Exogenous application of urea and a urease inhibitor improves drought stress tolerance in maize (Zea mays L.).

Drought is believed to cause many metabolic changes which affect plant growth and development. However, it might be mitigated by various inorganic substances, such as nitrogen. Thus, the study was carried out to investigate the effect of foliar-applied urea with or without urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on a maize cultivar under drought stress simulated by 15% (w/v) polyethylene glycol 6000. Foliar-applied urea resulted in a significant increase in plant dry weight, relative water content, and photosynthetic pigments under water stress condition. Furthermore, the activities of superoxide dismutase (SOD), peroxidase (POD), and hydrogen peroxidase (CAT), were enhanced with all spraying treatments under drought stress, which led to decreases in accumulation of hydrogen peroxide (H2O2), superoxide anion ([Formula: see text]) and malondialdehyde (MDA). The contents of soluble protein and soluble sugar accumulated remarkably with urea-applied under drought stress condition. Moreover, a further enhancement in above metabolites was observed by spraying a mixture of urea and urease inhibitor as compared to urea sprayed only. Taken together, our findings show that foliar application of urea and a urease inhibitor could significantly enhance drought tolerance of maize through protecting photosynthetic apparatus, activating antioxidant defense system and improving osmoregulation.

Evaluation of cytotoxic and antiviral activities of aqueous leaves extracts of different plants against foot and mouth disease virus infection in farming animals.

Cytotoxic and antiviral activity of aqueous leaves extracts of three plants: Azadirachta indica, Moringa oleifera and Morus alba against Foot and Mouth disease virus (FMDV) were determined using MTT assay (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide). Eight different concentrations of each plant were evaluated. Cytotoxic and antiviral activity of each extract was evaluated as cell survival percentage and results were expressed as Means ± S.D. From the tested plant extracts, Azadirachta indica & Moringa oleifera exhibited cytotoxicity at 200 & 100 µ/ml respectively. In case of antiviral assay, Moringa oleifera showed potent antiviral activity (p<0.05) while Azadirachta indica showed significant antiviral activity in the range of 12.5-50 µ/ml & 50-100 µ/ml respectively. In contrast no anti-FMDV activity in the present study was observed with Morus alba, although all the tested concentrations were found to be safe.

Paired observation on light-cured composite resin and nano-composite resin in dental caries repair.

To compare the value of light-cured composite resin with that of nano-composite resin in dental caries repair. 88 patients taking dental caries repair in our hospital from May 2014 to April 2015 were selected, and divided into observation group and control group by coin method with 44 patients in each group. Nano-composite resin was used in observation group, while light-cured composite resin in control group. Then, the occurrence rates of odontohyperesthesia, aesthetic satisfaction with dental caries repair and complications were compared between two groups by visual analogue scale (VAS). The occurrence rate of odontohyperesthesia in observation group is significantly lower than that in control group (9.09% (4/44) vs 31.82% (14/44), 6.82% (3/44) vs 22.73% (10/44), 2.27% (1/44) vs 13.64% (6/44)) with difference of statistical significance (P<0.05) 1 week, 4 weeks, and 8 weeks after repair. VAS score of patients in observation is significantly lower than that in control group ((2.78±0.56) scores vs (5.22±0.76) scores, (2.02±0.35) scores vs (4.32±0.57) scores, (1.12±0.14) scores vs (2.41±0.43) scores) 1 week, 4 weeks, and 8 weeks after repair. Moreover, the difference in comparison of interactive effects between two groups, between different time points, and between groups at different time points has statistical significance (P<0.05). Nano-composite resin can lower the occurrence rate of odontohyperesthesia in dental caries repair, reduce the pain of patients, and improve the satisfaction of patients with tooth appearance.

Evaluation of antiviral activity of plant extracts against foot and mouth disease virus in vitro.

The aim of this study was to evaluate antiviral activity of chloroformic leaves extracts of three plants: Azadirachta indica, Moringa oleifera and Morus alba against Foot and Mouth disease virus using MTT assay (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide). Antiviral and cytotoxic activity of each extract was evaluated as cell survival percentage and results were expressed as Means ± S.D. The concentrations which resulted in cell survival percentages of greater than 50% are considered to be effective antiviral concentrations. From the tested plant extracts, Moringa oleifera showed potent antiviral activity (p<0.05) while Azadirachta indica showed significant antiviral activity in the range of 1-50µ/ml & 12-100µ/ml respectively. In contrast no antiviral activity was observed by Morus alba as all the tested concentration resulted in significant reduction (p<0.05) in cell survival percentage.

pH-sensitive docetaxel-loaded chitosan/thiolated hyaluronic acid polymeric nanoparticles for colorectal cancer.

