Computational and Experimental Screening Approaches to Aripiprazole Salt Crystallization

INTRODUCTION

The screening of multicomponent crystal system (MCC) is a key method for improving physicochemical properties of active pharmaceutical ingredients (APIs). The challenges associated with experimental salt screening include a large number of potential counterions and solvent systems and tendency to undergo disproportionation to produce free form during crystallization. These challenges may be mitigated by a combination of experimental and computational approaches to salt screening. The goal of this study is to evaluate performance of the counterion screening methods and propose and validate novel approaches to virtual solvent screening for MCC crystallization.

METHODS

The actual performance of the ΔpKa > 3 rule for counterion selection was validated using multiple screenings reports. Novel computational models for virtual solvent screening to avoid MCC incongruent crystallization were proposed. Using the ΔpKa rule, 10 acid counterions were selected for experimental aripiprazole (APZ) salt screening using 10 organic solvents. The experimental results were used to validate the proposed novel virtual solvent screen models.

RESULTS

Experimental APZ salt screening resulted in a total of eight MCCs which included glucuronate, mesylate, oxalate, tartrate, salicylate and mandelate. The new model to virtually screen solvents provided a general agreement with APZ experimental findings in terms of selecting the optimal solvent for MCC crystallization.

CONCLUSION

The rational selection of counterions and organic solvents for MCC crystallization was presented using combined novel computational model as well as experimental studies. The current virtual solvent screen model was successfully implemented and validated which can be easily applied to newly discovered APIs.

Absolute Configuration Determination of Chiral API Molecules by MicroED Analysis of Cocrystal Powders Formed Based on Cocrystal Propensity Prediction Calculations

Establishing the absolute configuration of chiral active pharmaceutical ingredients (APIs) is of great importance. Single crystal X-ray diffraction (scXRD) has traditionally been the method of choice for such analysis, but scXRD requires the growth of large crystals, which can be challenging. Here, we present a method for determining absolute configuration that does not rely on the growth of large crystals. By examining microcrystals formed with chiral probes (small chiral compounds such as amino acids), absolute configuration can be unambiguously determined by microcrystal electron diffraction (MicroED). Our streamlined method employs three steps: (1) virtual screening to identify promising chiral probes, (2) experimental cocrystal screening and (3) structure determination by MicroED and absolute configuration assignment. We successfully applied this method to analyze two chiral API molecules currently on the market for which scXRD was not used to determine absolute configuration.

Functional outcome of conversion total hip arthroplasty (CTHA) using uncemented distally loading femoral stem for failed fixation of proximal femoral nail - A case series

Introduction and aims

There is paucity of prospective studies on conversion total hip arthroplasty (CTHA) for failed proximal femoral nailing. The objective of this study is to evaluate the functional outcome of CTHA using extensively porous coated distal loading stem for failed proximal femoral nailing.

Patients and methods

Fifteen consecutively operated patients for failed proximal femoral nail treated with single stage procedure of nail extraction and CTHA were included in this prospective observational study. All patients received metal-on-polyethylene bearing with uncemented press-fit acetabular cup (Pinnacle cup; DePuy, Warsaw [IN], USA) and extensively porous coated distally loading revision stem (Solution stem; DePuy, Warsaw [IN], USA). All patients were assessed preoperatively and postoperatively at one, three, six and more than twelve months using the Harris Hip Score (HHS). The responsiveness of HHS was assessed using Effect Size (ES) and Standardised Response Mean (SRM). ES and SRM >0.8 indicates adequate responsiveness.

Results

The mean duration of follow-up was 16.9 months for the overall cohort (SD: 7.9; range: 6-28 months). The mean preoperative HHS was 32 ± 6.1, the mean HHS at six months follow-up was 89.7 ± 4.0 and the mean HHS at final follow-up of atleast one year was 93.7 ± 3.0. There was a statistically and clinically significant improvement in the HHS from preoperatively to final follow-up postoperatively (p < 0.0001). At the final follow-up, twelve patients (80%) had an excellent outcome and three patients (20%) had a good outcome as per HHS grading. The ES was 9.87 and the SRM was 8.86 thereby suggesting adequate responsiveness. One patient developed surgical site infection and another patient developed dislocation. Both were successfully treated and subsequently the patients made uneventful recovery. None of the patients required revision surgery.

Conclusion

HHS has adequate responsiveness for assessing the functional outcome of CTHA. We recommend the use of an uncemented cup and uncemented extensively porous coated, distal loading stem for failed PFN fixation in intertrochanteric hip fractures.

Process Modelling, Scale-Up and Characterization of Acetaminophen Spray Dried Milk Powder as Novel Pediatric Dosage Form

PURPOSE

Successful drug therapy in children is contingent upon hassle-free administration of pediatric dosage forms. Pediatric patients suffer from difficulty in swallowing due to weak esophagus muscles in their early age. Considering this challenge liquid formulations are preferred over solid dosage form among pediatric patients to avoid the possibility of choking which can be a serious life-threatening condition in children. The main aim of the present research work was to develop a reconstitutable amorphous acetaminophen spray-dried milk powder (ASDM) as novel pediatric formulation.

