Volume 1

October-December 2009

Review Articles

Vinay Pandit, Sarasija Suresh

In this review, the concepts of biological rhythms, chronobiology, chronopharmacology, and chronotherapy for various diseases have been discussed. The presence of circadian rhythms in human health and illness has been alluded to since the time of Hippocrates. However, it was not until the 1960’s that a large variety of physiologic functions and biologic rhythms were described. Biologic variations have now been reported for several physiologic processes and play an important role in the manifestation of many illnesses. The past decade has witnessed rapid advances in the field of chronobiology, which are now being incorporated into clinical medicine, pharmacology and pharmacy practice. A number of chronotherapeutic medications, aiming at synchronizing medications and the intrinsic biorhythms of disease have been developed by novel drug delivery technology. In some cases, conventional medications are being administered according to circadian rhythms. This article focuses on biorhythms and the emerging role of chronotherapeutics in optimizing the treatment of several diseases.

Keywords: Biological Rhythms, Chronobiology, Chronotherapeutic, Hippocrates, Circadian Rhythms.

N G Nanjundswamy , Fatima S Dasankoppa , H N Sholapur

There has been considerable progress in recent years in addressing the clinical and pharmacological limitations of hydrogels for drug delivery applications but substantial challenges remain. Here we discuss recent progress in overcoming these challenges, particularly with regards to effectively delivering hydrogels inside the body without implantation, prolonging the release kinetics of drugs from hydrogels, and expanding the nature of drugs which can be delivered using hydrogel-based approaches.

Keywords: Hydrogels, In Situ, Ocular, pH Controlled, Ion Activation.

Research Articles

J G Hiremath, M D Sarfaraz, D Hiremath, S A Sarudkar

The purpose of this research work was to prepare the buccoadhesive bilayered tablet of simvastatin for the treatment of hypercholesterolemia, by using the mucoadhesive polymers such as carbopol (CP), hydroxy propyl methyl cellulose (HPMC) and polyvinylpyrrolidone (PVP) in different concentration. Ethyl cellulose is used in backing layer because of its water impermeable nature. Tablets were prepared by direct compression method. The first layer which adheres to mucosa was obtained by direct compression of mucoadhesive polymers and drug. The second layer containing water impermeable agent was compressed on the first layer. Tablets were subjected for physicochemical characterization tests such as FTIR, DSC, hardness, weight variation, friability, mucoadhesive strength, in vitro drug release study, in vitro drug permeation, and stability in human saliva. The FTIR and DSC analysis of drug, polymers, physical mixture and formulation indicated that the compatibility of drug with excipients. Tablets were found to be satisfactory when evaluated for weight variation, thickness, hardness and friability. The surface pH of all the tablets was close to neutral pH. The bilayered tablets containing a higher proportion of CP showed good mucoadhesive strength. The buccal tablets were found to be stable when tested for 8 h in natural human saliva. The present study concludes that mucoadhesive buccal devices of simvastatin can be a good way to bypass the extensive hepatic first pass metabolism and to improve the bioavailability of simvastatin.

Keywords: Bilayer Tablets, Buccal Delivery, Simvastatin, In Vitro Release.

N Manjunatha, G Prakash Naidu, Vasanti Sutrave, Kalpesh Patel, M K Samanta

Liposomes are well known to alter the biodistribution of entrapped substances by protecting the enclosed material. They are widely used as vehicles to target the specific molecule to specific organ especially in conditions of viral infections. A development of system which controls the release and enhances the bioavailability of Acyclovir an antiviral agent with low oral bioavailability (10-30%) is in demand. Thus present work is focused on design and development of acyclovir liposomes by reverse phase evaporation method using various ratios of phosphatidyl choline with cholesterol and Cephalin (phosphatidyl ethanolamine) with cholesterol. Based on evaluation of entrapment efficiency, the best formulations were subjected to physicochemical studies i.e., photo microscopy, in vitro drug release and stability studies. The % entrapped drug in soya lecithin liposomes of batch F17 and F21 are 60.51 and 59.69 and cephalin liposomes of F41 and F45 are 58.23 and 57.38 respectively. The formulations F17, F21, F41 and F45 sustained the release and at the end of 12 hr the % drug release was 73.89, 79.48, 76.78 and 79.77 % respectively. Short-term stability studies were carried out for the selected formulations (F17, F21, F41 and F45) for a period of two months at 4°C, 25±2°C/ 60±5% RH and 30±2°C/ 65±5% RH.  The liposomes stored at 4°C were found to be stable for duration of two months compared to other storage conditions. Hence it can be concluded that four formulations can be used for controlled release of acyclovir.

Keywords: Liposomes, Acyclovir, Phosphatidyl Choline, Cholesterol, Cephalin, Reverse Phase Evaporation.