Aim: This study aimed to develop and evaluate pH-sensitive docetaxel-loaded thiolated hyaluronic acid (HA-SH) nanoparticles (NPs) for targeted treatment of colon cancer. Materials & methods: HA-SH, synthesized via oxidation and subsequent covalent linkage to cysteamine, served as the precursor for developing HA-SH NPs through polyelectrolyte complexation involving chitosan and thiol-bearing HA. Results & conclusion: HA-SH NPs displayed favorable characteristics, with small particle sizes (184-270 nm), positive zeta potential (15.4-18.6 mV) and high entrapment efficiency (91.66-95.02%). In vitro, NPs demonstrated potent mucoadhesion and enhanced cytotoxicity compared with free docetaxel. In vivo assessments confirmed safety and biocompatibility, suggesting HA-SH NPs as promising pH-sensitive drug carriers with enhanced antitumor activity for colorectal cancer treatments.

Development and evaluation of a pH-responsive Mimosa pudica seed mucilage/ß- cyclodextrin-co-poly(methacrylate) hydrogel for controlled drug delivery: In vitro and in vivo assessment.

In this comprehensive investigation, a novel pH-responsive hydrogel system comprising mimosa seed mucilage (MSM), ß-cyclodextrin (ß-CD), and methacrylic acid (MAA) was developed via free radical polymerization technique to promote controlled drug delivery. The hydrogel synthesis involved strategic variations in polymer, monomer, and crosslinker content in fine-tuning its drug-release properties. The resultant hydrogel exhibited remarkable pH sensitivity, selectively liberating the model drug (Capecitabine = CAP) under basic conditions while significantly reducing release in an acidic environment. Morphological, thermal, and structural analyses proved that CAP has a porous texture, high stability, and an amorphous nature. In vitro drug release experiments showcased a sustained and controlled release profile. Optimum release (85.33 %) results were recorded over 24 h at pH 7.4 in the case of MMB9. Pharmacokinetic evaluation in healthy male rabbits confirmed bioavailability enhancement and sustained release capabilities. Furthermore, rigorous toxicity evaluations and histopathological analyses ensured the safety and biocompatibility of the hydrogel. This pH-triggered drug delivery system can be a promising carrier system for drugs involving frequent administrations.

Plastic footprint deteriorates dryland carbon footprint across soil-plant-atmosphere continuum.

Plastic fragments are widely found in the soil profile of terrestrial ecosystems, forming plastic footprint and posing increasing threat to soil functionality and carbon (C) footprint. It is unclear how plastic footprint affects C cycling, and in particularly permanent C sequestration. Integrated field observations (including 13C labelling) were made using polyethylene and polylactic acid plastic fragments (low-, medium- and high-concentrations as intensifying footprint) landfilling in soil, to track C flow along soil-plant-atmosphere continuum (SPAC). The result indicated that increased plastic fragments substantially reduced photosynthetic C assimilation (p < 0.05), regardless of fragment degradability. Besides reducing C sink strength, relative intensity of C emission increased significantly, displaying elevated C source. Moreover, root C fixation declined significantly from 21.95 to 19.2 mg m-2, and simultaneously root length density, root weight density, specific root length and root diameter and surface area were clearly reduced. Similar trends were observed in the two types of plastic fragments (p > 0.05). Particularly, soil aggregate stability was significantly lowered as affected by plastic fragments, which accelerated the decomposition rate of newly sequestered C (p < 0.05). More importantly, net C rhizodeposition declined averagely from 39.77 to 29.41 mg m-2, which directly led to significant decline of permanent C sequestration in soil. Therefore, increasing plastic footprint considerably worsened C footprint regardless of polythene and biodegradable fragments. The findings unveiled the serious effects of plastic residues on permanent C sequestration across SPAC, implying that current C assessment methods clearly overlook plastic footprint and their global impact effects.

Cardiac progenitor-derived exosomes protect ischemic myocardium from acute ischemia/reperfusion injury.

