Dissolution enhancement of carbamazepine using twin-screw melt granulation

Integrated continuous melt granulation-based powder-to-tablet line: process investigation and scale-up on the same equipment

In the last decades, continuous manufacturing (CM) has become a research priority in the pharmaceutical industry. However, significantly fewer scientific researches address the investigation of integrated, continuous systems, a field that needs further exploration to facilitate the implementation of CM lines. This research outlines the development and optimization of an integrated, polyethylene glycol aided melt granulation-based powder-to-tablet line that operates fully continuously. The flowability and tabletability of a caffeine-containing powder mixture were improved through twin-screw melt granulation resulting in the production of tablets with improved breaking force (from 15 N to over 80 N), excellent friability, and immediate release dissolution. The system was also conveniently scaleable: the production speed could be increased from 0.5 kg/h to 8 kg/h with only minimal changes in the process parameters and using the same equipment. Thereby the frequent challenges of scale-up can be avoided, such as the need for new equipment and separate optimization.

Nanonized carbamazepine for nose-to-brain delivery: pharmaceutical formulation development

Epilepsy is one of the most common neurological disorders in the world. The therapeutic treatment is challenging since conventional drugs have limited efficacy and several side effects that impair patient management. Efforts are being made to find innovative strategies to control epileptic seizures. Intranasal administration provides a convenient route to deliver the drug to the brain. Carbamazepine (CBZ) is an anticonvulsant characterized by poor water solubility, nanonization can improve its bioavailability. Therefore, the design of CBZ nanocrystals (NCs) was assessed to obtain a formulation suitable for nose-to-brain delivery. CBZ NCs were prepared by sonoprecipitation following the Quality by Design approach identifying the impact of process and formulation variables on the critical quality attributes of the final product. The formulation was characterized by a technological point of view (thermotropic behavior, crystallinity, morphology, mucoadhesive strength). Response surface methodology was a reliable tool (error % 2.6) to optimize CBZ NCs with size ≤300 nm. Incubation of CBZ NCs in artificial cerebrospinal fluid at 37 °C did not promote aggregation and degradation phenomena. Preliminary biological studies revealed the biocompatibility of CBZ NCs towards Olfactory Ensheating Cells. The suspension was successfully converted into a powder. The highly concentrated formulation can be obtained, providing the possibility to administer the maximum dose of the drug in the lowest volume.

Commercial scale transfer of a twin-screw melt granulation process for high drug load fevipiprant tablets

OBJECTIVE

This work summarizes select methodology of twin-screw melt granulation and process analytical technology that were used in the successful scaling-up and commercial transfer of high drug load (80.5% w/w) immediate release fevipiprant tablets.

SIGNIFICANCE

The unique and compelling learnings from this industry work are (1) insights into Novartis AG's commercial scale transfer using twin-screw melt granulation (2) rapid, non-destructive NIR methodology as a PAT tool for RTR testing. No prior literature combines these two aspects at the level of detail we present/disclose.

METHODS

Scaling up of twin-screw melt granulation (TSMG) was guided by specific energy values obtained for the 27 mm (pilot scale) and 50 mm (commercial scale) twin-screw extruders (TSE). Proven acceptable ranges (PAR) were confirmed by varying the critical process parameters (CPPs) for granulation (screw speed) and tableting (dwell time, crushing strength) at three process levels (upper, target, lower). An at-line NIR method was developed and validated for real-time release testing.

RESULTS

The combination of CPPs were selected to have the same effect on critical quality attributes (CQAs) i.e., lower (-) and upper (+) process level challenged tablet aspect/appearance and dissolution, respectively. TSMG was performed using a 50 mm extruder at constant feed rate. Compression of the six final blends (∼300 kg) showed no impact of varied granulation and compression process conditions on both CQAs. A near-infrared spectroscopy method was validated to determine content uniformity, assay, identity, and to predict CQAs on uncoated tablets in preparation for a real time release testing (RTRT) of future batches.

