Preparation of casein-chitosan microspheres containing diltiazem hydrochloride by an aqueous coacervation technique

Nanofibrous composite from chitosan-casein polyelectrolyte complex for rapid hemostasis in rat models in vivo

Bleeding causes ∼5.8 million deaths globally; half of the patients die if rapid hemostasis is not achieved. Here, we report a chitosan-casein (CC)-based nanofibrous polyelectrolyte complex (PEC) that could clot blood within 10 s in the rat femoral artery model in vivo. The nanofiber formation by self-assembly was also optimized for process parameters (concentration, mixing ratio, pH, and ultrasonication). Results showed that increasing the concentration of chitosan from 10 % to 90 % in the formulation increased the productivity (r = 0.99) of PECs but led to increased blood clotting time (r = 0.90) due to an increase in zeta potential (r = 0.98), fiber diameter (r = 0.93), and decreased surface porosity (r = -0.99), absorption capacity (r = -0.99). The pH also influenced the zeta potential of PEC, with an optimized pH of 8.0 ± 0.1 yielding clear nanofibers. Sonication improved the segregation of nanofibers by promoting water removal. The optimized PECs containing chitosan and casein in the ratio of 30:70 (CC30) at a pH of 8.0 and dehydration under sonication could clot the blood within 9 ± 2 s in vitro and 9 ± 2 s in rat femoral artery puncture model. The CC30 formulation did not cause any irritation or corrosion on rat skin. Histopathology and immunohistochemistry of various organs showed that CC30 was biocompatible and non-immunogenic under in vivo conditions.

Porous Chitosan/Hydroxyapatite Composite Microspheres for Vancomycin Loading and Releasing

Porous chitosan/hydroxyapatite (Chi-HAp) composite microspheres were prepared in an aqueous solution containing chitosan, calcium nitrate, and ammonium dihydrogen phosphate by using a hydrothermal method at various temperatures. The investigation indicated that temperature significantly impacted the final product's appearance. Hydroxyapatite (HAp) coupled with dicalcium phosphate dihydrate (DCPD) flakes were obviously found at 65 and 70 °C, while the latter gradually disappeared at higher temperatures. Conversely, synthesis at 90 °C led to smaller particle sizes due to the broken chitosan chains. The microspheres synthesized at 75 °C were selected for further analysis, revealing porous structures with specific surface areas of 36.66 m2/g, pores ranging from 3 to 100 nm, and pore volumes of 0.58 cm3/g. Vancomycin (VCM), an antibiotic, was then absorbed on and released from the microspheres derived at 75 °C, with a drug entrapment efficiency of 20% and a release duration exceeding 20 days. The bacteriostatic activity of the VCM/composite microspheres against Staphylococcus aureus increased with the VCM concentration and immersion time, revealing a stable inhibition zone diameter of approximately 4.3 mm from 24 to 96 h, and this indicated the retained stability and efficacy of the VCM during the encapsulating process.

Wet-Spun Chitosan-Sodium Caseinate Fibers for Biomedicine: From Spinning Process to Physical Properties

We designed and characterized chitosan-caseinate fibers processed through wet spinning for biomedical applications such as drug delivery from knitted medical devices. Sodium caseinate was either incorporated directly into the chitosan dope or allowed to diffuse into the chitosan hydrogel from a coagulation bath containing sodium caseinate and sodium hydroxide (NaOH). The latter route, where caseinate was incorporated in the neutralization bath, produced fibers with better mechanical properties for textile applications than those formed by the chitosan-caseinate mixed collodion route. The latter processing method consists of enriching a pre-formed chitosan hydrogel with caseinate, preserving the structure of the semicrystalline hydrogel without drastically affecting interactions involved in the chitosan self-assembly. Thus, dried fibers, after coagulation in a NaOH/sodium caseinate aqueous bath, exhibited preserved ultimate mechanical properties. The crystallinity ratio of chitosan was not significantly impacted by the presence of caseinate. However, when caseinate was incorporated into the chitosan dope, chitosan-caseinate fibers exhibited lower ultimate mechanical properties, possibly due to a lower entanglement density in the amorphous phase of the chitosan matrix. A standpoint is to optimize the chitosan-caseinate composition ratio and processing route to find a good compromise between the preservation of fiber mechanical properties and appropriate fiber composition for potential application in drug release.