BACKGROUND: Cardiac progenitors (CPC) mediate cardioprotection via paracrine effects. To date, most of studies focused on secreted paracrine proteins. Here we investigated the CPC-derived-exosomes on protecting myocardium from acute ischemia/reperfusion (MI/R) injury. METHODS AND RESULTS: CPC were isolated from mouse heart using two-step protocol. Exosomes were purified from conditional medium, and confirmed by electron micrograph and Western blot using CD63 as a marker. qRT-PCR shows that CPC-exosomes have high level expression of GATA4-responsive-miR-451. Exosomes were ex vivo labeled with PKH26, We observed exosomes can be uptaken by H9C2 cardiomyoblasts with high efficiency after 12 h incubation. CPC-exosomes protect H9C2 from oxidative stress by inhibiting caspase 3/7 activation invitro. In vivo delivery of CPC-exosomes in an acute mouse myocardial ischemia/reperfusion model inhibited cardiomyocyte apoptosis by about 53% in comparison with PBS control (p<0.05). CONCLUSION: Our results suggest, for the first time, the CPC-exosomes can be used as a therapeutic vehicle for cardioprotection, and highlights a new perspective for using non-cell exosomes for cardiac disease.

Temporomandibular Disorders among Dental Students in Pakistan: Assessment of Prevalence, Severity, and Associated Factors Based on Questionnaire.

Objective: To evaluate the prevalence, severity, and associated factors of temporomandibular disorder (TMD) among dental students. Methods: This cross-sectional study was performed on undergraduate dental students from four dental colleges in Punjab, Pakistan. Fonseca's questionnaire was used to measure the prevalence and severity of the TMD among the study participants. Bivariate and multiple logistic regression analyses were performed. Results: Of 364 dental students, 323 returned the completed questionnaires and the response rate of the study was 88.7%. The study included 52.6% males and 47.4% females. The prevalence of TMD was 66.9% with mild TMD in 40.90%, moderate TMD in 14.6%, and severe TMD in 11.50% of the participants. Psychological stress (29.6%), malocclusion (20%), and hypersensitivity (19.5%) were common among participants. The mean TMD score of the sample was 31.54 ± 24.86 which was significantly higher among participants with no/school-educated mothers (P=0.021) and fathers (P=0.002). The participants with arthritis (72.81 ± 32.19) and malocclusion (59.46 ± 31.09) and those who received orthodontic treatment (53.21 ± 34.21) demonstrated higher TMD. After controlling for other study variables, the participants with arthritis were 4.71 times more likely to have moderate/severe TMD (P=0.042) than those without arthritis. Similarly, the participants with malocclusion had significantly higher odds (OR = 3.57, P=0.029) of having moderate/severe TMD than those without malocclusion. Conclusion: This sample of dental students demonstrated a high prevalence and severity of TMD. The participants with arthritis and malocclusion demonstrated higher TMD. The study findings underscore the importance of prevention, early diagnosis, and management of TMD among the dental students.

Screening of hepatitis B and C viral infection, recognition of risk factors, and immunization of patients against hepatitis B virus: a module developed for effective hepatitis control.

Introduction: The continually increasing incidence of hepatitis, a worldwide health issue, in Pakistan, has highlighted the need to investigate the epidemiology factors and implement preventive measures accordingly. The purpose of this study was to scrutinize the prevalent and significantly associated risk factors of hepatitis in students and employees, screening them for hepatitis B and C virus and vaccinating them against HBV to make IUB hepatitis free. Methodology: A total of 12,912 participants including students (n = 10,948) and employees (n = 1964) were screened for HBV and HCV via immunochromatographic test. Hepatitis- positive participants' blood samples were further tested and viral load was estimated by quantitative PCR. All the hepatitis-negative participants were vaccinated against HBV. The demographic and risk factors-related data were collected using the questionnaire. Statistical analysis (Chi-square test and bivariate regression analysis) was performed using SPSS software to explore any association between risk factors and hepatitis. Results: Results indicated that 662/12912 participants (students = 478/10,948, employees = 184/1,964) tested positive for hepatitis. Among them, HCV was observed to be more prevalent than HBV among the study participants, employees, and students, and viral count was low in both HBV and HCV-infected participants. However, men were more affected than women. The studied risk factors represented higher frequency among hepatitis-positive participants relative to the hepatitis-negative participants. The Chi-square test revealed that students' gender, history of hepatitis in the family and relatives, dental treatment, sharing cosmetics and shaving blades were significant (p > 0.005) risk factors of hepatitis while in the employees group surgery and age were significant. Moreover, the reused of syringes was found to be associated with hepatitis in both groups. The bivariate analysis helped to identify various new risk factors which were independently, either positively or negatively, associated with hepatitis. Discussion: Our study enabled us to recognize different risk factors of hepatitis among the target population. The information thus generated can be usefully applied in planning hepatitis awareness, targeted screening, and effective control programs for other target populations. In general, this module can be further utilized for any other disease.

