Basic Excipients Research Articles

Exploration of the Safety and Solubilization, Dissolution, Analgesic Effects of Common Basic Excipients on the NSAID Drug Ketoprofen.

Since its introduction to the market in the 1970s, ketoprofen has been widely used due to its high efficacy in moderate pain management. However, its poor solubility and ulcer side effects have diminished its popularity. This study prepared forms of ketoprofen modified with three basic excipients: tris, L-lysine, and L-arginine, and investigated their ability to improve water solubility and reduce ulcerogenic potential. The complexation/salt formation of ketoprofen and the basic excipients was prepared using physical mixing and coprecipitation methods. The prepared mixtures were studied for solubility, docking, dissolution, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), in vivo evaluation for efficacy (the writhing test), and safety (ulcerogenic liability). Phase solubility diagrams were constructed, and a linear solubility (AL type) curve was obtained with tris. Docking studies suggested a possible salt formation with L-arginine using Hirshfeld surface analysis. The order of enhancement of solubility and dissolution rates was as follows: L-arginine > L-lysine > tris. In vivo analgesic evaluation indicated a significant enhancement of the onset of action of analgesic activities for the three basic excipients. However, safety and gastric protection indicated that both ketoprofen arginine and ketoprofen lysine salts were more favorable than ketoprofen tris.

Enhancing the Dissolution of Oral Dasatinib Tablets Using Zein–Hydroxypropyl Methylcellulose Solid Dispersions

Zein has been used in several pharmaceutical applications because of its unique composition. It is an amphiphilic molecule that is biodegradable, biocompatible, and has adhesive, matrix-forming, and film-coating properties, making it a promising pharmaceutical excipient. Zein-based formulations have been investigated in tablet-coating, nanoparticulate delivery systems, and controlled-release formulations. However, to date, very few studies have been performed on the inclusion of zein in solid dispersion formulations to enhance drug dissolution. This study aimed to improve the dissolution of the weakly basic and poorly soluble oral dasatinib (used as a model) using zein–hydroxypropyl methylcellulose (HPMC) solid dispersion to achieve rapid disintegration and dissolution in the gastric pH. Using the spray-drying technique, four solid dispersions were prepared with different zein, HPMC, and dasatinib ratios. Subsequently, five different tablets were directly compressed using the previously prepared solid dispersions along with basic excipients. Various in vitro characterization analyses were performed to predict their behavior in vivo. Particle size measurement, tablet weight variation and content assay, disintegration, and dissolution studies were also performed. The results indicated that zein solid dispersion improved the disintegration and dissolution of dasatinib in the gastric media by reducing the drug particle size and the formation of the dasatinib amorphous state. Moreover, the tablets exhibited desirable properties in terms of high drug content, friability, and tensile strength. In conclusion, tablets comprising zein–HPMC solid dispersion showed improved properties; however, including a higher ratio of zein in the solid dispersion adversely affected the disintegration and release properties of formulations.

Benzofurazan -based fluorophore for the spectrofluorimetric determination of 6-Aminocaproic acid: Application to spiked human plasma and urine

6-Aminocaproic acid is one of the most widely used antihemorrhagic and antifibrinolytic agent, therefore, it is essential to create a novel, sensitive, low cost and straightforward spectrofluorimetric method for its determination. The nucleophilic substitution interaction between the primary amine of 6-aminocaproic acid with 4-chloro-7-nitro benzofurazan (NBD-Cl) generated a yellow product. The reaction proceeded in borate buffer (pH 9) and its fluorescence has been measured at 525 nm after excitation at 472 nm. All of the parameters that have impact on the performance of the developed method were investigated and optimized. The range of linearity was 0.1–0.7 μg/mL while, the quantitation limit was down to 0.101 μg/mL and limit of detection was 0.033 μg/mL. This approach was effectively employed to evaluate the content of 6-aminocaproic acid in laboratory prepared dosage form with average percentage recovery of 100.19 ± 0.72% without any interference from basic excipients. Moreover, the proposed method was extended to determine 6-aminocaproic acid in spiked human plasma and urine.

