Drug-Excipient Compatibility Studies in Formulation Development: Current Trends and Techniques

The safety, efficacy, quality and stability of a formulation are the cornerstones of any new drug development process. In order to consistently maintain these attributes in a finished dosage form, it is important to have a comprehensive understanding of the physico-chemical characteristics of the active pharmaceutical ingredient (API), as well as all other components (e.g. excipients, manufacturing aids, packaging materials) of the drug product. In a new drug development process, a detailed characterization of the API and other formulation components is usually carried out during the preformulation stage. The preformulation stage involves characterization of several aspects of the API including solubility, dissolution, permeability, polymorph/salt screening, stability (solidstate and solution-state), ionization properties, particle size distribution, API-excipient compatibilities etc. [1]. Excipients are ubiquitous to virtually every pharmaceutical formulation, and facilitate the manufacture, stability, administration, delivery of the API, and/or provide other functionalities to the dosage form. Excipients are used to improve processing (e.g. improving powder flow [2, 3], powder compactibility [4-6] etc.), enhance aesthetics (e.g. identification, branding etc. [7]), optimize product performance (e.g. modified drug-release [8-11]), and/or to facilitate patient compliance (e.g. taste masking [12-15]). They may constitute anywhere from 1 to 99 % of the total formulation mass. Due to the intimate contact of the API with one or more excipients in a formulation, there exists a likelihood of physical and/or chemical interactions between them. Any such interactions may result in a negative impact on the physical, stability or performance attributes of the drug product [16, 17]. The choice of excipients is of crucial importance to avoid these negative effects, and to facilitate the development of a robust and an effective formulation [18-20]. Thus, for a rational selection of excipients, screening of excipient-API compatibility is recognized as an important aspect of formulation development. Moreover, the USFDA’s 21st century current Good Manufacturing Practices (cGMP) initiative and International Council on Harmonization (ICH) Q8 guidelines encourage the pharmaceutical manufacturers to apply Quality by Design (QbD) principles in their drug development process [21, 22]. These guidelines include expectations of a clear understanding of any interactions between the formulation components. Moreover, recent advances in various thermal and non-thermal analytical techniques have led to an improved efficiency in the detection, monitoring and prevention of the incompatibilities early in the drug development process [23, 24]. This article aims to provide a brief overview of the nature of drug-excipient incompatibilities; as well as current trends and techniques used to evaluate these compatibilities in formulation development

Dispersi Padat untuk Peningkatan Laju Disolusi Natrium Diklofenak dengan Variasi Konsentrasi Polivinil Pirolidon K30

Diclofenac sodium is included in the class II category based on the biopharmaceutics classification system (BCS), sodium diclofenac has low solubility and high permeability. Low solubility will affect the absorption of drugs in the body because the rate of dissolution will decrease. Polyvinyl Pyrrolidone (PVP) K30 is an inert carrier that dissolves easily in water and can affect the solubility of an active drug substance. To know solid dispersion system increasing dissolution rate of sodium diclofenac by adding variations concentration of PVP K30. Solid dispersion uses a solvent method with variations concentration of PVP K30 1:3, 1:5, 1:7, and 1:9. Test physical properties of solid dispersions using a moisture test and compressibility. Solid dispersion dissolution test using type 2 dissolutions test and determination of concentration using UV-VIS spectrophotometry. Test results were analyzed using One Way ANOVA and continued test. Solid dispersion has a good physical whit moisture percentage not >5% and compressibility not >20%. Solid dispersion of sodium diclofenac with the addition of PVP K30 can increase dissolution rate compared to pure sodium diclofenac (p<0,05) with the highest ratio 1:7. Each comparison has a significant difference (p<0,05) except in ratio 1:9. Solid dispersion of sodium diclofenac with PVP K30 can increase the dissolution rate of pure sodium diclofenac