Mechanistic understanding of the performance of personalized 3D-printed cardiovascular polypills: A case study of patient-centered therapy.

The 3D printing has become important in drug development for patient-centric therapy by combining multiple drugs with different release characteristics in a single polypill. This study explores the critical formulation and geometric variables for tailoring the release of Atorvastatin and Metoprolol as model drugs in a polypill when manufactured via pressure-assisted-microextrusion 3D printing technology. The effects of these variables on the extrudability of printing materials, drug release and other quality characteristics of polypills were studied employing a definitive screening design. The extrudability of printing materials was evaluated in terms of flow pressure, non-recoverable strain, compression rate, and elastic/plastic flow. The extrudability results helped in defining an operating space free of printing defects. The Atorvastatin compartment of polypill consisted of mesh-shaped layers while Metoprolol compartment consisted of a core surrounded by a release controlling shell with a hydrophobic septum between the two compartments. The results indicated that both the formulation and geometric variables govern the drug release of the polypill. Specifically, the use of HPMC E3 matrix, and a 2 mm distance between the strands at a weaving angle of 90° were critical in achieving the desired immediate-release profile of Atorvastatin. The core and shell design primarily determined the desired extended-release profile of Metoprolol. The carbopol and HPMC K100 concentration of 1% in the core and 10% in the shell and the number of shell layers in Metoprolol compartment were critical for achieving the desired Metoprolol dissolution. Polymer and Metoprolol content of the shell and shell-thickness affected the mechanical strength of the polypills. In conclusion, the 3D printing provides the flexibility for independently tailoring the release of different drugs in the same dosage form for patient centric therapy, and both the formulation and geometric parameters need to be optimized to achieve desired drug release.

Competency of groundwater recharge of irrigated cotton field subjacent to sowing methods, plastic mulch, water productivity, and yield under climate change.

Irrigated agriculture is a foremost consumer of water resources to fulfill the demand for food and fiber with an increasing population under climate changes; cotton is no exception. Depleting groundwater recharge and water productivity is critical for the sustainable cotton crop yield peculiarly in the semiarid region. This study investigated the water productivity and cotton yield under six different treatments: three sowing methods, i.e., flat, ridge, and bed planting with and without plastic mulch. Cotton bed planting without mulch showed maximum water productivity (0.24 kg.m-3) and the highest cotton yield (1946 kg.ha-1). Plastic mulching may reduce water productivity and cotton yield. HYDRUS-1D unsaturated flow model was used to access the groundwater recharge for 150 days under six treatments after model performance evaluation. Maximum cumulative recharge was observed 71 cm for the flat sowing method without plastic mulch. CanESM2 was used to predict climate scenarios for RCP 2.6, 4.5, and 8.5 for the 2050s and 2080s by statistical downscale modeling (SDSM) using historical data from 1975 to 2005 to access future groundwater recharge flux. Average cumulative recharge flux declined 36.53% in 2050 and 22.91% in 2080 compared to 2017 without plastic mulch. Multivariate regression analysis revealed that a maximum 23.78% reduction in groundwater recharge could influence future climate change. Further study may require to understand the remaining influencing factor of depleting groundwater recharge. Findings highlight the significance of climate change and the cotton sowing method while accessing future groundwater resources in irrigated agriculture.

Micro Electromechanical Systems (MEMS) Based Microfluidic Devices for Biomedical Applications.