Spectral Database of Pharmaceutical Common Excipients and Paracetamol API Using ASD Field Spec 4 Spectrordiometer

Adulteration in pharmaceutical products is common all over the world particularly in pharmaceutical oraldosage forms like tablets, gelatin capsules. According to previous studies there were many techniquesare available to recognize counterfeit medicines. Near Infrared Spectroscopic techniques is widely usedin this area due to its numerous advantages. In this work, we used ASD Field Spec4 Spectroradiometerhaving broad spectral range (350-2500 nanometer) and its supporting software’s to create Spectral libraryof pharmaceutical common drug Paracetamol and some basic excipients used in pharmaceutical industryas formulation process of tablets and capsules and finally also showed the absorption bands of ParacetamolAPI and Excipients.

Modulation of Microenvironmental Acidity: A Strategy to Mitigate Salt Disproportionation in Drug Product Environment.

Disproportionation of pioglitazone hydrochloride (PioHCl), leading to the free base formation, was observed in tablet formulations containing basic excipients such as magnesium stearate (Koranne et al, Mol. Pharmaceutics, 2017, 14, 1133-1144). The nature and concentration of excipients, by modulating the microenvironmental acidity (measured as pHeq), governed the disproportionation reaction. In the current work, we hypothesized that the addition of an organic acid, by lowering the pHeq, can stabilize PioHCl. Powder blends containing PioHCl, magnesium stearate and each oxalic, maleic, tartaric, fumaric, and glutaric acid were stored at 40 °C/75% RH for 15 days. The concentration of crystalline free base, a product of the disproportionation reaction, was quantified using synchrotron radiation. The pHeq of the powder blends was measured via ionization of probe molecules deposited on the surface. In general, the stronger the acid, the lower the pHeq of the formulation blend and more effective it was in stabilizing PioHCl and preventing disproportionation. Thus, controlling the microenvironmental acidity in a rational and systematic way provided an avenue to mitigate excipient-induced salt disproportionation. Even when the lattice of PioHCl was activated by milling, it remained stable in the presence of acid. The amount of water sorbed during tablet storage provided an indirect measure of the disproportionation.

THE DEVELOPMENT OF THE COMBAINED PHARMACEUTICAL COMPOSITION WITH PLEIOTROPIC ACTIVITY BASED ON ORIGINAL SPERMOMODULATING SUBSTANCE

The article is devoted to the results of the theoretical and experimental investigations on the development of the optimal formulation of the pharmaceutical composition based on Kathiazin and Succinic acid in the solid gelatinous capsules. The glutaminic acid has been introduced into the pharmaceutical composition to improve the bioavailability of the succinic acid. The content of active pharmaceutical substances has been determined. The single dose of Kathiazin is 120 mg, succinic and glutaminic acids — 100 mg. The kind of auxiliary substances used in modern pharmaceutical technology of the solid dosage forms has been grounded according to the literature data. The pharmacotechnological testing of the active pharmaceutical ingredients and auxiliary substances used in our research work has been carried out. The pharmaco-technological properties of the substances investigated according to the articles of State Pharmacopoeia of Ukraine (2 edition) have been estimated. The assessment of obtained data allowed to elaborate the composition of the experimental capsules masses. The flowability, bulk density, angle of repose, compressibility index and Hausner ratio of the mixtures created have been investigated due to requirements of the State Pharmacopoeia of Ukraine. On the base of scientific researching the most perspective pharmaceutical composition with excellent values of the flowability, angle of repose, bulk density, compressibility index and Hausner ratio has been chosen. This composition contains mannitol as the basic excipients for capsules mass. The silicon dioxide colloidal (Aerosil®) is considered to be glidant substance which provides excellent flowability. As the result of the pharmaco-technological researches the qualitative and quantitative composition of the combined capsules based on Kathiazin and succinic acid has been developed. The testing of the pharmaco-technological parameters has proved the composition obtained is suitable to be encapsulated using different types of laboratory and industrial equipment. The elaborated combined dosage form based on Kathiazin and succinic acid may be proposed as a new original medicine with pleiotropic activity for treatment hepatitis of different origin in men with spermatogenesis disturbances.

