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Sildenafil citrate is a phosphodiesterase-5 inhibitor that is approved by the U.S. Food and Drug Administration for the treatment of erectile dysfunction. Rapid-dissolving tablets are relatively novel dosage forms that can be prepared by extemporaneous compounding and potentially provide unique advantages for medications like sildenafil. However, such preparations may present newer stability considerations previously unreported. Therefore, the purpose of this study was to assess the physical and chemical stability of sildenafil 100-mg rapid-dissolving tablets prepared by a commonly practiced molding method, using two different proprietary rapid-dissolving tablet bases (Medi-RDT or RDTPlus) immediately after preparation and over six months of storage at ambient room temperature. To prepare the rapid-dissolving tablets, the powder ingredients were homogeneously mixed, filled, and compressed into a 96-cavity metal mold. The formulation was then heated at 110°C for 10 minutes in the mold, released from the mold, and cooled at room temperature for 15 minutes. The prepared tablets were packaged in amber-colored blister packs with cold-adhesive backing seals and stored at ambient room temperature. At predetermined time points, rapid-dissolving tablets of each formulation were retrieved to perform stability analyses. These analyses included weight variation, breaking force, disintegration, friability, and potency via high-performance liquid chromatography following the United States Pharmacopoeia methods and visual inspection. At time 0 (immediately after preparation), the results of the tests for rapid-dissolving tablets made with Medi-RDT base v. RDT-Plus base were as follows: average tablet weight (649.7 mg v. 753.6 mg); breaking force (24.01 N v. 32.34 N); friability (8.52% v. 7.55%); disintegration time (34 seconds v. 35 seconds); and potency (98.61% v. 101.41%), respectively. Over the six-month storage period, both formulations of rapid-dissolving tablets had no significant changes in visual appearance, tablet weight, breaking force, or disintegration time. High-performance liquid chromatographic-based tablet assays for both formulations were consistently above 95% label claim at each time point, with no chromatographic evidence of degradation. Thus, the studied formulations of compounded sildenafil 100-mg rapid-dissolving tablets prepared using both Medi-RDT or RDT-Plus were found to be physically and chemically stable over six months of storage at ambient room temperature.

The density, porosity, breaking force, viscoelastic properties, and the presence or absence of any structural defects or irregularities are important physical-mechanical quality attributes of popular solid dosage forms like tablets. The irregularities associated with these attributes may influence the drug product functionality. Thus, an accurate and efficient characterization of these properties is critical for successful development and manufacturing of a robust tablets. These properties are mainly analyzed and monitored with traditional pharmacopeial and non-pharmacopeial methods. Such methods are associated with several challenges such as lack of spatial resolution, efficiency, or sample-sparing attributes. Recent advances in technology, design, instrumentation, and software have led to the emergence of newer techniques for non-invasive characterization of physical-mechanical properties of tablets. These techniques include near infrared spectroscopy, Raman spectroscopy, X-ray microtomography, nuclear magnetic resonance (NMR) imaging, terahertz pulsed imaging, laser-induced breakdown spectroscopy, and various acoustic- and thermal-based techniques. Such state-of-the-art techniques are currently applied at various stages of development and manufacturing of tablets at industrial scale. Each technique has specific advantages or challenges with respect to operational efficiency and cost, compared to traditional analytical methods. Currently, most of these techniques are used as secondary analytical tools to support the traditional methods in characterizing or monitoring tablet quality attributes. Therefore, further development in the instrumentation and software, and studies on the applications are necessary for their adoption in routine analysis and monitoring of tablet physical-mechanical properties.

The apigenin-phospholipid phytosome (APLC) was developed to improve the aqueous solubility, dissolution, in vivo bioavailability, and antioxidant activity of apigenin. The APLC synthesis was guided by a full factorial design strategy, incorporating specific formulation and process variables to deliver an optimized product. The design-optimized formulation was assayed for aqueous solubility, in vitro dissolution, pharmacokinetics, and antioxidant activity. The pharmacological evaluation was carried out by assessing its effects on carbon tetrachloride-induced elevation of liver function marker enzymes in a rat model. The antioxidant activity was assessed by studying its effects on the liver antioxidant marker enzymes. The developed model was validated using the design-optimized levels of formulation and process variables. The physical-chemical characterization confirmed the formation of phytosomes. The optimized formulation demonstrated over 36-fold higher aqueous solubility of apigenin, compared to that of pure apigenin. The formulation also exhibited a significantly higher rate and extent of apigenin release in dissolution studies. The pharmacokinetic analysis revealed a significant enhancement in the oral bioavailability of apigenin from the prepared formulation, compared to pure apigenin. The liver function tests indicated that the prepared phytosome showed a significantly improved restoration of all carbon tetrachloride-elevated rat liver function marker enzymes. The prepared formulation also exhibited antioxidant potential by significantly increasing the levels of glutathione, superoxide dismutase, catalase, and decreasing the levels of lipid peroxidase. The study shows that phospholipid-based phytosome is a promising and viable strategy for improving the delivery of apigenin and similar phytoconstituents with low aqueous solubility.

