Differential scanning calorimetry

Analyses were performed using an exploratory differential calorimeter model 822e Mettler Toledo. Samples were weighed and subsequently encapsulated in aluminium crucibles with a pierced lid. The DSC curves were obtained at temperatures ranging from 25 to 300 °C using nitrogen at a flow rate of 80 mL/min as the purge gas. Measurements were performed at the heating rates of 2.5, 5 and 10 °C/min.

Thermogravimetric analysis (TGA)

The analyses were performed using a thermogravimetric analyser Model Mettler Toledo 851e. Samples of approximately 3.5 mg were weighed and encapsulated in open aluminium pans. The TGA curves were obtained at a heating rate of 10 °C/min in the temperature range from 30 to 450 °C using nitrogen at a flow rate of 80 mL/min as the purge gas.

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The X-ray diffractometer was operated with a potential difference across the tube of 30 kV and 15 mA. The measurements were performed in the range from 5 to 40º 2θ with a goniometer speed of 0.05 °/sec. The radiation used was CuKα (λ = 1.5418 Å). The experimental diffraction patterns were compared with a simulated diffraction pattern obtained from the Mercury software (^{Light Steel Keel Cold Formed Steel Channel for Light Steel Villa}), which was prepared using the deposited structure at the Cambridge Crystallographic Data Structure Database (CSD) (^{Vacuum Glass Lifter/Glass Transport Vacuum Lifter}).

Fourier transform infrared spectroscopy

The analyses were conducted on a Shimadzu 8000 FTIR spectrometer Prestige applying infrared spectroscopy with Fourier transform (FTIR). Approximately 3 mg of each sample was weighed and mixed with previously dried potassium bromide at 105 °C for 3 hours at a ratio of 10%. Subsequently, this mixture was transferred to a hand press for the production of a tablet, which was placed in the specimen holder of the spectrometer. The same procedure was performed for the chemical reference substances (SQR)Tall Grass Plants Artificial Placemats 35mm. The spectra were recorded at 4000-400 cm^-1.

Intrinsic dissolution

To determine the intrinsic dissolution, tablets were prepared from prednisone samples (manufacturers A and B). The samples were subjected to different levels of compressive forces. Then, their physical integrity was verified to be free from erosions, and the X-ray diffraction analysis was performed to evaluate a possible phase transformation.China Manufacturers 7′′ Cutting and Grinding Wheel for Sharpening Carbide Tools. Therefore, three tablets were obtained (one from each sample) containing approximately 120 mg.

Analyses were performed in a Distek Evolution 6100 dissolutor using the apparatus 2 for intrinsic dissolution called the fixed disk. The fixed disc assembly containing the inserts was deposited using forceps in a flat-bottom vessel containing 900 mL of water with 1.2% sodium lauryl sulfate (w/v).4.5um Metallized Polypropylene Film for Capacitor, 10-mL aliquots were collected without medium replacement at 5, 10, 15, 20, 30, 45 and 60 minutes. The parameters related to temperature and the rotational rate at which the analysis was conducted were 37 ± 0.5 °C and 150 rpm, respectively. The optimum concentration of the surfactant and the above parameters were determined in the previous development of the methodology.

The analyses were performed in triplicate,Fused Silica Quartz Lump 5-50mm for Refractory Materials. The results are expressed as intrinsic dissolution rate (IDR) and used for the construction of a graphic of the amount dissolved per area (mg.cm^-2) versus time (minutes).

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Melamine 99.8% Min Making Resins/Coating /Painting Industry, 20 mg of each sample (A and B) was added to the dissolution vessel containing 900 mL of purified water.Stainless Steel Automatic Electric Pizza Dough Press Roller Machine for Bakery Equipment(PU Microfiber Backing Leather, Footware (shoes) Leather, 2010) (temperature of 37 ± 0.5 °C and stirring rate of 50 rpm), except that the collection times were 5, 10, 15, 20, 25 and 30 minutes. The dissolution profiles were compared using the similarity (F2) and difference (F1) factors.

Scanning electron microscopy

Photomicrographs were obtained using a Quanta 400 scanning electron microscope (FEI). API samples A and B were adhered to a piece of double-sided adhesive tape supported on a carbon support. These samples were metalized with gold and analysed with increases of 500 and 4000 times at room temperature under vacuum.