Assessing the Risk of Salt Disproportionation Using Crystal Structure and Surface Topography Analysis

Salt disproportionation is a major issue for pharmaceutical products containing a salt form of a weakly basic drug, because conversion to the free base during processing or storage in the presence of excipients may negatively impact stability and bioperformance of the drug product. Several factors influencing disproportionation tendency have been elucidated; however, a complete mechanistic understanding of this phenomenon is still lacking. Specifically, it is unclear if the crystal structure of the salt plays a role, beyond influencing the salt solubility. Herein, by utilizing model compounds with similar pKa and pHmax values, and hence similar thermodynamic driving forces for disproportionation, we demonstrate that salt crystal structure appears to play a major role in influencing disproportionation tendency. Some salts with low pHmax values were found to be resistant to disproportionation, while other systems transformed to the free base following contact with the basic excipient, magnesium stearate. Fo...

Benzofurazan-based fluorophore for the selective determination of flupentixol dihydrochloride: Application to content uniformity testing.

One of the most commonly used drugs in treatment of schizophrenia is flupentixol dihydrochloride, therefore it is important to develop a simple, low cost and sensitive spectrofluorimetric method for the estimation of flupentixol dihydrochloride. The yellow fluorescent product that is generated from the nucleophilic substitution reaction of the free lone pair of the alcoholic hydroxyl group of the drug and 4-chloro-7-nitrobenzofurazan (NBD-Cl) in Mcllvaine buffer pH7.0 was estimated at 510nm (λex 460nm). The variables that affect the development of the reaction product were explored and optimized. The linear range of this method was 0.5-2.5μgml-1 with a limit of quantitation equal to 0.29μgml-1 . Our method was successfully applied for the assurance of flupentixol in tablet form with average percentage recovery of 99.08±1.01% without obstruction from the basic excipients exhibits. Furthermore, our strategy was extended to study the content uniformity testing of flupentixol in Fluaxnol® tablets.

Analysis of quetiapine in human plasma using fluorescence spectroscopy

A simple and sensitive spectrofluorimetric method has been development for the assurance of quetiapine fumarate (QTF). The proposed method was utilized for measuring the fluorescence intensity of the yellow fluorescent product at 510nm (λex 470nm). The fluorescent product has resulted from the nucleophilic substitution reaction of QTF with 4-chloro-7-nitrobenzofurazane (NBD-Cl) in Mcllvaine buffer (pH7.0). The diverse variables influencing the development of the reaction product were deliberately changed and optimized. The linear concentration range of the proposed method was of 0.2–2.0μgml−1.The limits of detection and quantitation were 0.05 and 0.17μgml−1, respectively. The proposed method was applied for the assurance of QTF in its tablets without interference from basic excipients. In addition, the proposed method was used for in vitro analysis of the QTF in spiked human plasma, the percent mean recovery was (n=3) 98.82±1.484%.

Impact of Solid-State Form on the Disproportionation of Miconazole Mesylate.

Approximately 50% of solid oral dosage forms utilize salt forms of the active pharmaceutical ingredient (API). A major challenge with the salt form is its tendency to disproportionate to produce the un-ionized API form, decreasing the solubility and negatively impacting product stability. However, many of the factors dictating the tendency of a given salt to undergo disproportionation remain to be elucidated. In particular, the role of the solid-state properties of the salt on the disproportionation reaction is unknown. Herein, various solid forms of a model salt, miconazole mesylate (MM), were evaluated for their tendency to undergo disproportionation when mixed with basic excipients, namely tribasic sodium phosphate dodecahydrate (TSPd) and croscarmellose sodium (CCS), and exposed to moderate relative humidity storage conditions. It was observed that the rate and extent of salt disproportionation were significantly different for the various solid forms of MM. As expected, the amorphous salt was highly susceptible to disproportionation, while the dihydrate salt form was resistant to conversion under the conditions tested. In addition, binary excipient blends of amorphous and anhydrous forms exhibited a reduced extent of disproportionation at a higher relative humidity storage condition. This was due to the competitive kinetics between disproportionation to the free base and conversion to the dihydrate salt form. The results of this study provide important insights into the impact of solid-state form on susceptibility to disproportionation that can be utilized for rationally designing robust pharmaceutical formulations.

Solid-state interactions at the core-coat interface: physicochemical characterization of enteric-coated omeprazole pellets without a protective sub-coat.