The main goal of the presented work was to understand changes in the microstructure of tablets, as well as the properties of its main component viz. polyethylene oxide (PEO) as a function of sintering. Key polymer variables and sintering conditions were investigated, and sintering-induced increase in tablet tensile strength was evaluated. For the current study, binary-component placebo tablets comprised of varying ratios of PEO and anhydrous dibasic calcium phosphate (DCP) were prepared at two levels of tablet solid fraction. The prepared tablets were sintered in an oven at 80°C at different time points ranging from 10 to 900 min and were evaluated for pore size, tablet expansion (%), and PEO crystallinity. The results showed that for efficient sintering and a significant increase in the tablet tensile strength, a minimum of 50% w/w PEO was required. Moreover, all microstructural changes in tablets were found to occur within 60 min of sintering, with no significant changes occurring thereafter. Sintering also resulted in a decrease in PEO crystallinity, causing changes in polymer ductility. These changes in PEO ductility resulted in tablets with higher tensile strength. Formulation variables such as PEO level and PEO particle size distribution were found to be important influencers of the sintering process. Additionally, tablets with high initial solid fraction and sintering duration of 60 min were found to be optimal conditions for efficient sintering of PEO-based compacts. Finally, prolonged sintering times were not found to provide any additional benefits in terms of abuse-deterrent properties.

The predictability of multivariate calibration models, calculated with offline near-infrared spectroscopy (NIRS), assessing impact of magnesium stearate (MgSt) fraction, blending time, and compression force on the tablet breaking force (TBF) of SPRESS® B820 was statistically compared. Tablets of lubricated SPRESS® B820 were prepared by varying lubrication and compression conditions using 24 full factorial design. Tablets were scanned in reflection mode on a benchtop NIRS. A qualitative principal component analysis and quantitative principal component regression (PCR) and partial least square (PLS) regression relationship between lubricant concentration, blending time, compression force, preprocessed NIR spectra, and measured TBF was calculated with calibration data set. The predictability of calibration models was validated with independent data set. Expected qualitative correlations between MgSt blending time and TBF and a nonlinear relationship between MgSt fraction and TBF were observed. Predictability of PLS comprehensive (0.25%-1% w/w MgSt) model was significantly different from individual 0.25%, 0.5%, and 1.0% w/w MgSt PLS models. In addition, PLS calibration models' predictability was different from PCR calibration models. Thus, added lubrication fraction and adopted multivariate methodology should be selected carefully during the calibration and validation stages as it may have a significant impact on the predictability of the developed models.

In the present study, a lyophilized milk-based solid dispersion (SD) of ritonavir (RTV) was developed with the goal of improving its aqueous solubility. The SD was prepared by lyophilization, and characterized for its physicochemical and functional properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photomicroscopy and powder X-ray diffraction (PXRD) were used to confirm the formation and robustness of the SD formulation. The prepared SD formulations were functionally evaluated by saturation solubility, in vitro drug release and ex vivo permeation studies. The optimized SD formulation exhibited a significantly higher (30-fold) aqueous solubility (11.36 ± 0.06 μg/mL), compared to the pure RTV (0.37 ± 0.03 μg/mL). The in vitro dissolution studies revealed a significantly higher (∼10-fold) efficiency of the optimized SD formulation in releasing the RTV, compared to the pure RTV. The ex vivo permeation studies with the everted intestine method showed that prepared SD formulation significantly improved the permeation of RTV (75.6 ± 3.09, % w/w), compared to pure RTV (20.45 ± 1.68, % w/w). Thus, SD formulation utilizing lyophilized milk as a carrier appears to be a promising alternative strategy to improve the aqueous solubility of poorly water soluble drugs.

This study quantifies the lubricating efficiency of two grades of crystalline vegetable-derived magnesium stearate (MgSt-V) using the DM3 approach, which utilizes design of experiments (D) and multivariate analysis techniques (M3) to evaluate the effect of a material's (M1) molecular and macroscopic properties and manufacturing factors (M2) on critical product attributes. A 23 factorial design (2 continuous variables plus 1 categorical factor) with three center points for each categorical factor was used to evaluate the effect of MgSt-V fraction and blend time on running powder basic flow energy (BFE), tablet mechanical strength (TMS), disintegration time (DT), and running powder lubricant sensitivity ratio (LSR). Molecular characterization of MgSt-V employed moisture sorption–desorption analysis, 13C nuclear magnetic resonance spectroscopy, thermal analysis, and powder X-ray diffraction. MgSt-V macroscopic analysis included mean particle size, specific surface area, particle morphology, and BFE. Principal component analysis and partial least squares multivariate analysis techniques were used to develop predictive qualitative and quantitative relationships between the molecular and macroscopic properties of MgSt-V grades, design variables, and resulting tablet formulation properties. MgSt-V fraction and blending time and their square effects showed statistical significant effects. Significant variation in the molecular and macroscopic properties of MgSt-V did not have a statistically significant impact on the studied product quality attributes (BFE, TMS, DT, and LSR). In setting excipient release specifications, functional testing may be appropriate in certain cases to assess the effect of statistically significant different molecular and macroscopic properties on product quality attributes.

