Burden of asymptomatic malaria among a tribal population in a forested village of central India: a hidden challenge for malaria control in India.

OBJECTIVE: Chhattisgarh in India is a malaria-endemic state with seven southern districts that contributes approximately 50-60% of the reported malaria cases in the state every year. The problem is further complicated due to asymptomatic malaria cases which are largely responsible for persistent transmission. This study was undertaken in one of the forested villages of the Keshkal subdistrict in Kondagaon district to ascertain the proportion of the population harbouring subclinical malarial infections. STUDY DESIGN: Community-based cross-sectional study. METHODS: Mass blood surveys were undertaken of the entire population of the village in the post-monsoon seasons of 2013 and 2014. Fingerprick blood smears were prepared from individuals of all ages to detect malaria infections in their blood. Individuals with fever at the time of the survey were tested with rapid diagnostic tests, and parasitaemia in thick blood smears was confirmed by microscopy. Malaria-positive cases were treated with anti-malarials in accordance with the national drug policy. RESULTS: Peripheral blood smears of 134 and 159 individuals, including children, were screened for malaria infection in 2013 and 2014, respectively. Overall, the malaria slide positivity rates were 27.6% and 27.7% in 2013 and 2014, respectively, and the prevalence rates of asymptomatic malaria were 20% and 22.8%. This study showed that, for two consecutive years, the prevalence of asymptomatic malaria infection was significantly higher among children aged ≤14 years (34.4% and 34.1% for 2013 and 2014, respectively) compared with adults (15.2% and 18.2% for 2013 and 2014, respectively; P = 0.023 and 0.04, respectively). CONCLUSION: The number of asymptomatic malaria cases, especially Plasmodium falciparum, is significant, reinforcing the underlying challenge facing the malaria elimination programme in India.

Development and validation of simultaneous quantification method for gemcitabine and betulinic acid: augmenting industrial application.

Combinatorial treatment utilizing a nucleoside analogue gemcitabine (GEM), with a characteristic pentacyclic triterpenoid betulinic acid (BET), has exhibited empowering adequacy in the therapy of cancer. It lessens the advancement of collagen and upgrades the saturation of tumour medicines. With the advancement in nanotechnology, the co-loaded formulation urges for a validated method of estimation. The purposed work entails a robust, simple, and economical analytical method for the simultaneous estimation of GEM and BET through RP-HPLC. Orthophosphoric acid (0.1%)-acetonitrile was considered as the mobile phase for the detection of GEM and BET at 248 nm and 210 nm with retention times of 5 min and 13 min, respectively. The method was further validated as per the regulatory guidelines with all the parameters found within the limit. The developed method with adequate resolution and quantification was found to be linear, accurate, precise, robust, and stable with an intra- and inter-day variability of less than 2%. The method was found specific for GEM and BET with no matrix interference of drug-spiked FBS samples. To demonstrate the applicability of the developed method, a nano-formulation containing GEM and BET was prepared and assessed for various parameters including encapsulation efficiency, loading efficiency, drug release, and drug stability. The method developed can be a possible tool for the simultaneous quantification of GEM-BET in analytical and biological samples.

Methotrexate bearing calcium pectinate microspheres: a platform to achieve colon-specific drug release.

In the present work calcium pectinate (Ca-pectinate) microspheres were prepared to deliver methotrexate in the environment of colon. Calcium pectinate microspheres were prepared by modified emulsification method using calcium chloride as cross linker. All the formulations were evaluated for various physicochemical parameters. Particle size of the microspheres was determined using laser diffraction particle size analyzer. Encapsulation efficiency was determined by digesting with enzyme pectinase for 24 hours and swellability by equilibrium swelling in simulated gastrointestinal fluid. The in vitro drug release studies were performed in simulated gastric fluid for 2 hours and simulated intestinal fluid for 3 hours. In vitro release rate studies were also carried out in simulated colonic fluid in presence of rat caecal contents. Moreover, release rate studies were also carried out after enzyme induction by treating the rats with 1 ml of 1% w/v aqueous dispersion of pectin for 7 days. Mean particle size of the microspheres was found to be in the range of 20.82+/-1.34 to 32.26+/-1.59 microm whereas the entrapment efficiency varied from 52.28+/-0.32 to 74.01+/-3.32%. The in vitro drug release studies in simulated gastric fluid and simulated intestinal fluid showed that only 8.15+/-0.49% drug was released in 5 hours whereas most of the loaded drug was released in simulated colonic fluid containing pectinase. In vitro release rate study showed release of 69.94+/-3.46% of drug in presence of 3% rat caecal contents, which was further increased to 94.43+/-4.48% when enzyme induction was carried out for 7 days. Thus, it is concluded that calcium pectinate microspheres can be used to effectively localize the release of drug in the physiological environment of colon.