Conventionally, scanning electron or transmission microscopy, Raman and near infrared (NIR) spectroscopy, terahertz, florescence, and nuclear magnetic resonance imaging have been used to characterize functional coating structure. This study highlights the use of fluorescence microscopy to investigate the physicochemical stability and coating integrity of the commercially available enteric-coated omeprazole pellets containing a basic excipient and prepared by extrusion and spheronization or drug layering on the nonpareil seed, immediately followed by enteric coating (i.e., absence of protective sub-coat). The nature of coating interface and the likely development of an in situ interfacial layer after the application of enteric coating solution was examined using HPLC, NMR, differential scanning calorimetry (DSC), and fluorescent imaging methods. Likewise for the characterization of the solid pellet structure via fluorescence microscopy, a new approach based on fracturing technique (to avoid surface contamination) rather than microtome sectioning was used and validated. Analytical data showed that the pellets containing omeprazole remained chemically stable (>99.5% recovered). Control of the microenvironmental pH by the addition of alkalinizing excipient within a core formulation or as part of drug layering on top of nonpareil seed appears to efficiently neutralize the acidic effect of enteric coating dispersion. Fluorescence images further illustrate the absence of any discernable in situ layer formation at the coat-core interface.

Processing-induced salt formation of two oxicams in solid dosage forms affects dissolution behavior and chemical degradation

There is a growing need to increase our understanding of physicochemical stability of pharmaceuticals during manufacturing. The present study has investigated effects of excipients and processing conditions on the physicochemical properties of two weakly acidic model drugs (piroxicam and lornoxicam) in solid dosage pharmaceuticals. By means of solid-state analysis it was observed that basic excipients (sodium bicarbonate and dicalcium phosphate) may induce salt formation of these drug compounds during wet granulation, whereby the drug dissolution rate from formulations containing lornoxicam was significantly increased while the dissolution from piroxicam-containing formulations was unaffected. Following preparation of the solid drug formulations, chromatographic analysis demonstrated that the processing-induced sodium salt formation increase chemical degradation of both model drugs during storage. Hence, the present study illustrate that processing-induced transformations in the solid phase of drugs encountered during manufacture of solid dosage pharmaceuticals may significantly impact critical quality attributes of the final medicinal product.

Incompatibility of croscarmellose sodium with alkaline excipients in a tablet formulation

The objective of the current work was to study an observed incompatibility between croscarmellose sodium and basic excipients in a tablet formulation. Significant dissolution slowdown was observed for alkaline tablet compositions of an acid-labile drug containing croscarmellose sodium (CCS) as a disintegrant. The severity of the dissolution slowdown was directly proportional to both the degree of alkalinity and the level of CCS in the tablet formulation. It is postulated that the ester cross-links in CCS were partially or fully hydrolyzed under basic conditions (pH values >9) forming by-products of increased water solubility. This increase in the level of water-soluble polymer can lead to the formation of a viscous barrier in the tablet upon moisture uptake, thus slowing down its dissolution. The dissolution slowdown was not observed for a similar alkaline tablet preparation containing crospovidone as a disintegrant.

Role of Salt and Excipient Properties on Disproportionation in the Solid-State

Approximately 50% of active pharmaceutical ingredients (APIs) are manufactured and formulated as salts, due to their enhanced dissolution rates or improved solid state properties. It is essential to maintain the appropriate solid state form of the drug during processing and over the lifetime of the product. The aim of this study was to investigate the contributing factors in the process of disproportionation, whereby the salt converts back to the free form of the drug. Infrared and Raman spectroscopy were used to detect and quantify the formation of free base in physical mixtures with excipients. The pH-solubility relationships were determined based on measured salt solubilities and properties of the free form. The mesylate salts of two model pharmaceutical compounds were found to disproportionate to the free base form when physically mixed with certain common basic excipients and exposed to moderate relative humidities. In contrast, the napsylate salts were much more resistant to disproportionation. The napsylate salts had solubilities more than 3 orders of magnitude lower than the respective mesylate salts, and showed little to no detectable formation of free base. The mesylate salts with higher solubilities showed significant levels of conversion to the free base. It appears that both the solubility and pH(max) (the pH of a solution where there is saturation of both ionized and unionized species) of the salts, as well as the base solubility, play important roles in determining the susceptibility of salts to disproportionate. The extent of conversion was also affected by excipient properties, including basicity, solubility, physical state and surface area.