Excipients are necessary and invaluable components of pharmaceutical formulations. While being biologically inert, excipients often determine the functionality and performance of a drug product. Excipients as a class belong to a wide variety of physically and chemically diverse materials. The source, processing, and manufacturing methods of excipients are equally diverse. Moreover, often excipients are multifunctional, with their functionality depending on a plethora of factors such as the drug, the dosage form, the route of administration, the incorporation level, and a particular grade of the excipient incorporated. Thus, inclusion/use of excipients in pharmaceutical drug products entails a rigorous regulatory scrutiny with regards to their identity, purity, quality, and functionality. Quality by Design (QbD), along with process analytical technology (PAT), and design space is a holistic, science-based, risk-averting approach geared to thoroughly understand the critical quality attributes (CQAs) of materials and processes during drug product development. This United States Food and Drug Association's (USFDA’s) 21st-century initiative, along with the International Conference on Harmonization (ICH) Q8 guidelines, encourages drug product manufacturers to apply QbD principles to formulations and processes to ensure development and manufacture robust drug products. Variability in the quality of excipients can significantly influence the robustness of a drug product. Thus, it is imperative that excipient manufacturing also embraces the principles and concepts of QbD. This chapter is aimed to provide a general overview on the current philosophy regarding applications of QbD principles in excipient manufacturing. After a brief introduction, the chapter discusses these aspects in various sections, that is, excipient manufacture, excipient functionality and performance, excipient variability, QbD principles in excipient manufacturing, and excipient safety assessment requirements.

Eslicarbazepine acetate is an anticonvulsant drug with a recent U.S. Food and Drug Administration approval for expanded use in children and adolescents. Currently, eslicarbazepine acetate is only available in the U.S. as 200-mg to 800-mg strength tablets (Aptiom), which are not easy to administer for pediatric patients. This study was initiated to develop an oral suspension formulation for extemporaneous compounding by pharmacists and to generate stability data for storage recommendations. Nine suspension formulations of eslicarbazepine acetate were prepared from Aptiom tablets and commercially available liquid vehicles using the standard mortar/pestle method. The vehicles varied mainly in their solvents, viscosities, and sweeteners. The formulations were evaluated for ease of preparation, physical properties, and initial potency. Two lead formulations were selected for a two-month stability study at room temperature or under refrigeration (2°C to 8°C). The stability samples were withdrawn at pre-determined time points and analyzed by visual inspection, pH measurement, and a stability-indicating high-performance liquid chromatographic assay. The majority of the 9 formulations were found to be easy to prepare and administer at a concentration of 40-mg/mL eslicarbazepine acetate. Particle settling was observed in several formulations over time, but they were re-suspended satisfactorily upon shaking. Two suspensions in 50:50 v/v mixtures of Ora-Sweet or Ora-Sweet SF with Ora-Plus were selected as the lead formulations for the two-month stability study. At the initiation of the study, all samples appeared as white and smooth suspensions with pH ranging from 4.39 to 4.46. The high-performance liquid chromatographic results confirmed that the initial samples contained 100.4% to 102.2% of the label claim strength. Over two months of storage at room temperature or refrigeration, there were no significant changes in visual appearance, re-suspendability, pH, or potency for any samples. No new degradation peaks were observed in any highperformance liquid chromatograms. Based on the study results, two eslicarbazepine acetate suspensions are recommended for extemporaneous compounding from Aptiom tablets. The formulations consist of 40 mg/mL eslicarbazepine acetate in 50:50 v/v Ora-Sweet:Ora-Plus or Ora-Sweet SF:Ora-Plus. Once prepared, these suspensions can be stored at room temperature or under refrigeration for up to two months.

The presented study assessed the influence of punch geometry (head-flat [HF] diameter) and tooling type ('B' or 'D') on the physical-mechanical properties of tablets prepared by direct-compression of two guaifenesin (25% or 40% w/w) formulations. Tablets of both formulations were prepared on instrumented, single-layer, rotary tablet press using 10 mm, flat-faced, 'B' or 'D'-type tooling with different HF diameters, and compression forces (CF) ranging from 5 to 25 kN with 5 kN increments. The tablets were evaluated for dimensions, weight variation, tensile strength (TS), friability, and capping index. In general, tablets prepared using 'D' tooling showed a significantly (p 0.05) higher TS compared to those prepared using 'B' tooling, likely due to higher dwell-times associated with 'D' tooling. Formulations containing 25% w/w guaifenesin showed a significantly (p 0.05) higher TS compared to those containing 40% w/w guaifenesin, at given compression CF, punch geometry, or tooling type. This could be due to the higher ratio of Prosolv

Low-order high-energy nifedipine (NIF) solid dispersions (SDs) were generated by melt solvent amorphization with polyethylene glycol (PEG) 1450 and hypromellose acetate succinate (HPMCAS-HF) to increase NIF solubility while achieving acceptable physical stability. HPMCAS-HF was used as a crystallization inhibitor. Individual formulation components, their physical mixtures (PMs), and SDs were characterized by differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy (FTIR). NIF solubility and percent crystallinity (PC) were determined at the initial time and after 5 days stored at 25 °C and 60% RH. FTIR indicated that hydrogen bonding was involved with the amorphization process. FTIR showed that NIF:HPMCAS-HF intermolecular interactions were weaker than NIF:PEG 1450 interactions. NIF:PEG 1450 SD solubilities were significantly higher than their PM counterparts (p 0.0001). The solubilities of NIF:PEG 1450:HPMCAS-HF SDs were significantly higher than their corresponding NIF:PEG 1450 SDs (p 0.0001-0.043). All the SD solubilities showed a statistically significant decrease (p 0.0001) after storage for 5 days. SDs PC were statistically lower than their comparable PMs (p 0.0001). The PCs of SDs with HPMCAS-HF were significantly lower than SDs not containing only PEG 1450. All SDs exhibited a significant increase in PC (p 0.0001-0.0089) on storage. Thermogravimetric analysis results showed that HPMCAS-HF bound water at higher temperatures than PEG 1450 (p 0.0001-0.0039). HPMCAS-HF slowed the crystallization process of SDs, although it did not completely inhibit NIF crystal growth.

