of b-elimination have been rather scarce. Recent development in the growth of antibodies that usually contain several disulfide bonds has however resulted in renewed interest in the role of role of thiols and disulfides in the chemical stability of protein pharmaceuticals. Heterocyclic cleavage of the disulfide bond in alkaline solutions via b-elimination results in the formation of products like dehydroalanine, persulfide and hydrosulfide some of which can participate in the thiol-disulfide exchange reactions and hence may lead to additional modifications within the protein. b-Elimination reaction can thus result in the inactivation of enzymes and destruction of protein pharmaceuticals. Rates of this alkali catalyzed b-elimination reaction is sensitive to various factors including pH, temperature and structure of the protein, and could similarly affect smaller peptides and as well as complex protein molecules. Lyophilized protein pharmaceuticals are also sensitive to this reaction and have been observed to undergo aggregation following b-elimination. In this overview an attempt is made to review the mechanism of
b-elimination reaction and the factors that affect the kinetics and rate of the reaction. Implications in the development of liquid and lyophilized pharmaceuticals are also discussed.


Asian Chemistry Letters                                                                                                             Vol. 16, No. 1 (2011)87-96

Overview of impurities in pharmaceuticals: Toxicological aspects

Ismet Cok and Esra Emerce
Gazi University, Faculty of Pharmacy, Department of Toxicology
Hipodrom, 06330, Ankara, Turkey,


In drugs, the presence of unwanted chemicals regarded as impurity may influence the efficacy and safety of pharmaceutical products even in very small amounts. Since 1994, certain regulations relative to impurities in drug applications were intended to be set by international regulatory authorities such as ICH (International Conference on Harmonization), FDA (Food and Drug Administration), EMEA (European Medicines Agency), particularly, considering genotoxic impurities in pharmaceuticals at trace level which may play a role in causing mutagenesis and carcinogenesis in humans. Often, technically it is not possible to remove all impurities from the drugs during the production process. These elimination processes also increase the costs. In this context, risk assessment should be conducted in order to set a balance between the need to reduce the impurity concentration at the lowest possible level and the practical feasibility of this reduction. Therefore, a monitoring study for impurities that may occur from the production process through the usage and storage of drug is needed. The monitoring studies should cover determination and quantification of impurities together with assessment of their toxicological results. In the present day, there is still little knowledge about impurities and their toxic effects in literature. This review covers the details of impurities in pharmaceuticals, their regulations, toxicological aspects, and analytical strategies