FORMULATION AND DEVELOPMENT OF FIXED-DOSE COMBINATION OF BI-LAYER TABLETS OF EFAVIRENZ, LAMIVUDINE AND TENOFOVIR DISOPROXIL FUMARATE TABLETS 600 MG/300 MG/300 MG

Objective: This study is to formulate bi-layer tablet as a multidrug regimen against each reference listed drugs of Brand SUSTIVA® (efavirenz tablets 600 mg), EPIVER®(lamivudine tablets 300 mg), and VIREAD®(tenofovir disoproxil tablets 300 mg) to treat human immunodeficiency virus (HIV) infections. Which provides highly active antiretroviral therapy to provide effective treatment. Methods: Bilayer formulation was developed with each blend of layer-I (efavirenz) and layer-II (lamivudine and tenofovir disoproxil fumarate) through wet granulation process and roller compaction process, respectively. Further, both layers were compressed by using bi-layer compression followed by film coating. Layer-I and II formulations were developed by using various concentrations of diluents, surfactants, and disintegrants to improve the solubility of efavirenz and improve the flowability and uniformity of layer-II. Finally, the optimum formulation was developed to compare the in vitro dissolution with each branded formulation. Results: Drug-excipients interaction results revealed that the mixtures of three drug substances in 50 °C/75 % relative humidity (RH) resulted in an increase in tenofovir IMP-E and the highest unknown impurity was significantly increased and additionally decreased tenofovir assay in the presence of efavirenz. Sodium lauryl sulfate is very critical and it acts as a wetting agent and increases the solubility of efavirenz, and directly influences the dissolution of a drug product. Microcrystalline and croscarmellose sodium have a chance to affect the dissolution and friability of tenofovir. Powdered cellulose was acting as a diluent and flow property of the lamivudine part and it also affects the uniformity and dissolution. So, these ranges were optimized. X-ray diffraction (XRD) indicates there are no polymorphic changes for the optimized formulation and there is no interaction between the three active substances, and finally, in vitro dissolution results for the optimized formulation against the reference drugs. Conclusion: Optimum formulation yielded consistent drug release against each branded drug to treat human immunodeficiency virus (HIV1) infections. This formulation is robust and easily scale up for the next stage.

Assessment of Fatigue Life and Stiffness of Asphalt Concrete After Implementation of Additives

Modifying asphalt binder with additives can enhance the overall physical properties of asphalt concrete. In the present investigation, an attempt has been made to use 2 % of silica fumes and 4 % of fly ash class F for modification of asphalt binder in wet process. Asphalt concrete wearing course slab samples have been prepared under roller compaction. The beam specimens of 400 mm length and 50 mm height and 63 mm width were extracted from the slab samples. The beam specimens were subjected to the four-point repeated flexural bending beam test. The flexural stiffness was calculated under three constant micro strain levels of (250, 400, and 750). The fatigue life was monitored in terms the number of load repetitions to reach the required reduction in stiffness of 50 %. It was concluded that the flexural stiffness increases by (11, and 15) %, (17.7, and 63.6) %, (57.2, and 65) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. However, the fatigue life increases by (40, and 72.8) %, (115, and 220.6) %, (46, and 94.6) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. It is recommended to use modified binder with silica fumes and fly ash in asphalt concrete to enhance the fatigue life and stiffness.

MODELLING COMPACTION BEHAVIOR OF TOUGHENED PREPREG DURING AUTOMATED FIBRE PLACEMENT

One of the most widely used automated manufacturing processes for composite parts is automated fibre placement (AFP). The deposition process involves the simultaneous warming, lay-up and consolidation of prepreg consisting of multitude of process parameters. Currently, AFP process parameters that ensure part conformance are derived by expensive and time-consuming trial-and-error approaches. The aim of this study is to demonstrate how physics-based finite element simulations that can predict the as manufactured geometry of a preform deposited by AFP can help reduce some of the empiricism associated with current industry practices. Here we particularly focus on the consolidation behaviour of toughened prepregs during the deposition process. An isothermal roller compaction model with thermal properties derived from an independent simplified thermo-mechanical model of the AFP head is used. Additionally, a fully characterised viscoelastic material definition is used for the prepreg tape along with a hyperelastic material for the compaction roller to accurately represent the physical parts. Various lay-up speeds, heater powers and compaction forces are simulated. To reduce the empiricism present in the manufacturing process, the viability of incorporating the numerical models into existing statistical relationships between process parameters and manufactured geometry is examined.

Study on effect of laboratory roller compaction on unconfined compressive strength of lime treated soils

Expansive soils are problematic due to their swell—shrinkage behavior and low compressive strength. They are modified generally with additives such as lime, fly ash, and various other inorganic and organic materials. Chemical stabilization treatments can improve expansive soil properties for its reuse in geotechnical applications. The present study investigates the properties of two types of subgrade soil treated with Lime and compacted by three different methods in the laboratory. The study is mainly focused to bring out the effect of different methods of compaction on the unconfined compressive strength of Lime treated soils and untreated soils. Laboratory investigation included pH, Atterberg limits, cation exchange capacity (CEC), compaction, unconfined compression strength (UCS), California Bearing Ratio (CBR), Scanning Electron Micrographs (SEM) and EDAX before and after lime treatment. Tests were performed on lime treated soils (2, 4, 6 and 8% of lime). The soil samples for unconfined compressive strength test were prepared by static, dynamic and roller compaction methods in the laboratory. Roller compaction was performed using indigenously fabricated Roller compactor cum Rutting Analyzer (RCRA). The results indicate that dry unit weight and UCS of roller compacted lime treated soil is lower than that of dynamic compacted soil. However, dry unit weight and UCS of lime treated roller compacted soil are closer to that of statically compacted soil. Cation exchange capacity of both soils before and after treatment with lime were examined, CEC reduced with increase in lime content.

Strength and Durability of Hybrid Fiber-Reinforced Latex-Modified Rapid-Set Cement Preplaced Concrete for Emergency Concrete Pavement Repair

The benefits of using reinforcing fibers in latex-modified rapid-set cement preplaced concrete for emergency pavement repairs were examined in terms of strength, permeability, and durability as functions of the type of fiber. Single-type fibers, including jute, poly (vinyl alcohol) (PVA), and nylon fibers, as well as hybrid fiber mixtures prepared with two of the aforementioned fibers at a 1:1 weight ratio, were evaluated. Fibers were incorporated into the concrete mixture at 1.2 kg/m3. A vibratory press compactor that simulates roller compaction was used to increase compaction and densification of the resulting pavement repair material. The hybrid fiber-reinforced latex-modified rapid-set cement preplaced concrete (HFLMC) was manufactured to satisfy the criteria for opening traffic, i.e., compressive strength of 21 MPa or higher, and flexural strength of 3.5 MPa or higher after 4 h. Pavement requiring repair was removed and replaced with coarse aggregate. The rapid-set binder, fibers, and latex were then mixed and placed onto the coarse aggregate layer. The repair was considered complete after compaction. The resulting HFLMC satisfied all of the test criteria. Furthermore, concretes made with hybrid fibers were more mechanically sound than those made with a single fiber variety. Hybrid fiber concretes made with PVA and nylon fibers exhibited the best properties for emergency pavement repair. These results indicate that HFLMC is suitable for emergency pavement repair.