METHODS

ASDM was prepared by spray drying process and the spray drying process was optimized using Box-Behnken design to study the effect of spray drying process parameters at X₁ [inlet temperature], X₂ [aspiration rate] and X₃ [feed rate] to Y₁ [% yield], Y₂ [angle of repose], Y₃ [Hausner's Ratio] and Y₄ [Carr's Index] as dependent variables of ASDM. In addition, each batch was characterized for particle size by polarized light microscopy and drug entrapment.

RESULTS

Predicted parameters from optimized spray drying process model were successfully employed to manufacture a scale up cum validation batch of ASDM, which showed notably improved yield and desirable flow properties. The scale-up validation batch was further characterized using thermal analysis, diffraction studies, spectroscopic analysis, dispersion studies, stability APAP in dispersion formulation and formulation stability studies to confirm the physico-chemical stability of ASDM.

CONCLUSIONS

Thus, ASDM for oral use can serve as a promising pediatric formulation and the developed prototype formulation can be further extended to future newly discovered drugs with similar characteristics.

Bayesian statistical approaches to drug product variability assessment and release

The determination of the variability of critical dosage form attributes has been a challenge in establishing the quality of pharmaceutical products. During the development process knowledge is minimal. Consequently, ad hoc statistical tools such as hypothesis or significance tests, with calibrated decision error rates are often used in an effort to vet CQAs (Critical Quality Attributes) and keep their levels "between the curbs". As progress moves towards product launch, process and mechanistic understanding grows considerably and there are opportunities to leverage that knowledge for predictive modeling. Bayesian models offer a coherent strategy for integrating prior knowledge into both experimental design as well as predictive analysis for optimal risk-based decision making. This is because the Bayesian paradigm, unlike the frequentist paradigm, can assign probabilities to underlying states of nature that directly impact safety and efficacy such as the population distribution of tablet potencies or dissolution profiles in a batch. However, there are challenges and reluctance in switching to a predictive modeling quality framework once regulatory approval has been attained. This paper offers encouragement to make this switch. In this paper, we review a joint Long Island University - Purdue University (LIU-PU) FDA funded project whose purpose was to further integrate the concepts of this adaptive approach to lot release with the rationale and methods for data generation and curation and to extend the testing of this approach. We discuss the utility of the approach in product development. We consider the regulatory compliance implications, with examples, and establish a potential way forward toward implementation of this approach for both industry and regulatory stake-holders.

Modeling of Adhesion in Tablet Compression at the Molecular Level Using Thermal Analysis and Molecular Simulations

The molecular basis of adhesion leading to sticking was investigated by exploring the correlation between thermal analysis and molecular simulations. It is hypothesized that intermolecular interactions between a drug molecule and a punch face are the first step in the adhesion process and the rank order of adhesion during tablet compression should correspond to the rank order of the energies of these interactions. In the present study, the sticking propensity was investigated using ibuprofen, flurbiprofen, and ketoprofen as model substances. At the intermolecular level, a thermal analysis model was proposed as an experimental technique to estimate the work of adhesion between ibuprofen, flurbiprofen, and ketoprofen in a DSC aluminum pan. The linear relationship was established between the enthalpy of vaporization and sample mass to demonstrate the accuracy of the instruments used. The threshold mass for ibuprofen, flurbiprofen, and ketoprofen was determined to be 107, 112, and 222 μg, respectively, after three replicate measurements consistent with the experimental results. Ketoprofen showed a 2-fold higher threshold mass compared to ibuprofen and flurbiprofen, which predicts that ketoprofen should have the highest sticking propensity. Computationally, the rank order of the work of adhesion between ibuprofen, flurbiprofen, and ketoprofen with the metal surface was simulated to be -75.91, 44.75, and -96.91 kcal/mol, respectively, using Materials Studio. The rank order of the interaction between the drug molecule and the iron superlattice decreases in the order ketoprofen > ibuprofen > flurbiprofen. The results indicate that the thermal model can be successfully implemented to assess the sticking propensity of a drug at the molecular level. Also, a new molecular simulation script was successfully applied to determine the interaction energy of the drug molecule upon contact with iron.

