Biomedical subjects

J Akbuğa

Publications and source records attributed to J Akbuğa.

11 recordsLinked to original sources

PubMed2006

Fucosphere--new microsphere carriers for peptide and protein delivery: preparation and in vitro characterization.

PURPOSE: Fucoidan is a complex polysaccharide containing sugars and high amounts of sulphate derived from marine brown algaes. In this study, a new microsphere-delivery system based on cross-linking of fucoidan with chitosan, named Fucosphere, was evaluated as a drug carrier. Bovine serum albumin (BSA) was used as a model protein. The effect of fucoidan (1.5, 1.75, 2.0 and 2.5%), chitosan (0.25, 0.50 and 0.75%) and protein (0.25, 0.50 and 0.75%) concentrations, the origin of chitosan and the preparation methods of the particles on the microsphere characteristics were evaluated. METHODS: The microspheres were prepared by a simple method based on the cross-linking of the opposite charged biopolymers. The shape and surface morphologies of the particles were evaluated by scanning electron microscopy (SEM) and the size, charge and encapsulation capacity of the microspheres were determined. The released amount of BSA from the microspheres into phosphate buffered saline (PBS pH 7.4) was determined spectrophotometrically by the Bradford method. SDS-PAGE was performed to check the structural integrity of BSA after the preparation. RESULTS: Smooth and spherical microspheres between the size ranges of 0.61-1.28 microm were obtained. BSA was efficiently encapsulated into the microspheres (51.8-89.5%). All formulation parameters affected the encapsulation capacity of Fucosphere (p < 0.05). The highest encapsulation was obtained with microspheres containing 2.5% of fucoidan (89.5%). CONCLUSIONS: The extent of drug release from the microspheres was dependent on the concentrations of polymers and BSA, chitosan origin and type of preparation method. When the addition methods of protein compared, BSA encapsulated into Fucosphere released slower than the adsorbed protein (E) (p < 0.05). The electrophoretic mobility values of Fucospheres changed between +6.9 and +32.3 mV. In general, BSA release from Fucosphere showed a three-phasic release curve. In conclusion, this new fucoidan microsphere system may be a potential delivery of macromolecular drug such as peptide and protein.

Animals↗

PubMed1992

Some factors affecting properties and dissolution behavior of tableted furosemide microspheres.

Furosemide (1) microspheres prepared by using Eudragit RS (1:4 and 1:2 drug:polymer ratios) were tableted. Microspheres were compressed with or without excipients (lactose, Avicel PH 101 or Emcompress). The thickness and crushing strength of tablets containing excipients were also found to be affected by the type of excipients. Dissolution characteristics of furosemide from tableted microspheres with or without excipients depended on the applied compression force but showed a controlled release behavior. Compression slowed down the release of 1. Addition of excipients to the formulation increased drug dissolution. The release from tablets followed Higuchi matrix model kinetics.

Drug Compounding↗

PubMed1988

The inhibitory effect of liposome-encapsulated indomethacin on inflammation and platelet aggregation.

A comparison has been made between liposome-encapsulated and free indomethacin for their anti-inflammatory activities in the carrageenan paw oedema test in rats, and their inhibitory effect on platelet aggregation induced by adenosine 5-diphosphate (ADP) in-vitro. Free indomethacin, 3 mg kg-1, strongly inhibited carrageenan-induced oedema and a similar inhibitory activity was shown by 0.3 mg kg-1 of encapsulated drug. For the inhibition of platelet aggregation, the threshold concentration of free drug was 0.559 mM. At this concentration, at least 5 min incubation was needed to achieve 12.5% and 45 min for 50% inhibition. The inhibition was much stronger with encapsulated drug, and pre-incubation of 28 microM encapsulated drug for 10 min with platelet-rich plasma before addition of ADP completely inhibited platelet aggregation.

Adenosine Diphosphate↗

PubMed1986

Film-coated zinc sulphate tablets and the effect of humidity on tablet properties.

Preparation of film-coated zinc sulphate tablets and the effect of relative humidity and aging on the physical properties of these coated tablets were investigated in this study. Shellac; Eudragit E and L, hydroxypropyl methylcellulose (HPMC) and HPMC-Eudragit E mixture were used as film-forming materials. As zinc sulphate has efflorescent properties, the effect of humidity on the coated tablets was studied and physical stability tests were carried out. Coated tablets were kept in bottles and in open petri-dishes at different relative humidities (30, 55 and 85%) at room temperature over 12 weeks, and the weight loss, hardness, and disintegration times of these tablets were followed. Findings indicated that film-coated zinc sulphate tablets having good tablet quality can be prepared using the formulations (F-VI) HPMC-Eudragit E mixture and (F-III) Eudragit E as coating materials. Thus, the effect of relative humidity on tablet properties can be reduced.

Drug Stability↗

PubMed1984

Effect of relative humidity on drug release from phenytoin sodium tablets and capsules. Part 1: Commercial preparations.