The physicochemical and biological properties of active pharmaceutical ingredients (APIs) are greatly affected by their salt forms. The choice of a particular salt formulation is based on numerous factors such as API chemistry, intended dosage form, pharmacokinetics, and pharmacodynamics. The appropriate salt can improve the overall therapeutic and pharmaceutical effects of an API. However, the incorrect salt form can have the opposite effect, and can be quite detrimental for overall drug development. This review summarizes several criteria for choosing the appropriate salt forms, along with the effects of salt forms on the pharmaceutical properties of APIs. In addition to a comprehensive review of the selection criteria, this review also gives a brief historic perspective of the salt selection processes.

In the present study, a phospholipid-based complex of standardized Centella extract (SCE) was developed with a goal of improving the bioavailability of its phytoconstituents. The SCE-phospholipid complex was prepared by solvent evaporation method and characterized for its physicochemical and functional properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photomicroscopy, and powder x-ray diffraction (PXRD) were used to confirm the formation of Centella naturosome (CN). The prepared complex was functionally evaluated by apparent solubility, in vitro drug release, ex vivo permeation, and in vivo efficacy studies. The prepared CN exhibited a significantly higher (12-fold) aqueous solubility (98.0 ± 1.4 μg/mL), compared to the pure SCE (8.12 ± 0.44 μg/mL), or the physical mixture of SCE and the phospholipid (13.6 ± 0.4 μg/mL). The in vitro dissolution studies revealed a significantly higher efficiency of CN in releasing the SCE (99.2 ± 4.7, % w/w) in comparison to the pure SCE (39.2 ± 2.3, % w/w), or the physical mixture (42.8 ± 2.09, % w/w). The ex vivo permeation studies with the everted intestine method showed that the prepared CN significantly improved the permeation of SCE (82.8 ± 3.7, % w/w), compared to the pure SCE (26.8 ± 2.4, % w/w), or the physical mixture (33.0 ± 2.7, % w/w). The in vivo efficacy studies using the Morris Water Maze test indicated a significant improvement of the spatial learning and memory in aged mice treated with CN. Thus, drug-phospholipid complexation appears to be a promising strategy to improve the aqueous solubility and bioavailability of bioactive phytoconstituents. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1208/s12248-015-9837-2) contains supplementary material, which is available to authorized users.

The aim of the present study was to develop and evaluate a thermoresponsive depot system comprising of docetaxel-loaded cubosomes. The cubosomes were dispersed within a thermoreversible gelling system for controlled drug delivery. The cubosome dispersion was prepared by dilution method, followed by homogenization using glyceryl monooleate, ethanol and Pluronic® F127 in distilled water. The cubosome dispersion was then incorporated into a gelling system prepared with Pluronic® F127 and Pluronic® F68 in various ratios to formulate a thermoresponsive depot system. The thermoresponsive depot formulations undergo a thermoreversible gelation process i.e., they exists as free flowing liquids at room temperature, and transforms into gels at higher temperatures e.g., body temperature, to form a stable depot in aqueous environment. The mean particle size of the cubosomes in the dispersion prepared with Pluronic® F127, with and without the drug was found to be 170 and 280 nm, respectively. The prepared thermoresponsive depot system was evaluated by assessing various parameters like time for gelation, injectability, gel erosion, and in-vitro drug release. The drug-release studies of the cubosome dispersion before incorporation into the gelling system revealed that a majority (∼97%) of the drug was released within 12 h. This formulation also showed a short lag time (∼3 min). However, when incorporated into a thermoresponsive depot system, the formulation exhibited an initial burst release of ∼21%, and released only ∼39% drug over a period of 12 h, thus indicating its potential as a controlled drug delivery system.

Colon-specific drug delivery systems (CDDS) are desirable for the treatment of a range of local diseases such as ulcerative colitis, Crohn's disease, irritable bowel syndrome, chronic pancreatitis, and colonic cancer. In addition, the colon can be a potential site for the systemic absorption of several drugs to treat non-colonic conditions. Drugs such as proteins and peptides that are known to degrade in the extreme gastric pH, if delivered to the colon intact, can be systemically absorbed by colonic mucosa. In order to achieve effective therapeutic outcomes, it is imperative that the designed delivery system specifically targets the drugs into the colon. Several formulation approaches have been explored in the development colon-targeted drug delivery systems. These approaches involve the use of formulation components that interact with one or more aspects of gastrointestinal (GI) physiology, such as the difference in the pH along the GI tract, the presence of colonic microflora, and enzymes, to achieve colon targeting. This article highlights the factors influencing colon-specific drug delivery and colonic bioavailability, and the limitations associated with CDDS. Further, the review provides a systematic discussion of various conventional, as well as relatively newer formulation approaches/technologies currently being utilized for the development of CDDS.

