An improved GBSO-TAENN-based EEG signal classification model for epileptic seizure detection.

Detection and classification of epileptic seizures from the EEG signals have gained significant attention in recent decades. Among other signals, EEG signals are extensively used by medical experts for diagnosing purposes. So, most of the existing research works developed automated mechanisms for designing an EEG-based epileptic seizure detection system. Machine learning techniques are highly used for reduced time consumption, high accuracy, and optimal performance. Still, it limits by the issues of high complexity in algorithm design, increased error value, and reduced detection efficacy. Thus, the proposed work intends to develop an automated epileptic seizure detection system with an improved performance rate. Here, the Finite Linear Haar wavelet-based Filtering (FLHF) technique is used to filter the input signals and the relevant set of features are extracted from the normalized output with the help of Fractal Dimension (FD) analysis. Then, the Grasshopper Bio-Inspired Swarm Optimization (GBSO) technique is employed to select the optimal features by computing the best fitness value and the Temporal Activation Expansive Neural Network (TAENN) mechanism is used for classifying the EEG signals to determine whether normal or seizure affected. Numerous intelligence algorithms, such as preprocessing, optimization, and classification, are used in the literature to identify epileptic seizures based on EEG signals. The primary issues facing the majority of optimization approaches are reduced convergence rates and higher computational complexity. Furthermore, the problems with machine learning approaches include a significant method complexity, intricate mathematical calculations, and a decreased training speed. Therefore, the goal of the proposed work is to put into practice efficient algorithms for the recognition and categorization of epileptic seizures based on EEG signals. The combined effect of the proposed FLHF, FD, GBSO, and TAENN models might dramatically improve disease detection accuracy while decreasing complexity of system along with time consumption as compared to the prior techniques. By using the proposed methodology, the overall average epileptic seizure detection performance is increased to 99.6% with f-measure of 99% and G-mean of 98.9% values.

Efficient strategy to isolate exosomes using anti-CD63 antibodies conjugated to gold nanoparticles.

Exosomes, a subpopulation of Extracellular vesicles (EVs), are cell-secreted vesicles found in the majority of biological fluids, including breast milk, tears, sweat, blood and, urine. The density and size of these vesicles depend on a variety of factors, including age, gender and the biological condition of the individual. Researchers are now focusing on the selective extraction of exosomes from bodily fluids due to the unique biomolecule composition of exosomes, which is critical for diagnosis, disease, and regeneration. Furthermore, current approaches for exosome isolation have limitations, necessitating the development of a simpler and more effective technique to achieve this goal. In this study, we investigated a quick and effective strategy for isolating exosomes from serum using a bench-top centrifuge. This was accomplished by raising antibodies against exosome surface tetraspanins (CD9, CD63 & CD81) in Leghorn chickens due to their phylogenetic distance from humans and cost-effectiveness for commercial use. In order to separate exosomes from a complex biological fluid, the antibodies were further coupled with gold nanoparticles (AuNPs). The findings were validated using ELISA, spectrophotometry, and transmission electron microscopy (TEM). Using this technique, exosome isolation from serum was achieved rapidly and these were captured by using anti CD63 antibodies bound to AuNPs. To summarize, exosomes were purified from serum using anti-CD63 antibodies conjugated to gold nanoparticles (IgY@AuNPs). Consequently, the approach for exosome isolation from biological fluid could be useful for clinically monitoring the biological state of the patients.

Anti-pathogenicity of Acanthus ilicifolius leaf extracts against A. hydrophila infection in Labeo rohita fingerlings.

Antibiotic resistance has become one of the inevitable barrier in aquaculture disease management. Herbal drugs has evolved to be the novel ways of combating drug resistant pathogens. In the current investigation, leaf extracts of mangrove plant, Acanthus ilicifolius were assessed for in vitro studies, among the selected four extracts, methanol extract has expressed highest antibacterial activity against P .aeruginosa (4 ± 0.3 mm), A. hydrophila (5.9 ± 0.5 mm), S. aureus (3.5 ± 0.7 mm) and B. subtilis (2.9 ± 0.5 mm) and antioxidant activity, DPPH (81.3 ± 1.0 AAEµg/ml) and FRAP (139.1 ± 1.5 AAEµg/ml).TPC and TFC were higher in the methanolic extract and has exhibited positive correlation with both DPPH and FRAP assays. Considering the in vitro efficiency, methanol extract was purified successively by column and thin layer chromatography and characterisation by GC-MS unveiled the presence of 2-Propanethiol, Trimethylphosphine, Pentanoyl chloride, Dimethylhydroxymethylphosphine and Propanedinitrile, ethylidene. A. hydrophila infected L. rohita fingerlings has survival percentage 81% and 94% in extract treated groups over 0% in negative control and 71% in positive control.

