9 research outputs found
Analysis of kinetics of poorly water-soluble drug release from hydrogels based on poly (methacrylic acid) and casein with different crosslinker amount
Nowadays, humanity are faced with many challenges which affect health of people all around the globe (such as climate change, new diseases and/or already present ones for which cure has not been found yet ā cancer). The efforts of researchers on the field of drug delivery systems bring everyday novel tools for safer and more effective therapy. pH sensitive hydrogels based on poly(methacrylic acid) are recognized as materials with huge potential for controlled release of drugs. The encapsulation and controlled release of many chemotherapeutics is quite challenge due to their poorly water-solubility. In our previous research we overcome this problem by modifying hydrophilic pol(methacrylic acid) with amphiphilic casein and showed that prepared material have potential for encapsulation and controlled release of poorly watersoluble model drug ā caffeine (PMAC carriers). In present study we deepened further our research and employed various models: Ritger-Peppas, Higuchi and Kopcha model to analyze how the change of crosslinker amount affect the mechanism of release kinetics of caffeine in medium with pH of 6.8 (which simulated the environment in human intestines). Obtained results showed that only by changing one parameter such as crosslinker amount it is possible to fine tune the type of drug release mechanism, due to which the PMAC carriers would be able to respond to the specific demands of therapy
The effect of encapsulated amount of caffeine on the mechanism of its release from hydrogels based on poly(methacrylic) and casein
Researchers are making everyday efforts to develop new drugs or improve present ones in order to enhance therapies of various diseases, especially serious ones like cancer. Drug delivery systems (DDS) are one of the solutions for safer and more efficient therapy. Hydrogels based on poly(methacrylic acid) (PMAA) are extensively investigated as DDS due to their nontoxicity, biocompatibility and pH sensitivity. Many chemotherapeutics are poorly watersoluble, so it is quite challenging to encapsulate them into highly hydrophilic PMAA. In our previous study we overcome this limitation by modifying PMAA with amphiphilic casein and demonstrated that poorly water-soluble model drug ā caffeine can be successfully encapsulated and released in control manner from these samples (H hydrogels). In present study we go step forward and investigated how the change in the amount of encapsulated caffeine affect the mechanism of caffeine release from the H hydrogels in medium with pH of 6.8 (which simulates the environment in human intestines). Commonly used models for the analysis of kinetics of drug release from hydrogels: Ritger-Peppas, Higuchi and Kopcha model are employed for the analysis of the mechanism of caffeine release. Presented results indicate that it is possible to adjust the manner and mechanism of drug release by changing the amount of encapsulated drug, due to which the H hydrogels can adapt to the unique requirements of the therapy
Analysis of kinetics of poorly water-soluble drug release from hydrogels based on poly(methacrylic acid) and casein with different crosslinker amount
Nowadays, humanity are faced with many challenges which affect health of people all around
the globe (such as climate change, new diseases and/or already present ones for which cure has
not been found yet ā cancer). The efforts of researchers on the field of drug delivery systems
bring everyday novel tools for safer and more effective therapy. pH sensitive hydrogels based
on poly(methacrylic acid) are recognized as materials with huge potential for controlled release
of drugs. The encapsulation and controlled release of many chemotherapeutics is quite
challenge due to their poorly water-solubility. In our previous research we overcome this
problem by modifying hydrophilic pol(methacrylic acid) with amphiphilic casein and showed
that prepared material have potential for encapsulation and controlled release of poorly watersoluble model drug ā caffeine (PMAC carriers). In present study we deepened further our
research and employed various models: Ritger-Peppas, Higuchi and Kopcha model to analyze
how the change of crosslinker amount affect the mechanism of release kinetics of caffeine in
medium with pH of 6.8 (which simulated the environment in human intestines). Obtained
