Decoding the Postulated Entourage Effect of Medicinal Cannabis: What It Is and What It Isn't.

The 'entourage effect' term was originally coined in a pre-clinical study observing endogenous bio-inactive metabolites potentiating the activity of a bioactive endocannabinoid. As a hypothetical afterthought, this was proposed to hold general relevance to the usage of products based on Cannabis sativa L. The term was later juxtaposed to polypharmacy pertaining to full-spectrum medicinal Cannabis products exerting an overall higher effect than the single compounds. Since the emergence of the term, a discussion of its pharmacological foundation and relevance has been ongoing. Advocates suggest that the 'entourage effect' is the reason many patients experience an overall better effect from full-spectrum products. Critics state that the term is unfounded and used primarily for marketing purposes in the Cannabis industry. This scoping review aims to segregate the primary research claiming as well as disputing the existence of the 'entourage effect' from a pharmacological perspective. The literature on this topic is in its infancy. Existing pre-clinical and clinical studies are in general based on simplistic methodologies and show contradictory findings, with the clinical data mostly relying on anecdotal and real-world evidence. We propose that the 'entourage effect' is explained by traditional pharmacological terms pertaining to other plant-based medicinal products and polypharmacy in general (e.g., synergistic interactions and bioenhancement).

Clinical Research Evidence Supporting Administration and Dosing Recommendations of Medicinal Cannabis as Analgesic in Cancer Patients.

The analgesic potential of Cannabis sativa L.-based medicinal cannabis products for treatment of cancer associated chronic pains has gained increased interest in recent years. To ensure a controlled distribution of these products and investigate their therapeutic potential, several countries have established so-called pilot trials. Many doctors, however, are hesitant to prescribe medicinal cannabis primarily due to lack of research evidence regarding the products' efficacy, safety and thus questionable dosing guidelines. This review aims to elucidate clinical research supporting administration of medicinal cannabis in cancer patients for analgesic purposes. The cannabinoids' effects on the endocannabinoid system (ECS) and its implication in pain regulation is included to illustrate the complexity related to this research field. Published clinical studies on medicinal cannabis primarily consist of observational studies and only one pilot randomized controlled trial (RCT), where more RCTs exist on the cannabis-based product, Sativex® (GW Pharma Ltd., Cambridge, UK). The studies indicate analgesic potential, however non-significantly, for most patients and with acceptable safety profile. Summarizing, high-quality RCTs are scarce in this research field, and the limitations of the observational studies complicates interpretation of clinical outcomes. Despite discrepancy among the studies, they do show indications for administration and dosing regimens providing analgesic effects for some cancer patients.

Near-infrared spectroscopy for cocrystal screening. A comparative study with Raman spectroscopy.

Near-infrared (NIR) spectroscopy is a well-established technique for solid-state analysis, providing fast, noninvasive measurements. The use of NIR spectroscopy for polymorph screening and the associated advantages have recently been demonstrated. The objective of this work was to evaluate the analytical potential of NIR spectroscopy for cocrystal screening using Raman spectroscopy as a comparative method. Indomethacin was used as the parent molecule, while saccharin and l-aspartic acid were chosen as guest molecules. Molar ratios of 1:1 for each system were subjected to two types of preparative methods. In the case of saccharin, liquid-assisted cogrinding as well as cocrystallization from solution resulted in a stable 1:1 cocrystalline phase termed IND-SAC cocrystal. For l-aspartic acid, the solution-based method resulted in a polymorphic transition of indomethacin into the metastable alpha form retained in a physical mixture with the guest molecule, while liquid-assisted cogrinding did not induce any changes in the crystal lattice. The good chemical peak selectivity of Raman spectroscopy allowed a straightforward interpretation of sample data by analyzing peak positions and comparing to those of pure references. In addition, Raman spectroscopy provided additional information on the crystal structure of the IND-SAC cocrystal. The broad spectral line shapes of NIR spectra make visual interpretation of the spectra difficult, and consequently, multivariate modeling by principal component analysis (PCA) was applied. Successful use of NIR/PCA was possible only through the inclusion of a set of reference mixtures of parent and guest molecules representing possible solid-state outcomes from the cocrystal screening. The practical hurdle related to the need for reference mixtures seems to restrict the applicability of NIR spectroscopy in cocrystal screening.

NIR transmission spectroscopy for rapid determination of lipid and lyoprotector content in liposomal vaccine adjuvant system CAF01.