Gamma oryzanol niosomal gel for skin cancer: formulation and optimization using quality by design (QbD) approach

Skin cancer is fifth most diagnosed disease in human population due to ultraviolet radiation (UV) exposure. Gamma oryzanol (OZ) is a natural antioxidant, and it also has skin anti-aging properties. OZ is naturally found in rice bran oil. The main aim of the present work was to optimize OZ niosomal formulation using quality by design approach including one variable at a time and full factorial design. Niosomes were prepared by solvent injection method and characterized for size, polydispersity index, drug entrapment, and transmission electron microscopy. The optimized batch obtained at X1 [drug to span 60 molar ratio (1:5)], X2 [volume of hydration (75 mL)], and X3 [stirring speed (2500 rpm)] to Y1 [average vesicle size (196.6 nm)] and Y2 [entrapment efficiency (78.31%)] as dependent variables. The optimized OZ noisomes were formulated by niosomal gel to provide improved physicochemical stability upon topical application against UV. The niosomal gel was characterized using pH meter, viscometer, Draize test for skin irritancy, ex vivo permeation studies, and stability studies. Ex vivo permeation studies of OZ niosomal gel not only showed fourfold higher permeation but also exhibited better drug retention in dermal layers of skin as compared to OZ gel. Quality Target Product Profile of OZ niosomal formulation was generated. Risk analysis of optimized OZ gel suggested most critical quality attributes (CQAs) and critical process parameters (CPPs) to be characterized as low risk. Thus, γ-oryzanol niosomal gel for topical use can serve as a promising prophylactic treatment in skin cancer, and the developed prototype formulation can be further extended to future newly discovered drugs with similar characteristics.

Graphical abstract

Predictive Performance Comparison of Computed Linear and Quadratic Multivariate Models for In-Situ UV Fiber Optics Tablet Dissolution Testing

A present investigation aimed for multivariate modeling as a solution to resolve inaccuracy in dissolution testing experienced in the use of in-situ UV fiber optics dissolution systems (FODS) due to signal saturation problems. This problem is specifically encountered with high absorbance of moderate to high dose formulations. A high absorbance not only impede a real-time assessment but can also result in inaccurate dissolution profiles. Full spectra (F) and low absorbance regions (L) were employed to develop linear and quadratic (Q) partial least squares (PLS) and principal component regression (PCR) models. The conventional dissolution of atenolol, ibuprofen, and metformin HCl immediate-release (IR) tablets followed by HPLC analysis was used as a reference method to gauge multivariate models' performance in the 'built-in' Opt-Diss model. The linear multivariate modeling outputs resulted in accurate dissolution profiles, despite the potentially high UV signal saturation at later time points. Conversely, the 'built-in' Opt-Diss model and multivariate quadratic models failed to predict dissolution profiles accurately. The current studies show a good agreement in the predictions across both low absorbance region and full spectra, demonstrating the multivariate models' robust predictability. Overall, linear PLS and PCR models showed statistically similar results, which demonstrated their applicative flexibility for using FODS despite signal saturation and provides a unique alternative to traditional and labor-intensive UV or HPLC dissolution testing.

Molecular Insights into Warfarin Sodium 2-Propanol Solvate Solid Form Changes and Disproportionation Using a Low Volume Two-Stage Dissolution Approach

The current research work focuses on understanding the reported discrepancies and our observations in the dissolution profiles of warfarin sodium tablets and potential patient-based failure modes during oral warfarin therapy. It was hypothesized that freely soluble crystalline warfarin sodium (WAR_C) at first transforms into noncrystalline warfarin sodium (WAR_NC) under stress conditions. The WAR_C → WAR_NC conversion facilitates the rapid formation of the poorly soluble unionized form, which could lead to dissolution failures and potential poor in vivo performance. Depressed warfarin concentrations locally in the gastrointestinal tract (GIT) may in turn lead to inadequate absorption and thereby affect bioavailability. A low volume two-stage dissolution method was developed to mimic in vivo GIT conditions. Warfarin sodium tablets exposed to room temperature and 75% relative humidity for 1 week showed approximately 23% decrease in drug release. The decline in drug release supports the hypothesis that WAR_NC is converted to the unionized form faster than WAR_C does under the same conditions. Solid state characterization (powder X-ray diffractometry and differential scanning calorimetry) data demonstrated the disproportionation of warfarin sodium to unionized warfarin after solubility and dissolution studies. The findings support the hypothesis and a possible failure mode of warfarin sodium tablets. This work is a second case study from our laboratory on narrow therapeutic index drug products in which the instability of the solid state of the drug substance is potentially responsible for observed clinical failures.

Protocol development, validation, and troubleshooting of in-situ fiber optic bathless dissolution system (FODS) for a pharmaceutical drug testing