Solid lipid nanoparticles bearing flurbiprofen for transdermal delivery.

Topical application of the drugs at the pathological sites offer potential advantages of delivering the drug directly to the site of action and thus producing high tissue concentrations of the drug. The solid lipid nanoparticles (SLN) bearing flurbiprofen were prepared by microemulsion method by dispersing o/w microemulsion in a cold aqueous surfactant medium under mechanical stirring. The SLN gel was prepared by adding SLN dispersion to polyacrylamide gel prepared by using polyacrylamide (0.5%), glycerol (10%), and water (69.5%). Shape and surface morphology was determined by scanning electron microscopy that revealed fairly spherical shape of the formulation. Percent drug entrapment was higher in SLN dispersion in comparison to SLN gel formulations. In vitro drug release, determined using cellophane membrane, showed that SLN dispersion exhibited higher drug release compared with SLN gel formulations. Both the SLN dispersion and SLN-gel formulation possessed a sustained drug release over a 24-hr period, but this sustained effect was more pronounced with SLN-gel formulations. The percent inhibition of edema after 8 hr was 55.51 +/- 0.26% in case of SLN-T4-gel, whereas flurbiprofen and SLN-T4 dispersion exhibited 28.81 +/- 0.46 and 31.89 +/- 0.82 inhibition of edema. The SLN-T4-gel not only decreased the inflammation to larger magnitude, but also sustained its effect.

Design and development of multivesicular liposomal depot delivery system for controlled systemic delivery of acyclovir sodium.

The aim of the present study was to design a depot delivery system of acyclovir sodium using multivesicular liposomes (MVLs) to overcome the limitations of conventional therapies and to investigate its in vivo effectiveness for sustained delivery. MVLs of acyclovir were prepared by the reverse phase evaporation method. The loading efficiency of the MVLs (45%-82%) was found to be 3 to 6 times higher than conventional multilamellar vesicles (MLVs). The in vitro release of acyclovir from MVL formulations was found to be in a sustained manner and only 70% of drug was released in 96 hours, whereas conventional MLVs released 80% of drug in 16 hours. Following intradermal administration to Wistar rats, the MVL formulations showed effective plasma concentration for 48 hours compared with MLVs and free drug solution (12-16 hours). C(max) values of MVL formulations were significantly less (8.6-11.4 microg/mL) than MLV and free drug solution (12.5 microg/mL). The AUC(0-48) of the MVL formulations was 1.5- and 3-fold higher compared with conventional liposomes and free drug solution, respectively. Overall, formulations containing phosphatidyl glycerol as negatively charged lipid showed better results. The MVL delivery system as an intradermal depot offers the advantage of a very high loading and controlled release of acyclovir for an extended period of time. The increase in AUC and decrease in C(max) reflects that the MVL formulations could reduce the toxic complications and limitations of conventional iv and oral therapies.

Potential of guar gum microspheres for target specific drug release to colon.

Various approaches for colon targeted drug delivery have been studied over the last decade including, pro-drugs, timed-released systems, coating of pH-dependant polymer and the use of polysaccharides. In the present work, a novel formulation consisting of cross-linked microspheres of guar gum has been investigated for colon-targeted delivery of metronidazole. An emulsification method involving the dispersion of aqueous solution of guar gum in castor oil was used to prepare spherical microspheres. Process parameters were analyzed in order to optimize the formulation. Shape and surface morphology of the microspheres were examined using scanning electron microscopy. Placebo microspheres exhibited a smooth surface while the incorporation of drug imparted a slight roughness to the surface texture. Particle size of the microspheres was determined using laser diffraction particle size analyzer. The in vitro drug release studies were performed in simulated gastric fluid for 2 h and intestinal fluid for 3 h, which revealed that the drug was retained comfortably inside the microspheres and that only 15.27+/-0.56% of the drug was released in 5 h. In vitro release rate studies were also carried out in simulated colonic fluid (SCF) in the presence of rat cecal contents, which showed improved drug release. Moreover, to induce the enzymes that specifically act on guar gum, the rats were treated with 1 ml of 1% w/v dispersion of guar gum for 2, 4 and 6 days and release rate studies were repeated in SCF in the presence of 2 and 4% w/v of cecal matter. A marked improvement in the drug release was observed in presence of cecal matter obtained after induction when compared to those without induction. In vitro release studies exhibited 31.23+/-1.49% drug release in 24 h in dissolution medium without rat cecal matter. However, the incorporation of 4% w/v cecal matter obtained after 6 days of enzymes induction increased the drug release to 96.24+/-4.77%.

Pharmaceutical approaches to colon targeted drug delivery systems.