The influence of formulation variables, i.e., a hydrophilic polymer (Methocel(®) E15) and a film-forming polymer (Eudragit(®) RL 100 and Eudragit(®) RS 100), on the physicochemical and functional properties of a transdermal film formulation was assessed. Several terpenes were initially evaluated for their drug permeation enhancement effects on the transdermal film formulations. D-Limonene was found to be the most efficient permeation enhancer among the tested terpenes. Transdermal film formulations containing granisetron (GRN) as a model drug, D-limonene as a permeation enhancer, and different ratios of a hydrophilic polymer (Methocel(®) E15) and a film-forming polymer (Eudragit(®) RL 100 or Eudragit(®) RS 100) were prepared. The prepared films were evaluated for their physicochemical properties such as weight variation, thickness, tensile strength, folding endurance, elongation (%), flatness, moisture content, moisture uptake, and the drug content uniformity. The films were also evaluated for the in vitro drug release and ex vivo drug permeation. The increasing ratios of Methocel(®):Eudragit(®) polymers in the formulation linearly and significantly increased the moisture content, moisture uptake, water vapor transmission rate (WVTR), and the transdermal flux of GRN from the film formulations. Increasing levels of Methocel(®) in the formulations also increased the rate and extent of the GRN release and the GRN permeation from the prepared films.

Pharmaceutical excipients are essential components of most modern dosage forms. Although defined as pharmacologically inert, excipients can be thought of as the true enablers of drug product performance. Unintentional variability in the properties of the excipients may be unavoidable, albeit minimizable. The variability may originate from the source, the excipient-manufacturing process, or during the manufacturing of dosage forms. Excipient variability may have a range of influences on their functionality and performance in the dosage form. A better understanding of these influences on the critical quality attributes of the final product is of prime importance. Modern analytical tools provide a significant assistance in characterizing excipient variability to achieve this understanding. The principles and concepts of Quality-by-Design, process analytical technology, and design space, provide a holistic risk-based approach toward manufacture and application of excipients in pharmaceutical formulations. The International Pharmaceutical Excipients Council (IPEC) has developed guidelines for proper selection, use, and evaluation of excipients in pharmaceutical products.

Purpose: The feasibility of preparing an eslicarbazepine acetate suspension using Aptiom tablets for administration via enteral feeding tubes was evaluated. Methods: Eslicarbazepine acetate suspension (40 mg/mL) was prepared using Aptiom tablets after optimizing the tablet crushing methods and the vehicle composition. A stability-indicating high-performance liquid chromatography (HPLC) method was developed to monitor the eslicarbazepine stability in the prepared suspension. Three enteric feeding tubes of various composition and dimensions were evaluated for the delivery of the suspensions. The suspension was evaluated for the physical and chemical stability for 48 hours. Results: The reproducibility and consistency of particle size reduction was found to be best with standard mortar/pestle. The viscosity analysis and physical stability studies showed that ORA-Plus:water (50:50 v/v) was optimal for suspending ability and flowability of suspension through the tubes. The developed HPLC method was found to be stability indicating and suitable for the assay of eslicarbazepine acetate in the prepared suspension. The eslicarbazepine concentrations in separately prepared suspensions were within acceptable range (±3%), indicating accuracy and reproducibility of the procedure. The eslicarbazepine concentrations in suspensions before and after delivery through the enteric feeding tubes were within acceptable range (±4%), indicating absence of any physical/chemical interactions of eslicarbazepine with the tubes and a successful delivery of eslicarbazepine dosage via enteric feeding tubes. The stability study results showed that eslicarbazepine concentration in the suspension remained unchanged when stored at room temperature for 48 hours. Conclusion: The study presents a convenient procedure for the preparation of a stable suspension of eslicarbazepine acetate (40 mg/mL) using Aptiom tablets, for administration via enteral feeding tubes.

Currently, the compressed tablet and its oral administration is the most popular drug delivery modality in medicine. The accurate porosity and tensile strength characterization of a tablet design is vital for predicting its performance such as disintegration, dissolution, and drug-release efficiency upon administration as well as ensuring its mechanical integrity. In current work, a non-destructive contact ultrasonic approach and an associated testing procedure are presented and employed to quantify and relate the acoustically extracted mechanical properties of pharmaceutical compacts to direct porosity and tensile strength measurements. Based on a comprehensive set of experimental data, it is demonstrated how strongly the acoustic wave propagation is modulated and correlated to the tablet porosity and tensile strength of a compact made using spray-dried lactose and microcrystalline cellulose with varying mixture ratios. The effect of mixing ratio on the porosity and tensile strength on the resulting compacts is quantified and, with the acoustic experimental data, mixing ratio is related to the compact ultrasonic characteristics. The ultrasonic techniques provide a rapid, non-destructive means for evaluating compacts in formulation development and manufacturing. The presented approach and data could find critical applications in continuous tablet manufacturing, its real-time quality monitoring, as well as minimizing batch-to-batch quality variations.

Despite a well-established manufacturing-process understanding, tablet quality issues are frequently encountered during various stages of drug-product development. Compact breaking force (tensile strength), capping and friability are among the commonly observed characteristics that determine the integrity, quality and manufacturability of tablets. In current study, a design space of the compaction pressure, compaction speed and head flat types is introduced for solid dosage compacts prepared from pure silicified microcrystalline cellulose, a popular tableting excipient. In the reported experiments, five types of head flat types at six compaction pressure levels and two compaction speeds were employed and their effects on compact mechanical properties evaluated. The mechanical properties of the tablets were obtained non-destructively. It is demonstrated these properties correlate well with compact porosity and tensile strength, thus their availability is of practical value. The reported mechanical properties are observed to be linearly sensitive to the tableting speed and compaction pressure, and their dependency on the head-flat profile, while clearly visible in the presented waveforms, was found to be nonlinear in the range of the parameter space. In this study, we detail a non-destructive, easy-to-use approach for characterizing the porosity and tensile strength of pharmaceutical tablets.