The Preparation and Characterization of Chitosan/Calcium Phosphate Composite Microspheres for Biomedical Applications

In this study, we successfully prepared porous composite microspheres composed of hydroxyapatite (HAp), di-calcium phosphate di-hydrated (DCPD), and chitosan through the hydrothermal method. The chitosan played a crucial role as a chelating agent to facilitate the growth of related calcium phosphates. The synthesized porous composite microspheres exhibit a specific surface area of 38.16 m2/g and a pore volume of 0.24 cm3/g, with the pore size ranging from 4 to 100 nm. Given the unique properties of chitosan and the exceptional porosity of these composite microspheres, they may serve as carriers for pharmaceuticals. After being annealed, the chitosan transforms into a condensed form and the DCPD transforms into Ca2P2O7 at 300 °C. Then, the Ca2P2O7 initially combines with HAp to transform into β tricalcium phosphate (β-TCP) at 500 °C where the chitosan is also completely combusted. Finally, the microspheres are composed of Ca2P2O7, β-TCP, and HAp, also making them suitable for applications such as injectable bone graft materials.

Contemporary Aspects of Designing Marine Polysaccharide Microparticles as Drug Carriers for Biomedical Application

The main goal of modern pharmaceutical technology is to create new drug formulations that are safer and more effective. These formulations should allow targeted drug delivery, improved drug stability and bioavailability, fewer side effects, and reduced drug toxicity. One successful approach for achieving these objectives is using polymer microcarriers for drug delivery. They are effective for treating various diseases through different administration routes. When creating pharmaceutical systems, choosing the right drug carrier is crucial. Biomaterials have become increasingly popular over the past few decades due to their lack of toxicity, renewable sources, and affordability. Marine polysaccharides, in particular, have been widely used as substitutes for synthetic polymers in drug carrier applications. Their inherent properties, such as biodegradability and biocompatibility, make marine polysaccharide-based microcarriers a prospective platform for developing drug delivery systems. This review paper explores the principles of microparticle design using marine polysaccharides as drug carriers. By reviewing the current literature, the paper highlights the challenges of formulating polymer microparticles, and proposes various technological solutions. It also outlines future perspectives for developing marine polysaccharides as drug microcarriers.

The Use of Natural Materials in Film Coating for Controlled Oral Drug Release

BACKGROUND

Although synthetic materials have been used in film coating processes for drug delivery for many years, substantial studies on natural materials have also been conducted because of their biodegradable and unique properties.

METHODS

Because of the ability to form and modify films for controlled oral drug delivery, increasing attention has been shown to these materials in the design of film coating systems in recent research.

RESULTS

This review aims to provide an overview of natural materials focusing on film coating for oral delivery, specifically in terms of their classification and their combinations in film coating formulations for adjusting the desired properties for controlled drug delivery.

CONCLUSIONS

Discussing natural materials and their potential applications in film coating would benefit the optimization of processes and strategies for future utilization.

Chitosan grafted/cross-linked with biodegradable polymers: A review

Public perception of polymers has been drastically changed with the improved plastic management at the end of their life. However, it is widely recognised the need of developing biodegradable polymers, as an alternative to traditional petrochemical polymers. Chitosan (CH), a biodegradable biopolymer with excellent physiological and structural properties, together with its immunostimulatory and antibacterial activity, is a good candidate to replace other polymers, mainly in biomedical applications. However, CH has also several drawbacks, which can be solved by chemical modifications to improve some of its characteristics such as solubility, biological activity, and mechanical properties. Many chemical modifications have been studied in the last decade to improve the properties of CH. This review focussed on a critical analysis of the state of the art of chemical modifications by cross-linking and graft polymerization, between CH or CH derivatives and other biodegradable polymers (polysaccharides or proteins, obtained from microorganisms, synthetized from biomonomers, or from petrochemical products). Both techniques offer the option of including a wide variety of functional groups into the CH chain. Thus, enhanced and new properties can be obtained in accordance with the requirements for different applications, such as the release of drugs, the improvement of antimicrobial properties of fabrics, the removal of dyes, or as scaffolds to develop bone tissues.