Micro Electromechanical Systems (MEMS) based microfluidic devices have gained popularity in biomedicine field over the last few years. In this paper, a comprehensive overview of microfluidic devices such as micropumps and microneedles has been presented for biomedical applications. The aim of this paper is to present the major features and issues related to micropumps and microneedles, e.g., working principles, actuation methods, fabrication techniques, construction, performance parameters, failure analysis, testing, safety issues, applications, commercialization issues and future prospects. Based on the actuation mechanisms, the micropumps are classified into two main types, i.e., mechanical and non-mechanical micropumps. Microneedles can be categorized according to their structure, fabrication process, material, overall shape, tip shape, size, array density and application. The presented literature review on micropumps and microneedles will provide comprehensive information for researchers working on design and development of microfluidic devices for biomedical applications.

Fabrication and dialysis performance of functionalized multiwall carbon nanotubes integrated cellulose acetate/poly(vinylpyrrolidone) membranes.

Mixed matrix membranes (MMMs) of cellulose acetate/poly(vinylpyrrolidone) (CA/PVP) infused with acid functionalized multiwall carbon nanotubes (f-MWCNTs) were fabricated by an immersion phase separation technique for hemodialysis application. Membranes were characterized using FTIR, water uptake, contact angle, TGA, DMA and SEM analysis. The FTIR was used to confirm the bonding interaction between CA/PVP membrane matrix and f-MWCNTs. Upon addition of f-MWCNTs, TGA thermograms and glass transition temperature indicated improved thermal stability of MMMs. The surface morphological analysis demonstrated revealed uniform distribution of f-MWCNTs and asymmetric membrane structure. The water uptake and contact angle confirmed that hydrophilicity was increased after incorporation of f-MWCNTs. The membranes demonstrated enhancement in water permeate flux, bovine serum albumin (BSA) rejection with the infusion of f-MWCNTs; whereas BSA based anti-fouling analysis using flux recovery ratio test shown up to 8.4% improvement. The urea and creatinine clearance performance of MMMs were evaluated by dialysis experiment. It has been found that f-MWCNTs integrated membranes demonstrated the higher urea and creatinine clearance with increase of 12.6% and 10.5% in comparison to the neat CA/PVP membrane. Thus, the prepared CA/PVP membranes embedded with f-MWCNTs can be employed for wide range of dialysis applications.

Smart pH-responsive Co-polymeric Hydrogels for Controlled Delivery of Capecitabine: Fabrication, Optimization and In Vivo Toxicology Screening.

BACKGROUND: Despite exhibiting promising anticancer potential, the clinical significance of capecitabine (a potent prodrug of 5-fluorouracil used for the treatment of colorectal cancer) is limited owing to its acidic and enzymatic hydrolysis, lower absorption following the oral administration, poor bioavailability, short plasma half-life, and poor patient compliance. OBJECTIVES: The present study was aimed to fabricate the capecitabine as a smart pH-responsive hydrogel network to efficiently facilitate its oral delivery while shielding its stability in the gastric media. METHODS: The smart pH-sensitive HP-ß-CD/agarose-g-poly(MAA) hydrogel network was developed using an aqueous free radical polymerization technique. The developed hydrogels were characterized for drug-loading efficiency, structural and compositional features, thermal stability, swelling behaviour, morphology, physical form, and release kinetics. The pH-responsive behaviour of developed hydrogels was established by conducting the swelling and release behaviour at different pH values (1.2 and 7.4), demonstrating significantly higher swelling and release at pH 7.4 as compared with pH 1.2. The capecitabine-loaded hydrogels were also screened for acute oral toxicity in animals by analysing the body weight, water and food intake, dermal toxicity, ocular toxicity, biochemical analysis, and histological examination. RESULTS: The characteristic evaluations revealed that capecitabine (anticancer agent) was successfully loaded into the hydrogel network. The range of capecitabine loading was from 71.22% to 90.12%. An interesting feature of hydrogel was its pH-responsive behaviour which triggers release at basic pH (94.25%). Optimum swelling (95%)was seen at pH 7.4. Based upon regression coefficient R2(0.96 - 0.99) the best-fit model was zero-order. The extensive toxicity evaluations evidenced a good safety profile with no signs of oral, dermal, or ocular toxicities, as well as no variations in blood parameters and histology of vital organs. CONCLUSION: Our findings conclusively evinced that the developed hydrogel exhibited excellent pharmaceutical and therapeutic potential and thus can be employed as a pH-responsive system for the controlled delivery of anticancer agents.