The Biopharmaceutics Classification System (BCS) classifies pharmaceutical compounds based on their aqueous solubility and intestinal permeability. The BCS Class III compounds are hydrophilic molecules (high aqueous solubility) with low permeability across the biological membranes. While these compounds are pharmacologically effective, poor absorption due to low permeability becomes the rate-limiting step in achieving adequate bioavailability. Several approaches have been explored and utilized for improving the permeability profiles of these compounds. The approaches include traditional methods such as prodrugs, permeation enhancers, ion-pairing, etc., as well as relatively modern approaches such as nanoencapsulation and nanosizing. The most recent approaches include a combination/hybridization of one or more traditional approaches to improve drug permeability. While some of these approaches have been extremely successful, i.e. drug products utilizing the approach have progressed through the USFDA approval for marketing; others require further investigation to be applicable. This article discusses the commonly studied approaches for improving the permeability of BCS Class III compounds.

The predictability of multivariate calibration models, calculated with offline near-infrared spectroscopy (NIRS), assessing impact of magnesium stearate (MgSt) fraction, blending time, and compression force on the tablet breaking force (TBF) of SPRESS

In an attempt to improve the solubility and permeability of Standardized Bacopa Extract (SBE), a complexation approach based on phospholipid was employed. A solvent evaporation method was used to prepare the SBE-phospholipid complex (Bacopa Naturosome, BN). The formulation and process variables were optimized using a central-composite design. The formation of BN was confirmed by photomicroscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Powder X-ray Diffraction (PXRD). The saturation solubility, the in-vitro dissolution, and the ex-vivo permeability studies were used for the functional evaluation of the prepared complex. BN exhibited a significantly higher aqueous solubility compared to the pure SBE (20-fold), or the physical mixture of SBE and the phospholipid (13-fold). Similarly, the in-vitro dissolution revealed a significantly higher efficiency of the prepared complex (BN) in releasing the SBE (>97%) in comparison to the pure SCE (~42%), or the physical mixture (~47%). The ex-vivo permeation studies showed that the prepared BN significantly improved the permeation of SBE (>90%), compared to the pure SBE (~21%), or the physical mixture (~24%). Drug-phospholipid complexation may thus be a promising strategy for solubility enhancement of bioactive phytoconstituents.

This chapter aims to provide the readers a systematic overview of the pharmacokinetics and pharmacodynamics of the drugs intended for ophthalmic use. The concepts of ocular pharmacokinetics and pharmacodynamics are briefly discussed in the introduction. The chapter begins with a discussion on the common anatomical and physiological factors such as blood–ocular and tear fluid–corneal barriers, as well as anterior segment drug loss; and the challenges these factor pose in describing ocular pharmacokinetics and pharmacodynamics. The biopharmaceutics of the ocular drugs describes common pathways of ocular drug absorption. Further, commonly employed routes of administration for ocular drugs are discussed with respect to the choice of the route, properties of the drug, the nature of the ocular disease, the targeted ocular tissue, and the pharmacokinetic behavior of the drugs administered through the route. The pharmacokinetic–pharmacodynamic models that describe the fate of ocular drugs are further reviewed. Finally, recent advances and current trends in understanding of the pharmacokinetics/pharmacodynamics of ocular drugs are discussed based on the reported findings of the scientific and medical community.

This chapter aims to provide the readers a comprehensive review of the current trends and approaches used in the development of ocular drug delivery systems. After the introduction to the topic, the chapter begins with a brief description of the common anatomical and physiological factors that are barriers to ocular drug transport and presents a persistent challenge to the development of formulations targeted to ophthalmic tissues. Further, traditional as well as relatively newer approaches used in the development of ocular formulations are discussed. Approaches such as viscosity modifiers, penetration enhancers, liposomal delivery, niosomes, microemulsions, prodrugs, and nanotechnology-derived approaches are extensively reviewed. These approaches are described with respect to the materials, formulation development, formulation performance, relative advantages and drawbacks, and recent advances in the technology. Additionally, the design approaches for the modified ocular drug delivery such as ocular implants, inserts, lenses, and ocular shields are described with respect to the formulation development. Finally, ocular drug delivery systems that are relatively newer or employed less frequently such as intravitreal injections, ocular iontophoresis, etc. are discussed. All approaches described are supported with relevant examples and up-to-date literature reports.

Topical anti-inflammatory activity of Dalbergia lanceolaria Linn. bark ethanol extract was demonstrated in albino mice using TPA-, EPP- and AA-induced ear edema models. The systemic activity of extract was confirmed using acute and sub-acute anti-inflammatory models in albino rats. The ethanol extract exhibited significant systemic anti-inflammatory activity in Carrageenan-induced rat paw edema, by inhibition of histamine and prostaglandin phases of acute inflammation. The extract also showed significant activity against turpentine-induced exudative changes and no activity against granular tissue formation in cotton pellet-induced granuloma in albino rats. Thus, resultant anti-inflammatory activity might be due to effects on several mediators involving cyclo-oxygenase pathway resulting in prostaglandin formation and leukocyte migration from the vessels.

