Zero-order Kinetic Model Research Articles

PH-sensitive castor oil/PEG-based polyurethane films for drug delivery

Apart from the frequent conventional use of polyurethanes (PUs), synthesizing bio-based polyurethanes from renewable sources is a new exciting way. The most intriguing issue in this respect is the use of bio-based PUs in biomedical applications. In the present study, PU films were synthesized from castor oil (CO) and poly(ethylene glycol) (PEG) in different CO:PEG ratios with a different molecular weight of PEG. Procaine was chosen as a model drug. After the characterization of all films by FT-IR, DSC, and SEM methods, they were loaded with the drug in buffer solution at pH 9.1. The drug release behavior of the films in buffer solutions at pH 2.3, 5.8, and 6.4 was determined. Their swelling and degradation behaviors were also determined to explain their drug release mechanism. We found that decreasing the molecular weight of the PEG improved the drug release. Additionally, CO:PEG ratio and medium pH are critical factors for the release behavior of the films. Almost 100% of the total drug was released at pH 2.3 in 24 h, which was approximately more than three-fold than that at pH 6.4. Zero-order, first-order, Higuchi, Korsmeyer-Peppas, and Kopcha kinetic models were used for the evaluation of the release data.

Synthesis, spectroscopic, thermal properties, in vitro release, and stability studies of ibuprofen-loaded microspheres cross-linked with hexachlorocyclotriphosphazene/octachlorocyclotetraphosphazene

Ibuprofen (IBU) is a non-steroidal anti-inflammatory drug (NSAID) with anti-inflammatory, analgesic, and antipyretic properties used to treat rheumatoid arthritis, osteoarthritis, and mild to moderate pain. However, it has extremely low aqueous solubility, rapid biotransformation with a half-life of nearly 2 h and poor tissue absorption resulting in poor bioavailability. One of the most important strategies for avoiding NSAID-related toxicity is modified release polymeric systems. Cross-linked polyphosphazene microspheres are attractive systems in drug delivery, as they are biocompatible and biodegradable. In the current work, novel cross-linked inorganic hybrid polyphosphazene microspheres were synthesized by self-assembly precipitation polymerization between hexachlorocyclotriphosphazene (trimer)/octachlorocyclotetraphosphazene (tetramer) as a cross-linker and 4,7-dihydroxyisoflavone (4.7 DHF) as a monomer. The structure of synthesized microspheres was identified several techniques in detail. IBU was successfully incorporated into the trimeric and tetrameric polyphosphazene microspheres. Particle size, zeta potential, drug loading, morphology, thermal, FT-IR, and XRD analyses, and IBU quantification using UPLC method were carried out to evaluate the microspheres. Considering the higher drug loading values and smaller particle size, trimer-based microspheres (4.7 DHF-TRI-IBU) were selected for further studies. In vitro release studies from 4.7 DHF-TRI-IBU demonstrated modified release pattern which followed zero-order kinetic model. Characteristics of 4.7 DHF-TRI-IBU were found to remain stable at 4 °C ± 1 °C, 25 °C ± 1 °C and 40 °C ± 1 °C during the storage period of 3 months. In vitro characterization analyses showed that spherical, micron-sized 4.7 DHF-TRI-IBU microspheres with prolonged release pattern has the potential of enhancing analgesic and anti-inflammatory activity.

Removal Kinetics of Heavy Metals and Nutrients from Stormwater by Different Filter Materials