Quality and In Vivo Assessment of a Fulvic Acid Complex: A Validation Study

The present work aimed to re-assess the bioavailability enhancement potential of fulvic acid (FA). Carbamazepine (CBZ) and peat were used as a model drug and FA source, respectively. Our group has already evaluated the bioavailability enhancement potential of a less commercially viable source of FA, i.e., shilajit. In the present work, the phase solubility of CBZ was analyzed with varying concentrations of peat-sourced FA (2–12% w/v). The prepared complex (CBZ-FA) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Dissolution, pharmacokinetic, and pharmacodynamic studies were also carried out. The results showed the presence of an interaction between the drug and FA within the complex, which led to 98.99 ± 2.0% enhancement in drug solubility. The results also showed 79.23 ± 2.1% dissolution of the complexed drug over 60 min and 69.32 ± 2.2% permeation from the intestinal gut sac over 90 min, which led to a significant enhancement of bioavailability and a reduction in the duration of epileptic seizures. Thus, this study re-authenticates our earlier results and suggests switching the FA source (shilajit to peat) for commercial product development.

Binder-free twin-screw melt granulation: An effective approach to manufacture high-dose API formulations

This study investigates the use of twin-screw binder-free melt granulation (BFMG) in the development of high-dose solid dose formulations for low melting point thermally stable drugs. Both ibuprofen and guaifenesin are examined. By granulating pure API powder, it is shown that BFMG can successfully be used to produce granules that contain 100% API. A design of experiments (DoE) response surface methodology was used to establish the design space for the end-product. The effects of the most relevant process variables (barrel operating temperature, powder feed rate, screw speed and screw configuration) on granule properties (outlet temperature, size distribution, morphology, flowability, compressibility, porosity) and tablet attributes (tensile strength and in-vitro dissolution) were thoroughly studied. Barrel temperature (alone or in interactions with the other variables) represented the most significant variable for both drugs since it governs the formation of granules by partial melting and subsequent agglomeration of the fed powder. Interestingly, the shear action originated by screw speed and screw configuration resulted in various significant responses depending on the drug substance, indicating that it can also be affected by the nature of the processed molecule. Flow properties were improved (i.e., lower Hausner ratio) for both drugs after formation of granules. Tabletability was also tested by preparing 600 mg tablets for all samples. Surprisingly, the resulting granules were highly compactible, requiring only 1% lubricant to form strong tablets containing 96% API and 3% disintegrant. The results also showed that tablets become harder as the granule size increased, especially for guaifenesin. As expected, in-vitro dissolution results indicated that tablets and capsules showed slightly slower dissolution rates than the granules.

Immediate-Release Formulations Produced via Twin-Screw Melt Granulation: Systematic Evaluation of the Addition of Disintegrants

The current study evaluated the effect of location and amount of various superdisintegrants on the properties of tablets made by twin-screw melt granulation (TSMG). Sodium-croscarmellose (CCS), crospovidone (CPV), and sodium starch glycolate (SSG) were used in various proportions intra- and extra-granular. Tabletability, compactibility, compressibility as well as friability, disintegration, and dissolution performance were assessed. The extra-granular addition resulted in the fasted disintegration and dissolution. CPV performed superior to CCS and SSG. Even if the solid fraction (SF) of the granules was lower for CPV, only a minor decrease in tabletability was observed, due to the high plastic deformation of the melt granules. The intra-granular addition of CPV resulted in a more prolonged dissolution profile, which could be correlated to a loss in porosity during tableting. The 100% intra-granular addition of the CPV resulted in a distinct decrease of the disintegration efficiency, whereas the performance of SSG was unaffected by the granulation process. CCS was not suitable to be used for the production of an immediate-release formulation, when added in total proportion into the granulation phase, but its efficiency was less impaired compared to CPV. Shortest disintegration (78 s) and dissolution (Q₈₀: 4.2 min) was achieved with CPV extra-granular. Using CPV and CCS intra-granular resulted in increased disintegration time and Q₈₀. However, at a higher level of appx. 500 s and appx. 15 min, only SSG showed a process and location independent disintegration and dissolution performance.