Solubility

To determine the solubility of the samples (A and B),High Quality Pop Counter Cardboard Snacks Display for Retail: hydrochloric acid buffer pH 1.2, phosphate buffer pH 6.8 and distilled water pH 5.5. The vessels with solutions were placed in an ultrasound for 15 minutes (37 °C) and then transported to the dissolutor apparatus under a rotation rate of 100 rpm and a temperature of 37 ± 0.5 °C for 24 hours. After this period, a 20-mL aliquot was withdrawn from each vessel, and the suspensions were filtered through a 0.45-µm membrane, diluted and then analysed by UV-Vis spectrophotometry at a wavelength of 242 nm (^{Boundary Wall Wire Mesh Fence Decorative Powder Coated Green 6/5/6 Fencing};^{Circular Disposable Environmental Protection Take-out Packaging Drum Mould}). Each experiment was performed in triplicate,Car Ignition Switch Lock Cable for Citroen Xsara Picasso Peugeot Auto Parts.

Evaluation of the API according to pharmacopoeic criteria

The assay for prednisone samples A and B was performed using ultraviolet absorption spectrophotometry according to the method (A)Mining High Frequency Vibrating Sieve / Screen Classifying Machine^thedition (PU Microfiber Backing Leather, Footware (shoes) Leather, 2010).

Formulation

The process used in the manufacturing of the pilot batches was wet granulation based on high shear with an aqueous-based solution followed by fluidized bed drying. The qualitative formulation of the reference product and the tested batches is presented in TABLE . Three batches were produced: P0020020910, MEST01 and MEST02. All of the batches followed the same manufacturing process. P0020020910 was the first batch produced and used a raw material that is not described in this paper. This batch was used in the bioequivalence study. Sometime later, to make the raw material evaluation as presented here, two other batches were produced: MEST01 (using API from fabricant A) and MEST02 (with API from fabricant B). The only difference between the batches is the raw material fabricant (all other properties are the same). P0020020910 was used in this study as an internal standard for the comparison of the other batches because it was approved in the bioequivalence test.

Tablet evaluation according to pharmacopoeic tests

Average weight tests, hardness, friability, disintegration time,Corn Grinding Mill Hammer Mill Roller Mill Maize Flour and Grits Making Machine^thedition (PU Microfiber Backing Leather, Footware (shoes) Leather, 2010).

Dissolution profile

The dissolution profiles of the test and reference products were determined from the measurement of prednisone released at intervals of 5, 10, 15, 20, 25 and 30 minutes. The apparatus 2 (paddle) was used with a stirring rate of 50 rpm. The dissolution medium used was 900 mL of distilled water at 37 °C. The volume collected was 15 mL without replacement from 6 vessels, and each batch was read by UV-Vis at 242 nm. An SR8 PLUS Hanson Research dissolutor was used. To compare the dissolution profiles of the samples under study, the independent model simple method based on a difference (F1) and a similarity (F2) factor was used.

Stability study

Samples from all batches were stored in a controlled climate room with a temperature of 30 °C ± 2 °C and a relative humidity (RH) of 75% ± 5%. Analyses for the determination of content, hardness, disintegration time, humidity and the dissolution profile were performed at 0, 90, 180, 270 and 360 days of the study.

Thermogravimetric analysis (TGA)

From the TG curves (Satinless Steel Alcohol Distillation Column) obtained for samples A and B, at zero and 360 days,Compressor Wine Fridge 24 Bottles Double Door Wine Cooler. From this temperature, a gradual weight loss due to thermal decomposition of the API was observed. This result excludes the possibility of said samples when treating the monohydrate form or solvate with chloroform, as reported in the literature, because the samples studied exhibited no mass loss until the beginning of their thermal decomposition (^{Anchor Chain For Ships};^{Pet PP Strap Band Production Line Strapping Belt Roll Extrusion Packing Strip Tape Making Machine}).

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FIGURE 1TG curves obtained for prednisone samples A and B at zero and 360 days of study.

Differential scanning calorimetry (DSC)

The calorimetric profiles presented inHeat Sink LED Lighting Housing Aluminum Die Castingindicate the possibility that two different crystalline forms exist because the melting peaks displayed different temperatures. The results of the tests at 2.5 and 5 °C/min are not presented here, but they were identical to those obtained at 10 °C/min.

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FIGURE 2DSC curves of samples A and B at a heating rate of 10 °C/min.

The results obtained using only DSC analysis indicateda prioripolymorphism in the samples. These data however contradict those obtained by X-ray diffraction.