Ultrahigh verapamil-loaded controlled release polymeric beads using superamphiphobic substrate: D-optimal statistical design, in vitro and in vivo performance

Controlled-release multiparticulate systems of hydrophilic drugs usually suffer from poor encapsulation and rapid-release rate. In the present study, ultra-high loaded controlled release polymeric beads containing verapamil hydrochloride (VP) as hydrophilic model drug were efficiently prepared using superamphiphobic substrates aiming to improve patient compliance by reducing dosing frequency. Superamphiphobic substrates were fabricated using clean aluminum sheets etched with ammonia solution and were treated with 1.5% (w/v) perfluorodecyltriethoxysilane (PFDTS) alcoholic solution. The effect of the main polymer type (lactide/glycolide (PLGA) 5004A, PLGA 5010, and polycaprolactone (PCL)), copolymer (Eudragit RS100) content together with the effect of drug load on encapsulation efficiency (EE%) and in vitro drug release was statistically studied and optimized via D-optimal statistical design. In vivo pharmacokinetic study was carried out to compare the optimized system relative to the market product (Isoptin®). Results revealed that superamphiphobic substrates were successfully prepared showing a rough micro-sized hierarchical structured surface upon observing with scanning electron microscope and were confirmed by high contact angles of 151.60 ± 2.42 and 142.80°±05.23° for water and olive oil, respectively. The fabricated VP-loaded beads showed extremely high encapsulation efficiency exceeding 92.31% w/w. All the prepared systems exhibited a controlled release behavior with Q12 h ranging between 5.46 and 95.90%w/w. The optimized VP-loaded system composed of 150 mg (1.5% w/v) PCL without Eudragit RS100 together with 160 mg VP showed 2.7-folds mean residence time compared to the market product allowing once daily administration instead of three times per day.

Preparation and Characterization of Hot Melt Copolyester (PBTI) Ultrafine Particles and Their Effect on the Anti-Pilling Performance of Polyester/Cotton Fabrics

An ultrafine particle aqueous-phase system of hot melt copolyester was prepared by an inverse emulsion–precipitation method. Laser particle size analysis showed that the diameter of the obtained copolyester particles was mostly distributed between 20 and 100 nm. The structure of the copolymer was characterized by FT–IR and ¹H-NMR, and the melting point of the particles was determined to be 125 °C, as measured by differential scanning calorimetry (DSC). Intrinsic viscosity analysis showed that the particle intrinsic viscosity decreased by 6.73% compared with that of the original copolyester. Polyester/cotton woven fabrics were padded with the ultrafine copolyester particles at different concentrations, and the corresponding SEM showed that the fibers were well bonded to each other. The pilling test results showed that these ultrafine copolyester granules improved the pilling performance of the polyester/cotton woven fabrics to a grade of 4.5–5.

Effect of mesenchymal stem cells and galantamine nanoparticles in rat model of Alzheimer's disease

AIM

The present study investigated the efficacy of bone marrow-derived mesenchymal stem cells (BM-MSCs) in combination with galantamine hydrobromide-loaded solid lipid nanoparticles (GH-SLNs) in intracerebroventricular (ICV)-isoproterenol-induced rat model of Alzheimer's disease.

MATERIALS & METHODS

BM-MSCs were harvested by dissecting femur and tibia of 8-10-week-old Wistar rats. 1 × 10(6) cells were administered intravenously once in ICV-isoproterenol-induced rats followed by GH-SLNs (5 mg/kg) for 3 weeks.

RESULTS & CONCLUSION

ICV-isoproterenol resulted in significant memory deficit. The results demonstrated rapid regain of memory in isoproterenol-induced amnesic rats, following single intravenous administration of BM-MSCs and oral administration of GH-SLNs for 21 days. The combination of BM-MSCs and GH-SLNs produced a more pronounced protective effect, therefore, could be explored for the management of Alzheimer's disease.