During storm events, contaminants and sediments from roadways, curbside, parking lots, and lawns in urban environments are mobilized and transported by the stormwater runoff. These contaminants are finally discharged in waterbodies, such as rivers and lakes, with adverse effects on public health and ecosystems. Several studies have reported high levels of heavy metals and nutrients in urban stormwater runoff. Best management practices such as sedimentation and bioretention are not practical in urban environments due to the lack of adequate space; however, filtration systems, such as an in-ground permeable filter system, are being developed because they are practical and feasible. Four different filter materials (calcite, zeolite, sand, and iron filings) were effective in removing individual contaminants (Cd, Cu, Ni, Cr, Zn, nitrate, and phosphate) in tests at 24 h. The present investigation assessed the removal kinetics of contaminants from a simulated stormwater consisting of multiple heavy metals and nutrients by the four filter materials. Batch experiments were conducted to evaluate the removal kinetics of co-existing heavy metals and nutrients from the simulated stormwater. The rate of contaminant removal and overall removal efficiency was found to be dependent on the filter material and contaminant nature, as well as the induced pH changes caused by the filter media. The zero-order kinetic model best described the removal rate of Cu and Ni by sand. The first-order kinetic model was only applicable for nitrate removal by iron filings, and the second-order kinetic model described the removal rates of other contaminants and filter media combinations.

A novel CuO–Cu2O/Ag–Ag3PO4 nanocomposite: Synthesis, characterization, and its application for 2-chlorophenol decontamination under visible light

Herein, a facile one-pot coprecipitation strategy was used to prepare CuOCu2O/Ag–Ag3PO4 heterojunction nanocomposite as an effective catalyst for 2-chlorophenol (2-CP) degradation under visible light. The novel CuOCu2O/Ag–Ag3PO4 nanocomposite was calcined at various temperatures (i.e., 250, 400, and 550 °C) to enhance its photocatalytic properties. The physicochemical properties of the as-prepared nanocomposite and the calcined forms were investigated using XRD, TGA, FTIR, XPS, and SEM. The results indicated that the optical properties were greatly affected by calcination temperature up to 400 °C, while the calcination temperature of 550 °C resulted in melting of CuOCu2O/Ag–Ag3PO4 nanocomposite. Compared to the annealed forms at 250 and 550 °C, the CuOCu2O/Ag–Ag3PO4 treated at 400 °C showed the highest decomposition percentage (82.5%) for 2-CP. This maximum value was mainly due to the reduction in band gap energy and the formation of heterojunction between CuO|Cu2O|Ag|Ag3PO4, which enhanced the separation of photo-generated charge carriers. The degradation of 2-CP was investigated under different solution pH values, and the optimum degradation was detected at pH 3.0 within 180 min. The photocatalysis data were also fitted to the zero-order, first-order, and second-order kinetic models. The highest rate of 2-CP degradation (k1= 9.3 × 10−3 1/min) by Cu2O/Ag–Ag3PO4–400 nanocomposite followed the first-order kinetic model. The reusability study revealed that CuOCu2O/Ag–Ag3PO4 annealed at 400 °C is considered as an effective photocatalyst for the decomposition of 2-CP–bearing solutions.

Differences in oxidative susceptibilities between glycerophosphocholine and glycerophosphoethanolamine in dried scallop (Argopecten irradians) adductor muscle during storage: an oxidation kinetic assessment.

Phospholipids, the main lipid component in marine shellfish, mainly comprise glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE). GPC and GPE in marine shellfish, especially scallop, carry n-3 long-chain polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), although different types of glycerophospholipids (GP) have different health benefits on human health. Moreover, different GP subclasses such as GPC and GPE have different oxidative susceptibilities in complex food systems. The present study compared the oxidative susceptibilities of GPC and GPE in dried scallop during storage by high-performance liquid chromatography-tandem mass spectrometry and kinetic models, and also investigated the effects of natural phenolic antioxidant on their susceptibilities. The results showed that GPC and GPE molecular species (carrying EPA or DHA) contents in samples continuously reduced during storage at two different temperatures. The first-order kinetic model better reflected the changes of GPC and GPE molecular species (carrying EPA or DHA) in samples than the zero-order kinetic model during storage. According to the oxidation rate (k) obtained from first-order kinetic models, GPE possessed a greater oxidation rate than GPC during storage. Moreover, the results showed that antioxidants of bamboo leaves (AOB, polar polyphenolic antioxidants) significantly decreased the oxidation rates of GPC and GPE molecular species (carrying EPA or DHA) in samples during storage, and GPC could be more effectively protected by AOB compared to GPE. The present study provides a practical method for accurately evaluating the oxidative susceptibility of different phospholipid classes in complex food systems. © 2020 Society of Chemical Industry.