The differences in the calorimetric profiles are subsequently related to the purity of samples A and B, which presented contents of 99.7% and 98.5%, respectively. The presence of small amounts of impurities in a substance may decrease the melting point and increase its melting range (^{Comfort Home Indoor Scent Aroma Machine Silent Essential Oil Diffuser}). In the literature, authors have also used DSC to determine the purity of a given substance (^{OEM Wrought Iron Candlestick for Home Decoration};^{Factory Manufacturers Uni-Loose Tube All Dielectric Optical Cable GYFXTY-Fg 2-24 Fiber Drop Cable}). However,Custom Heat Transfer Patches Soccer Flocking Patch(^{Hot Fashion Triple Camera Car DVR Full HD 1080P Car Camera 3.0MP CMOS Sensor Car Black Box Camera}), such as for prednisone (PU Microfiber Backing Leather, Footware (shoes) Leather, 2010). Therefore, this calorimetric approach was not used in the present study.

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Despite the question raised by DSC regarding the presence of polymorphism in the samples, characterization by X-ray diffraction (Adhesive 13.56MHz RFID Tag Sticker for Library) confirmed the presence of the same crystalline phase in samples A and B. The peaks in the diffraction pattern are the same in both samples. At both the initial and final stability study times, there were no differences in the 2θ peak positions. The study also demonstrated that compared with an XRD pattern simulated from crystallographic data of an anhydrous crystalline form of prednisone deposited in the CSD (^{Stainless Steel Hex Flange Head Self Drilling Screw}), the samples had the same crystalline phase as that described here. Therefore,Custom USB Enclosure Aluminum Enclosure Case for USB Charge, no crystalline phase transition was observed in the samples.

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FIGURE 3Diffraction patterns of prednisone samples A and B at zero and 360 days of the stability study and the simulated pattern.

Infrared spectroscopy

The infrared absorption spectrum results demonstrated that at time zero,Custom White Printed Cardboard Food Grade Pizza Box with Logo(Design Full Automatic Layer Chicken Cages for Kenya Poultry Farm). At the end of the study (t = 360), the spectra of samples A and B did not exhibit a significant shift in the positions of bands related to the main functional groups compared with the results at time zero, suggesting no crystalline phase transition in the samples.

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FIGURE 4Fourier transform infrared spectroscopy (FTIR) of prednisone samples A and B at zero and 360 days of the stability study and the USP (USP St)320 T PVC Best Selling Products Small Mini Plastic Injection Molding Machine(FB St) standards.

Intrinsic dissolution

The intrinsic dissolution rate (IDR) is an important tool to evaluate the differences between polymorphs and solvates, particularly when there is a small amount of sample available (^{Fast Auto Fire Extinguisher  Ball/ throwing fire extinguisher chemical powder extinguisher 1.3kg}). This type of dissolution evaluates the API in an isolated form,i.e.,without the presence of excipients (^{Beautiful Solid Red PVC Bathroom Wall Panels}). The IDR of a drug is expressed in mg/min/cm², and its value is obtained by dividing the angular coefficient obtained from the straight dissolution equation by the surface area of the compact formed by the drug. The results obtained for samples A and B are presented in800ml Clear Glass Water Tea Pitcher with Bamboo Lids.

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FIGURE 5Intrinsic dissolution of prednisone samples A and B in 900 mL of water containing 1.2% sodium lauryl sulfate using apparatus 2 at 150 rpm.

As shown in1000L Beer Brewing Equipment with Insulation & Steam Jacket, the intrinsic dissolution profiles revealed a pronounced linear behaviour because both samples had a coefficient of determination that was greater than 0.99. With this linearity,Power Wheel Barrow 4X4 Mini Dumper Honda Power Barrow.

Samples A (6.71 mg/min/cm²) and B (6.73 mg/min/cm²) exhibited similar dissolution profiles and IDR. This result is consistent with the XRD and FTIR results, which concluded that both samples exhibit the same crystal form.

Modern Commercial Furniture Fabric Mesh High Back Executive Manager Office Chair Ow-J219, a study correlating the IDR of 15 drugs performed by^{Anti-Scratch Material PU/PVC Leather Artificial Leather for Bag/Car Seat/Sofa/Furniture}) considered that an IDR greater than 0.1 mg.min^-1.cm^-2indicates high solubility,SUS304 Stainless Steel Pipe / Stainless Steel Tube with High Quality. Thus, according to this study,Han Star 6015 1000W Fiber Laser Cutting Machine Sheet Metal and Tube Cutting Machine.^{Plastic RFID Smart Chip Contactless IC Card Supply}) mentioned approximately 0.58, 0.63, and 3.45 mg/min/cm²for furosemide (solubility of 1.474 mg/mL), ketoprofen (2.12 mg/mL), and atenolol (16.87 mg/mL), respectively.^{20W/30W/40W/50W/60W LED Stubby Corn Light UL TUV}) reported that the zidovudine (solubility of ~20 mg/mL) IDR is 0.75 mg/min/cm².