In this study the release rate of the active substance from different lots of commercial tablets and capsules of phenytoin sodium kept in different relative humidities (56, 75, 95%) was studied. It was observed that in both tablets and capsules, the effect of relative humidity and ageing was evident on the in vitro dissolution rate when compared with the in vitro dissolution profiles obtained before storage. The release rate differed from one lot to another after storage, the lots with higher release rates before storage in general showing a decrease and the ones with lower dissolution rates showing a higher release rate after storage.

Capsules↗

PubMed1984

Effect of relative humidity and ageing on drug release. Part 2: Experimental phenytoin sodium capsules.

In this study the effect of ageing and relative humidity on the release rate of phenytoin sodium was investigated for an experimental capsule formulation. Phenytoin sodium capsules containing lactose as the excipient were kept in 75 and 95% relative humidities, for 8 weeks, and the variances in the in vitro dissolution profiles of the active substance were observed. In vitro dissolution results were also evaluated kinetically. In general, it was observed that there was a decrease in the in vitro dissolution rate after storage at 95% relative humidity.

Capsules↗

PubMed1983

Studies on flufenamic acid capsules and tablets.

In this study, the in vitro dissolution rate of flufenamic acid was investigated in two different dosage forms, tablets and capsules, and the influence of the commonly used additives (lactose, corn starch, magnesium stearate, sodium lauryl sulphate). Using lactose, starch, Avicel PH 101, and methyl cellulose as additives, direct compression and wet granulation techniques were tried for preparing flufenamic acid tablets. The rotating basket method of U.S.P. XIX was used for determination of release rate. The findings were compared to the dissolution rate results of the commercial flufenamic acid capsules.

Capsules↗

PubMedDate not supplied

Release characteristics of chitosan treated alginate beads: II. Sustained release of a low molecular drug from chitosan treated alginate beads.

The aim of this paper was to investigate the possible applicability of chitosan treated alginate beads as a controlled release system of small molecular drugs with high solubility. Timolol maleate (mw 432.49) was used as a model drug. The beads were prepared by the ionotropic gelation method and the effect of various factors (alginate, chitosan, drug and calcium chloride concentrations, the volume of external and internal phases and drying methods) on bead properties were also investigated. Spherical beads with 0.78-1.16 mm diameter range and 10.8-66.5% encapsulation efficiencies were produced. Higher encapsulation efficiencies and retarded drug release were obtained with chitosan treated alginate beads. Among the different factors investigated such as alginate, drug, chitosan and CaCl2 concentrations, the volumes of the external and internal phases affected bead properties. The drying technique has an importance on the bead properties also. The release data was kinetically evaluated. It appeared that chitosan treated alginate beads may be used for a potential controlled release system of small molecular drugs with high solubility, instead of alginate beads.

Alginates↗

PubMedDate not supplied

Effect of formulation variables on cis-platin loaded chitosan microsphere properties.

Chitosan microspheres containing cis-platin were prepared using a w/o emulsion system. Variables important for microsphere properties were investigated: these include; chitosan, cis-platin and glutaraldehyde concentrations, the types of chitosan and oil, the cross-linking process and stirring rate. Chitosan and glutaraldehyde concentrations, the types of oil and chitosan have a significant effect on cis-platin entrapment in chitosan microspheres. In general, incorporation efficiency was high and ranged from 28-99%. The type and concentration of chitosan affected cis-platin release from microspheres. The type of oil was also important for release properties. Cis-platin release from microspheres is characterized by an initial burst effect.

Antineoplastic Agents↗

PubMedDate not supplied

Release characteristics of chitosan treated alginate beads: I. Sustained release of a macromolecular drug from chitosan treated alginate beads.

Alginate and chitosan treated alginate beads were prepared and compared as an oral controlled release system for macromolecular drugs. Dextran (M.W. 70,000) was used as a model substance. The beads were prepared by the ionotropic gelation method and the effect of various factors (alginate, chitosan, drug and calcium chloride concentrations, the volume of external and internal phases and drying methods) on bead properties were investigated. The addition of chitosan increased the drug loading capacity of the beads, and larger beads were obtained in the presence of chitosan. On the other hand, addition of chitosan in the gel structure reduced the drug release from beads. The erosion of the beads was suppressed by chitosan treatment. The drying method was important to the properties of the chitosan-alginate beads. It is proposed that chitosan treated alginate beads may be used as a potential controlled release system of such macromolecules.

Alginates↗

PubMedDate not supplied

5-Fluorouracil-loaded chitosan microspheres: preparation and release characteristics.

Cross-linked chitosan microspheres containing 5-Fluorouracil (5-FU) were prepared. Variables believed to be important for microsphere properties were examined; these included: drug and chitosan concentrations, cross-linking process, the type of oil, stirring rate and also additives. Initial 5-FU concentration, the type and concentration of chitosan, the viscosity of oil phase and glutaraldehyde concentration affected drug release from chitosan microspheres. 5-FU release from cross-linked chitosan microspheres is characterized by an initial rapid release of drug. Addition of substances such as alginic acid, chitin, agar, sodium caprylate and stearic acid changed the release properties of 5-FU microspheres.

Chitin↗