Surface Deposition and Coalescence and Coacervation Phase Separation Methods: In Vitro Study and Compatibility Analysis of Eudragit RS30D, Eudragit RL30D, and Carbopol-PLA Loaded Metronidazole Microspheres

Metronidazole (MTZ) has extremely broad spectrum of protozoal and antimicrobial activity and is clinically effective in trichomoniasis, amoebic colitis, and giardiasis. This study was performed to formulate and evaluate the MTZ loaded microspheres by coacervation phase separation and surface deposition and coalescence methods using different polymers like Gelatin, Carbopol 934P, Polylactic Acid (PLA), Eudragit RS30D, and Eudragit RL30D to acquire sustained release of drug. In vitro dissolution studies were carried out in phosphate buffer (pH 7.4) for 8 hours according to USP paddle method. The maximum and minimum release of MTZ from microspheres observed were 84.81% and 76.6% for coacervation and 95.07% and 80.07% for surface deposition method, respectively, after 8 hours. Release kinetics was studied in different mathematical release models. The SEM and FTIR studies confirm good spheres and smooth surface as well as interaction between drug and polymers. Though release kinetic is uncertain, the best fit was obtained with the Korsmeyer kinetic model with release exponent (n) lying between 0.45 and 0.89. In vitro studies showed that MTZ microspheres with different polymers might be a good candidate as sustained drug delivery system to treat bacterial infections.

Nanoparticle formulation by Büchi B-90 Nano Spray Dryer for oral mucoadhesion

Diabetes is considered one of the main threats to global public health in this era. It is increasing rapidly in every part of the world; the prevalence of the disease will grow to the point where 366 million people will be affected by 2030. The prevalence of diabetes mellitus (DM) in the Saudi population is high, and the majority of patients suffer from type 2 DM. Marketed oral antidiabetic drugs have indicated poor tolerability during chronic treatments, and this contributes to the moderately large proportion of type 2 DM patients that remain inadequately managed. Vildagliptin nanospheres were prepared with aminated gelatin using a spray-drying method; narrow particle-size distribution was seen at 445 nm. The angle of repose was found to be θ <33.5°. The nanospheres appeared to be spherical with a smooth surface. The drug content and percentage yield of the nanospheres were found to be 76.2%±4.6% and 83%±2%, respectively. The nanosphere-swell profile was found to be 165%±7%. The pure drug was 100% dissolved in 30 minutes, and the nanosphere formulation took 12 hours to dissolve (97.5%±2%), and followed a Korsmeyer-Peppas kinetic model with an R (2) of 0.9838. The wash-off test of nanospheres found that they exhibited an excellent mucoadhesive property at 86.7% for 8 hours. The stability-study data showed no changes in the physicochemical properties of the nanospheres, and suggested that the nanospheres be stored below room temperature. The amount of vildagliptin retained was 1.6% within 3 hours, and in comparison with the gelatin vildagliptin nanoparticles formulation, the percentage that was retained was much higher (98.2% in 12 hours).

Ultrasonic fabrication of TiO2/chitosan hybrid nanoporous microspheres with antimicrobial properties

We report a sonochemical method for the fabrication of stable TiO₂–chitosan hybrid microspheres possessing nanoporous structure and antimicrobial properties.

Controlled release matrices and micro/nanoparticles of chitosan with antimicrobial potential: development of new strategies for microbial control in agriculture

The control of micro-organisms responsible for pre- and postharvest diseases of agricultural products, mainly viruses and fungi, is a problem that remains unresolved, together with the environmental impact of the excessive use of chemicals to tackle this problem. Current efforts are focused on the search for efficient alternatives for microbial control that will not result in damage to the environment or an imbalance in the existing biota. One alternative is the use of natural antimicrobial compounds such as chitosan, a linear cationic biopolymer, which is biodegradable, biocompatible and non-toxic, has filmogenic properties and is capable of forming matrices for the transport of active substances. The study of chitosan has attracted great interest owing to its ability to form complexes or matrices for the controlled release of active compounds such as micro- and nanoparticles, which, together with the biological properties of chitosan, has allowed a major breakthrough in the pharmaceutical and biomedical industries. Another important field of study is the development of chitosan-based matrices for the controlled release of active compounds in areas such as agriculture and food for the control of viruses, bacteria and fungi, which is one of the least exploited areas and holds much promise for future research.

