Pharmacy

Topical delivery systems for the treatment of different infected cutaneous wounds based on natural biopolymers are widely studied. The development of some topical hydrogels with type I collagen and minocycline by the experimental design technique, based on response surface methodology and Taguchi's approach, and the evaluation of their kinetic properties is presented. The concentrations of polymer, drug and cross-linking agent were selected as independent variables for the face centered composite design and low, medium and high concentration as variation levels for each factor. Minocycline kinetic release was investigated using a modified Franz diffusion cell. The drug release followed the Higuchi model. Three formulations having optimal minocycline release profiles were selected. They can be used as potential drug topical release systems for the treatment of infected cutaneous tissue.

Tannic acid cross-links collagen both in acid (pH 3.8) and weakly basic (pH 7.4) medium. The cross-linking does not affect the integrity of triple helical structure of collagen as spectral characteristics, enzymatic degradation and release data of tannic acid from collagen matrices demonstrate. Intermolecular bridging produces changes in the amide III IR band of the collagen-tannic acid matrices. The higher the amount of tannic acid in the matrix, the slower the enzymatic degradation process. The release of tannic acid from the collagen-tannic acid matrices is slower for samples obtained at pH 3.8 than for those resulted at pH 7.4 due to the higher amount of intermolecular bonds formed. The kinetic of tannic acid release from each collagen-tannic acid matrix follows the Peppas mechanism, with a value of the exponent of about 0.6.

Periodontitis is one of the most common chronic disease in the world affecting both the adults and young people, having severe consequences at cardiovascular level, and causing the premature birth. Moreover, the untreated periodontal disease is the major cause for tooth loos. Thus, the purpose of this study was to design and investigate some collagen supports with metronidazole and strontium ranelate as a treatment option for bone dental regeneration and an effective way to remove the pathogen agents incriminated in the periodontal disease. Type I fibrillar collagen gel was extracted from calf hide. Collagen hydrogels with various ratios of metronidazole and strontium ranelate were rheologically tested at two temperatures: 23°C and 37°C. The collagenic supports obtained by hydrogels lyophilization were investigated by goniometric analysis. The in vitro metronidazole release from spongious matrices was conducted with a sandwich device adapted to a dissolution equipment. The hydrogels presented a pseudoplastic behaviour facilitating the formulation flow and their good manipulation. The Power law model fitted well the kinetic data indicating a non-Fickian drug transport mechanism. The physico-chemical properties were in relation with the drug release patterns from spongious supports. Based on the results obtained, we could conclude that the designed formulations are potentially usable as a favorable solution in periodontal disease.

Three series of drug delivery systems consisting of type I collagen hydrogel containing 0, 0.02, 0.05 and 0.10% chlorhexidine digluconate (CHXD) and having pHs 3.8 and 7.4, the last noncrosslinked and crosslinked with 0.15% glutaraldehyde (GA), were prepared to be used for wound healing. FT-IR spectra show no effect of CHXD on triple helical conformation of collagen irrespective of pH and crosslinking. CD spectra also indicate the absence of CHXD and GA effect on collagen conformation. Rhoogram show pseudoplastic behaviour for all the hydrogels and a decrease of viscosity at zero shear rate with increasing CHXD concentration, regardless of pH and crosslinking, due to its binding to collagen and GA. Dynamic rheological measurements reveal the prevalence of elastic component of viscoelasticity in all the hydrogels and the insignificant effect of CHXD on viscosity in acid medium. CHXD reduces the elastic component in slight basic medium, while GA increases it significantly both in the absence and presence of CHXD, excepting the highest concentration, for which the values are similar with those in acid medium. The acid hydrogels release the lowest amounts of CHXD irrespective of initial concentration, the crosslinked hydrogels release less CHXD than the noncrosslinked ones, but the differences are small and increase a bit with CHXD concentration.

Liquid marbles are versatile structures demonstrating a pseudo-Leidenfrost wetting regime formed by encapsulating microscale volumes of liquid in a particle shell. The liquid core is completely separated from the exterior through air pockets. The external phase consists of hydrophobic particles, in most cases, or hydrophilic ones distributed as aggregates. Their interesting features arise from the double solid-fluid character. Thus, these interesting formations, also known as “dry waters”, have gained attention in surface science. This review paper summarizes a series of proposed formulations, fabrication techniques and properties, in correlation with already discovered and emerging applications. A short general review of the surface properties of powders (contact angle, superficial tension) is proposed, followed by a presentation of liquid marbles’ properties (superficial characteristics, elasticity, self-propulsion etc.). Finally, applications of liquid marbles a...

The pain management is therefore of paramount importance and the local anesthetic treatment has to be considered. Thus, the purpose of this study was to design and characterize some collagen microcapsules incorporating an anesthetic. The collagen hydrolysate was prepared by spray-drying forming micro sizes spheres (microcapsules) which were loaded with 1% lidocaine (anesthetic) and cross-linked with different cross-linking agent: tannic acid, glutaraldehyde and genipin, in order to obtain solution for tooth pain. The wetting behavior of dried microcapsules powders was determined by contact angle measurement. The microcapsule solutions were characterized by dynamic light scattering (DLS) and in vitro release of lidocaine was investigated. These therapeutically products, based on collagen microcapsules, a local anesthetic and three cross-linking agents, could have potential biomedical application in tooth pain healing treatment.