It is of crucial importance to determine the concentration of the different components in the formulation accurately, during production. In this respect, near-infrared (NIR) spectroscopy represents an intriguing alternative that offers rapid, non-invasive and non-destructive sample analysis. This method, combined with multivariate data analysis was successfully applied to quantify the total concentration of lipids in the liposomal CAF01 adjuvant, composed of the cationic surfactant dimethyldioctadecylammonium bromide (DDA) and the immunomodulator alpha,alpha'-trehalose 6,6'-dibehenate (TDB). The near-infrared (NIR) detection method was compared to a validated high-performance liquid chromatography (HPLC) method and a differential scanning calorimetry (DSC) analysis, and a blinded study with three different sample concentrations was performed, showing that there was no significant difference in the accuracy of the three methods. However, the NIR and DSC methods were more precise than the HPLC method. Also, with the NIR method it was possible to differentiate between various concentrations of trehalose added as cryo-/lyoprotector. These studies therefore suggest that NIR can be used for real-time process control analysis in the production of CAF01 liposomes.

Solvent diversity in polymorph screening.

Selecting a diverse set of solvents to be included in polymorph screening assignments can be a challenging task. As an aid to decision making, a database of 218 organic solvents with 24 property descriptors was explored and visualized using multivariate tools. The descriptors included, among others, log P, vapor pressure, hydrogen bond formation capabilities, polarity, number of pi-bonds and descriptors derived from molecular interaction field calculations (e.g., size/shape parameters and hydrophilic/hydrophobic regions). The data matrix was initially analyzed using principal component analysis (PCA). Results from the PCA showed 57% cumulative variance being explained in the first two principal components (PCs), although relevant information was also found in the third, fourth and fifth component, revealing distinct clusters of solvents. Since five dimensions were not suitable for visual presentation, a nonlinear method, self-organizing maps (SOMs), was applied to the dataset. The constructed SOM displayed features of clusters observed in the first three PCs, however in a more compelling way. Thus, the SOM was chosen as the visually most convenient way to display the diversity of the 218 solvents. In addition, it was demonstrated how safety aspects can be considered by labeling a large fraction of the solvents in the SOM with toxicological information.

Roller compaction scale-up using roll width as scale factor and laser-based determined ribbon porosity as critical material attribute.

Due to the complexity and difficulties associated with the mechanistic modeling of roller compaction process for scale-up, an innovative equipment approach is to keep roll diameter fixed between scales and instead vary the roll width. Assuming a fixed gap and roll force, this approach should create similar conditions for the nip regions of the two compactor scales, and thus result in a scale-reproducible ribbon porosity. In the present work a non-destructive laser-based technique was used to measure the ribbon porosity at-line with high precision and high accuracy as confirmed by an initial comparison to a well-established volume displacement oil intrusion method. The ribbon porosity was found to be scale-independent when comparing the average porosity of a group of ribbon samples (n=12) from small-scale (Mini-Pactor®) to large-scale (Macro-Pactor®). A higher standard deviation of ribbons fragment porosities from the large-scale roller compactor was attributed to minor variations in powder densification across the roll width. With the intention to reproduce ribbon porosity from one scale to the other, process settings of roll force and gap size applied to the Mini-Pactor® (and identified during formulation development) were therefore directly transferrable to subsequent commercial scale production on the Macro-Pactor®. This creates a better link between formulation development and tech transfer and decreases the number of batches needed to establish the parameter settings of the commercial process.

Quantitative surface topography assessment of directly compressed and roller compacted tablet cores using photometric stereo image analysis.

Surface topography, in the context of surface smoothness/roughness, was investigated by the use of an image analysis technique, MultiRay™, related to photometric stereo, on different tablet batches manufactured either by direct compression or roller compaction. In the present study, oblique illumination of the tablet (darkfield) was considered and the area of cracks and pores in the surface was used as a measure of tablet surface topography; the higher a value, the rougher the surface. The investigations demonstrated a high precision of the proposed technique, which was able to rapidly (within milliseconds) and quantitatively measure the obtained surface topography of the produced tablets. Compaction history, in the form of applied roll force and tablet punch pressure, was also reflected in the measured smoothness of the tablet surfaces. Generally it was found that a higher degree of plastic deformation of the microcrystalline cellulose resulted in a smoother tablet surface. This altogether demonstrated that the technique provides the pharmaceutical developer with a reliable, quantitative response parameter for visual appearance of solid dosage forms, which may be used for process and ultimately product optimization.

Investigation of surface porosity measurements and compaction pressure as means to ensure consistent contact angle determinations.