PURPOSE: Although oral delivery has become a widely accepted route of administration of therapeutic drugs, the gastrointestinal tract presents several formidable barriers to drug delivery. Colonic drug delivery has gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon but also for its potential for the delivery of proteins and therapeutic peptides. To achieve successful colonic delivery, a drug needs to be protected from absorption and /or the environment of the upper gastrointestinal tract (GIT) and then be abruptly released into the proximal colon, which is considered the optimum site for colon-targeted delivery of drugs. Colon targeting is naturally of value for the topical treatment of diseases of colon such as Chron's diseases, ulcerative colitis, colorectal cancer and amebiasis. Peptides, proteins, oligonucleotides and vaccines pose potential candidature for colon targeted drug delivery. METHODS: The various strategies for targeting orally administered drugs to the colon include covalent linkage of a drug with a carrier, coating with pH-sensitive polymers, formulation of timed released systems, exploitation of carriers that are degraded specifically by colonic bacteria, bioadhesive systems and osmotic controlled drug delivery systems. Various prodrugs (sulfasalazine, ipsalazine, balsalazine and olsalazine) have been developed that are aimed to deliver 5-amino salicylic acid (5-ASA) for localized chemotherapy of inflammatory bowl disease (IBD). Microbially degradable polymers especially azo crosslinked polymers have been investigated for use in targeting of drugs to colon. Certain plant polysaccharides such as amylose, inulin, pectin and guar gum remains unaffected in the presence of gastrointestinal enzymes and pave the way for the formulation of colon targeted drug delivery systems. The concept of using pH as a rigger to release a drug in the colon is based on the pH conditions that vary continuously down the gastrointestinal tract. Times dependent drug delivery systems have been developed that are based on the principle to prevent release of drug until 3-4 h after leaving the stomach. Redox sensitive polymers and bioadhesive systems have also been exploited to deliver the drugs into the colon. RESULTS: The approach that is based on the formation of prodrug involves covalent linkage between drug and carrier. The type of linkage that is formed between drug and carrier would decide the triggering mechanism for the release of drug in colon. The presence of azo reductase enzymes play pivotal role in the release of drug from azo bond prodrugs while glycosidase activity of the colonic microflora is responsible for liberation of drugs from glycosidic prodrugs. Release of drugs from azo polymer coated dosage forms is supposed to take place after reduction and thus cleavage of the azo bonds by the azoreductase enzymes present in the colonic microflora. Natural polysaccharides have been used as tools to deliver the drugs specifically to the colon. These polysaccharides remain intact in the physiological environment of stomach and small intestine but once the dosage form enters into colon, it is acted upon by polysaccharidases, which degrades the polysaccharide and releases the drug into the vicinity of bioenvironment of colon. However, they should be protected while gaining entry into stomach and small intestine due to enormous swelling and hydrophilic properties of polysaccharides. This has been achieved either by chemical crosslinking or by addition of a protective coat. Formulation coated with enteric polymers releases drug when pH move towards alkaline range while as the multicoated formulation passes the stomach, the drug is released after a lag time of 3-5 h that is equivalent to small intestinal transit time. Drug coated with a bioadhesive polymer that selectively provides adhesion to the colonic mucosa may release drug in the colon. CONCLUSIONS: Improved drug delivery systems are required for drugs currently in use to treat localized diseases of the colon. The advantages of targeting drugs specifically to the diseased colon are reduced incidence of systemic side effects, lower dose of drug, supply of the drug to the biophase only when it is required and maintenance of the drug in its intact form as close as possible to the target site.

Design and development of multiparticulate system for targeted drug delivery to colon.

A multiparticulate system combining pH-sensitive property and specific biodegradability for colon-targeted delivery of metronidazole has been investigated. Cross-linked chitosan microspheres were prepared from an emulsion system using liquid paraffin as the external phase and solution of chitosan in acetic acid as the disperse phase. The multiparticulate system was prepared by coating cross-linked chitosan microspheres exploiting Eudragit L-100 and S-100 as pH-sensitive polymers. Morphology and surface characteristics of the formulations were determined by scanning electron microscopy. Particle size of the chitosan microspheres was determined by optical microscopy while that of coated microspheres was determined by particle size analyzer. In vitro drug-release studies were performed in conditions simulating stomach-to-colon transit in presence and absence of rat caecal contents. The size of the microspheres was small and they were efficiently microencapsulated within Eudragit microspheres, forming a multireservoir system. By coating the microspheres with Eudragit pH-dependant release profiles were obtained. No release was observed at acidic pH; however, when it reached the pH where Eudragit starts solublizing there was continuous release of drug from the formulation. Further, the release of drug was found to be higher in the presence of rat caecal contents, indicating the susceptibility of chitosan matrix to colonic enzymes released from rat caecal contents.