Understanding the Effect of Nucleation in Amorphous Solid Dispersions through Time-Temperature Transformation.

In an earlier investigation, the critical cooling rate to prevent drug crystallization (CRcrit) during the preparation of nifedipine (NIF) amorphous solid dispersions (ASDs) was determined through a time-temperature transformation (TTT) diagram (Lalge et al. Mol. Pharmaceutics 2023, 20 (3), 1806-1817). The current study aims to use the TTT diagram to determine the critical cooling rate to prevent drug nucleation (CRcrit N) during the preparation of ASDs. ASDs were prepared with each polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose acetate succinate (HPMCAS). The dispersions were first stored under conditions promoting nucleation and then heated to the temperature that favors crystallization. The crystallization onset time (tC) was determined by differential scanning calorimetry and synchrotron X-ray diffractometry. TTT diagrams for nucleation were generated, which provided the critical nucleation temperature (50 °C) and the critical cooling rate to avoid nucleation (CRcrit N). The strength of the drug-polymer interactions as well as the polymer concentration affected the CRcrit N, with PVP having a stronger interaction than HPMCAS. The CRcrit of amorphous NIF was ∼17.5 °C/min. The addition of a 20% w/w polymer resulted in CRcrit of ∼0.05 and 0.2 °C/min and CRcrit N of ∼4.1 and 8.1 °C/min for the dispersions prepared with PVP and HPMCAS, respectively.

Implications of Drug-Polymer Interactions on Time-Temperature-Transformation: A Tool to Assess the Crystallization Propensity in Amorphous Solid Dispersions.

The critical cooling rate (CRcrit) to prevent drug crystallization during the preparation of nifedipine amorphous solid dispersions (ASDs) was determined through the time-temperature-transformation (TTT) diagram. ASDs were prepared with polyvinylpyrrolidone, hydroxypropylmethyl cellulose acetate succinate, and poly(acrylic acid). ASDs were subjected to isothermal crystallization over a wide temperature range, and the time and temperature dependence of nifedipine crystallization onset time (tC) was determined by differential scanning calorimetry (DSC) and synchrotron X-ray diffractometry. TTT diagrams were generated for ASDs, which provided the CRcrit for the dispersions prepared with each polymer. The observed differences in CRcrit could be explained in terms of differences in the strength of interactions. Stronger drug-polymer interactions led to longer tC and decreased CRcrit. The effect of polymer concentrations (4-20% w/w) was also influenced by the strength of the interaction. The CRcrit of amorphous NIF was ∼17.5 °C/min. Addition of 20% w/w polymer resulted in a CRcrit of ∼0.05, 0.2, and 11 °C/min for the dispersions prepared with PVP, HPMCAS, and PAA, respectively.

Design of Ternary Amorphous Solid Dispersions for Enhanced Dissolution of Drug Combinations.

Using sulfamethoxazole (SMZ) and trimethoprim (TMP) as model drugs, we designed amorphous solid dispersions (ASDs) for the simultaneous solubility enhancement of two active pharmaceutical ingredients (APIs) by exploiting the drug-drug and drug-polymer interactions. In order to make this approach broadly applicable and over a wide dose range, a mixture of SMZ and TMP at weight ratios of 5:1 and 1:5 (w/w) were formulated into ternary ASDs. Depending on the dose ratio of the two drugs, the polymer used was either an aminoalkyl methacrylate copolymer (Eudragit, EDE) or polyacrylic acid. The drug-drug and drug-polymer interactions were characterized to be ionic by infrared and solid-state nuclear magnetic resonance spectroscopy. The interactions resulted in a substantial reduction in molecular mobility, evident from the increase in the structural relaxation time determined by dielectric spectroscopy. The drug-drug interaction resulted in ∼3 orders of magnitude reduction in molecular mobility. The addition of a polymer led to a further decrease in molecular mobility of up to 4 orders of magnitude. The strength of intermolecular interactions was also estimated from the glass transition temperatures of the ASDs obtained by differential scanning calorimetry. The strong intermolecular interactions yielded highly stable ASDs with no evidence of crystallization, both at elevated temperatures and under accelerated storage conditions (40 °C/75% relative humidity; 6 weeks). The dissolution performances of the ASDs were evaluated using the area under the curve (AUC) obtained from the concentration-time profiles under the non-sink condition. SMZ and TMP in their ternary ASDs, when compared with their crystalline counterparts, exhibited up to 6.4- and 4.6-fold increases in AUC, respectively. Importantly, the synchronized release of the two drugs was observed, a desirable attribute in synergistic formulations. A single-phase ternary ASD, stabilized by drug-drug and drug-polymer interactions, is likely responsible for the unique release profile.