Formulation study for lansoprazole fast-disintegrating tablet. III. Design of rapidly disintegrating tablets.

Lansoprazole fast-disintegrating tablets (LFDT) are a patient-friendly formulation that rapidly disintegrates in the mouth. LFDT consist of enteric-coated microgranules (mean particle size, approximately 300 microm) and inactive granules. In the design of the inactive granules, mannitol was used as a basic excipient. Microcrystalline cellulose, low-substituted hydroxypropyl cellulose (L-HPC), and crospovidone were used as binders and disintegrants. A new grade of L-HPC (L-HPC-33), with a hydroxypropoxy group content of 5.0-6.9%, was developed and it has no rough texture due to a decrease in water absorption. It was clarified that L-HPC-33 could be useful as a binder and disintegrant in rapidly disintegrating tablets. LFDT contain enteric-coated microgranules in tablet form. The enteric-coated microgranule content in LFDT affect qualities such as tensile strength, disintegration time in the mouth, and dissolution behavior in the acid stage and in the buffer stage of LFDT. The 47.4% content of the enteric-coated microgranules was selected to give sufficient tensile strength (not less than 30 N/cm(2)), rapid disintegration time in the mouth (not more than 30 s), and dissolution behavior in the acid stage and buffer stage similar to current lansoprazole capsules. Compression force affected the tensile strength and the disintegration time in the mouth, but did not affect the dissolution behavior in the acid and buffer stages.

Effect of a basic organic excipient on the dissolution of diclofenac salts

Dissolution of diclofenac from compressed discs containing mixtures of a diclofenac salt and a basic excipient, in various w/w ratios, was examined. Two diclofenac salts, diclofenac deanol (DDNL) and diclofenac tert‐butylamine, and the basic excipient 2‐amino‐2‐methyl‐1,3‐propanediol (AMPD) were examined. Inclusion of the soluble basic excipient at high loadings enhanced the dissolution rate of diclofenac tert‐butylamine fivefold; however, it retarded dissolution of the DDNL salt 40‐fold in the weight fraction range 40–80% AMPD, despite the fact that AMPD is more than four times more soluble than DDNL. These findings were attributed to the solubilities of salts formed between diclofenac and the basic excipient used. The “salt conversion model” was developed to predict dissolution from mixtures of a salt of an ionizable drug and an ionizable excipient capable of forming a salt with the drug. Deviations from the model at high weight fractions of base and, in the case of the systems containing the more soluble drug, at low weight fractions of base were attributed to carrier‐controlled dissolution. The present work illustrates that the solubility of potential salts, which may form between the drug and ionizable excipients present has an important influence on the dissolution of the drug from such compressed mixtures. © 2002 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2271–2281, 2002

Improved biocompatibility of a viscous bioerodible poly(ortho ester) by controlling the environmental pH during degradation

The poly(ortho ester), POE, used in this investigation, is a viscous bioerodible polymer (8 kDa), which rapidly degrades into a triol and an acidic by-product, acetic acid. In order to improve biocompatibility, we have evaluated the addition of various basic excipients, such as sodium acetate, hydroxyapatite, calcium carbonate and magnesium hydroxide, which buffered and neutralized the acidic degradation product and prolonged the polymer lifetime and drug release. This decrease of POE degradation rate results in a decreased rate of formation of the acidic by-product. Similarly, a POE of higher molecular weight (14 kDa) has been tested. Sodium acetate was too hydrophilic to affect the drug release and the biocompatibility of the polymer, whereas the presence of magnesium hydroxide markedly prolonged the drug release and improved the acceptability of the polymer. The increased molecular weight POE did not improve biocompatibility and a similar but delayed, inflammatory reaction was observed.