results showed that only by changing one parameter such as crosslinker amount it is possible to
fine tune the type of drug release mechanism, due to which the PMAC carriers would be able
to respond to the specific demands of therapy
pH-sensitive hydrogels based on poly(methacrylic acid), casein and liposomes for targeted delivery of poorly water-soluble active substances
Polymeric carriers for targeted delivery of poorly water-soluble active substances (PWSAS)
are facing two challenges. First, encapsulation of PWSAS depends on structure of the carrier. Second
limitation is caused by the phenomenon of burst drug release. Despite the fact that the fast release
of drug in a burst stage is utilized in certain drug administration strategies, the negative effects
brought about by burst can be pharmacologically dangerous and economically inefficient. This study
presents a novel strategy for encapsulation and targeted delivery of PWSAS - caffeine without the
possibility of burst effect. Hydrophilic carrier based on poly(methacylic acid) was modified by amphiphilic substances - casein and centrifuged liposomes to ensure caffeine encapsulation. The caffeine was encapsulated in liposomes which further were incorporated into the carrier networks during the synthesis of the carriers. The release kinetic of caffeine was analyzed with respect to morphology of the carriers and interactions that could be established between the components of the
carrier. The swelling of carriers and release of caffeine were further investigated depending on the
neutralization degree of methacrylic acid in two media with different pH simulating the path of the
carrier through the upper and lower human gastrointestinal tract. Synthesized carriers showed significant potential for encapsulation and targeted delivery of PWSAS.Kod razvoja polimernih nosaÄa za ciljano otpuÅ”tanje slabo vodorastvornih aktivnih supstanci
(SVAS) postoje dva ograniÄenja. Prvo, inkapsulacija SVAS zavisi od strukture nosaÄa. Drugo ograniÄenje je vezano za naglo oslobaÄanje leka. Uprkos Äinjenici da je naglo oslobaÄanje leka, tzv. burst
efekat poželjno kod nekih sistema, negativni efekti naglog oslobaÄanja leka u veÄini sluÄajeva mogu
biti farmakoloÅ”ki opasni i ekonomski neefikasni. U ovom radu je prikazana nova strategija za inkapsulaciju i ciljano otpuÅ”tanje SVAS ā kofeina bez burst efekta. Hidrofilni nosaÄ na bazi poli(metakrilne
kiseline) je modifikovan amfifilnim supstancama ā kazeinom i centrifugiranim lipozomima kako bi se
postigla inkapsulacija kofeina. Kofein je inkapsuliran u lipozome koji su zatim inkorporirani u mrežu
nosaÄa tokom sinteze nosaÄa. Analiziran je uticaj morfologije nosaÄa i interakcija koje su se uspostavile izmeÄu njegovih komponenti na kinetiku otpuÅ”tanja kofeina. Zatim je analiziran uticaj stepen
neutralizacije metakrilne kiseline na bubrenje nosaÄa i otpuÅ”tanje kofeina u dve sredine razliÄitih pH
vrednosti koje su simulirale pH sredinu u gastrointestinalnom traktu Äoveka. Pokazano je da sintetisani nosaÄi imaju veliki potencijal za inkapsulaciju i ciljano otpuÅ”tanje SVA
Effect of crosslinker amount on hybrid hydrogels swelling and drug release
Targeted drug delivery is powerful tool which researchers use to achieve safer and more efficient
therapy of many diseases, including various types of cancer. Many chemotherapeutics are poorly watersoluble, so their encapsulation and targeted delivery remain quite challenge. Hydrogels based on
poly(methacrylic acid) (PMAA) are widely investigated for targeted drug delivery due to their pH
sensitivity, non-toxicity and biocompatibility. Still, due to the PMAA highly hydrophilic nature, PMAA
can only be used for encapsulation and targeted delivery of water-soluble drugs. Our previous research
was directed towards overcoming this limitation: PMAA was modified with amphiphilic protein ā
casein and poorly-water soluble model drug ā caffeine ā was encapsulated (PMAC). Present study is
focused on investigation how variation of amount of one of the most important hydrogels network
parameter such as crosslinker affect PMAC swelling properties and caffeine release. The group of
hybrid hydrogels ā PMAC ā was synthesized with various amount of crosslinker: 0.4mol%, 0.8mol%,
1.6mol% and 3.2mol% with respect to methacrylic acid. Swelling behavior of hybrid hydrogels and
caffeine release was investigated in two environments which simulated human stomach and intestines.