Polysaccharides for colon targeted drug delivery.

Colon targeted drug delivery has the potential to deliver bioactive agents for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. Various strategies, currently available to target the release of drugs to colon, include formation of prodrug, coating of pH-sensitive polymers, use of colon-specific biodegradable polymers, timed released systems, osmotic systems, and pressure controlled drug delivery systems. Among the different approaches to achieve targeted drug release to the colon, the use of polymers especially biodegradable by colonic bacteria holds great promise. Polysaccharidases are bacterial enzymes that are available in sufficient quantity to be exploited in colon targeting of drugs. Based on this approach, various polysaccharides have been investigated for colon-specific drug release. These polysaccharides include pectin, guar gum, amylose, inulin, dextran, chitosan, and chondroitin sulphate. This family of natural polymers has an appeal to drug delivery as it is comprised of polymers with a large number of derivatizable groups, a wide range of molecular weights, varying chemical compositions, and, for the most part, low toxicity and biodegradability yet high stability. The most favorable property of these materials is their approval as pharmaceutical excipients.

Development and characterization of mucoadhesive microspheres bearing salbutamol for nasal delivery.

Mucoadhesive drug delivery systems are those that provide intimate contact of the drug with the mucosa for an extended period of time. In our present work, mucoadhesive chitosan microspheres were prepared by emulsion solvent method. Formulations were characterized for various physicochemical attributes, shape, surface morphology, size, and size distribution, drug payload, swelling ability, and mucoadhesion. The effect of drug, citric acid, and permeation enhancer concentration on the physicochemical properties was studied. Crosslinked chitosan microspheres showed very good mucoadhesion, which was decreased on increasing the drug concentration and citric acid concentration, and slightly improved upon incorporation of permeation enhancer. The in vitro drug release and in vitro drug permeability through mucous membrane were performed, and slow release/permeation was noted with chitosan citrate complexed microspheres compared with noncomplexed chitosan microspheres. The in vivo performance of mucoadhesive microspheres formulations showed prolonged and controlled release of salbutamol as compared with oral administration of conventional dosage form.

Development and characterization of transdermal drug delivery systems for diltiazem hydrochloride.

Transdermal drug delivery system of diltiazem hydrochloride was developed to obtain a prolonged controlled drug delivery. Both the matrix diffusion controlled (MDC) and membrane permeation controlled (MPC) systems were developed. The matrix diffusion controlled systems used various combinations of hydrophilic and lipophillic polymers, whereas membrane permeation controlled systems were developed using the natural polymer chitosan. The MDC systems were prepared using the cast film method and the MPC systems by an adhesive sealing technique. Both the systems were characterized for in vitro and in vivo performance. The MDC systems were characterized for physicochemical properties such as tensile strength, moisture content, and water vapor transmission. The in vitro release studies showed that the release from the matrix diffusion controlled transdermal drug delivery systems follows a nonfickian pattern and that from the membrane permeation controlled transdermal drug delivery systems follow zero-order kinetics. The release from the matrix systems increased on increasing the hydrophilic polymer concentration, but the release from the membrane systems decrease on cross-linking of the rate controlling membrane and also on addition of citric acid to the chitosan drug reservoir gel. The in vivo studies of the selected systems showed that both systems are capable of achieving the effective plasma concentration for a prolonged period of time. The MPC system achieved effective plasma concentration a little more slowly than the MDC system, but it exhibited a more steady state plasma level for 24 hr.

An insight into potential of nanoparticles-assisted chemotherapy of cancer using gemcitabine and its fatty acid prodrug:a comparative study.

Gemcitabine (dFdC) mediated cancer treatment faces obstacles, due to its high hydrophilicity. A valuable strategy was executed by synthesizing lipophilic fatty acid derivative of dFdC i.e., 4-(N)-stearoyl gemcitabine (C18dFdC), built-in into polymeric poly-lactic-co-glycolic acid nanoparticles (PLGA NPs) and compared with that of parent drug. Encapsulation of derivative within NPs was higher (68.24 +/- 3.64%) than dFdC and showed comparatively sustained drug release (19.87 +/- 1.73% within 12 hours), with a proof of increased biological half life. The cytotoxicity and flow cytometric analysis displayed enhanced MCF-7 cell inhibition by C18dFdC-NPs with higher uptake compared to dFdC-NPs. Interestingly, like gemcitabine, C18dFdC-NPs did not induce appreciable differences in blood parameters and in vivo tissue toxicity study demonstrating safe use of derivative at 40 mg/kg dose. In conclusion, the preclinical data obtained in vitro and in vivo demonstrate the C18dFdC-nanocarrier as an advantageous and promising delivery system for cancer treatment along with the potential to improve the clinical outcome of gemcitabine chemotherapy.