Lady with Long Eyelashes !

A sixty years postmenopausal lady presented with growing longer eyelashes for 8 years. She had thick, dark, curly eyelashes measuring 23 mm and 15 mm at the centre and periphery respectively suggesting marked trichomegaly. Increased vellus hair was noticed above lips and chin suggesting hypertrichosis. An important clue in history was the use of chemotherapeutic agent Erlotinib after bronchoscopic surgery for non-small cell lung carcinoma for the past 8 years. Erlotinib competitively binds to the tyrosine kinase domain of Epidermal Growth Factor Receptor inhibiting receptor activation and blocking the signal transduction. Thus, disrupting the transition of hair growth from anagen to telogen phase, leading to aberrant anagen phase and consequently abnormal hair growth. Trichomegaly is seen after 2-5 months of treatment. Mostly innocuous, it can lead to eyelid infections and rarely corneal ulceration. EGFR inhibitors are associated with hypertrichosis in other areas, as was the case in this patient. This case highlights the significance of detailed history including drugs, thus abating additional work-up for trichomegaly.

Probing the competitive inhibitor efficacy of frog-skin alpha helical AMPs identified against ACE2 binding to SARS-CoV-2 S1 spike protein as therapeutic scaffold to prevent COVID-19.

In COVID-19 infection, the SARS-CoV-2 spike protein S1 interacts to the ACE2 receptor of human host, instigating the viral infection. To examine the competitive inhibitor efficacy of broad spectrum alpha helical AMPs extracted from frog skin, a comparative study of intermolecular interactions between viral S1 and AMPs was performed relative to S1-ACE2p interactions. The ACE2 binding region with S1 was extracted as ACE2p from the complex for ease of computation. Surprisingly, the Spike-Dermaseptin-S9 complex had more intermolecular interactions than the other peptide complexes and importantly, the S1-ACE2p complex. We observed how atomic displacements in docked complexes impacted structural integrity of a receptor-binding domain in S1 through conformational sampling analysis. Notably, this geometry-based sampling approach confers the robust interactions that endure in S1-Dermaseptin-S9 complex, demonstrating its conformational transition. Additionally, QM calculations revealed that the global hardness to resist chemical perturbations was found more in Dermaseptin-S9 compared to ACE2p. Moreover, the conventional MD through PCA and the torsional angle analyses indicated that Dermaseptin-S9 altered the conformations of S1 considerably. Our analysis further revealed the high structural stability of S1-Dermaseptin-S9 complex and particularly, the trajectory analysis of the secondary structural elements established the alpha helical conformations to be retained in S1-Dermaseptin-S9 complex, as substantiated by SMD results. In conclusion, the functional dynamics proved to be significant for viral Spike S1 and Dermaseptin-S9 peptide when compared to ACE2p complex. Hence, Dermaseptin-S9 peptide inhibitor could be a strong candidate for therapeutic scaffold to prevent infection of SARS-CoV-2.

Crystallization Propensity of Amorphous Pharmaceuticals: Kinetics and Thermodynamics.

Four model compounds, nifedipine, indomethacin, felodipine, and ketoconazole, all with nearly identical glass transition temperatures, were chosen to study the effects of thermodynamics and molecular mobility on their crystallization propensities. The time and temperature dependence of the crystallization induction time of each compound was determined by differential scanning calorimetry (DSC) and enabled the generation of their time-temperature-transformation (TTT) diagrams. The relaxation times (τα) were measured by dielectric spectroscopy, and the Gibbs free energy (ΔG) and entropy (ΔS) difference between the crystalline and amorphous states were obtained by DSC. The temperature dependence of the crystallization induction time (τ0(T)) is a function of the thermodynamic activation barrier and the frequency of "attempted jumps" (1/τα(T)) to overcome the barrier. Even though the four model compounds exhibited very similar molecular mobility (relaxation time) over a wide range of temperatures, their crystallization propensities were very different. The observed difference in crystallization propensity was explained in terms of the difference in the thermodynamic barrier, and it is correlated to the empirical relation (TΔS3)/ΔG2.