Potential therapeutic effect of nanobased formulation of rivastigmine on rat model of Alzheimer's disease

Background

To sustain the effect of rivastigmine, a hydrophilic cholinesterase inhibitor, nanobased formulations were prepared. The efficacy of the prepared rivastigmine liposomes (RLs) in comparison to rivastigmine solution (RS) was assessed in an aluminium chloride (AlCl₃)-induced Alzheimer’s model.

Methods

Liposomes were prepared by lipid hydration (F1) and heating (F2) methods. Rats were treated with either RS or RLs (1 mg/kg/day) concomitantly with AlCl₃ (50 mg/kg/day).

Results

The study showed that the F1 method produced smaller liposomes (67.51 ± 14.2 nm) than F2 (528.7 ± 15.5 nm), but both entrapped the same amount of the drug (92.1% ± 1.4%). After 6 hours, 74.2% ± 1.5% and 60.8% ± 2.3% of rivastigmine were released from F1 and F2, respectively. Both RLs and RS improved the deterioration of spatial memory induced by AlCl₃, with RLs having a superior effect. Further biochemical measurements proved that RS and RLs were able to lower plasma C-reactive protein, homocysteine and asymmetric dimethy-larginine levels. RS significantly attenuated acetylcholinesterase (AChE) activity, whereas Na⁺/K⁺-adenosine triphosphatase (ATPase) activity was enhanced compared to the AlCl₃-treated animals; however, RLs succeeded in normalization of AChE and Na⁺/K⁺ ATPase activities. Gene-expression profile showed that cotreatment with RS to AlCl₃-treated rats succeeded in exerting significant decreases in BACE1, AChE, and IL1B gene expression. Normalization of the expression of the aforementioned genes was achieved by coadministration of RLs to AlCl₃-treated rats. The profound therapeutic effect of RLs over RS was evidenced by nearly preventing amyloid plaque formation, as shown in the histopathological examination of rat brain.

Conclusion

RLs could be a potential drug-delivery system for ameliorating Alzheimer’s disease.

Chitosan matrix with three dimensionally ordered macroporous structure for nimodipine release

Three dimensionally ordered macroporous (3DOM) chitosan (3D-CS) matrix with interconnected pores in the nanometer range was developed as a drug carrier for the first time. 3D-CS was prepared using a template-assisted assembly and characterized by SEM, TGA, N(2) adsorption and FT-IR. As a model drug, nimodipine (NMDP) was incorporated into the pores of 3D-CS matrix. The solid state properties of NMDP-loaded samples were characterized by SEM, XRD, DSC and FT-IR. Dissolution studies showed that release behavior of the drug was markedly affected by the particle size of the matrix. With a relatively small matrix particle size, formulations of NMDP-3D-CS-0.5 and NMDP-3D-CS-1 exhibited rapid release patterns. However, on increasing the amount of carrier, release rate of the drug decreased. The pH-dependent slow-release characteristic of 3D-CS matrix delivery system was demonstrated by investigating the release behavior of NMDP at different pH values.

Preparation and in vitro Evaluation of Ethylcellulose Coated Egg Albumin Microspheres of Diltiazem Hydrochloride

The aim of the present investigation was to develop sustained release ethylcellulose-coated egg albumin microspheres of diltiazem hydrochloride (DH) to improve patient compliance. The microspheres were prepared by the w/o emulsion thermal cross-linking method using different proportion of the polymer to drug ratio (1.0:1.0, 1.0:1.5 and 1.0:2.0). A 3² full factorial design was employed to optimize two independent variables, polymer to drug ratio (X₁) and surfactant concentration (X₂) on dependent variables, namely % drug loading, % drug release in 60 min (Y₆₀) and the time required for 80 % drug release (t₈₀) were selected as dependable variable. Optimized formulation was compared to its sustained release tablet available in market. The polymer to drug ratio was optimized to 1:1 at which a high drug entrapment efficiency 79.20% ± 0.7% and the geometric mean diameter 47.30 ± 1.5 mm were found. All batches showed a biphasic release pattern; initial burst release effect (55% DH in 1 h) and then were released completely within 6 h. In situ coating of optimized egg albumin DH microspheres using 7.5% ethylcellulose significantly reduced the burst effect and provided a slow release of DH for 8-10 h. Finally, it was concluded that ethylcellulose-coated egg albumin DH microspheres is suitable for oral SR devices in the treatment of angina pectoris, cardiac arrhythmias, and hypertension due to their size and release profile.