Currently, there is no systematic approach available for the validation, quantitative assessment, and troubleshooting for the in-situ fiber optic/bathless dissolution system (FODS). In this report, a dissolution protocol was developed and validated for a model product, chlorpheniramine maleate (CPM) 4 mg IR tablets. Dissolution runs were conducted at 37 ± 0.2 °C using a USP apparatus II, at 50 rpm in 500 mL of 0.01 N hydrochloric acid. The dissolution system was validated for linearity, accuracy, precision, specificity, and robustness analogously to an HPLC method validation. The linearity determination method was developed using five concentration levels between 25-125 % of the expected concentration, while for accuracy, 80 %, 100 %, and 120 % levels were used, and precision was determined using six runs at the 100 % level. Probe sampling depth, orientation, analytical wavelength, and paddle speed were varied to evaluate the robustness of the system tested. Method equivalence was established by comparing the dissolution results from FODS and the traditional dissolution method using UV spectrophotometry. Based on the statistics generated using the dissolution tests, the results are linear, accurate, precise, and specific. Robustness testing demonstrates that small changes in operating conditions did not significantly change the result. No significant difference in the amount dissolved at Q-timepoint was observed between FODS and traditional testing. Therefore, the FODS is a suitable alternative to traditional dissolution for CPM immediate-release tablets (many other drug products have been tested in the laboratory, and reports are in preparation). Additionally, the current work discusses problems related to media preparation, probe sensitivity, and excipient effects on data collected using FODS. The instrument-specific artifacts and data analysis problems are addressed and troubleshooting with possible solutions to eliminate or mitigate the errors. Although the FODS method was developed and evaluated using CPM in 500 mL dissolution volume, the dissolution method using a more common pharmacopoeial dissolution volume, i.e., 900 mL, was used to demonstrate the troubleshooting experiments for the drug products requiring 900 mL dissolution media.

Similarity of dissolution profiles from biorelevant media: Assessment of interday repeatability, interanalyst repeatability, and interlaboratory reproducibility using ibuprofen and ketoconazole tablets

Biorelevant media are increasingly being employed as dissolution media in drug development, including in smaller volumes than 900ml and under non-sink conditions. The objectives were to assess interday repeatability, interanalyst repeatability, and interlaboratory reproducibility of dissolution profiles from biorelevant media, as well as to assess the impacts of biorelevant media production method and biorelevant medium volume on dissolution profiles. Ibuprofen and ketoconazole tablets were subjected to dissolution testing in 500ml, 300ml, and 40ml of fasted state simulated gastric fluid (FaSSGF), fed state simulated gastric fluid (FeSSGF), fasted state simulated intestinal fluid version 2 (FaSSIF-V2), and fed state simulated intestinal fluid version 2 (FeSSIF-V2). f₂ was used to assess repeatability and reproducibility of dissolution profiles. Results indicate favorable interday repeatability (83 of 88 comparisons were similar), favorable interanalyst repeatability (19 of 21 comparisons were similar), and favorable interlaboratory reproducibility (10 of 14 comparisons were similar) of dissolution profiles from biorelevant media, with commercial media showing greater interlaboratory reproducibility than 'from scratch' media. However, biorelevant medium production had low impact on profiles when one analyst conducted all medium preparations and study procedures at one location. Additionally, biorelevant media detected differences when products were not similar. Overall, biorelevant media showed favorable repeatability and reproducibility performance.

Development and Validation of Sample Preparation and an HPLC Analytical Method for Dissolution Testing in Fed-State Simulated Gastric Fluid-Illustrating Its Application for Ibuprofen and Ketoconazole Immediate Release Tablets

Dissolution testing and solubility determinations in different biorelevant media have gained considerable interest in the pharmaceutical industry from early-stage development of new products to forecasting bioequivalence. Among all biorelevant fluids, the preparation of fed-state simulated gastric fluid (FeSSGF) and handling of samples from dissolution/solubility testing in FeSSGF is considered to be relatively challenging. Challenges include maintaining the stability of FeSSGF medium upon sampling, filtration, and mitigating analytical interference of excipients and milk components. To overcome these challenges, standard and uniform working practices are required that are not only helpful in preparation of stable FeSSGF but also serve as a harmonizing guide for the collection of dissolution/solubility samples and their subsequent processing (i.e., handling and assay). The optimization of sample preparation methodology is crucial to reduce method-related variance by ensuring specificity, robustness, and reproducibility with acceptable recovery of the analytes. The sample preparation methodology includes a combination of techniques including filtration, solvent treatment, and centrifugation to remove the interfering media-related components and excipients from the analyte. The analytes of interest were chromatographically separated from the interfering analytes to quantify the drug concentration using the new high-performance liquid chromatography methods with ultraviolet detection. The methods developed allow rapid sample preparation, acceptable specificity, reproducible recoveries (greater than 95% of label claim), and quantification of study drugs (ibuprofen and ketoconazole). The sample preparation technique and method considerations provided here for ibuprofen and ketoconazole can serve as a starting point for solubility and dissolution testing of other small molecules in FeSSGF.

Contribution of Crystal Lattice Energy on the Dissolution Behavior of Eutectic Solid Dispersions

In the literature, it is reported that eutectics lead to the enhanced dissolution of a poorly soluble compound. However, the solubility theory suggests that since crystal structures of two components are unchanged that all else being equal, the dissolution rates of a fused mixture (FM) should be the same as a physical mixture (PM). The influence of crystal lattice energy on dissolution profiles was investigated using the PM and FM. Experimental phase diagrams constructed using differential scanning calorimetry data were compared with those theoretically derived. Deviation of the experimental phase diagram curves from the theoretical model indicates the nonideal behavior of both systems (ibuprofen/poly(ethylene glycol)-6000 and acetaminophen/caffeine). Both the binary systems showed an increase in the dissolution rate of the PM and FM. However, the dissolution from the PM was comparable with the FM's dissolution profile. The theoretical solubility calculations using the modified solubility equation showed that the use of the eutectic temperature instead of the drug's melting point should give a 3-4-fold increase in drug solubility. However, the correlation between dissolution and solubility calculation showed that the FM did not improve the dissolution when compared with the respective PM's dissolution profile. The proposed explanation is that the unchanged crystal lattice energy in eutectics still limits the solubility and therefore the dissolution rate.