Photoelectrocatalytic degradation of 17α-ethinylestradiol and estrone under UV and visible light using nanotubular oxide arrays grown on Ti-0.5wt%W

Environmental concern with emerging contaminants has increased in recent years, especially with regard to endocrine-disrupting compounds (EDCs), among them hormones. Conventional water treatment processes have been shown to be ineffective in removing these compounds from water and sewage, while heterogeneous photocatalysis has been demonstrated to be a promising technique. However, the catalytic efficiency is strongly related to the choice of the photocatalyst material. In order to obtain a fast and efficient degradation of these endocrine disruptors, nanotubes grown on Ti-0.5wt%W alloy (NT/Ti-0.5W) were used in photocatalytic (PC) and photoelectrocatalytic (PEC) processes for the degradation of estrone (E1) and 17α-ethinylestradiol (EE2) under irradiation with ultraviolet (UV) and visible light. The NT/Ti-0.5W catalysts were synthesized by an anodization process, followed by thermal treatment at 450 °C. Raman, X-ray diffraction and diffuse reflectance spectroscopic analyses indicated that the tungsten doping process had modified the nanotubular TiO2. The doped samples exhibited superior photoactivity compared to un-doped samples and other semiconductors under UV and visible irradiation due to a reduction in the rate of recombination of photogenerated charges and the displacement of the flat-band potential to more negative values. Higher values of the degradation rate constant were found for both hormones in the PEC process using NT/Ti-0.5W under UV radiation; the percentage removals of EE2 and E1 were 66% and 53.4%, respectively, after only 2 min of treatment. With visible light, 1.8 min and 4.6 h were required for the removal of 50% of E1 and EE2, respectively. The degradation of E1 could be fit with a zero-order kinetic model, while a first-order kinetic model was required for EE2 degradation. Degradation routes were suggested for E1 and EE2. The results demonstrate that the combined use of NT/Ti-0.5W and the PEC process provides excellent performance for the degradation of emerging contaminants in wastewater when compared to a NT/TiO2 electrode.

Liquisolid Technique: a Novel Tool to Develop Aceclofenac-Loaded Eudragit L-100 and RS-100-Based Sustained Release Tablets

One of the main problems with NSAIDs is the dosing frequency, which leads to patients’ noncompliance. To overcome this, fabrication of sustained release formulation of the drug is considered a well-reputed technique. The present study aimed to develop sustained release formulation of a model drug aceclofenac through the new liquisolid technique. Liquisolid powder prepared using glycerin as the liquid vehicle was subjected to pre-compression evaluation, including bulk and tapped densities, Carr’s compressibility index, Hausner’s ratio, angle of slide, FTIR, and atomic force microscopy (AFM). Differential scanning calorimetry (DSC) and X-ray crystallography studies were investigated for any complex formation between drug and excipients, as well as crystal form alterations during the manufacturing process. Powders were compressed into tablets and quality control tests; in vitro dissolution test and storage stability studies were carried out. The release of aceclofenac was at a predetermined rate and followed zero-order kinetic models. AFM confirmed the surface morphology and particles were well adsorbed by the carrier material. FTIR and DSC studies suggested no drug–excipients interaction and the drugs were found in an amorphous form, which was confirmed through XRD. Upon storage at the given conditions of humidity and temperature, the formulation was found stable. The study proved that liquisolid technique can be used successfully to develop a sustained release formulation.