The effects of PURE-DENT® and SPRESS® starch properties on their compression behavior was characterized using "SM(2) " approach (structural properties, macroscopic properties, and multivariate analysis). Moisture sorption rate constants, moisture content, amylose and amylopectin degradation enthalpy, percent crystallinity, amylose-amylopectin ratio, and cross-linking degree were used to profile starch structural properties. Particle density, particle size distribution, and Heckel compression descriptors [yield pressure (YP) of plastic deformation, and elastic recovery] were used as macroscopic descriptors. The structural and macroscopic properties were correlated qualitatively [principal component analysis (PCA)] and quantitatively [standard least square regression (SLSR)] with the tablet mechanical strength (TMS). These analyses revealed that the differences correlated with amylose-amylopectin content, particle density, compression mechanisms, and TMS between the starch grades. Univariate analysis proved lacking; however, PCA identified the particle size, moisture content, percent crystallinity, amylose-amylopectin ratio, and YP of plastic deformation and elastic recovery as the main factors influencing the starch TMS. SLSR quantified the positive influence of Fourier transform infrared spectra absorbance ratio at 1022-1003 and YP of the immediate elastic recovery, and the negative contribution of amylopectin content on the TMS. Therefore, starch amylose and amylopectin content, crystallinity, and lower elastic recovery are mainly responsible for better TMS.

Amorphous drug-polymer systems or amorphous solid dispersions are commonly used in pharmaceutical industry to enhance the solubility of compounds with poor aqueous solubility. The degree of miscibility between drug and polymer is important both for solubility enhancement as well as for the formation of a physically stable amorphous system. Calculation of solubility parameters, Computational data mining, Tg measurements by DSC and Raman mapping are established traditional methods used to qualitatively detect the drug-polymer miscibility. Calculation of Flory-Huggins interaction parameter, computational analysis of X-Ray Diffraction (XRD) data, solid state Nuclear Magnetic Resonance (NMR) spectroscopy and Atomic Forced Microscopy (AFM) have been recently developed to quantitatively determine the miscibility in amorphous drug-polymer systems. This brief review introduces and compiles these qualitative and quantitative methods employed in the evaluation of drug-polymer miscibility. Combination of these techniques can provide deeper insights into the true miscibility of the drug-polymer systems.

The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a fixed roll-gap of 1.5 mm, feed screw speed to roller speed ratio of 5:1 and roll pressure of 4 MPa. The granules, after removing fines, were compacted into tablets on a Stokes B2 rotary tablet press at a compression force of 7 kN. The tablets were thermally treated at different temperatures (Room Temperature, 50, 75 and 100 °C) for 5 h. These tablets were scanned in reflectance mode in the wavelength range of 400-2500 nm and were evaluated for breaking force. Tablet breaking force significantly increased with increasing plasticizer levels and with increases in the sintering temperature. An increase in tablet hardness produced an upward shift (increase in absorbance) in the NIR spectra. The principle component analysis (PCA) of the spectra was able to distinguish samples with different plasticizer levels and sintering temperatures. In addition, a 9-factor partial least squares (PLS) regression model for tablets containing Eudragit® RL PO had an r(2) of 0.9797, a standard error of calibration of 0.6255 and a standard error of cross validation (SECV) of 0.7594. Similar analysis of tablets containing Eudragit® RS PO showed an r(2) of 0.9831, a standard error of calibration of 0.9711 and an SECV of 1.192.

The rapid and continuous progress of medical and pharmaceutical sciences has resulted in the availability of modern medicines that can efficiently prevent, control and/or manage disease states. Despite a plethora of benefits, adverse reactions to medicines are not uncommon and are associated with most newly developed drugs. The adverse effects range from milder side-effects to severe hypersensitivities and often result in new illness, disabilities and death. Adverse drug reactions of medicines have increased in prevalence over the years; and in many countries they rank among the major causes of mortalities. It is thus imperative to have a well-organized system to continuously monitor and assess the safety of medicines. Pharmacovigilance is such a system. The concept of pharmacovigilance is not new and its origins date back over 50 years. The thalidomide tragedy of 1961 drew attention to the importance of the assessment of the adverse effects of drugs. Between 1965 and 1970, after several meetings and resolutions, the International Drug Monitoring Program was formed by the World Health Assembly. Pharmacovigilance is defined by the World Health Organization (WHO) as “the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other possible drug-related problems”.

Ammonio methacrylate copolymers Eudragit(®) RS PO and Eudragit® RL PO have found widespread use as key components in various types of extended release solid dosage forms. The deformation behavior of neat polymers and binary mixes was evaluated using Heckel Analysis, strain rate sensitivity, work of compaction and elastic recovery index. Additionally, the compact forming ability of neat materials and binary mixes were evaluated by analyzing their tabletability, compressibility and compactibility profiles. The Heckel analysis of both polymers exhibited a speed-sensitive deformation behavior typical to plastic materials. The yield values of the binary mixes of the polymers with microcrystalline cellulose revealed a linear relationship with the weight fractions of individual components. The yield values of binary mixes of both the polymers with dibasic calcium phosphate exhibited slight negative deviations from linearity. Both polymers exhibited axial relaxation after ejection typical of viscoelastic materials, as measured by the elastic recovery index values. The work of compaction and the elastic recovery index values of the binary mixtures were found to be linearly related to the weight fractions of the individual components thus, confirming ideal mixing behavior based on the composition. Addition of microcrystalline cellulose to both polymers significantly improved their tabletability and compactibility. The tensile strengths of the compacts prepared with neat materials and binary mixes with microcrystalline cellulose, dibasic calcium phosphate and lactose were the function of their solid fraction and independent of the tableting speeds tested; thus, validating compactibility as a reliable parameter in predicting acceptable tablet properties.