A threefold superstructure of the anti-epileptic drug phenytoin sodium as a mixed methanol solvate hydrate

Phenytoin sodium, a salt of 5,5-diphenylimidazolidine-2,4-dione, or phenytoin, is commercially available in various dosage forms for its anti-epileptic properties to treat and prevent seizures. The title compound, poly[aquatris(μ₃-4,4-diphenyl-2,5-dioxoimidazolidin-1-ido)trimethanoltrisodium(I)], [Na₃(C₁₅H₁₁N₂O₂)₃(CH₄O)₃(H₂O)_1.08]_n, a methanol solvate and hydrate of phenytoin sodium, forms a modulated crystal structure that consists of a supercell made up of three close-to-identical repeat units. Each of the basic fragments consists of one phenytoin anion, a sodium cation, and either a methanol, or a methanol and a water molecule coordinated to the sodium ion, yielding a formula unit of Na(C₁₅H₁₁N₂O₂)(CH₃OH)_x(H₂O)_y for each of the three segments (x, y = 0 or 1; x + y = 1 or 2). Modulation along the b axis is introduced due to the presence or absence of water or methanol molecules at sodium and by the alternating torsion angles of one of the two phenytoin phenyl rings. Individual segments within the asymmetric unit are linked by covalent Na-O and Na-N bonds, with each sodium ion coordinated to one anionic amide N atom and three keto O atoms. The Na-N and one of the Na-O bonds connect (C₁₅H₁₁N₂O₂)·Na units along the modulation direction, creating an infinite [(C₁₅H₁₁N₂O₂)·Na]_n chain that is further stabilized by intramolecular N-H...O hydrogen bonding parallel to [010]. The second Na-O bond connects this chain with a symmetry-equivalent copy of itself created by a screw-axis operation, yielding double strands of [(C₁₅H₁₁N₂O₂)·Na]_n chains. Two of these double strands, propagating in opposite directions, constitute the content of the unit cell. Neighboring double strands are connected with each other to form layers perpendicular to the a axis, tethered together via O-H...O hydrogen bonds involving the water and methanol molecules. In addition to modulation, each of the repeat units also exhibits disorder of the modulated segments. Phenyl rings of each repeat unit are rotationally disordered, and sodium-coordinated methanol and water molecules are also positionally disordered and/or partially occupied. The solvated structure reported here, while not matching the patterns reported for any of the known forms of phenytoin sodium, does provide a first insight into the complications and complexities involved in resolving the structure of anhydrous phenytoin sodium.

Stability of Insulin Detemir Injection in Different Primary Packaging Systems at Room Temperature

PURPOSE

To assess the stability of insulin detemir at controlled room temperature (RT) at 25°C in different packaging systems over 7 days.

METHODS

The degradation characteristics of insulin detemir were determined based on the assay results in different packaging systems (pinhole glass vial, closed glass vial, glass syringe, and plastic syringe) at RT using a reverse-phase high-performance liquid chromatography (HPLC) assay method for insulin injection. Each packaging system was compared to insulin detemir stored in the original packaged closed glass vial at 2°C to 8°C.

RESULTS

Insulin detemir stored in a closed glass vial and a glass syringe showed minor degradation at the end of day 7 (98.96% ± 1.49% and 99.78% ± 0.10%, respectively). Insulin detemir stored in plastic syringe decreased to 94.90% ± 2.50% by day 3 and to 93.52% ± 0.29% by day 7. Storage in pin-hole glass vial showed an increase in the assay (152.13% ± 0.12%) by day 7.

CONCLUSION

Stability studies in different packaging systems demonstrated that insulin detemir remained stable for at least 7 days in a closed glass vial or glass syringe, but for only 3 days in a plastic syringe at RT. This study will allow pharmacists in the hospital setting to deliver patient-specific insulin doses into an insulin syringe with confidence in the stability.