Development and validation of a stability indicating HPLC method for the determination of buprenorphine in transdermal patch

A rapid and sensitive stability indicating HPLC method has been developed and validated for the determination of buprenorphine (BPN) in transdermal patch. Chromatographic separation was achieved isocratically on an XBridge(superscript TM) Shield RP18 column with a mobile phase of acetonitrile/0.063 M ammonium bicarbonate buffer (pH 9.5) (58:42, v/v) at the flow rate of 1.5 mL/min with UV absorbance monitoring at 230 nm. The system performance was evaluated and the result showed that BPN and degradation products were separated. Buprenorphine was subjected to neutral, acidic and basic hydrolysis as well as chemical oxidation to evaluate the specificity. The calibration curve of buprenorphine was linear in the range of 30~70 μg/mL (r=0.9999, n=5). The values of RSD (%) for the intra-day and inter-day precision ranged from 0.04 to 0.22 and 0.65 to 0.88%, respectively. The average of the recovery percentage ranged from 98.86 to 99.36%. The detection limit (DL) and quantitation limit (QL) for buprenorphine were 0.008 and 0.024 μg/mL, separately. The robustness of this method was also evaluated on the small fluctuations of pH in the mobile phase, the mobile phase compositions, and the flow rate. The results of stability studies showed the hydrolysis reaction of buprenorphine followed zero-order kinetics model in acidic and basic environment and followed first-order kinetics model in the presence of hydrogen peroxide. This analytical method was successfully applied to the determination of buprenorphine in transdermal patch and can be used for routine quality control work.

Investigation of gelatin/chitosan as potential biodegradable polymer films on swelling behavior and methylene blue release kinetics

The aim of this study was to design genipin-cross-linked gelatin/chitosan films and investigate the swelling behavior of these films and also investigate the release kinetics for methylene blue as a model drug. It was shown that the change in the gelatin ratio did not have much effect on the swelling behavior, but the change in genipin concentration had a significant effect on the swelling behavior of the films. The influence of pH was investigated on the release profiles of Methylene Blue. When the diffusion exponent value of “n” was calculated, it was observed that the diffusion type in an acidic environment (pH 1.5) changed from anomalous to less Fickian due to the increase in genipin ratio. In basic conditions (pH 8.0), completely anomalous diffusion behavior was observed. As a result of the ninhydrin test, it was revealed that the cross-linking ratio reached up to 65% when 1.5% genipin was used. In the methylene blue model drug release studies, a very controllable release was observed, complying with the zero-order kinetic model at low pH (pH 1.5), except for the 1.5% genipin ratio. At high pH (pH 8.0), only 4.1 percent of the model drug was released. It was also observed that a zero-order kinetic model was seen for all genipin ratios. “K0,” the kinetic rate constant of model drug release, was calculated an average 0.025 mg.min−1 at pH 1.5 and 0.001 mg.min−1 at pH 8.0, respectively. These values show that release rate at pH 8.0 was significantly lower than at pH 1.5.

Effect of roasting conditions on the formation and kinetics of furan in various nuts.

In this study, the effect of roasting on the formation of furan in nuts was investigated. Nut samples were roasted at 150-200°C for 5-25min. As the roasting temperature and roasting time increased, the levels of furan in the nuts increased up to 348ng/g. The concentration of furan was 2.76-224, 0.71-69.0, 1.46-348, 2.68-87.0, and 3.70-94.4ng/g in almonds, peanuts, cashew nuts, hazelnuts, and sacha inchi, respectively. In kinetics analysis, the chemical reaction responsible for the production of furan in nuts followed the zero-order kinetic model, with reaction constants of 3.26×10-9 to 16.5×10-9mol/L.h at 200°C. The apparent activation energy (Ea) was 125.0, 93.6, 86.5, 62.0, and 70.1kJ/mol for almonds, peanuts, cashew nuts, hazelnuts, and sacha inchi, respectively. These results can be used to predict or to calculate furan formation in roasted nuts.