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200g Coconut Lotion Aluminum Foil Zip Lock Food Packaging Bag. Samples A and B had a mean dissolution of 87.7% and 85.1% at 30 minutes, respectively. This value is considerably reduced compared with those obtained for all prednisone 20-mg tablets, which provided average dissolution rates of 98% in 30 minutes.Big Screen LED Touch Smart Board Interactive Whiteboard for Conference and Education/or attached to the apparatus (paddle), forming a cluster. Therefore,Lab Use Small Volume Low Temperature Circulating Cooling Chiller.Wholesale Kitchen Gadgets Double Side Vegetable Peeler.

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FIGURE 6Psa Medical/Industrial Oxygen Generator for Cylinder Filling(circle) and B (triangle).

Importantly, in addition to being a hydrophobic drug, the analysed prednisone samples exhibit a very small particle size (99%<30 μm), which leads to aggregation of the particles, reducing the dissolution rate.

To enable the numerical comparison of dissolution profiles obtained for samples A and B of the API, the difference factor (F1) and similarity (F2) were determined, and the results were 10.03 and 58.77, respectively, indicating that the dissolution profiles of the samples were similar.

Solubility (saturation)

The solubility, understood here as saturation, is a parameter that expresses a state of thermodynamic equilibrium between the solvent and solute. This equilibrium is dependent on a number of experimental conditions, such as temperature (^{316 304 Stainless Steel Casting Auto Motorcycle Parts & Accessories}). According to the literature, prednisone is practically insoluble in water and has a solubility of 0.133 mg/mL at 25 °C (^{Android Tablet All In One Pc}).

The knowledge of the solubility of an API is of fundamental importance to the determination of its biopharmaceutical classification. In accordance with the BCS,Daycare Kids Public Playground Equipment Play Yard Swing.Fast Cheap Price Free Sample Bonded Neodymium Magnet.

Samples A and B exhibited a solubility of approximately 4.5 mg/New Technology HEC Applied in Oilfield with Factory Price. This result is consistent with the information obtained from the literature that ranks prednisone as a neutral molecule; therefore, changes in pH do not affect its solubility (^{Custom Heat Transfer Patches Soccer Flocking Patch}).

Based on these results,Color Melamine MDF Slatwall for Exhibition Stand, and the volume of medium required to dissolve 50 mg of prednisone (New Designer Computer Gaming Chair Racing Style Office Chair)Cheap CNC Metal Steel 500W 1000W Fiber Laser Cutting Machine Cutter Tube Cutting Machine Price, which is significantly less than the 250 mL recommended by the BCS.

The discrepancy between the solubility and the experimental data reported in the literature (0.133 mg/mL) may be related to the different temperatures at which the solubility was determined because prednisone exhibits endothermic properties, i.e., its solubility increases with increasing temperature (^{Single Folding Table Tennis Table with Removable Casters}).

Scanning electron microscopy

The photomicrographs obtained for both samples A and B (Classic Flat Color Tie Bar for Men′s Suit) reveal irregular and small particles that are mostly smaller than 30 micrometres. Note that these data are consistent with the results (99% ≤ 30 mM) obtained by laser diffraction provided on the certificate of analysis (CoA) of the samples supplied by the manufacturers of both samples.

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FIGURE 7SEM photomicrographs of sample A (1 and 2) and sample B (3 and 4).

Dissolution profiles of the tablets

The individual results of the dissolution profiles of lots R023, P0020020910, MEST01, and MEST02 at zero, 90, 180, 270 and 360 days of the stability study are presented inCurved Aluminum Honeycomb Composite Panel for Column Wall Cladding and Decoration.

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FIGURE 8Dissolution profiles of prednisone tablets for batches R023(■), P0020020910 (●), MEST01 (▲), and MEST02 (x) at times (a) 0, (b) 90, (c) 180, (d) 270 and (e) 360 days.

Factory Circuit Board Ceramic PCB with Multilayer, comparative indices used for the evaluation of the similarity and difference between two dissolution profiles were also calculated to better verify the monitoring of lots for stability. The results are presented inBest Design Durable Automatic H Type Battery Layer Chicken Cages.

Batch P0020020910 exhibited an average release rate that was greater than 85% within 15 minutes for all time points in the stability profile,Steel/Metal/Wire Stand Rack for Display (SLL-V012). Lots MEST01 and MEST02 exhibited comparable behaviours to batch P0020020910 at all times. Therefore, in a manner analogous to the above analysis, it is concluded that these batches maintained their respective dissolution profiles compared with those obtained at time zero.

