Current Drug Delivery (v.10, #2)

Objectives: The aim of the present study was to formulate and characterize solid lipid nanoparticles (SLNs) ofessential oil of Zataria multiflora. Methods: The essential oil was extracted from the leaves of Z. multiflora and was analyzedby GC-MS. SLNs were prepared using two methods including precipitation technique and hot homogenizationmethod for achieving the best encapsulation. The SLNs were characterized by Differential Scanning Calorimetery (DSC),Transmission Electron Microscopy (TEM) and particle size analysis. The release of essential oil was determined using adialysis membrane method. Key findings: The results showed that the encapsulation efficiency was 38.66%. Results ofparticle size determination showed a mean size of 650 nm and SLNs were spherical as shown by TEM. The DSC curve ofsodium dodecyl sulfate (SDS), polyethyleneglycol (PEG), cetyl alcohol and essential oil were different from essential oilcontaining SLNs, which indicated that the essential oil can interact with the matrix of lipid during the preparation of theSLNs. 93.2% of the essential oil was released after 24 h. Conclusions: The results of characterization of the SLNs indicatedthe potential application of essential oil of Z. multiflora loaded SLN as carrier system.

Characterization and Pharmacokinetic Evaluation of Gamma Sterilized Ketorolac Tromethamine Loaded Albumin Microspheres for Intramuscular Administration by Sam Thomarayil Mathew, Gayathri Devi Subbiah, Prasanth Viswanadhan Vasantha, Vinod Balan (158-166).
Pharmacokinetic parameters of ketorolac tromethamine (KT) loaded albumin (KTAL) microspheres were determinedusing New Zealand white rabbits. Each rabbit (n=6) was injected 5 mg/kg body weight of plain KT or anequivalent dose in microsphere form in 2 mL water for injection. Prior to animal studies microspheres were tested fortoxic residues and were gamma sterilized. Sterilized microspheres were evaluated for their integrity by physico-chemicalcharacterization. Test for toxic residues was negative, the sterilization process utilized was effective and did not alter anyphysicochemical characteristics and showed good syringeability. When KT was administered in the form of microspheresthere was a significant increase in Cmax, AUC, t1/2 and MRT (P < 0.05). When administered as microspheres, plasma concentrationof drug sustained for 24 hours. It was concluded that KTAL microsphere formulation improved the systemicexposure and sustained the drug release and could be used for once-a-day administration of KT.

Design and Evaluation of Matrix Diffusion Controlled Transdermal Patches of Coumarin by S. Lakshmana Prabu, S. Thiyagarajan, T.N.K. Suriyaprakash (167-173).
The aim of the present investigation was to prepare coumarin matrix transdermal systems using the combinationsof Eudragit RL-100/Eudragit RS-100. The formulations were evaluated for various physicochemical properties(thickness, weight variation, drug content uniformity, moisture content and water absorption uptake), in vitro release studies,in vitro skin permeation studies and skin irritation studies. In vitro skin permeation and skin irritation studies werecarried out on rat skin and rabbit respectively. The drug

The present studies entail the formulation development and evaluation of chronomodulated drug delivery systemof amoxicillin trihydrate (AMT), which comprises of a bilayer tablet containing a delayed release and a sustained releaselayer. Direct compression method was employed for the preparation of bilayer matrix tablets containing rationalblend of polymers, such as Eudragit-L100 D55 as delayed release polymer and HPMCK4M, HPMCK15 and HPMCK100are sustained release polymers. In- vitro drug release studies of bilayer tablets observed a good sustained release actionwith time-dependent burst release after a lag-time of 3 hrs. Evaluation of drug release kinetics from sustained release layerof bilayer tablets followed Higuchi model via quasi-Fickian diffusion mechanism. SEM studies revealed formation ofpores on sustained release layer, which confirmed the drug release through diffusion and predominantly by surface erosionmechanism. Evaluation of antimicrobial activity showed a decrease in minimum inhibitory concentration of optimizedbilayer tablets vis-