Purification and characterization of bioactive compounds extracted from Suaeda maritima leaf and its impact on pathogenicity of Pseudomonas aeruginosa in Catla catla fingerlings.

Incidence of various dreadful microbial infections and the development of antibiotic resistance by infection causative microbes are the main reasons for reducing aquaculture productivity. Hence, there is an immense need for the discovery of alternative and efficient treatment for quick recovery of diseased fishes. In the present study, Suaeda maritima leaf extracts (hexane, diethyl ether, ethanol, and water) were screened for in vitro and in vivo antibacterial and antioxidant activities. Out of all the four extracts, ethanolic extract showed highest antibacterial activity against S. aureus (4.9 ± 1.3 mm), B. subtilis (1.6 ± 0.3 mm), K. pneumoniae (4.2 ± 1.8 mm), and P. aeruginosa (4.1 ± 1.2 mm). Similarly, antioxidant activity was also higher for ethanolic extract (500 µg/mL) based on DPPH radical scavenging ability (71.6 ± 1.4%) and reducing potential (149 µg/mL) assays. Further, ethanolic extract was purified consecutively via column chromatography and preparative TLC where an active fraction was selected based on highest antibacterial (10.1 ± 1.4 mm) and antioxidant properties (82.3 ± 2.8%). Active fraction was loaded onto mass spectroscopy and identified the presence of four active constituents such as 1,2,9,10-tetramethoxy-6-methyl-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinolin-3-yl) methanol; 3',7-Dimethoxy-3-hydroxyflavone; Saponin and (19R)9acetyl19hydroxy10,14dimethyl20oxopentacyclo[11.8.0.0 < 2,10 > .0 < 4,9 > .0 < 14,19 >]henicos-17-yl-acetate. Besides, in vivo studies were conducted on Catla catla fingerlings infected with P. aeruginosa under laboratory conditions. The fingerlings were segregated into 5 groups, among which group 4 and 5 were treated with crude and purified extracts. Both the extracts were efficient in treating infected fingerlings and recorded 100% survival rate which is even better than group-3 treated with a synthetic antibiotic (77%). Hence, S. maritima leaf extract can be considered as a possible alternative medicine in aquaculture.

Post Music Session Real-Time EEG Changes in Patients who Underwent Neurosurgical Intervention for Neuronal Dysfunction.

Music is universal and is present in all cultures and capable of conveying emotions irrespective of verbal content. The present study was conducted to understand the impact of music on brain with real-time monitoring of EEG changes in patients with moderate-to-severe neuronal dysfunction. In this prospective study, adult patients who had brain trauma and unconscious were considered for the study. Two different music pieces were selected to give music experience. One is Revathi raga with Upanishads' stands. Another is Ragamalika, an instrumental music piece comprising various Carnatic ragas. For EEG recording, electrode montage was done according to international 10-20 system. After music experience, again EEG recording was done without music. Comparison of EEG activity during different musical pieces was not considered. A total of six adults were studied. During the time of music session, there was no change in the EEG at other channels, but at T6 electrode, EEG did not have the arc like fast theta. That fast theta was disappeared in T6 electrode and it was suppressed like a contralateral sided electrode. After the music session (post music session), the EEG is back to baseline, but the temporal arc like fast theta speed was decreased (2-4 seconds per page). In this case series, we observed that in one case, there was appearance of slow activity in EEG. However, there is a need for larger studies to confirm these findings.

Biodiesel Production From Lignocellulosic Biomass Using Oleaginous Microbes: Prospects for Integrated Biofuel Production.

Biodiesel is an eco-friendly, renewable, and potential liquid biofuel mitigating greenhouse gas emissions. Biodiesel has been produced initially from vegetable oils, non-edible oils, and waste oils. However, these feedstocks have several disadvantages such as requirement of land and labor and remain expensive. Similarly, in reference to waste oils, the feedstock content is succinct in supply and unable to meet the demand. Recent studies demonstrated utilization of lignocellulosic substrates for biodiesel production using oleaginous microorganisms. These microbes accumulate higher lipid content under stress conditions, whose lipid composition is similar to vegetable oils. In this paper, feedstocks used for biodiesel production such as vegetable oils, non-edible oils, oleaginous microalgae, fungi, yeast, and bacteria have been illustrated. Thereafter, steps enumerated in biodiesel production from lignocellulosic substrates through pretreatment, saccharification and oleaginous microbe-mediated fermentation, lipid extraction, transesterification, and purification of biodiesel are discussed. Besides, the importance of metabolic engineering in ensuring biofuels and biorefinery and a brief note on integration of liquid biofuels have been included that have significant importance in terms of circular economy aspects.