The influence of plasticizer level, roll pressure and sintering temperature was investigated on the granule properties, tablet breaking force and theophylline release from tablets. Nine formulations using theophylline as a model drug, Eudragit(®) RL PO, Eudragit(®) RS PO, or both as a matrix former and triethyl citrate (TEC) as a plasticizer were prepared. The formulations were roller compacted and the granules obtained were evaluated for particle size distribution and flowability. These granules were compacted into tablets at a compression force of 7 kN. The tablets were thermally treated at different temperatures (50 and 75°C) for 5 h and were evaluated for breaking force and dissolution. Increase in roll pressure and TEC levels resulted in a progressive increase in the mean particle size of the granules. The flowability of the granules also improved with increasing roll pressures and TEC levels. Tablet breaking force increased with an increase in TEC levels and sintering temperatures. But these effects were significant only at the highest level of plasticizer and sintering temperature respectively. For the tablets containing Eudragit(®) RS PO, theophylline release decreased proportionately with increase in TEC levels and sintering temperatures. Tablets containing either Eudragit(®) RL PO or a mixture of RS PO and RL PO failed to impart an extended-release property to the tablets at the studied variables i.e. roll pressure, TEC levels and sintering temperature. It was clearly demonstrated that with suitable optimization of these parameters, the release-rate of a water soluble drug from the matrix tablets prepared via roller compaction can be finely controlled.

The purpose of this study was to assess the porosity variation of roller compacted ribbons made using different process parameters; in addition, the feasibility of using near-infrared chemical imaging (NIR-CI) to evaluate porosity variations was examined. Ribbons of neat microcrystalline cellulose were compacted using a range of roll pressures (RP), roll speeds (RS) and feed screw speeds (FSS). The ribbon porosity decreased as RP increased with the exception of ribbons produced by the combination of high RS and low FSS where increasing RP increases the porosity of the ribbons. Lower RS was found to produce ribbons with lower porosity and the porosity increases as the RS increased. Increased FSS will decrease ribbon porosity at higher RS while it slightly increase the ribbon porosity at lower RS. A simple linear regression model showed NIR-CI was able to predict the ribbon porosity with a correlation of 0.9258. NIR-CI is able to characterize differences in porosity as a function of position on the ribbon where regions with lower porosity show higher absorbance. Nevertheless, NIR-CI is able to show sinusoidal variation in intensities along the roller compacted ribbon among all settings studied.

The current work describes the formulation and evaluation of a phospholipid complex of kaempferol to enhance the latter’s aqueous solubility, in vitro dissolution rate, in vivo antioxidant and hepatoprotective activities, and oral bioavailability. The kaempferol-phospholipid complex was synthesized using a freeze-drying method with the formulation being optimized using a full factorial design (32) approach. Our results include the validation of the mathematical model in order to ascertain the role of specific formulation and process variables that contribute favorably to the formulation’s development. The final product was characterized and confirmed by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), and Powder X-ray Diffraction (PXRD) analysis. The aqueous solubility and the in vitro dissolution rate were enhanced compared to that of pure kaempferol. The in vivo antioxidant properties of the kaempferol-phospholipid complex were evaluated by measuring its impact on carbon tetrachloride (CCl4)-intoxicated rats. The optimized phospholipid complex improved the liver function test parameters to a significant level by restoration of all elevated liver marker enzymes in CCl4-intoxicated rats. The complex also enhanced the in vivo antioxidant potential by increasing levels of GSH (reduced glutathione), SOD (superoxide dismutase), catalase and decreasing lipid peroxidation, compared to that of pure kaempferol. The final optimized phospholipid complex also demonstrated a significant improvement in oral bioavailability demonstrated by improvements to key pharmacokinetic parameters, compared to that of pure kaempferol.

The objective of the work presented here was to assess the feasibility of using glucosamine HCl as a solid-dispersion (SD) carrier to enhance the biopharmaceutical properties of a BCS class III/IV drug, acyclovir (ACV). The solid-dispersions of acyclovir and glucosamine HCl were prepared by an ethanol-based solvent evaporation method. The prepared formulations characterized by photomicroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectrophotometry (FTIR), powder x-ray diffractometry (PXRD) and drug content analysis. The functional characterization of ACV-SD was performed by aqueous solubility evaluation, dissolution studies, fasted versus fed state dissolution comparison, ex vivo permeability, and stability studies. Photomicroscopy and SEM analysis showed different surface morphologies for pure ACV, glucosamine HCl and ACV-SD. The physical-chemical characterization studies supported the formation of ACV-SD. A 12-fold enhancement in the aqueous solubility of ACV was observed in the prepared solid dispersions, compared to pure ACV. Results from in vitro dissolution demonstrated a significant increase in the rate and extent of ACV dissolution from the prepared ACV-SD formulations, compared to pure ACV. The rate and extent of ACV permeability across everted rat intestinal membrane were also found to be significantly increased in the ACV-SD formulations. Under fed conditions, the rate and extent of the in vitro dissolution of ACV from the formulation was appreciably greater compared to fasted conditions. Overall, the results from the study suggest the feasibility of utilizing glucosamine HCl as a solid dispersion carrier/excipient for enhancement of biopharmaceutical properties of acyclovir, and similar drugs with low solubility/permeability characteristics.