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Carboxymethyl fenugreek galactomannan-gellan gum-calcium silicate composite beads for glimepiride delivery

Bera H, Mothe S, Maiti S, Vanga S

Int J Biol Macromol, 2018 Feb;107(Pt A):604-614.
PMID: 28916379 DOI: 10.1016/j.ijbiomac.2017.09.027

Novel carboxymethyl fenugreek galactomannan (CFG)-gellan gum (GG)-calcium silicate (CS) composite beads were developed for controlled glimepiride (GLI) delivery. CFG having degree of carboxymethylation of 0.71 was synthesized and characterized by FTIR, DSC and XRD analyses. Subsequently, GLI-loaded hybrids were accomplished by ionotropic gelation technique employing Ca+2/Zn+2/Al+3 ions as cross-linkers. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 48-97%) and sustained drug release behaviour (Q8h, 62-94%). These quality attributes were remarkably influenced by polymer-blend (GG:CFG) ratios, cross-linker types and CS inclusion. The drug release profile of the optimized formulation (F-6) was best fitted in zero-order model with anomalous diffusion driven mechanism. It also conferred excellent ex vivo mucoadhesive property and considerable hypoglycemic effect in streptozotocin-induced diabetic rats. Furthermore, the beads were characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the developed hybrid matrices are appropriate for controlled delivery of GLI for Type 2 diabetes management.

Matched MeSH terms: Polysaccharides, Bacterial/chemistry
Gamma-scintigraphic study of the gastrointestinal transit and in vivo dissolution of a controlled release diclofenac sodium formulation in xanthan gum matrices

Billa N, Yuen KH, Khader MA, Omar A

Int J Pharm, 2000 May 15;201(1):109-20.
PMID: 10867269

A xanthan gum matrix controlled release tablet formulation containing diclofenac sodium was evaluated in vitro and was found to release the drug at a uniform rate. The gastrointestinal transit behaviour of the formulation as determined by gamma scintigraphy, using healthy male volunteers under fasted and fed conditions, indicated that gastric emptying was delayed with food intake. In contrast, the small intestinal transit remained practically unchanged under both food statuses. Therefore, the delay in caecal arrival observed in the fed state can be attributed to the delay in gastric emptying. Rate of diclofenac sodium absorption was generally higher in the fed state compared to the fasted state, however the total amount absorbed under both food statuses remained practically the same. The rate of in vivo dissolution of the drug in the fed state was faster compared to that in the fasted state. Thus, at the time of caecal arrival, in vivo dissolution was complete in the fed state, unlike in the fasted state, where almost 60% of the drug was delivered to the colon.

Matched MeSH terms: Polysaccharides, Bacterial
Economic Impact of Pneumococcal Protein-D Conjugate Vaccine (PHiD-CV) on the Malaysian National Immunization Programme

Aljunid S, Maimaiti N, Ahmed Z, Muhammad Nur A, Md Isa Z, Azmi S, et al.

Value Health Reg Issues, 2014 May;3:146-155.
PMID: 29702920 DOI: 10.1016/j.vhri.2014.04.008

OBJECTIVE: To assess the cost-effectiveness of introducing pneumococcal polysaccharide and nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in the National Immunization Programme of Malaysia. This study compared introducing PHiD-CV (10 valent vaccine) with current no vaccination, as well as against the alternative 13-valent pneumococcal conjugate vaccine (PCV13).

METHODS: A lifetime Markov cohort model was adapted using national estimates of disease burden, outcomes of pneumococcal disease, and treatment costs of disease manifestations including pneumonia, acute otitis media, septicemia, and meningitis for a hypothetical birth cohort of 550,000 infants. Clinical information was obtained by review of medical records from four public hospitals in Malaysia from the year 2008 to 2009. Inpatient cost from the four study hospitals was obtained from a diagnostic-related group-based costing system. Outpatient cost was estimated using clinical pathways developed by an expert panel. The perspective assessed was that of the Ministry of Health, Malaysia.

RESULTS: The estimated disease incidence was 1.2, 3.7, 70, and 6.9 per 100,000 population for meningitis, bacteremia, pneumonia, and acute otitis media, respectively. The Markov model predicted medical costs of Malaysian ringgit (RM) 4.86 billion (US $1.51 billion) in the absence of vaccination. Vaccination with PHiD-CV would be highly cost-effective against no vaccination at RM30,290 (US $7,407) per quality-adjusted life-year gained. On comparing PHiD-CV with PCV13, it was found that PHiD-CV dominates PCV13, with 179 quality-adjusted life-years gained while saving RM35 million (US $10.87 million).

CONCLUSIONS: It is cost-effective to incorporate pneumococcal vaccination in the National Immunization Programme of Malaysia. Our model suggests that PHiD-CV would be more cost saving than PCV13 from the perspective of the Ministry of Health of Malaysia.

Study site: UKM Medical Centre, Hospital Kuala Lumpur, Hospital
Alor Setar, and Hospital Queen Elizabeth, Kota Kinabalu

Matched MeSH terms: Polysaccharides
Fulltext Attachment of Salmonella strains to a plant cell wall model is modulated by surface characteristics and not by specific carbohydrate interactions

Tan MS, Moore SC, Tabor RF, Fegan N, Rahman S, Dykes GA

BMC Microbiol, 2016 09 15;16:212.
PMID: 27629769 DOI: 10.1186/s12866-016-0832-2

BACKGROUND: Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface.
RESULTS: We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin.
CONCLUSIONS: Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.

Matched MeSH terms: Polysaccharides