Extraction of bioactive compounds from Psidium guajava leaves and its utilization in preparation of jellies.

Psidium guajava L. (guava) is predominantly grown throughout the world and known for its medicinal properties in treating various diseases and disorders. The present work focuses on aqueous extraction of bioactive compounds from the guava leaf and its utilization in the formulation of jelly to improve the public health. The guava leaf extract has been used in the preparation of jelly with pectin (1.5 g), sugar (28 g) and lemon juice (2 mL). The prepared guava leaf extract jelly (GJ) and the control jelly (CJ, without extract) were subjected to proximate, nutritional and textural analyses besides determination of antioxidant and antimicrobial activities. GJ was found to contain carbohydrate (45.78 g/100 g), protein (3.0 g/100 g), vitamin C (6.15 mg/100 g), vitamin B3 (2.90 mg/100 g) and energy (120.6 kcal). Further, the texture analysis of CJ and GJ indicated that both the jellies showed similar properties emphasizing that the addition of guava leaf extract does not bring any change in the texture properties of jelly. GJ exhibited antimicrobial activity against various bacteria ranging from 11.4 to 13.6 mm. Similarly, GJ showed antioxidant activity of 42.38% against DPPH radical and 33.45% against hydroxyl radical. Mass spectroscopic analysis of aqueous extract confirmed the presence of esculin, quercetin, gallocatechin, 3-sinapoylquinic acid, gallic acid, citric acid and ellagic acid which are responsible for antioxidant and antimicrobial properties.

Immunotherapeutics for Covid-19 and post vaccination surveillance.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) has emerged as a pandemic and named as novel coronavirus disease (nCOVID-19). SARS-CoV-2 is different from other known viruses due to multiple mutations on the sites of nonstructural proteins (NSP) 2 and 3, and the varying nature of virulence between different persons. Immunotherapies such as vaccines and monoclonal antibodies have a protective effect on the patients bringing them to the front of the line of potential treatments. The present review intends to cover the development of 20 different vaccine candidates categorized under live attenuated vaccines, inactivated vaccines, subunit vaccines, viral vector-based vaccines, and nucleic acid vaccines. Formulation of these vaccine candidates by various companies in collaboration with global organizations and their status of clinical trials were addressed. On the other hand, various approaches for post-vaccination surveillance using nucleic acid and protein biomarkers imbued on suitable platforms were also highlighted to sum up the immune therapeutics for Covid-19.

Nanobubbles in Reconstituted Lyophilized Formulations: Interaction With Proteins and Mechanism of Formation.

Reconstitution of lyophilized disaccharide formulations results in the formation of nanosized air bubbles that persist in suspension for weeks. If proteins are present, interactions with nanobubbles may cause loss of monomeric protein and formation of subvisible particles. The goals of this work are to determine the mechanism(s) by which nanobubbles form in reconstituted lyophilized formulations and to develop strategies for reducing nanobubble generation. We hypothesize that nanobubbles are created from nanosized gas pockets within lyophilized solids, which become bubbles when the surrounding matrix is dissolved away during reconstitution. Nanosized voids may originate from small ice crystals formed within the concentrated liquid during freezing that subsequently sublime during drying. Nanobubble concentrations are correlated with the extent of mannitol crystallization during freezing. Nanosized ice crystals, induced by the release of water during mannitol crystallization, were responsible for nanobubble formation. The presence of trehalose or sucrose, in formulations with low mannitol concentrations, inhibited excipient crystallization during lyophilization and reduced nanobubble levels following reconstitution. Our results show a correlation between nanobubble formation and concentrations of insoluble IL-1ra aggregates, suggesting that minimizing nanobubble generation may be an effective strategy for reducing protein aggregation following reconstitution.

Chitosan as an environment friendly biomaterial - a review on recent modifications and applications.

Amongst the natural polymers, chitin is the second most abundant, present mainly in fungi and exoskeleton of crustaceans. It forms a major part of the seafood waste as compiled and presented in this review and is de-acetylated to produce chitosan. Structure and properties of chitosan have been described. Biocompatible and biodegradable characteristics of chitosan have been well studied. In addition to the environmental sustainability associated with its use, the malleability of chitosan due to its reactive amino and hydroxyl groups, adds to its wide repertoire in usage through various modifications. Recent publications of chitosan and derivatives have been classified into its various applications in food, pharmaceutical, biotechnology, medical, textile, paper, agriculture and environmental applications. The abundance of chitosan and diversity in modifications can be effectively utilized in various applications leading to environmental friendly solutions as highlighted in this review.