New Insights on Solid-State Changes in the Levothyroxine Sodium Pentahydrate during Dehydration and its Relationship to Chemical Instability

Levothyroxine sodium pentahydrate (LEVO) tablets have been on the US market since the mid-twentieth century and remain the most highly prescribed product. Unfortunately, levothyroxine sodium tablets have also been one of the most highly recalled products due to potency and dissolution failures on stability. In 2008, the assay limits were tightened, yet the recalls did not decline, which highlights the serious quality concerns remaining to be elucidated. The aim of the present investigation was to test the hypothesis that the solid-state physical instability of LEVO precedes the chemical instability leading to product failure. The failure mode was hypothesized to be the dehydration of the crystal hydrate, when exposed to certain humidity and temperature conditions, followed by the oxidation of the API through vacated channels. It was previously reported by the authors that LEVO degradation occurred in the presence of oxygen at a low relative humidity (RH). Furthermore, powder X-ray diffractometry shows changes in the crystal lattice of LEVO initially and through the dehydration stages. Storage of LEVO at RT and 40 °C at 4-6% RH for 12 days shows a decrease in d-spacing of the (00 l) planes. Based on a structure solution from the powder data of the dehydrated material, the basic packing motif persists to varying degrees even when fully dehydrated along with disordering. Therefore, the crystal structure changes of LEVO depend on RH and temperature and are now explicable at the structural level for the first time. This exemplifies the dire need for "new prior knowledge" in generic product development.

Crystal anisotropy explains structure-mechanics impact on tableting performance of flufenamic acid polymorphs

Anisotropic features with other crystallographic properties like d-spacing, and attachment energy (E_att) can predict material performance during the secondary pharmaceutical processing. A newly developed state-of-the-art compression cell lodged in a powder X-ray diffractometer was used to measure anisotropic Young's moduli (YM) of flufenamic acid (FFA) polymorphs in this study. Methodology is based on the generation of a single crystal deformation in this cell, which reflects as a change in the d-spacing in the PXRD pattern. Anisotropic YM was calculated from such information gathered along different FFA planes. Measured FFA crystallographic molecular features were concatenated to understand macroscopic compaction (Heckel and Shapirao's parameters) and tableting performance. Block shaped crystals of FFA form I, and III after initial characterization with SEM, DSC, PXRD, and FTIR were compressed normal to X, Y, and Z-planes, identified from calculated PXRD pattern using the reported single crystal structure. YM of X and Y planes of form I was significantly higher than corresponding planes of form III. Z plane of form III showed significantly higher YM than that for form I. Low YM of form III can be attributed to its large d-spacing regardless of their high E_att than form I, as well as orientation of supramolecular acid dimer (OH⋯O) homosynthon chains in the FFA planes. FFA form I stiffness was further confirmed with lower densification and higher yield pressure of deformation than form III. Clearly, form III exhibited better compressibility, compactibility, and tableting performance than form I due to favorable molecular and macroscopic features. Thus, developed anisotropic measurement approach can be used to distinguish material performance in the early development stage of the pharmaceutical processes.

Trauma care systems in India

Trauma-care systems in India are at a nascent stage of development. Industrialised cities, rural towns and villages coexist, with almost complete lack of organised trauma care. There is gross disparity between trauma services available in various parts of the country. Rural India has inefficient services for trauma care, due to the varied topography, financial constraints and lack of appropriate health infrastructure. There is no national lead agency to co-ordinate various components of a trauma system. No mechanism for accreditation of trauma centres and professionals exists. Education in trauma life-support (TLS) skills has only recently become available. A nation-wide survey encompassing various facilities has demonstrated significant deficiencies in current trauma systems.Although injury is a major public-health problem, the Government of India has failed to recognise it as a priority. Significant efforts to develop trauma-care systems across the country are seen mainly in the private sector. New initiatives under National Health Policy 2002 are expected to result in improvement in the systems, but the allocation of funds remains grossly inadequate for any significant impact on the outcome.

The Antley-Bixler syndrome: two new cases

The Antley-Bixler syndrome is a rare multiple congenital anomaly with a high mortality rate. The characteristic manifestations include craniosynostosis, radiohumeral synostosis, midface hypoplasia, joint contractures and arachnodactyly. We report two new cases of this syndrome and address the diagnostic features, associated malformations, inheritance patterns, prenatal findings, and briefly review the literature.

Diffuse reflectance spectroscopy of particulate systems: a comparative study of discrete models

A comparative study of statistical particle model theory of diffuse reflectance has been made. Theories have been applied to six particulate samples having different optical characteristics and average particle sizes that vary from 42 to 106 mum. We made an overall assessment of each theoretical model by determining the CIELAB color difference using experimentally measured and theoretically predicted diffuse reflectance spectra in the visible spectral range. We discuss the performance ratings of the models of other researchers and discovered numerous typographical errors in Fresnel reflection coefficient expressions. We provide the correct versions for these expressions.

An evaluation of the role and practices of the acute-care nurse practitioner

The advanced practice, professional nurse in the acute-care setting with autonomy, prescriptive authority, and authority to coordinate care delivery is a role currently evolving. Evaluation data from a small number of individuals on a learning curve from students to novice practitioners were collected over a 2.5-year period. The results show that self-efficacy increases with clinical experience, whereas clinical reasoning and technical competency are challenging to beginning practitioners. Attention to consultative and educational role components should take low priority until these areas become comfortable to students and novice practitioners. Even early in their role development however, acute care nurse practitioners are regarded as highly valuable and contributory members of the patient management team.