Kırmızıbiber (Capsicum annuum L.) Dilimlerinin Vakumla Kurutulması Sırasında Renk ve Askorbik Asidin Bozunma Kinetiği

Red pepper slices were dried in a vacuum dryer at three different temperatures (45, 55 and 65°C) and two absolute pressures (21.5 kPa and 48.0 kPa). Drying temperature and absolute pressure significantly influenced drying time. Degradation kinetics of ascorbic acid in red pepper slices during vacuum drying followed a first-order kinetic model. The highest ascorbic acid retention occurred in the samples dried the combination of 45°C and 21.5 kPa. In addition to the temperature effect, the drying absolute pressure was effective on the loss of ascorbic acid. The activation energy values for ascorbic acid under both absolute pressure of 48.0 kPa and 21.5 kPa were calculated as 70.85 kJ/mol and 81.43 kJ/mol, respectively. The sample surface color degradation after drying was also determined. The color values (Hunter L, a and b) decreased, while ΔE (The color difference) increased during drying. Mathematical modeling of color degradation kinetics indicated that both the zero-order and first-order kinetic model were found to describe the Hunter L, a and b values. However, ΔE followed zero-order kinetic model.

MnFe2O4 nanoparticles/cellulose acetate composite nanofiber for controllable release of naproxen

Nanofibers have been demonstrated to be highly effective for drug delivery applications. Although magnetic nanoparticles (MNPs) have been potentially added to nanofibers for improved drug release stimulation, the effect has been limited. In this study, a magnetic nanofiber membrane composed of cellulose acetate (CA), collagen (COL), and MnFe2O4 MNPs was prepared by electrospinning. Naproxen (NAP) drug was deposited on the nanofibers, and the drug release mechanism and effect of the MNPs on the stimulated NAP release were investigated. The electrical conductivity of the dope solution strongly affected the nanofiber characteristics. Moreover, the MTT cytotoxicity assay proved that CA-COL, CA-COL-NAP, and CA-COL-NAP-MNP nanofibers had low toxicity, as the cell viability was >80%. The NAP release mechanism was determined using zero-order, first-order, Higuchi, and Korsmeyer-Peppas kinetics models. According to the dissolution results, for all nanofibers, the NAP release followed the Korsmeyer-Peppas kinetics model, and the transport mechanism was Fickian diffusion. A high MNP concentration and neutral pH condition were conducive to NAP release.

Fabrication and evaluation of Olopatadine hydrochloride ocular inserts

Development of the novel delivery provides optimal drug delivery via facilitated transcorneal penetration and ultimately improved retention time in eye. The present study was to fabricate and evaluate the performance of ocular inserts of Olopatadine hydrochloride by consuming polymers such as hydroxypropyl methylcellulose, gelatin, and chitosan at various concentrations with different plasticizers using solvent casting technique. Prepared formulations were evaluated for thickness, weight variations, drug content, surface pH, swelling studies, and in vitro drug release. Fourier transform infrared spectroscopy studies showed that interaction occurred between polymer and drug, and successful drug entrapment occurred in the matrix. All formulations showed excellent film-forming capacity with good thickness and weight uniformity. Folding endurance proved that the inserts were soft, elastic, and flexible. Chitosan-based ocular inserts showed greater swelling index as compared to gelatin and hydroxypropyl methylcellulose inserts. In vitro studies showed prolonged drug release and followed zero-order kinetic model and non-Fickian drug release.

Formulation and Evaluation of Proniosomal Topical Antifungal Gel of Miconazole Nitrate