Compounds wettability is critical for a number of central processes including disintegration, dispersion, solubilisation and dissolution. It is therefore an important optimisation parameter both in drug discovery but also as guidance for formulation selection and optimisation. Wettability for a compound is determined by its contact angle to a liquid, which in the present study was measured using the sessile drop method applied to a disc compact of the compound. Precise determination of the contact angle is important should it be used to either rank compounds or selected excipients to e.g. increase the wetting from a solid dosage form. Since surface roughness of the compact has been suggested to influence the measurement this study investigated if the surface quality, in terms of surface porosity, had an influence on the measured contact angle. A correlation to surface porosity was observed, however for six out of seven compounds similar results were obtained by applying a standard pressure (866 MPa) to the discs in their preparation. The data presented in the present work therefore suggest that a constant high pressure should be sufficient for most compounds when determining the contact angle. Only for special cases where compounds have poor compressibility would there be a need for a surface-quality-control step before the contact angle determination.

Fluorescence spectroscopy in process analytical technology (PAT): simultaneous quantification of two active pharmaceutical ingredients in a tablet formulation.

Many pharmaceuticals include highly potent active pharmaceutical ingredients (API), which only require a small dosage to obtain the desired therapeutic effect. This leads to a challenge for quantification of the API using process analytical technology, since the standard nondestructive measurement technique, near-infrared spectroscopy, is not able to quantify below 1% (weight/weight (w/w)) API content. In formulations with more than one API, this challenge is further increased. The purpose of this study is to scrutinize the potential of fluorescence spectroscopy for the simultaneous quantification of two APIs: flupentixol (FLU) in low dosage (0.208-0.625% w/w free base) and melitracen (MEL) (4.17-12.5% w/w free base) in a tablet formulation. Despite internal quenching between the ingredients and the two APIs, this paper demonstrates that it is possible to establish calibrations using partial least squares (PLS) regression on unfolded fluorescence landscapes with a root mean square error of prediction and relative error of 0.038% (w/w) and 9.1%, for FLU and 0.344% (w/w) and 4.1% for MEL, respectively.

Evaluation of ring shear testing as a characterization method for powder flow in small-scale powder processing equipment.

Powder flow in small-scale equipment is challenging to predict. To meet this need, the impact of consolidation during powder flow characterization, the level of consolidation existing during discharge of powders from a tablet press hopper and the uncertainty of shear and wall friction measurements at small consolidation stresses were investigated. For this purpose, three grades of microcrystalline cellulose were used. Results showed that powder flow properties depend strongly on the consolidation during testing. The consolidation during discharge in terms of the major principal stress and wall normal stress were approximately 200 Pa and 114 Pa, respectively, in the critical transition from the converging to the lower vertical section of the hopper. The lower limit of consolidation for the shear and wall friction test was approximately 500 Pa and 200 Pa, respectively. At this consolidation level, the wall and shear stress resolution influences the precision of the measured powder flow properties. This study highlights the need for an improved experimental setup which would be capable of measuring the flow properties of powders under very small consolidation stresses with a high shear stress resolution. This will allow the accuracy, precision and applicability of the shear test to be improved for pharmaceutical applications.

Measurement of active content in escitalopram tablets by a near-infrared transmission spectroscopy model that encompasses batch variability.

Near-infrared transmission (NIT) spectroscopy, with high-performance liquid chromatography as reference method, was used to study the variation of the active pharmaceutical ingredient (API), escitalopram, in five tablet batches (4%-12%, w/w) manufactured by direct compression. This study investigates the influence of sample orientation, powder segregation, and compression force on the NIT spectra. For this purpose, tablet samples were taken at six different production time points, at three different compression forces, and presented to the spectrometer in four different orientations and in three spectroscopic replicates. A total set of 2160 NIT spectra was recorded. The variances between the spectra at each level of API content were thoroughly investigated by partial least squares regression using theory of sampling. The results show that a minimum of 18 tablets from each level of API content is required to establish a robust NIT calibration. The identified number of spectra is required for covering small differences in the spatial heterogeneity of the API as well as minor variations in optical properties, due to variations in the tablet compression force. NIT spectroscopy is demonstrated to be a powerful technique not only for measuring the API content in escitalopram tablets but also for routine content uniformity analysis.

Phase transformations of amlodipine besylate solid forms.

Hydrate formation and dehydration phenomena are frequently encountered phase transformations during manufacturing and storage of the drug products. It is essential to understand, monitor, and control these transformations to ensure that the quality attributes of the drug product are not affected. In this work, phase transformations of the solid forms of amlodipine besylate (AMB) were studied using Raman and near-infrared (NIR) spectroscopy. AMB exists as anhydrate (AH), monohydrate (MH), dihydrate (DH), and amorphous (AM) form. Solid form quantification models based on multivariate data analysis of the Raman and NIR spectra were developed. The AH, MH, and AM form were transformed to the DH during solubility measurements. The AH to DH transformation also occurred during wet granulation. The transformation kinetics were faster during wet granulation than during the solubility experiments. This was due to the shear forces involved in granulation that can facilitate nucleation and can enhance the overall transformation. The DH form present in the wet granules persisted after drying, and final granules contained a mixture of the AH and DH. The relative importance of the dissolution, nucleation, and growth steps for the transformation was elucidated using optical microscopy experiments. The transformation kinetics were found to be limited by nucleation and growth.