Activities and interactions of baccalaureate nursing students in clinical practica

Basic nursing education is governed by individual state rules and regulations lacking in uniformity across the United States and based on unstated and perhaps mistaken assumptions. At the same time, there is increasing evidence of problems and difficulties with the current traditional model of nursing education. Before proposing changes in said model, the authors chose to examine what it is that a nursing student does in a clinical area. The perspective of activities and interactions was chosen to illustrate, through a nonparticipant observation study, the patterns and utilization of time during a scheduled clinical experience for baccalaureate nursing students. The goal of the study was to determine who, other than the client/patient, influences the student learning at the clinical site and how learning time is spent. Two schools (one private and one public) and nine clinical sites with 37 observations were used to collect the data for this study. Findings are best summarized in four (overlapping) categories of school time, registered nurse (RN) staff time, hospital staff time, and supervised time. School time, or time spent interacting with the instructor, another student, and/or the student on his/her own in the practice setting (time exclusive of staff input) constituted 84 per cent of all time. RN staff time that was time spent with either the primary nurse or other RNs on the unit used 10 per cent of the student time, Fourteen per cent of student time was spent in hospital staff time, which includes interactions with any nursing staff or other hospital personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

Rules and regulations governing nursing education

The purpose of this article is to report on a national survey of the 51 state boards of examiners in the United States that govern and regulate nursing education. Data were gathered from the written rules and regulations of each of the state agencies, and content analysis was performed focusing on the following categories: qualifications (State board members, program directors, faculty, and preceptors); roles and responsibilities (state board members, faculty, preceptors, and clinical agencies); and process and content of the nursing education curriculum and program. Findings of the study indicate specific problem areas in the regulating of basic nursing education programs. The following were among the major issues identified: (1) educational qualifications for board membership are virtually nonexistent, (2) in many situations different requirements exist for various types of programs, and (3) there is great disparity from state to state regarding both the content deemed as necessary in nursing education and in the mandated process of that education. The investigators noted that several patterns lend credence to a need for a national plan regarding the state regulation of basic nursing education.

Preparing acute care nurse practitioners at the University of Connecticut

To meet the pressing demands for enhanced quality of patient care in a time of shrinking resources, a cooperative effort between the School of Nursing and the University Hospital (John Dempsey) Department of Nursing was initiated to educate nurses for a new role. Acute care nurse practitioners are master's prepared nurses in advanced practice who are capable of case management. Major functions include creating an initial data base, ordering diagnostic tests, therapeutics interventions, and medications, and monitoring their results in collaboration with attending physicians. Results show promise for unprecedented interdisciplinary patient management and nurse-to-nurse cooperation.

Transforming growth factor-alpha (TGF-alpha) in a semisolid dosage form: preservative and vehicle selection

The selection of an ideal semisolid vehicle for growth factors presents a challenge. Some antimicrobial agents are known to delay wound healing. The objective of this investigation was to identify appropriate preservatives and vehicles for TGF-alpha. Criteria for acceptance are noninterference with the mitogenic activity of TGF-alpha as well as adequate product preservation. Vehicles considered were o/w creams, ointments, and a gel. Combinations of six preservatives were tested. Selection was determined using both microbial preservative challenge and TGF-alpha mitogenic assay. In the former, 10 species of microorganisms were inoculated into formulation samples. At selected time intervals, it was determined whether colonies decreased, increased, or remained constant. In the mitogenic assay, samples of either preservatives or formulation prototypes were introduced to TGF-alpha-stimulated fibroblast cell cultures. Mitogenesis was determined by measuring 3H-dThd uptake into newly synthesized DNA. As preservatives, sorbic acid and quaternium-15 appear to satisfy both selection criteria. A thermosetting gel appears most promising as vehicle.

Percutaneous transluminal coronary angioplasty in totally occluded arteries

Out of 321 consecutive cases of Percutaneous Transluminal Coronary Angioplasty (PTCA), 28 (8.7%) patients underwent PTCA for nonacute total occlusion with no visible antegrade flow. All patients had evidence of reversible ischaemia in the territory of totally occluded artery. Overall initial success rate was 66% and was mainly related to the duration of the occlusion (85% for occlusion of 1 month or less, 70% for 1-6 months, and nil for more than 6 months duration). In 21 (75%) cases where collateral circulation to the occluded vessel could be demonstrated before PTCA, was not visible after successful PTCA. Failure was mainly due to inability to cross the lesion with the guide wire (8 out of 10 failures). Emergency Coronary Artery Bypass Graft (CABG) surgery was required in 2 cases where dissection of nontarget vessels occurred during manipulation of the guide wire. Acute reocclusion occurred in 2 cases, both were redilated successfully. There was no death. Although the primary success rate is lower than that associated with conventional stenotic lesions, with improvement in the hardware-balloon catheters and guide wires, coronary angioplasty can be performed successfully in majority of the patients with total coronary occlusion.