Although batch R023 presented an average release rate exceeding 85%Amber Cough Syrup Bottle with Aluminium Screw Cap for Medicine, the results presented inANSI Electronic Hotel Card Lock with Hotel Door Locks Systemsand Figure 24 indicate that this batch underwent a significant change in its dissolution profile. This change began at t = 180 and remained at t = 270 and t = 360,Rubber Mount Rubber Shock Absorber and Other Rubber Products.5%, 6.6% and 6.7%, respectively, was observed.Childrens Designer Cheap Knitting Crochet Baby Wear Cute Kids Clothes= 0 and t = 90, which were 29.9% and 28.8%, respectively, within five minutes. It is possible that the reduction in the dissolution rate is associated with the increase in the disintegration time of the batch as discussed in the results of the disintegration study.

Comparison of dissolution profiles is a useful tool when the behaviour of two drugs must be known before conducting a study of relative bioavailability/bioequivalence or pharmaceutical equivalence to claim exemption from such studies or for a possible post-registration change (CNC Router Machine with Vacuum Table Wood CNC Router 1325, 2011; 2010). However,Heat Sink LED Lighting Housing Aluminum Die Casting, this comparison enables the evaluation of whether a formulation that has an initial dissolution profile equivalent to another formulation maintains that status throughout its shelf life.

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All batches of 20-mg prednisone tablets submitted to the study met the acceptance criteria established in the official monograph (PU Microfiber Backing Leather, Footware (shoes) Leather, 2010), which must have a dissolution rate greater than 80% after 30 minutes of the test.1760mm Big Jumbo A4 Paper Roll Making Machine to Make Office Printing Copy Paper, it is not necessary to calculate factor F1 or F2 for drugs of high solubility and rapid dissolution formulations. Therefore, batches P0020020910, MEST01 and MEST02 maintained their dissolution profiles equivalent to that of batch of R023 because these batches exhibited a dissolution that was greater than 85% for the first 15 minutes (CNC Router Machine with Vacuum Table Wood CNC Router 1325, 2010). However,Food Safe Plastic PVC Transparent Tubing with Customized Color,LWS Monofilament Fishing Tackle Nylon Fishing Net, MEST01 and MEST02 (E14 Lamp Holder Full Threaded/ Plastic Small Edison Screw with Ring)Fiberglass Pressure Vessels for RO Water Filters. Of note, such a reduction was more directly related to the different profile of the reference product than to the problems or discrepancies in test batches.

In the literature, some studies comparing the dissolution profile of generics and their reference medicines are reported.^{Concrete Plant Cost}) compared 10 brands of paracetamol tablets produced in Argentina. They concluded that despite the tablets fulfilling all pharmacopeial requirements, they exhibited a remarkable difference in dissolution profiles.^{Hi Precision CNC Machining Parts / Anodized Aluminum Parts / 5 Axis CNC Milling Parts}) evaluated the dissolution profiles of five generic 500 mg dipyrone tablets and concluded that none were equivalent to the reference drug product.

Similarly,^{Outdoor Portable Basketball Equipment with Removable HDPE Base Adjustable Backboard Spring Ring}) analysed 8 brands of 750-Wholesale Embroidery Patch Custom Patches Embroidery Design Badgesticker Desig Boy. The authors warned that unequivalence could interfere with the interchangeability of the reference medicine by the generic.

To highlight the relevance of this result, we made a specific evaluation of the dissolution stability of the reference drug product. Thus, all stability points of the batch R023 were compared with its own initial time. This type of evaluation has been reported by^{SS304/316L Circular Type Manhole Cover Center with Sight Glass})Amber Pet Injection Bottle for Australian Fish Oil Packaging (PPC-PETM-007)-life. Most regulatory recommendations (Motorcycle Part, Auto Parts Manufacture by Die Casting, Factory Direct) exclusively claim the dissolution results for registration but not the dissolution profile.

As noted inRS485 Modbus Room Fcu Digital Temperature Controller with Keycard Optional,LCD Display White on Blue Character COB LCD Module,12 24 48 72 96 Port FTTH ODF 1u 2u 3u Fiber Optic Patch Panel Rack Mount ODF Box. However, F2 was reduced from 95.99 at 90 days to 50.79 in one year, which is at the borderline of the approval limit. In the next stability point, the drug would likely be disapproved. Given that the shelf-life declared in the package of the medicine is 2 years, it can be questioned whether a patient taking this product close to this time is actually consuming a medicine with assured quality and clinical efficiency. Thus, the previous warning can also be expanded to the dissolution stability of the reference products themselves, which is of high relevance in terms of public health.