Development, in vitro and in vivo Evaluation of Novel Injectable Smart Gels of Azithromycin for Chronic Periodontitis by M.P. Venkatesh, T.M. Pramod Kumar, B.S. Avinash, G. Sheela Kumar (188-197).
Periodontitis is an inflammatory condition affecting teeth resulting in progressive destruction of periodontalligaments, resorption of alveolar bone and loss of teeth. Treatment of periodontitis includes surgical and non surgicalmanagement. Systemic antibiotics are also used for the treatment of periodontitis. The aim of this research was to formulatesmart gel system of azithromycin (AZT) and to evaluate in vitro and in vivo for non-surgical treatment of chronic periodontitis.Azithromycin dihydrate, used systemically in the treatment of periodontitis, was formulated into smart gels usingbiodegradable, thermosensitive polymer Pluronic

Potential of Plant Mucilages in Pharmaceuticals and Therapy by Jyoti Wadhwa, Anroop Nair, Rachna Kumria (198-207).
Mucilages, and in particular plant mucilages, have gained more attention over the last few decades due to theirreputable medicinal properties. Some publications have appeared in reputable Scientific Journals that have made appreciablecontributions to the discovery of the functions and utilizations of such naturally occurring products. Therapeuticvalue of mucilages has been extended to wound healing, diabetes, immunostimulation, cancer, angiotensin converting enzymeinhibition, stomachic, and antioxidant properties. Based on their sustaining capacities as well as binding and gellingproperties, mucilages have been proposed to be one of the most useful materials to modulate drug delivery. Chemicalanalysis reveals that generally these contain monosachrides along with a range of other organic and inorganic components.Although physiological properties of various plant mucialges have been described, it still remains uncertain as towhich of the component(s) is responsible for these physiological properties. Further research needs to be done to unravelthe myth surrounding the biological activities and the functional properties of them. This review presents an overview ofthe current status and knowledge on the applications of plant mucilages as therapeutic agent and pharmaceutical additives.

The development of the vectorized delivery systems combining advantages of the colloidal carriers, with activetargeting to the receptors sites suggests that nanoparticles have a considerable potential for treatment after biophase internalizationand pharmacokinetics, as for example gene therapy. Two major mechanisms can be distinguished for addressingthe desired sites for drug release: (i) passive and (ii) active targeting. Examples of passive targeting were presented:organ targeting by the Enhanced Permeability and Retention (EPR) effect; targeting the mononuclear phagocitic system;organ targeting by chemoembolization or local (organ) administration;sterical stabilization of nanoparticles (PEGylation).A strategy that could allow active targeting involves the surface functionalization of drug carriers with ligands that are selectivelyrecognized by receptors on the surface of the cells of interest. The source for biophase bioavailability can be thesystemic bioavailability following common routes of adminstration (generally for systemic delivery of medicines), or directlythe site specific biophase bioavailability for the formulations capable of cellular or nuclear drug internalizationwhere the drug release only will take place (for nanoparticulate drug delivery systems, DDS). Once the pharmaceuticalnanosystem was internalized, begins the release of the active moiety by different mechanisms, as for example the escapefrom endosome, or biodegradation of the polymer carrier or liberation of the active peptide or gene from a biological constructin the nucleus, etc. The presentation will discusses the pharmacokinetics of drugs after systemic administration butespecially the biophase bioavailability and pharmacokinetics after the administration of biotechnology origin of therapeuticproteins like monoclonal antibodies, gene transfer products, plasmid DNAs, nucleotides, antisense oligonucleotides(AODNs) or small interfering RNAs (siRNA).

The present study deals with preparation, optimization and in-vitro drug release study of hydroxyapatite (HAp)-ofloxacin for bone-implantable delivery in osteomyelitis treatment. The effect of drug amount added, and orthophosphoricacid addition rate as process parameters on the drug loading into HAp-system by precipitation method was optimized byusing 32 factorial design. The response surface methodology utilizing polynomial equation was used to search for optimaldrug loading into HAp-system. The responses observed coincided well with the predicted values obtained through optimizationtechnique. HAp-ofloxacin bone-implants were manufactured using synthesized HAp-ofloxacin composite powdersand 2 % w/v aqueous solution of sodium alginate was used as binder. Characterization of the delivery system was done byFTIR spectroscopy. The in-vitro ofloxacin release from optimized HAp-ofloxacin bone-implants was slow and sustainedover 10 weeks. The drug release pattern was correlated well with Korsmeyer-Peppas model and was followed by Fickian(diffusional) release mechanism.