Formulation, characterization and pharmacokinetics of praziquantel-loaded hydrogenated castor oil solid lipid nanoparticles

Aim: The purpose of this study was to formulate praziquantel (PZQ)-loaded hydrogenated castor oil (HCO) solid lipid nanoparticles (SLN) to enhance the bioavailability and prolong the systemic circulation of the drug. Materials & methods: PZQ was encapsulated into HCO nanoparticles by a hot homogenization and ultrasonication method. The physicochemical characteristics of SLN were investigated by optical microscope, scanning electron microscopy and photon correlation spectroscopy. Pharmacokinetics were studied after oral, subcutaneous and intramuscular administration in mice. Results: The diameter, polydispersivity index, ζ potential, encapsulation efficiency and loading capacity of the nanoparticles were 344.0 ± 15.1 nm, 0.31 ± 0.08, -16.7 ± 0.5 mV, 62.17 ± 6.53% and 12.43 ± 1.31%, respectively. In vitro release of PZQ-loaded HCO-SLN exhibited an initial burst release followed by a sustained release. SLN increased the bioavailability of PZQ by 14.9-, 16.1- and 2.6-fold, and extended the mean residence time of the drug from 7.6, 6.6 and 8.2 to 95.9, 151.6 and 48.2 h after oral, subcutaneous and intramuscular administration, respectively. Conclusion: The PZQ-loaded HCO-SLN could be a promising formulation to enhance the pharmacological activity of PZQ.

Double Cross-linked Chitosan—Gelatin Particulate Systems for Ophthalmic Applications

Gelatin/chitosan particles suitable for application in ocular drug administration were prepared by a two-step cross-linking process performed in an emulsion-phase separation system. The particles were characterized by scanning electron microscopy and laser diffractometry, and the diameters were 0.202—4.596 µm. The microparticles pH-dependent behavior was monitored by their mean diameter changes in aqueous environment. Adrenalin was drug used to study loading and release characteristics. The prepared particles were nontoxic, with the DL50 values of 6.9—8.19 g/kg body mass. The in vivo biocompatibility tests consisted of subcutaneous administration of a microparticle suspension in physiological serum followed by morpho histological analysis of the implantation site. The in vivo adrenalin ocular delivery was tested on both animals and a voluntary human patient to determine the adrenalin action and by tears. The particles showed good adherent properties without irritation to the patient; adrenalin was released cleared the ocular congestion.

Significant delivery of tacrine into the brain using magnetic chitosan microparticles for treating Alzheimer's disease

Alzheimer's disease (AD) is a progressive degenerative disorder of the brain characterized by a slow, progressive decline in cognitive function and behavior. As the disease advances, persons have a tough time with daily tasks like using the phone, cooking, handling money or driving the car. AD affects 15 million people worldwide and it has been estimated that AD affects 4.5 million Americans. Tacrine is a reversible cholinesterase inhibitor used for treating mild to moderate AD. In the present study, an attempt was made to target the anti-Alzheimer's drug tacrine in the brain by using magnetic chitosan microparticles. The magnetic chitosan microparticles were prepared by emulsion cross-linking. The formulated microparticles were characterized for process yield, drug loading capacity, particle size, in vitro release, release kinetics and magnetite content. The particle size was analyzed by scanning electron microscope. The magnetite content of the microparticles was determined by atomic absorption spectroscopy. For animal testing, the microparticles were injected intravenously after keeping a suitable magnet at the target region. The concentrations of tacrine at the target and non-target organs were analyzed by HPLC. The magnetic chitosan microparticles significantly increased the concentration of tacrine in the brain in comparison with the free drug.