Brewing yeast biomasses may be converted into valuable products, including supplements for ruminant diets. This paper presents experimental data on a nutraceutical suspension formulation containing post-fermentation brewing yeasts and the brewing yeast strain, Saccharomyces pastorianus ssp. carlsbergensis W34/70, which was intended to be administered to ruminants. The brewing yeast biomass is a component of oral suspensions designed as dietary supplements that prevent digestive acidosis in ruminants. The brewing yeast strain W34/70 was cultivated using molasses (M) and glucose (G) as carbon sources and was lyophilized at different freezing temperatures (0�C, �10�C, �20�C, �30�C, and �40�C). The post-fermentation brewing yeast biomass was spray dried (AAY) and lyophilized (ALY). Both dried yeast biomasses were analyzed in terms of wettability using a contact angle (CA�) evaluation at the solid/liquid interface. Suspensions were subsequently formulated and tested. Their physical and a...

The aim of this study was to formulate and evaluate two types of O/W emulsions based on collagen and other natural ingredients that can be used as color correcting (CC-cream) and cream foundation. Both types of emulsions obtained are stable at different temperatures and the pH values of emulsions correspond to the natural pH of the skin, indicating that emulsions can be safely applied to the skin. Results from the optical microscopy analysis show that all emulsions present foam-like appearance. The rheological properties of emulsions were studied and it was proved that all emulsions present a non-Newtonian pseudoplastic behaviour and thixotropic characteristics at two operating temperatures (24 and 33�C). It can be concluded that all emulsions can be used as a natural alternative to a CC-cream or a cream foundation. Further microbiological tests and clinical trials are necessary for the obtained emulsions.

Collagen is able to heal wounds but, being a protein, it serves as a substrate for bacteria and can not promote it. Associated with antibiotics/antiseptics and applied topically, it becomes a local drug delivery system for wound infection control. Three series of collagen hydrogels with pHs 3.8 and 7.4 containing 0, 0.02, 0.05 and 0.10% chlorhexidine digluconate (CHD), w/w, the last without or with 0.15% glutaraldehyde (GA), w/w dry collagen, were prepared. Checking of triple helical structure of collagen molecules was performed by FT-IR and CD. FT-IR spectra show no effect of CHD on triple helical conformation irrespective of pH and crosslinking. The same is shown by CD spectra. Rheograms show pseudoplastic behaviour for all the hydrogels and a decrease of viscosity at zero shear rate with increasing CHD concentration, regardless of pH and cross-linking due to its binding to collagen and GA. Dynamic rheological measurements reveal the prevailing of elasticity in all the hydrogels, ...

Cartilage damage is difficult to self-heal due to an avascular microenvironment and distinct mechanical properties. These features are a challenge in designing a cartilaginous tissue with repairing effect without producing any local infections. Thus, a biodegradable scaffold in which the drug can be incorporated is preferable. Drug delivery systems based on collagen sponges have progressively become remarkable biomaterials for different medical applications. The aim of this work was to design and characterize some collagen/chondroitin sulfate supports with doxycycline for cartilage tissue regeneration. The doxycycline should prevent the development of potential infections. Collagen, chondroitin sulfate and doxycycline gels were cross-linked with different concentrations of glutaraldehyde and then freeze-dried in order to obtain collagen matrices. The structural characteristics for the new synthesized biomaterials were firstly assessed by infrared spectroscopy (FT-IR), and scaffolds ...

For the acute or chronic wounds, the associated pain is an important aspect that has to be considered in the management of their therapy. Among the local anesthetics, the lidocaine proved its efficiency for topical application, in different aetiology pains. Collagen, a well tolerated biomaterial and biodegradable, represents a favorable matrix for the drugs release. In this study some collagen hydrogels different cross-linked with lidocaine were developed, according to a 32 factorial design. The lidocaine in vitro release from the hydrogels was determined using a modified Franz diffusion cell. For establishing the mechanism of the lidocaine release from hydrogel different kinetic models were used. The formulations were also characterized from their rheological properties. Rheological measurements were performed using a rotational viscometer. The flow behaviour was quantified through different rheological models. The designed topical systems presented a thinning through shearing beha...

The goal of this work was to formulate and characterize some O/W emulsions, designed as skin anti-aging creams. The cosmetic formulations based on collagen hydrolysate, caffeine and natural ingredients (essential and vegetable oils) were evaluated organoleptically, in terms of pH, morphological, superficial and rheological properties. The rheological measurements were carried out at 23 and 32°C, and the shear stress versus shear rate ascending and descending rheograms were built, as well as the flow patterns viscosity versus shear rate. All emulsions obtained are stable at different temperatures and the pH values correspond to the skin physiological one, indicating that cosmeceuticals can be safely applied to the skin. Results from the optical microscopy analysis show that all emulsions presented a creamy and foamy appearance. The superficial profiles, quantified through contact angle at solid/liquid interface, indicated a high emulsions hydrophilicity degree. The emulsions showed a...

