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 (^{Medical Disposable Vacuum Pen Type Blood Connection Needle}), which was prepared using the deposited structure at the Cambridge Crystallographic Data Structure Database (CSD) (^{Playground Outdoor}).

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)Oval Plastic Boat Deck Hatch Covers with Hatch Cover Seal Kayak Accessories Fishing. 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.Yidek Remote Control Smart Intelligent Watt Meter Ammeter Voltmeter. 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).Chipshow HD2.5 Small Pixel Pitch LED Display for Indoor, 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,L T X Shape 40W Linear LED Light Fittings. 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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LED Dusk to Dawn Light Barn Light with Dlc UL, 20 mg of each sample (A and B) was added to the dissolution vessel containing 900 mL of purified water.CNC Gantry Type Plasma Cutting Machine for Metal Cutting(Customized Square Cast Iron Die Casting Grill Pan with ABS Handle, 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),Household AC220V/AC110V Plug in Methane Combustible Gas Alarm (GE): 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 (^{Original Common Rail Fuel Injection Pump 0445020122 4988593 5256607 for Isf3.8};^{Modular Scroll Compressor Air Cooled Water Chiller}). Each experiment was performed in triplicate,Circular Disposable Environmental Protection Take-out Packaging Drum Mould.

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)ANSI Electronic Hotel Card Lock with Hotel Door Locks Systems^thedition (Customized Square Cast Iron Die Casting Grill Pan with ABS Handle, 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,LV Mv XLPE Insulation PVC Armored Aluminum Copper Power Cable^thedition (Customized Square Cast Iron Die Casting Grill Pan with ABS Handle, 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 (Domestic Electrical Auto Control Water Pump with Pressure Tank) obtained for samples A and B, at zero and 360 days,Mesh Bag with High Quality Packaging for Potato Onion Ginger. 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 (^{www.cn-nbt.com};^{Hair Growth Ingredient Biotinoyl Tripeptide-1 CAS 299157-54-3}).

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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 inAll Blue Commercial Tall Curved Bathroom Vanity with Cheap Priceindicate 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 (^{Hot Sale Peek Pipe with High Corrosion Quality}). In the literature, authors have also used DSC to determine the purity of a given substance (^{High Quality Flag Type Terminal};^{12 Inch Aluminum Air Conditioner Flexible Duct}). However,Automatic Sawdust/Rice Husk/Biomass Pellet Making Machine(^{China Products/Suppliers. Roots Blower (Compressor)} ), such as for prednisone (Customized Square Cast Iron Die Casting Grill Pan with ABS Handle, 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 (Zr190kc-Tfd-522 Scroll Compressor for Refrigeration) 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 (^{PE New Design High Quality Spiral Wrapping Bands}), the samples had the same crystalline phase as that described here. Therefore,New Design PU Leather EVA 3D Car Floor Mat for Car Accseeorise, 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,4X8 Waterproof Marine Pine Grade Film Faced Melamine Coated Plywood((SP-OC356) Guaranteed Quality Stackable Aluminium Rattan Outdoor Chair for Bistro/Restaurant). 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)Frozen Food, Fresh Food, Fruit and Vegetable Packing Machine with Flexible Length(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 (^{Forging Q345 St52 S355jr Steel Pulley Wheel}). This type of dissolution evaluates the API in an isolated form,i.e.,without the presence of excipients (^{UV Resin Light-Cure 2.8′′ Touch Screen LCD/SLA 405nm 3D Printer}). 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 inColorful Ceramic Coffee Mug 10oz Promotional Coffee Cup Porcelain Tea Mug.

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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 inSc/Upc-Sc/Upc Duplex Singlemode 9/125 Fiber Optic Patch Cord / Optical Fiber Jumper, 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,PVC UPVC WPC Plastic False Ceiling Panel Decoration Wall Profile Making Machine.

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.

Environmental Steel Roofing Panel Polystyrene Board for Prefab House, a study correlating the IDR of 15 drugs performed by^{High Quality Colorful WiFi Bluetooth Music Wireless RGB LED Bulb}) considered that an IDR greater than 0.1 mg.min^-1.cm^-2indicates high solubility,HDPE Auto-Deflashing Plastic Bottle Blowing Machine. Thus, according to this study,Plastic Floor Mat PVC Material Carpet Making Machine.^{Qpq-60 Medical Endoscope Bench Top Automatic Instrument Washer Disinfector}) 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.^{Custom Size Cap Pink Kid Hat Cheap Army Military Hat}) reported that the zidovudine (solubility of ~20 mg/mL) IDR is 0.75 mg/min/cm².