Development andin-vitroevaluation of modified release tablets including ethylcellulose microspheres loaded with diltiazem hydrochloride

In this study, development of modified release tablet formulations containing diltiazem hydrochloride-loaded microspheres to be taken once rather than two or three times a day was attempted. For this purpose, ethylcellulose microspheres were prepared by emulsion-solvent evaporation technique. The influence of emulsifier type and drug/polymer ratio on production yield, encapsulation efficiency, particle size, surface morphology and in-vitro release characteristics of the microspheres was evaluated. Suitable microspheres were selected and tabletted using different tabletting agents, Ludipress, Cellactose80, Flow-Lac100 and excipients Compritol888 ATO, KollidonSR. Tablets were evaluated from the perspective of physical and in-vitro drug release characteristics. It was seen that type and ratio of the excipients played an important role in the tabletting of the microspheres. As a result, two tablet formulations containing 180 mg diltiazem hydrochloride and using either Compritol888 ATO or KollidonSR were designed successfully and maintained drug release for 24 h with zero order and Higuchi kinetics, respectively.

Development of a novel casein-protamine based microparticles for early feeding of fish larvae:In vitroevaluation

OBJECTIVE

The objective of this study was to develop novel type of protein walled microparticles suitable for using in early feeding of fish larvae.

METHODS

The microparticles were made of casein and protamine through complex coacervation and did not require further cross-linking or use of environmentally problematic reagents. The methodology was oriented to generate microparticles with an appropriate size range for easy recognition and ingestion by fish larvae (50-200 microm), adequate floating properties in saline, sufficient stability in terms of protein leakage and appropriate digestibility by the gut enzymes of fish larvae.

RESULTS

Desired particle size and stability against protein leakages over 8 h were successfully achieved by optimizing the coacervation process conditions. The floating properties under static conditions were considered appropriate as a main particle fraction remained in suspension during at least 10 min. Very importantly, an enzyme extract from larval gut readily digested the particles. The digestibility of the casein-protamine particles was similar to that measured for Artemia nauplii and for two previously developed casein-based microparticles produced by interfacial polymerization and ionic gelation; the latter microparticle type had previously achieved good results of digestibility in early feeding of marine fish larvae.

CONCLUSION

The in vitro evaluation of the newly developed casein-protamine microparticles revealed promising characteristics as artificial larval feed. Thus, these particles merit further development with respect to entrapping nutrients and testing them in larval cultures for their nutritional value.

In vitro and in vivo evaluation of mucoadhensiveness of chitosan/cellulose acetate multimicrospheres

Chitosan/cellulose acetate multimicrospheres (CCAM) with or without ranitidine (RT) were prepared by the method of W/O/W emulsion with no toxic reagents and had the size interval of 200-280 microm. The angles of repose were only a little more than 30 degrees and the maximum angles of one-plane-critical-stability (OPCS phi) were about 20 degrees . The CCAM had good suspension ability for the tapped density of CCAM was less than 0.127g/mL. The pH value affected the swelling ability of CCAM and the relative humidity had little effect on the characteristics of CCAM when it was not more than 75%. The CCAM system had good effect on the controlled release of RT in vitro and the release rate was almost 60% during 48 h. Furthermore the release of RT was not affected by pH value of release medium. The mucoadhesive tests showed that CCAM could retain in gastrointestinal tract for an extended period of time. There were 53.7% of CCAM remained in stomach after administered for 2(1/2) h and 98.9% of CCAM remained in stomach and small intestine after administered for 3(1/2) h. These results suggest that CCAM is a useful dosage form targeting the gastric mucosa or prolonging gastric residence time as a multiple-unit mucoadhesive system.

Biodegradable Chitosan-Silicate Porous Hybrids for Drug Delivery

Porous chitosan-silicate hybrids were prepared by freeze-drying the precursor sol solutions synthesized from chitosan and 3-glycidoxypropyltrimethoxysilane (GPTMS). Degradability of and the release of cytochrome C in to phosphate buffer saline solution (PBS) were examined as a function of the GPTMS content. The hybrids were less degradable with larger GPTMS contents, and the cytochrome C release profile was so controllable as to give either burst release or slow one due to the GPTMS content. Thus, the present porous chitosan-silicate hybrids were considered applicable to drug delivery systems.