With a long tradition in pharmaceutical design, emulsions are functional formulations that can maintain their adaptive power connected with the new formulation requirements. Hence, this study proposed preliminary assays concerning the obtaining of natural emulsions for oral administration, incorporating pumpkin seed oil and hemp seed oil as oil phases, with lecithin as emulsifying agent. Using emulsification method, O/W and W/O emulsions were prepared and characterized from a stability point of view considering organoleptic parameters, conductivity properties followed by an extensive superficial analysis by fitting two different goniometric approaches like contact angle and pendant drop models. The emulsions obtained were stable, homogeneous, their properties being reflected by composition. Conductivity values confirmed the type of emulsions, completing their profile. Superficial analysis revealed that lecithin can sustain a proper stability due to a variation of surface tension val...

Collagen is a significant constituent of the natural extracellular matrix (ECM) and matrices made from it are used as a scaffold for tissue engineering and as a reservoir for drug delivery. Collagen matrices are important porous structures because they influence hydrophily, drug diffusion through network, the degradation properties and interaction with cells. The aim of this work was obtaining collagen-doxycycline matrices, uncross-linked and cross-linked with glutaraldehyde ones, which have variable pore sizes, studying influence of pore sizes on kinetics release of doxycycline from collagen systems and biocompatibility of porous collagen matrices with human endothelial and osteoprogenitor cells. In order to obtain matrices we used freeze-drying process. This is an advantageous conditioning technique which consists of drying frozen samples through ice sublimation into vacuum. During this process pores appear in the place of ice crystals and collagen is being renaturated into fibril...

Collagen-based biomaterials represent an ideal support for the release of the drug, on condition that the collagen structure is as close as possible to that of the human body collagen. Collagen, as drug delivery system, offers the advantage of a natural biomaterial with haemostatic and wound healing properties. The GEVICOL is a well known collagen dressing used in treatment of varicous ulcers. Besides collagen, it contains lidocaine and crystal violet. Lidocaine belongs to the local anesthetics class and it is used to relieve the pain by stopping nerves from sending pain signals. The aim of this study is to develop such dressings with improved properties, so, they must degrade in a certain period of time and lidocaine is controlledly released. In this paper collagen dressings were obtained by freeze-drying gels which contain different collagen concentrations, a known amount of lidocaine and different amount of cross-linking agent (glutaraldehyde). Cross-linking degree and degradatio...

The rheological behaviour of collagen hydrogels in the absence and presence of doxycycline hyclate or/and glutaraldehyde shows that both compounds increase their viscosities, the highest viscosity being obtained for the hydrogel containing the highest amount of collagen, doxycycline hyclate and glutaraldehyde. All the hydrogels have pseudoplastic non-Newtonian behaviour. The kinetics of in vitro release of doxycycline hyclate from the collagen hydrogels demonstrates that the amount of released drug decrease with increasing collagen concentration. Glutaraldehyde as cross-linking agent has the same effect, so the slowest release was obtained for the most viscous hydrogel. The rheological properties of hydrogels and the rate of doxycycline release can thus be controlled by the concentration of collagen, drug and cross-linking agent.

The aim of this study is to design, develop and evaluate new biohybrid sponges based on polymers (collagen and polyvinyl alcohol) with and without indomethacin as anti-inflammatory drug model to be used for tissue regeneration in wound healing. Type I fibrillar collagen in the form of a gel and different concentrations of polyvinyl alcohol were mixed together to prepare composite gels. Both control samples, without indomethacin and with indomethacin, were obtained. All samples were crosslinked with glutaraldehyde. By freeze-drying of hydrogels, the spongious forms (matrices) were obtained. The matrices were characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), water absorption, enzymatic degradation and in vitro indomethacin release. The pharmacological effect of the spongious biohybrid matrices was determined on an experimental model of burns induced to Wistar rats. The SEM images showed a porous structure with interconnected pores. Collagen sponges present a str...

Since ancient times humans observed animal and plants features and tried to adapt them according to their own needs. Biomimetics represents the foundation of many inventions from various fields: From transportation devices (helicopter, airplane, submarine) and flying techniques, to sports' wear industry (swimming suits, scuba diving gear, Velcro closure system), bullet proof vests made from Kevlar etc. It is true that nature provides numerous noteworthy models (shark skin, spider web, lotus leaves), referring both to the plant and animal kingdom. This review paper summarizes a few of "nature's interventions" in human evolution, regarding understanding of surface wettability and development of innovative special surfaces. Empirical models are described in order to reveal the science behind special wettable surfaces (superhydrophobic /superhydrophilic). Materials and methods used in order to artificially obtain special wettable surfaces are described in correlation w...