Stabilization of pH-Induced Degradation of Porcine Insulin in Biodegradable Polyester Microspheres

The purpose of this research project was to stabilize the pH-induced degradation of porcine insulin encapsulated within biodegradable polyester microspheres through the incorporation of a basic additive. Insulin microspheres fabricated using Poly(L-lactide) (L-PLA) and Poly(DL-lactide-co-glycolide) (50:50 DL-PLGA) were subjected to in vitro release studies and the stability of unreleased insulin encapsulated within microspheres was investigated. The intramicrosphere pH was estimated by encapsulating acid-base indicators covering a wide pH transition range within 50:50 DL-PLGA microspheres. Finally, a basic excipient sodium bicarbonate was incorporated in 50:50 DL-PLGA microspheres to minimize acid-induced insulin degradation. The in vitro release was slow and incomplete (<30% in 30 days). Extraction and analyses of the unreleased insulin within the microspheres revealed that an average of ∼11% remained intact. The degradation products observed consisted of ∼15% of three distinct deamidated hydrolysis products including A-21 Desamido insulin, ∼22% Covalent Insulin Dimer and trace amounts of High Molecular Weight Transformation Products. Comparison of the degradation profile of unreleased insulin contained in various microsphere formulations with the in vitro release kinetics indicated that an increase in covalent dimer formation within the microspheres prior to release is associated with a decrease in the cumulative percent insulin released during a 30-day incubation period. In an attempt to correlate insulin degradation with the drop in intra-microsphere pH due to polymer hydrolysis, it was determined that the pH within a degrading microsphere reaches a value of ∼1.8 after 4 weeks. The incorporation of a basic excipient, sodium bicarbonate, in 50:50 DL-PLGA microspheres resulted in an improved in vitro release profile (cumulative release ∼47.3% in 30 days) as well as a significant reduction in covalent dimerization of the unreleased insulin to barely detectable levels. The low pH microenvironment within a degrading microsphere is one of the major factors leading to protein instability, and the degradation of proteins encapsulated within polyester microspheres can be minimized by the incorporation of a basic excipient.

The use of acidic and basic excipients in the release of 5-fluorouracil and mitomycin C from a semi-solid bioerodible poly(ortho ester)

Semi-solid poly(ortho esters) (POE) prepared by a transesterification reaction between trimethyl orthoacetate and 1,2,6-hexanetriol were investigated as injectable bioerodible polymers for the controlled release of 5-fluorouracil (5-FU) and mitomycin C (MMC). The release from POE is controlled principally by erosion (weight loss) and diffusion. Both of these parameters are dependent on the hydrolytic cleavage of the polymer backbone. The use of two antimetabolites characterized by different physicochemical properties shows that the nature of the therapeutic agent incorporated into the polymer plays an important role in the release rate. Incorporation of a highly water-soluble drug increases polymer hydrophilicity and leads to a fast release by diffusion. Other parameters affecting uniformity of rate of drug release are small particle size and a good dispersion in the polymer, or solubilization of the drug in the polymer. Because 5-FU is a weakly acidic compound, its release is faster than the neutral MMC, despite the higher water-solubility of the latter. The influence of acid catalysts dispersed in the polymer on the erosion rate of POE in aqueous buffered solutions has been investigated. Five acidic excipients having different pK a, values and varying degrees of water solubility investigated were ascorbic, itaconic, adipic, suberic and sebacic acids. The concentration of the acidic excipient in the polymer was found to have a significant effect on the rate of erosion and drug release. In order to extend polymer lifetime and decrease drug release rate, the use of the sparingly water-soluble base Mg(OH) 2 was investigated. It was possible to produce POEs that release drugs over an extended period of time. However, as the amount of Mg(OH) 2 was increased, increasing divergence between polymer erosion and drug release was noted.

PH‐Independent Controlled‐Release Microspheres Using Polyglycerol Esters of Fatty Acids

The release of a drug having low solubility in a certain pH range from controlled‐release microspheres using tetraglycerol pentastearate and tetraglycerol monostearate in combination as the matrix base showed pH dependence. Trepibutone, an acidic drug having lower solubility in an acidic medium, was released pH‐independently from the microspheres which incorporated magnesium oxide, a solid base. It might have resulted from the pH inside the matrix being kept in an optimum range for drug release due to the incorporation of a solid base. On the other hand, the addition of water soluble acidic or basic excipients was ineffective to achieve pH‐independent release. For papaverine, a basic drug, pH‐independent drug‐release characteristics could be achieved by adding Eudragit L100‐55, an enteric polymer. It is thought that the enteric polymer increased the pores for drug release by dissolving in a higher pH range, where the solubility of papaverine is low, and thereby made the release pH‐independent. Further, selecting a polyglycerol ester of a fatty acid with an appropriate hydrophile–lipophile balance as the matrix could yield a drug with the desired release rate at any pH.