Obtained results showed that targeted delivery of poorly water-soluble model drug was achieved and
that its release can be prolonged up to 24h. Also, kinetic of poorly water-soluble drug release can be
easily modified only by changing crosslinker amount. PMAC hybrid hydrogels have huge potential for
targeted delivery of poorly water-soluble active substances
Three dimensional polymeric networks based on poly(methacrylic acid) and protein for targeted delivery of poorly water-soluble drugs
Three dimensional polymer networks, hydrogels, have shown a great potential in
controlled release and targeted delivery of active substances. pH sensitive hydrogels
based on poly(methacrylic acid) have attracted significant attention due to their
biocompatibility, non-toxicity and the possession of the huge number of ionogenic
carboxylic groups. On the other hand, the usage of these hydrogels for controlled release
and targeted delivery of poorly water-soluble drugs is limited by their highly hydrophilic
nature. We overcame this limitation by modifying PMAA with amphiphilic substance -
casein. The addition of this natural protein enabled the encapsulation, targeted delivery
and controlled release of poorly water-soluble model drug - caffeine. Three carriers with
different neutralization degree of methacrylic acid were synthesized via free radical
polymerization. The FTIR spectra revealed that two types of interactions were
established between casein and caffeine: hydrophobic interactions and hydrogen bonds.
The SEM micrographs showed that the structure of the carriers depended on the change
of neutralization degree of the methacrylic acid. The swelling of synthesized carriers and
the caffeine in vitro release were monitored in two environments at 37Ā°C: 0.1M HCl
pH=1.2 (simulation of environment in human stomach) and phosphate buffer pH=6.8
(simulation of environment in human intestines). The synthesized carriers had higher
swelling degree and the higher release rate of caffeine in the phosphate buffer pH=6.8
than in 0.1M HCl. The increase in neutralization degree of methacrylic acid caused the
increase in swelling degree of the carriers and the increase in release rate of caffeine.
Presented results showed that synthesized carriers are promising candidates for targeted
delivery of poorly water-soluble drugs
Exchange between the stagnant and flowing zone in gas-flowing solids-fixed bed contactors
In countercurrent gas flowing solids fixed bed contactors, a fraction of the flowing solids is in motion (dynamic holdup), while the other fraction is resting on the fixed bed elements. In this study it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles. Combining a mathematical model with tracer experiments, the rate of exchange was determined and it was shown that only a small part (ca. 20 %) of the stagnant region should be considered as a dead one
Effect of neutralization degree of methacrylic acid on hydrogel swelling and drug release
Drug delivery system is an amazing tool which is widely used for drug
protection and its controlled release in order to enhance drug bioavailability,
reduce side effects and therefore to improve overall therapy. Hydrogels have
been attracted great attention as drug carriers due to their great physicochemical
properties, similarity to the living tissues and biocompatibility. One group of
pH sensitive hydrogels are based on poly(methacrylic acid) (PMAA). These
non-toxic hydrogels are used as drug delivery system because they swell as
a response to the change in pH of external environment and drug is being
released during the process. In present study, in order to improve the control of
drug release rate, caffeine was encapsulated in liposomes which were further
embedded into PMC hydrogel (PMCL). It was investigated how the change in
neutralization degree of methacrylic acid affect the swelling degree of PMCL
hydrogels and caffeine release in two environments at 37 Ā°C for 24 h: 0.1 M
hydrochloride acid (pH 1) and phosphate buffer with pH value of 6.8 (pH 6.8), as
a simulation of pH environment in human stomach and intestines, respectively.
Obtained results show that PMCL hydrogels have great potential for controlled
release of poorly water-soluble drugs in human intestines
Modification of hydrophilic polymer network to design a carrier for a poorly water-soluble substance
pH sensitive, nontoxic, and biocompatible poly(methacrylic) acid (PMAA) based soft networks have been extensively used in the design of systems for targeted drug delivery. Still, their highly hydrophilic nature limits their potential to be used as a carrier of poorly water-soluble substances. With the aim to overcome this limitation, the present study details a new approach for modification of PMAA based carriers using two amphiphilic components: casein and liposomes. The FTIR analysis revealed structural features of each component as well as the synergetic effect that originated from the formation of specific interactions. Namely, hydrophobic interactions between the poorly water-soluble model drug (caffeine) and casein enabled caffeine encapsulation and controlled release, while addition of liposomes ensured better control of the release rate. The morphological properties of the carriers, swelling behavior, and release kinetics of caffeine were investigated depending on the variable synthesis parameters (neutralization degree of methacrylic acid, concentration of caffeine, presence/absence of liposomes) in two different media simulating the pH environment of human intestines and stomach. The data obtained from in vitro caffeine release were correlated and analyzed in detail using several mathematical models, indicating significant potential of investigated carriers for targeted delivery and controlled release of poorly water-soluble substances