The clinical teaching partnership

Nursing educators have struggled to find the optimal solution for students' clinical learning. The authors discuss a potential avenue to address this problem. Through the combined efforts of a hospital-based clinical nurse specialist and a university-based faculty member, the authors promoted effective learning for their students. Their combined strengths resulted in a positive experience for students, staff, and the instructors.

Nurses' views on sexuality. Why, what, and how to change

What practicing professional nurses believe about the sexual functioning of their patients has a direct influence on the patients' psychological well being. A preliminary investigation identifying some of nurses' beliefs demonstrated their attitudes and knowledge about the effects of chronic disease on sexuality. Staff development educators can assist nursing staff to change attitudes and improve knowledge through an educational program outlined in this article.

Organizational structure: blueprint for action

"Organizational structure is the way a group is formed and the way it functions." The authors describe the successful revision of the structure of one school. Its change process and outcome can serve as a blueprint for action for other schools that are changing or considering changing their organizational structure.

Magnetic resonance imaging--the evaluation of choice in residual shunt after congenital heart disease surgery?

Accurate anatomic diagnosis presents a dilemma in patients with residual shunt after corrective surgery for congenital heart disease. We describe a patient who, after atrial septal defect repair, developed dyspnea and central cyanosis despite normal pulmonary arterial pressures and right heart chamber size. A role for early MRI is suggested.

Circulating antibodies against human colonic extract enriched with a 40 kDa protein in patients with ulcerative colitis

We have previously described a 40 kDa colonic protein(s) which is specifically recognised by tissue-bound immunoglobulin G obtained from the colon of patients with ulcerative colitis. We now report the presence of circulating antibodies against this antigen using an enzyme-linked immunosorbent assay with a highly enriched preparation of the 40 kDa protein from normal colon extracts. Serum was collected from 79 patients with ulcerative colitis, 36 with Crohn's disease, 16 with specific diarrhoeal syndromes, and from 19 normal subjects. Twenty nine of 79 patients with ulcerative colitis, 21 of 36 with Crohn's disease, and all patients with diarrhoea were symptomatic during the collection of sera. The difference in optical density values between patients with symptomatic ulcerative colitis and each of the other groups, including patients with ulcerative colitis in remission, was highly significant (p less than 0.01). Seventy nine per cent of patients with symptomatic ulcerative colitis had optical density values above the means for all other groups. Fifty five per cent of sera from patients with symptomatic ulcerative colitis had optical densities beyond two SDs of the values for all other groups and only two of 71 sera from non-ulcerative colitis patients (one Crohn's disease and one normal subject) had values in this range. These results show the presence of anti-colon antibodies against the 40 kDa protein(s) in the sera of many patients with symptomatic ulcerative colitis.

Theoretical aids for the determination of colorimetric curves of binary powder mixtures

Colorimetric assessment of powder mixtures or pigmented specimens can be made by determining CIE color coordinates from sample spectral reflectance curves. The diffuse reflectance spectra of five particulate systems having different hues are determined using modified particle model theory for wavelengths of 400 (20) 700 nm. Six binary powder mixtures are prepared from these particulate systems. The reflectance spectra of binary powder mixtures are then predicted assuming the contribution of each component to be equal to the product of its reflectance and the total surface area of particles. The theoretically predicted diffuse reflectance spectral curves agree well with experimentally measured ones. The evaluation of the theoretical technique is made by determining the color difference between the measured and predicted color coordinates. The color difference calculated for all the samples is <2 CIELAB units. The study establishes a theoretical aid to predict diffuse reflectance spectra of powder mixtures from the fundamental morphological and optical properties of particulate matter.

Induced optical anisotropy in heterodispersed systems

Magnetically induced extinction and birefringence of systems containing a mixture of ultramicroscopic particles with different optical and magnetic properties have been theoretically investigated. It is shown that the effects may exhibit an extremum and an inversion in sign with increasing applied field strength if the system contains diamagnetic as well as ferromagnetic particles. The field strengths at which the effects exhibit the extremum and the inversion in sign are found to depend on the relative number distribution of the two types of particles and on the wavelength of the incident radiation. Experimental results from systems containing particles of bentonite and chromium ferrite in different proportions are also discussed.

Estimation of particle size distribution parameters with forward-scattering techniques

A polydisperse sample can be statistically represented by a log-normal distribution having two parameters, viz., geometrical standard deviation sigma(g) and modal size parameter X(m). In an earlier paper a method to determine sigma(g) from the shift in the angular position of the maximum in Itheta(2) vs theta plot was discussed. The present paper describes a method of determining the other parameter X(m) from the polarization measurement in the forward direction. This can be achieved by comparing the angular position of maxima in P (degree of polarization) vs theta with that of the similar curve of a single particle. Certain experimental results are also discussed. This method is expected to be useful in routine particle size analysis.