A quadruple blinded placebo controlled randomised trial to evaluate the effectiveness of an Iodine complex for patients with mild to moderate COVID-19 in Pakistan (I-COVID-PK): A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: The objective of the study is to measure the efficacy of ionic-iodine polymer complex [1] for clinical and radiological improvement in coronavirus disease 2019 (COVID-19) patients. TRIAL DESIGN: The trial will be closed label, randomized and placebo-controlled with a 1:1:1:1 allocation ratio and superiority framework. PARTICIPANTS: All PCR confirmed COVID-19 adult patients including non-pregnant females, with mild to moderate disease, will be enrolled from Shaikh Zayed Post-Graduate Medical Complex, Ali Clinic and Doctors Lounge in Lahore (Pakistan). Patients with any pre-existing chronic illness will be excluded from the study. INTERVENTION AND COMPARATOR: In this multi-armed study ionic-iodine polymer complex with 200 mg of elemental iodine will be given using three formulations to evaluate efficacy. Patients will be receiving either encapsulated iodine complex of 200 mg (arm A), iodine complex syrup form 40 ml (arm B), iodine complex throat spray of 2 puffs (arm C) or empty capsule (arm D) as placebo; all three times a day. All the 4 arms will be receiving standard care as per version 3.0 of the clinical management guidelines for COVID-19 established by the Ministry of National Health Services of Pakistan. MAIN OUTCOMES: Primary outcomes will be viral clearance with radiological and clinical improvement. SARS-CoV-2 RT-PCR and HRCT chest scans will be done on the admission day and then after every fourth day for 12 days or till the symptoms are resolved. RT-PCR will only be shown as positive or negative while HRCT chest scoring will be done depending on the area and severity of lung involvement [2]. Time taken for the alleviation of symptoms will be calculated by the number of days the patient remained symptomatic. 30-day mortality will be considered as a secondary outcome. RANDOMISATION: Stratification for initial COVID-19 status (or days from initial symptoms as a proxy), age groups, gender, baseline severity of symptoms and co-morbidities will be used to ensure that the study arms remain balanced in size for the 1:1:1:1 allocation ratio. Randomization will be done using the lottery method. As patients are being admitted at different times, they will be recruited after obtaining their voluntary written informed consent following all standard protocols of the infection, control and disinfection. BLINDING (MASKING): This is a quadruple (participants, care providers, investigators and outcomes assessors) blinded study where only the study's Primary Investigator will have information about the arms and their interventions. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): 200 patients will be randomized into four groups with three experimental and one placebo arm. TRIAL STATUS: Protocol Version Number is 2.3 and it is approved from IRB Shaikh Zayed Hospital with ID SZMC/IRB/Internal0056/2020 on July 14th, 2020. The recruitment is in progress. It was started on July 30, 2020, and the estimated end date for the trial is August 15, 2021. TRIAL REGISTRATION: Clinical Trial has been retrospectively registered on www.clinicaltrials.gov with registration ID NCT04473261 dated July 16, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). With the intention of expediting dissemination of this trial, the conventional formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines.

Influence of residual solvents on the physical properties of transdermal drug delivery systems.

The purpose of this investigation was to systematically assess the effect of residual solvents on the physical properties of a silicone adhesive-based transdermal system (TDS) containing n-heptane and o-xylene as residual solvents. The processing temperature was varied in this study to obtain various contents of residual solvents in the TDS. The adhesion performance was determined by evaluating the tack, shear, and peel of these TDS at week 0 and week 2. The adhesion measurements showed significant changes in tack values with a decrease in the contents of residual solvents, but the changes in peel and shear were insignificant. The rheological characteristics such as linear viscoelastic region, loss modulus and storage modulus were also measured. The outcome of the rheological measurements was found to be more sensitive to the changes in the contents of residual solvents in comparison to adhesion measurements. These results show that the residual solvent content may affect TDS performance and should be controlled from a product quality and performance perspective.

Application of synthetic membranes in establishing bio-predictive IVPT for testosterone transdermal gel.