Extraction of bioactive compounds from Psidium guajava and their application in dentistry.

Guava is considered as poor man's apple rich in phytochemicals with medicinal value and hence it is highly consumed. Gas chromatography-mass spectroscopy (GC-MS) analysis of guava leaf extract revealed the presence of various bioactive compounds with antimicrobial, antioxidant, anticancer, and antitumor properties. Hence, it is used in tooth paste formulations along with other ingredients such as Acacia arabica gum powder, stevia herb powder, sea salt, extra virgin coconut oil, peppermint oil in the present study. Three formulations F1, F2 and F3 have been made by varying the concentration of these ingredients and the prepared formulations were studied for their antimicrobial activity and physico-chemical parameters such as pH, abrasiveness, foaming activity, spreading and cleaning ability. Among these, F3 showed significant antioxidant and antimicrobial properties, minimal cytotoxicity, maximum spreadability and very high cleaning ability. This study surmises that the herbal toothpaste formulation is greener, rich in medicinal values and imparts oral hygiene.

Extraction and characterization of collagen from the skin of Pterygoplichthys pardalis and its potential application in food industries.

The primary objective of this study was to extract collagen from underutilized fish species owing to its cost effective nature and also its ability to address the demand of type I collagen arising from food and pharmaceutical industries. Acid and pepsin soluble collagen (ppASC and ppPSC) were extracted from the skin of sucker catfish (Pterygoplichthys pardalis) with a yield of 19.6 and 23.8% on wet weight basis respectively. The same were characterized and confirmed as type I collagen by SDS-PAGE, FTIR and UV-Vis spectroscopy, amino acid analysis, and Zeta potential. Taking into consideration the application of collagen in food industry, a food product was developed by incorporating with fresh cheese. This fortification was found to be acceptable and had not altered the taste, odor and other sensory properties of the product.

Crosslinking: An avenue to develop stable amorphous solid dispersion with high drug loading and tailored physical stability.

Influence of crosslinking (crosslinker concentration and crosslinking condition) on molecular mobility and physical stability of ketoconazole (KTZ) solid dispersions was investigated over a wide temperature range in the supercooled state. Amorphous solid dispersions (ASDs) with very high drug loading (95% w/w) were prepared by thermal crosslinking. As the crosslinker concentration increased (from 0.25-1.0% w/w), there was a progressive decrease in molecular mobility as evident from both the longer α-relaxation time, and higher viscosity values. Consequently, there was progressive enhancement in physical stability (crystallization inhibition). At 1.0% w/w crosslinker concentration, when compared with the drug alone, there was ~4 orders of magnitude increase in both viscosity and α-relaxation times. Elevating the crosslinking temperature, by increasing the crosslinking density, provided a second avenue to enhance physical stability. Hence, crosslinking density offers a simple method to enhance physical stability and control drug release. We have formulated ASDs: (i) with very high drug loading (95% w/w), and (ii) pronounced stability even when exposed to elevated temperatures and water vapor pressure. Also, during dissolution study, the degree of supersaturation in the dissolution medium generated by the crosslinked systems gradually increased and maintained the supersaturation for a longer period.

Stability of lyophilized albumin formulations: Role of excipient crystallinity and molecular mobility.

In freeze-dried protein formulations, the composition governs the physical forms of the excipients and hence their functionality. It is also necessary to understand the effect of composition on the molecular relaxation behavior, a key factor influencing protein stability. Mannitol (bulking agent) - trehalose (lyoprotectant) - bovine serum albumin (BSA) lyophiles with varying trehalose to BSA mass ratios were investigated. The crystalline phases were characterized by X-ray diffractometry. The secondary structure of albumin in lyophiles and reconstituted solutions was evaluated by IR spectroscopy and circular dichroism, respectively. Dielectric spectroscopy was used to obtain the relaxation time of freeze-dried samples. When trehalose to BSA ratio was 0.2, while mannitol crystallized predominantly as the δ-anhydrous polymorph, trehalose remained amorphous. At lower concentrations of BSA, mannitol crystallized in both hemihydrate and anhydrous forms, and trehalose as dihydrate. The extent of dehydration during subsequent drying was dictated by the trehalose to BSA ratio in the formulation. A gradual increase in the Johari-Goldstein relaxation time was observed as the concentration of trehalose increased in the formulation. BSA was more susceptible to stresses from thawing than drying.