B S Mangond, V Sreedhar, V V Baraskar, R V Kulkarni

Compared to single unit-dosage forms, multi-unit controlled release dosage forms like microbeads and microparticles are advantageous as they prevent the exposure of absorbing site to high drug concentration on chronic dosing. Gellan gum based hydrogel microbeads loaded with ketoprofen were prepared by ionotropic gelation method and evaluated for size analysis, surface morphology, dynamic swelling and drug release behavior. The scanning electron microscopy (SEM) revealed that the prepared beads were spherical in nature. The effects of crosslinking agent and polymer concentrations on the release of drug were studied. With increase in concentrations of crosslinking agent and polymers, a decreased drug release was observed. The release data were fitted to an empirical equation to calculate the release mechanism. Drug release followed non-Fickian mechanism. Thus the prepared microbeads are useful carriers for controlled release of ketoprofen.

Keywords: Ketoprofen, Hydrogel Beads, Gellan Gum, Controlled Release.


V A Sawant, R B Unhale, V S Shende, S N Borkar, V K Chatap

The HIV epidemic has reached an important threshold in India. India has the World’s second largest burden of HIV-infected persons. The objective of the present study was to formulate and evaluate once-daily sustained release matrix tablets of Stavudine using hydrophilic hydroxypropyl methylcellulose alone, combination of two different viscosity grades of hydroxypropyl methylcellulose and combination of hydroxypropyl methylcellulose with ethyl cellulose. Stavudine (Antiviral agent) has a short half life 1.22 h and usual oral dosage regimen 30mg and 40 mg twice daily. The most commonly used method of modulating the drug release is to include it in a matrix system. The viscosity of hydroxypropyl methylcellulose polymer influences the erosion rate of matrix tablet. The rate of tablet erosion can be adjusted by the choice of hydroxypropyl methylcellulose polymer viscosity or by mixing hydroxypropyl methylcellulose polymer of varying viscosities. The drug release for extended duration using a hydrophilic matrix system is restricted because of rapid diffusion of dissolved drug through the hydrophilic gel network. For such circumstances, hydrophobic polymers are suitable, along with a hydrophilic matrix for developing sustained release dosage forms. Hydrophobic polymers provide several advantages, ranging from good stability at varying pH values and moisture levels to well established safe applications. Therefore, in this study, the hydrophilic polymer (hydroxypropyl methylcellulose) was used as matrix material and hydrophobic polymer (ethyl cellulose) was used to extend the drug release. The results of invitro dissolution study shown that the formulation F8 (HPMC K15M: Ethyl cellulose, 1:1) exhibited satisfactory drug release pattern and total drug release pattern was very close to theoretical release profile. The mechanism of the drug release from sustained release matrix tablet of formulation F8 was fickanian diffusion.

Keywords: Stavudine, Hydrophilic Polymer, Hydrophobic Polymers, Antiviral Agent.

S B Chandra Mohan, N Manjunatha, Kalpesh Patel, M K Samanta, Shyamala Bhaskaran

In situ gels are capable of releasing drug in a sustained manner affording relatively constant plasma profiles. The study evaluates the potential of oral sustained delivery of famotidine with gellan gum and sodium alginate as gelling agents. Calcium ions present in the formulation helps in formation of gel when administered as oral aqueous solutions. Aqueous solutions of gellan gum and sodium alginate form gels on warming to body temperature in the presence of cations. The Famotidine a H2 receptor antagonist, with short half life of 3 h is chosen as candidature. Different Solutions (sols) were prepared varying the concentration from 0.25 %w/v to 6.0 % w/v and 0.5 % w/v to 7.0 % w/v in case of gellan gum and sodium alginate respectively. The sols were evaluated for rheological properties using brookfield viscometer. In vitro release rate studies were carried out using gastric buffer (pH 1.2) for 2 h followed by acidic buffer (pH 4) for 2h and than the phosphate buffer (pH 6.8) for 2 h respectively. Diffusion studies were carried out in franz diffusion cell using cellophane membrane and water uptake studies was also done. 1.0 % w/v sols and suspensions of the polymers showed pseudoplastic flow with a satisfactory release rate following diffusion mechanism. The diffusion co-efficient was found to be 2.5488 x 10-7 Cm2/Sec and 3.9648 x 10-7 Cm2/Sec for gellan gum and sodium alginate formulations. The sols of gellan gum or sodium alginate results in the formation of in situ gel of famotidine for better treatment of ulcer.

Keywords: Famotidine, In Situ Gel, Gellan Gum, Sodium Alginate.

Short Communications

J S Mulla, I M Khazi

Solid lipid nanoparticles (SLNs) were prepared via microemulsion method. SLNs formulation consists of lipid (glyceryl monostearate (GMS), stearic acid (SA) and trilurin (TLN)), stabilizers (soy lecithin and tween 80) and water. Influence of type of lipid, concentration of lipid, individual and in combination of stabilizers and homogenizer speed on particle size were studied intensively. Particle sizes were determined by laser scattering using a Malvern Mastersizer 2000 particle size analyzer. A higher concentration of lipid was found to rapidly increase the size of nanoparticles. In contrast, an increase in stirring rate and concentration of stabilizer agent were found to reduce moderately the size of the nanoparticles.

Keywords: Solid Lipid Nanoparticles, Microemulsion, Particle Size, Glyceryl Monostearate, Stearic Acid, Trilurin.

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