The current study investigated the use of synthetic membranes in developing a bio-predictive in vitro permeation testing (IVPT) method for 1.62% testosterone gel. The IVPT studies were carried out using both Franz (FC), and Flow-through (FTC) diffusion cells. The experimental variables included the type of synthetic membranes (hydrophilic polyamide nylon, polysulfone tuffryn and STRAT-M (SM) membrane) and the type of receiver media (phosphate buffer containing various concentrations of sodium lauryl sulfate). In vivo drug release rates were obtained from published reports for 1.62% testosterone gel applied to either abdominal area (treatment group A), upper arms/shoulders (treatment group B), or alternating between abdomen and arms/shoulders (treatment group C). The in vitro-in vivo correlations were established using GastroPlus software. The best IVPT method was selected based on establishing point-to-point correlation with the in vivo data of treatment group A with minimal prediction errors (%PE) of AUC0-24 and Cmax. The results showed that the IVPT method which employed the FTC diffusion system, SM membrane and phosphate buffer without surfactant established the best IVIVR model with a correlation coefficient (R2) of 0.9966 and an exponential function of Y = (1.35)5 × X3.6. The in vivo data obtained from treatment group A and B was used for internal validation of the prediction model. The validation data was acceptable, with %PE of less than 10% for both AUC0-24 and Cmax. In conclusion, these results suggest that bio-predictive IVPT methods for testosterone gels may be developed using synthetic membranes and diffusion apparatus by varying the composition of the receiver medium.

Factors affecting the particle size distribution and rheology of brinzolamide ophthalmic suspensions.

Drug particle size distribution (PSD) and dispersion viscosity are two critical quality attributes that govern the performance of topical ophthalmic suspensions, such as suspension physical stability, ocular retention, and drug release characteristics.. An in-depth knowledge of the effects of formulation and manufacturing process on these critical quality attributes may facilitate the product and process development, quality control, as well as support regulatory policy and approval. The current study has investigated the effect of formulation and process parameters on the quality attributes of brinzolamide ophthalmic suspensions. In the first step, three milling techniques (probe sonication, microfluidization, and media milling with a planetary centrifugal mixer) were evaluated for manufacturing of brinzolamide suspension. Out of the three techniques, the planetary centrifugal media milling yielded the narrowest PSD and thus was considered the most viable lab-scale technique for this purpose. In the next step, various process parameters of media milling were evaluated using a central-composite experimental design. The independent variables included bead size, agitating intensity, and process time while the PSD of drug particles (D50) was the response variable. The effect of shear rate and shear time of the homogenization process and the concentration of carbomer on the rheological properties of the suspension were studied using a Box-Behnken design. Additionally, effects of sodium chloride and mannitol concentration on the rheological properties of the suspension was also investigated. Sodium chloride was found to exert a pronounced effect on rheology of the suspension. Despite variations in the carbomer concentration, a suspension of comparable rheology could be prepared by controlling the process parameters namely the shear rate and process time.

Evaluation of commercially available meth-deterrent pseudoephedrine hydrochloride products.

Pseudoephedrine (PSE) extracted from its dosage forms can be used as the starting material to prepare methamphetamine by drug abusers. Recently, some pseudoephedrine drug products marketed under the over the counter (OTC) monograph have been promoted as 'meth-deterrent'. The goal of this investigation was to evaluate the extraction and dissolution of these product against controls of non-meth-deterrent products of pseudoephedrine. Immediate release (IR) PSE OTC Product-C, Product-D and Product-E with meth-deterrent claim on their packaging were selected for this study. Accordingly, OTC IR PSE tablet Product-A and OTC extended release (ER) PSE tablet Product-B, with no meth-deterrent claims, were used as controls. The extraction studies were performed on intact tablets or capsules and on manipulated products employing water, ethanol and 0.l N HCl as solvents. The extraction studies were also performed in water at elevated temperatures by heating the water in an oven and in a microwave. The dissolution studies were performed in water and 0.1 N HCl. The amount of PSE extracted from Product-C was found similar to the amount extracted from the non-meth-deterrent control Product-A. The amount of PSE extracted from Product-D and Product-E was found lower than the amount extracted from control Product-A under the conditions studied. Product-A, Product-B, and Product-C met their respective dissolution acceptance criteria. The IR Products D and E released less than 50% drug in 12 h and did not meet either IR or ER PSE tablet USP dissolution acceptance criteria. In summary, the extraction of Product-C was found to be high (approximately 85% in 30 min) and was similar in extraction to the control Product-A. The extraction of Product-D and Product-E was found less than the extraction of control Product-A. Also, Product-D and Product-E did not exhibit complete drug release. This study showed that PSE can be extracted from Product D and Product E.