Proniosomal gel formulations of miconazole nitrate (MCZ) were prepared by using combinations of different grades of (non-ionic surfactant) span, cholesterol, and lecithin by coacervation phase separation method. Developed 10 proniosomal gel formulations were characterized for particle size, shape, % entrapment efficiency, drug content, in vitro drug permeation, scanning electron microscopy (SEM), DSC, stability study. The fourier transform infrared spectroscopy (FTIR) studies confirmed the compatibility of the drug with excipients. The results showed that all the formulations were pale yellow to pale brown in color, pH was is in the range of 5.60 to 7.20, and encapsulation efficiency was found is in the range of 83 to 91.25% and particle size in between 5.81 ± 0.2 to 07.52 ± 0.07. Among the ten formulations MF2, MF3, MF5, MF6, and MF8 showed maximum drug release in a controlled manner at 12 hours of study and developed into carbopol proniosomal topical gel and evaluated for ex-vivo drug permeation. Formulationoptimized formulation C5MF8 showed higher drug permeation 74.19 ± 0.16% at 12 hr. with a flux valueof 6.829 ± 0.12 μg/cm2 /hr. The permeability coefficient of 0.341 ±0.08 cm2 /hrs., higher correlation coefficient R2 0.9944 for zero-order drug release kinetic model, and follows zero-order release kinetics. Among the 5 formulations, optimized carbopol proniosomal topical gel formulation C5MF8 drug release and in-vitro antifungal activity was compared with marketed formulation cream.C5MF8 showed sustain drug release and zone of inhibition value was very near to marketed preparation. Hence it was concluded that developed carbopol proniosomal topical gel had the potential to act as a controlled release drug carrier,which sustains the drug release for many hours and exhibit good antifungal activity

Numerical simulation and experimental study on slow cook-off response characteristics of composite B

The response characteristics of compose B explosives (Shellless and shelled) under slow heating strips were numerically simulated using a zero-order reaction kinetics model. And the slow cook-off experiment was carried out on shell explosives and shellless explosives respectively. Comparing the experimental results with the calculated results, the key parameters such as melting process, temperature field evolution, ignition time, ignition temperature and ignition area of the slow cook-off test of the cast-casting charge were obtained. The results show that when the casting explosive is heated slowly, it is a heat conduction process before melting, the internal temperature gradient is large, the temperature of the liquid explosive tends to be uniform after melting, and the upper layer temperature is slightly higher than the lower layer temperature; When the temperature rises to a certain value, the explosive decomposes to generate a large amount of gas, and can be discharged from the pressure relief hole of the casing; Eventually, a high temperature region is formed in the middle of the top layer of the liquid explosive, and the ignition reacts violently.

Kinetics of quality changes in papayas (Carica papaya L.) coated with Malaysian stingless bee honey

There have been increased efforts to identify new edible coating and preservative compounds derived from natural sources. This study aimed to investigate the effect of two different concentrations (1.0 % and 1.5 %) of Malaysian stingless bee honey (SBH) as an edible coating agent on the quality attributes of papayas (Carica papaya L.) during storage. Quality parameters such as fresh weight loss (FWL), firmness, soluble solids content (SSC), titratable acidity (TA), colour, and respiration rate were investigated during 12 d of storage at 12 ± 1 °C. The results indicated that papayas coated with 1.0 % and 1.5 % of SBH significantly retained their firmness, colour, SSC, and TA, in addition to the reduced FWL and respiration rate as well as delayed decay development in fruits compared to the uncoated samples. The results of the Field Emission Electron Microscopy revealed that the SBH coating also prevented the ultrastructural features of the mitochondria. In addition, the zero-order and first-order kinetic models fitted well with the experimental data for both coated and uncoated papayas using the Arrhenius law approach. These results suggest that the SBH-coated layer not only improved the postharvest quality of papayas during storage but also prolonged their storage life.

Preparation and evaluation of aceclofenac dental pastes using dillenia fruit gum for periodontitis treatment

The present research deals with preparation and evaluation of aceclofenac dental pastes containing extracted dillenia fruit gum (DG) for periodontitis treatment. Dental pastes containing 1% w/w aceclofeanc were prepared with/without using extracted DG as a mucoadhesive polymer via conventional trituration method. The drug contents, viscosities and pHs of these dental pastes were observed within the permissible ranges. The tube extrudability and tube spreadability of these pastes containing extracted DG were found favorable. The in vitro aceclofenac release from all these dental pastes was found slower sustained over 6 h, which followed zero-order kinetic model (R2 = 0.9917–0.9988) with super case-II transport mechanism (n = 1.00–1.03). The in vitro aceclofenac release was found decreased with the viscosity increment of these dental pastes. These aceclofenac dental pastes containing extracted DG demonstrated excellent mucoadhesion onto excised porcine buccal mucosal membrane, which can be beneficial to get intimate contact with the action site during and after application to uphold the constant release of drugs over prolonged time. These dental pastes containing 1% w/w aceclofeanc can be applied for effective management of dental pain and inflammation with local delivery in the treatment of periodontitis.