The Effect of Process Variables and Binder Concentration on Tabletability of Metformin Hydrochloride and Acetaminophen Granules Produced by Twin Screw Melt Granulation with Different Polymeric Binders

In twin screw melt granulation, granules are produced by passing mixtures of drug substances and polymeric binders through twin screw extruder such that temperatures are maintained below melting point of drugs but above glass transition of polymers used, whereby the polymers coat surfaces of drug particles and cause their agglomeration into granules. Since various formulation factors, such as binder type and concentration, and processing variables like extrusion temperature, screw configuration, and screw speed, can influence the granulation process, the present investigation was undertaken to study their effects on tabletability of granules produced. Three different types of polymeric binders, Klucel® EXF (hydroxypropyl cellulose), Eudragit® EPO (polyacrylate binder), and Soluplus® (polyvinyl caprolactam-co-vinyl acetate-ethylene glycol graft polymer), were used at 2, 5, and 10% concentrations. Metformin hydrochloride (HCl) (mp: 222°C) and acetaminophen (mp: 169°C) were used as model drugs, and drug-polymer mixtures with metformin HCl were extruded at 180, 160, and 130°C, while those with acetaminophen were extruded at 130 and 110°C. Other process variables included screw configurations: low, medium, and high shear for metformin HCl, and low and medium shear for acetaminophen; feed rates: 20 and 60 g/min; and screw speed of 100 and 300 RPM. Formulation and process variables had significant impact on tabletability. The target tensile strength of ≥2 MPa could be obtained with all polymers and at all processing temperatures when metformin HCl was granulated at 180°C and acetaminophen at 130°C. At other temperatures, the target tensile strength could be achieved at certain specific sets of processing conditions.

Twin-Screw Melt Granulation for Oral Solid Pharmaceutical Products

This article highlights the advantages of pharmaceutical continuous melt granulation by twin-screw extrusion. The different melt granulation process options and excipients are described and compared, and a case is made for expanded use of twin-screw melt granulation since it is a flexible and continuous process. Methods for binder selection are profiled with a focus on rheology and physical stability impacts. For twin-screw melt granulation, the mechanism of granulation and process impact on granule properties are described. Pharmaceutical applications of melt granulation ranging from immediate release of soluble and insoluble APIs, taste-masking, and sustained release formulation are reviewed, demonstrating the range of possibilities afforded by twin-screw melt granulation.

Towards predicting the product quality in hot-melt extrusion: Small scale extrusion

In product development, it is crucial to choose the appropriate drug manufacturing route accurately and timely and to ensure that the technique selected is suitable for achieving the desired product quality. Guided by the QbD principles, the pharmaceutical industry is currently transitioning from batch to continuous manufacturing. In this context, process understanding and prediction are becoming even more important. With regard to hot melt extrusion, the process setup, optimization and scale-up in early stages of product development are particularly challenging due to poor process understanding, complex product-process relationship and a small amount of premix available for extensive experimental studies. Hence, automated, quick and reliable process setup and scale-up requires simulation tools that are accurate enough to capture the process and determine the product-process relationships. To this end, the effect of process settings on the degradation of the active pharmaceutical ingredient (API) in a lab-scale Leistritz ZSE12 extruder was investigated. As part of the presented study, the limitations of traditional process analysis using integral process values were investigated, together with the potential that simulations may have in predicting the process performance and the product quality. The results of our investigation indicate that the average melt temperatures and the exposure times in specific zones along the screw configuration correlate well with the API degradation values and can be used as potent process design criteria to simplify the process development.

Melt granulation: A comparison of granules produced via high-shear mixing and twin-screw granulation

Melt granules of DI-CAFOS® A12 and 15% (w/w) Kolliphor® P407 were manufactured in a twin-screw granulator (TSG) at five different conditions (screw speed and throughput varied) and compared to granules manufactured in a high-shear granulator (HSG) (rotation speed of chopper/impeller and granulation time varied). Evaluated granules characteristics were process yield, particle-size distribution (PSD), particle morphology, flowability, porosity, specific surface area (SSA), tabletability, compressibility and binder distribution. Compared to TSG, granules produced from HSG were more spherical in shape with lower porosity, smaller mean particle size and a superior flowability. Granules made by TSG showed a more elongated structure, higher porosity and larger mean particle size with smaller SSA instead. Concerning the compression process of granules, tablets made of TSG granules exhibited a higher tabletability compared to HSG granules, whereas the compressibility remained similar. In the case of the TSG granules, energy-dispersive-X-ray (EDX) measurements of the tablet surface indicated an enhanced homogenous binder distribution. Additionally, the EDX-analyses determined that more binder was available between the individual particles, resulting in a stronger bonding.