Towards effective solid form screening.

Solid form screening is commonly performed using solvent-based crystallizations. However, less attention is paid to the role of secondary manufacturing, during which process-induced transformations of the active pharmaceutical ingredient (API) may occur, and potentially a new solid form may be discovered. In this study a new approach for effective solid form screening is presented. The technology combines well-plate-based crystallizations with miniaturized processing equipment, mimicking essential unit operations. Process-induced stresses (heat, solvent, shear, pressure) can be introduced directly to the well-plate unit. Theophylline and nifedipine were used as model compounds. Small-scale wet massing of theophylline resulted in an anhydrate-to-monohydrate transformation, followed by dehydration upon drying at 60 degrees C. Amorphous nifedipine was subjected to small-scale milling and compaction. Kinetic profiling of the milling operation enabled the detection of an intermediate, metastable polymorph (beta form), while the stable polymorph (alpha form) was the predominant form after 20 min of milling. Compaction of amorphous nifedipine at 100 MPa resulted in a complete conversion into the stable polymorph. The reported expanded approach is expected to maximize the outcome of solid form screening with minimal consumption of the compound of interest.

Enhanced dissolution rate and synchronized release of drugs in binary systems through formulation: Amorphous naproxen-cimetidine mixtures prepared by mechanical activation.

Naproxen, a non-steroidal anti-inflammatory drug (NSAID), is a biopharmaceutics classification system (BCS) class II drug whose bioavailability is rate-limited by its dissolution. Cimetidine is sometimes co-administered with naproxen for the treatment of NSAID-induced gastro-intestinal disorders. Hence, there is interest in the design of new formulations that offer (1) concomitant release of both drugs, and (2) an enhanced dissolution rate of naproxen. This study investigates the formation of amorphous binary systems with naproxen and cimetidine. The binary mixtures of all tested molar ratios were found to become amorphous upon co-milling for 60 min at 4 degrees C. In contrast, pure naproxen could not be transformed to the amorphous state by mechanical activation. The 1:1 sample was the most physically stable when stored for 33 days at 40 degrees C, even though it did not have the highest T(g) when compared to the 1:2 sample. The 1:1 sample was further stored for 186 days and remained amorphous under all conditions. Raman spectroscopy suggested a 1:1 solid-state interaction between the imidazole ring of cimetidine and the carboxylic acid moiety of naproxen in the co-milled amorphous sample. Thus, the stabilization of the amorphous binary system is dictated by molecular-level interactions rather than bulk-level phenomena. No recrystallization of either drug in the 1:1 co-milled sample was observed during dissolution testing, with naproxen and cimetidine having a four and two times higher intrinsic dissolution rate, respectively, compared to their crystalline counterparts. Further, the release of the two drugs could be synchronized using this formulation approach.

Increasing process understanding by analyzing complex interactions in experimental data.

There is a recognized need for new approaches to understand unit operations with pharmaceutical relevance. A method for analyzing complex interactions in experimental data is introduced. Higher-order interactions do exist between process parameters, which complicate the interpretation of experimental results. In this study, experiments based on mixed factorial design of coating process were performed. Drug release was analyzed by traditional analysis of variance (ANOVA) and generalized multiplicative ANOVA (GEMANOVA). GEMANOVA modeling is introduced in this study as a new tool for increased understanding of a coating process. It was possible to model the response, that is, the amount of drug released, using both mentioned techniques. However, the ANOVA model was difficult to interpret as several interactions between process parameters existed. In contrast to ANOVA, GEMANOVA is especially suited for modeling complex interactions and making easily understandable models of these. GEMANOVA modeling allowed a simple visualization of the entire experimental space. Furthermore, information was obtained on how relative changes in the settings of process parameters influence the film quality and thereby drug release.

Solid form screening--a review.

Solid form screening, the activity of generating and analysing different solid forms of an active pharmaceutical ingredient (API), has become an essential part of drug development. The multi-step screening process needs to be designed, performed and evaluated carefully, since the decisions made based on the screening may have consequences on the whole lifecycle of a pharmaceutical product. The selection of the form for development is made after solid form screening. The selection criteria include not only pharmaceutically relevant properties, such as therapeutic efficacy and processing characteristics, but also intellectual property (IP) issues. In this paper, basic principles of solid form screening are reviewed, including the methods used in experimental screening (generation, characterisation and analysis of solid forms, data mining tools, and high-throughput screening technologies) as well as basics of computational methods. Differences between solid form screening strategies of branded and generic pharmaceutical manufacturers are also discussed.