Comparison of In-Vitro Dissolution of Griseofulvin Tablet made from Nano Particles and Solid Dispersion

Objectives: To find out the comparison of dissolution results of griseofulvin tablets made from nanoparticles, solid dispersions, and conventional materials.
 Interventions: Different types of active ingredients in the form of nanoparticles and solid dispersions can affect the dissolution results of tablets.
 Main outcomes measure: The results obtained in this study are the cumulative dissolution percentage and the order kinetics of the release of active ingredients.
 Conclusion: There was no significant cumulative percent drug release difference (p> 0.05) between nano particles, solid dispersions, and conventional materials. Tablets containing active nanoparticles, solid dispersions, and conventional materials show a linear relationship with a correlation coefficient (R2) close to 1, shown in zero-order kinetics models.
 

Mathematical Modelling of Dissolution Kinetics in Dosage forms

Drug delivery is a technique by which the drug substances are administered to attain the therapeutic responses in humans or animals. It is crucial to study about the drug release or dissolution for a new solid dosage form. The prediction of correct data of discharge from the drug in the dissolution using mathematical model, which can help to understand the innovation in drug design and formulation with desired therapeutic efficacy and safety. Generally, the mathematical models are used to determine the release of drug profiles are zero-order kinetic model, first order kinetic model, Korsmeyer-peppas model, Higuchi model, Hopfenberg model, Baker Lonsdale model, Hixson Crowell model and Weibull model. Zero-order model explains the constant releases from the formulation such as transdermal, implantable depot, oral control release, matrix tablet with low solubility and suspension. First-order have explained about the release from the formulation like matrix dissolution controlled release, matrix diffusion controlled release, sustained release. Higuchi model explained the drug has released from matrix type. Hixson Crowell cube root law described the drug release has occurred from the variation in particles diameter of system and in surface area. Korsmeyer-peppas model created the experimental equation to evaluate the both fickian and non-fickian release of drug. From the Higuchi model, the Baker and Lonsdale has improved which describes the drug discharge from the matrices of spherical. The Weibull model defined the drug release from the aggregated fraction of drug ‘m’ at time ‘t’ in solution. Hopfenberg model compares the drug release from surface eroding polymers.

Boiling-induced changes on physicochemical, bioactive compounds, color, and texture properties of pumpkin (Cucurbita maxima).

The objective of the present study was to evaluate the effect of boiling duration on physicochemical, bioactive compounds, antioxidant activity, color, and texture properties of pumpkin (Cucurbita maxima). The pumpkin was subjected to boiling for 1, 5, 10, and 20 min at 100 ℃. The physicochemical analyses showed that pH, moisture, and water solubility index were increased, whereas ash content was decreased with increasing the boiling time. Prolong boiling exhibited a detrimental effect on bioactive compounds of pumpkin, and it was found that 20 min of boiling caused about 25.91% ± 2.21% loss of total phenolic content, 14.79% ± 1.03% loss of total carotenoids content, and 18.46% ± 1.34% loss of antioxidant activity. A kinetic study was conducted to quantify the losses occurring in bioactive compounds, antioxidant activity, changes in color, and firmness of pumpkin. The study revealed that the logistic model can predict the variation in bioactive compounds and antioxidant activity with higher R2. However, first-order kinetic models were found suitable to predict the changes occurring in bioactive compounds, antioxidant activity, color properties (L*, a*, b*, Chroma), and firmness. The total color changes (ΔE) showed a good fit with zero-order kinetic models (R2 = 0.98). The t1/2 and D-value were calculated for all measured parameters of pumpkin. These findings would be useful in designing thermal processes and related calculations of pumpkin.