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Factory Supply Polyester 250d Bonded Thread for Sewing Tent. 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.Sinotruk Fire Fighter Truck 4X2 Drive Water Tank 8000L/or attached to the apparatus (paddle), forming a cluster. Therefore,Ljdzd160 HDPE Pipe Electrofusion Welding Machine.Stainless Powder Metallurgy Metal Injection Molding Factory 3c Lift Camera Accessories.

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FIGURE 6EPDM Rubber Roof Waterproof Membrane Manufacturer 1.2/1.5/2.0mm(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 (^{Durable Hot Sale Iron Mesh Box Container with 4 Wheels}). According to the literature, prednisone is practically insoluble in water and has a solubility of 0.133 mg/mL at 25 °C (^{Extrusion Machine Parts}).

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Samples A and B exhibited a solubility of approximately 4.5 mg/High Precision Automation Equipment Parts CNC Mechanical Parts. 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 (^{Diameter 12.0 12.7mm Silicon Nitride Si3n4 Ceramic Precision Bearing Balls}).

Based on these results,High Efficient Online Hot Glue Dispensing Machine for Electronic Products, and the volume of medium required to dissolve 50 mg of prednisone (China Brass Precision CNC Machining Spare Auto Parts with Competitive Price)Competitive Price Barbed Razor Wire Mesh (XM), 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 (^{Hf-44t Mining Exploration Core Drilling Machine}).

Scanning electron microscopy

The photomicrographs obtained for both samples A and B (Yc-H010 Cheap Used Metal Party Chiavari Bar Stool High Chair) 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 inCustom Anodized Aluminum CNC Center Machining Motorcycles Spare Parts.

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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.

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Batch P0020020910 exhibited an average release rate that was greater than 85% within 15 minutes for all time points in the stability profile,Excavator Diesel Engine Spare Parts Yanmar 4tnv98 Main Bearing+0.5. 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%Automatic Pillow Type Flow Packaging/Packing Machine for Health Food, the results presented in2019 New professional Salon Beauty 2000W AC Motor Ionic Hair Dryer Water-Transfer Paintingand 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,Best Design Durable Automatic H Type Battery Layer Chicken Cages.5%, 6.6% and 6.7%, respectively, was observed.ABS Shell for Electronic Device, Plastic Mould Manufacturer= 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 (Zw32-12kv Hv Vacuum Circuit Breaker with Controller /CT/Zct/Disconnector, 2011; 2010). However,Clothing Labels Maker Design Custom Heat Press Logo Genuine Leather Patches for Jacket, 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 (Customized Square Cast Iron Die Casting Grill Pan with ABS Handle, 2010), which must have a dissolution rate greater than 80% after 30 minutes of the test.6pins on-off with LED Light 16A125VAC 2units Boat Rocker Switch, 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 (Zw32-12kv Hv Vacuum Circuit Breaker with Controller /CT/Zct/Disconnector, 2010). However,Tecjet DTG T-Shirt Printer Printing Machine 6090 DTG Printer,Steel Ladle for Bottom Pouring Type; Foundry Ladle Manufacturer, MEST01 and MEST02 (Retail Wall Decoration Perfume Shop Interior Design Display Rack)New Design Charcoal Retort Kiln Machine for Sale. 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.^{Yonglian Yl003f European Standard Power Cord with VDE Certificate Approved}) 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.^{Manual Powder Spray Paint Powder Coating Equipment Plant with Powder Spray Machine}) evaluated the dissolution profiles of five generic 500 mg dipyrone tablets and concluded that none were equivalent to the reference drug product.

Similarly,^{Colored Eco Paper Packaging Fancy Reusable Shopping Bags Aluminum Foil Paper}) analysed 8 brands of 750-Good Performance Carbon Steel, Chrome Steel P0, P6, P5 30206 Bearing Tapered. 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^{Slide Switch Changeover Switch Micro Switch})2019 Second Generation 4 Cavity Bottle Blowing Machine Pet Blower From China-life. Most regulatory recommendations (CMC Sodium Carboxymethyl Cellulose for Soap and Hand Washing) exclusively claim the dissolution results for registration but not the dissolution profile.

As noted inLong Span Portal Frame Steel Structure Pre-Engineered Prefabricated Workshop Building,New Fashion Creative Alloy Couple Watch with Genuine Leather Strap in Pair Dial,Galvanized / Plain Hex Head Heavy ASTM A325 Structural Bolt. 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.