IN VITRO-IN VIVO EVALUATION OF FAST-DISSOLVING TABLETS CONTAINING SOLID DISPERSION OF OXCARBAZEPINE

Objective: Investigation of in vitro/in vivo behaviour of fast-dissolving tablets containing solid dispersions of oxcarbazepine is the focus of the present research work.Methods: The effect of various hydrophilic polymers on the aqueous solubility of oxcarbazepine was studied. Polyethylene glycol 6000 carrier was selected and solid dispersions were prepared by various methods. A total of nine formulations were compressed into fast-dissolving tablets using avicel PH 102 as a directly compressible filler and ac-di-sol, sodium starch glycolate and crospovidone as super disintegrants and evaluated for pre and post compression parameters and in vitro drug release. In vivo studies of the pure drug, optimized formulation and marketed formulation were carried out on male Wistar rats and pharmacokinetic parameters were calculated using the pk function for Microsoft excel.Results: Mathematical analysis of in vitro data suggested that the first order was the most suitable mathematical model for describing the optimized formulation. The first-order plot was found to be fairly linear for optimized formulation as indicated by its high regression value. Stability studies indicated that the effect of storage was insignificant at 5% level of confidence. The optimized formulation has shown Tmax of 0.5 h, which was highly significant (P<0.05) when compared with pure drug and marketed formulation.Conclusion: Therefore, the solid dispersions prepared by melting method using polyethylene glycol 6000 as hydrophilic carrier can be successfully used for the improvement of dissolution of oxcarbazepine and resulted in faster onset of action as indicated by in vitro and in vivo studies

A Design of Experiment Approach for Optimization and Characterization of Clarithromycin Ternary System Using Spray Drying

The aim of present work was to characterize Clarithromycin (CLT), Polyvinyl pyrrolidone K30 (PVP K30) and Hydroxypropyl β-cyclodextrin (HPB) ternary system so as to check the effect of complexation on solubility of CLT. Physical mixtures of a drug and polymers in several weight ratios (1:1, 1:2) were prepared to check the effect of individual polymers on solubility of CLT. Spray drying method was accustomed investigate the combined effect of PVP K30 and HPB on Drug release (DR), Dissolution efficiency (DE) and mean dissolution time (MDT) of CLT. For the preparation and optimization of ternary system the Design of experiment (DoE) was used . Drug polymer interactions were analyzed with Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and particle size analysis. Results of solubility study suggested that there was significant increase in solubility of CLT with increase within the concentration of PVP K30 and HPB (*p<0.05). This may be thanks to the solubilizing effect of PVP K30 and sophisticated formation of CLT with HPB. Various combinations of PVP K30 and HPB prepared using DoE approach by spray drying method showed greater solubility of CLT than its physical mixtures (*p<0.05). Results of FTIR, DSC, XRD and particle size analysis revealed the interaction between CLT, PVP K30 and HPB. This suggested formation of amorphous ternary system with mean particle diameter within the range of 312±1.35 nm. Combine use of PVP K30 and HPB with DoE approach was an efficient tool for formulating ternary system of CLT. Keywords: Clarithromycin, Spray drying, polyvinyl pyrrolidone K30, Hydroxypropyl β-cyclodextrin, Design of experiments, Ternary system.&nbsp

Antisolvent precipitation technique: a very promising approach to crystallize curcumin in presence of polyvinyl pyrrolidon for solubility and dissolution enhancement

Curcumin with a vast number of pharmacological activities is a poorly water soluble drug which its oral bioavailability is profoundly limited by its dissolution or solubility in GI tract. Curcumin could be a good anticancer drug if its solubility could be increased. Therefore, the aim of the present study was to increase the dissolution rate of curcumin by employing antisolvent crystallization technique and to investigate the effect of polyvinyl pyrrolidone K30 (PVP) as colloidal particles in crystallization medium on resultant particles. Curcumin was crystalized in the presence of different amounts of PVP by antisolvent crystallization method and their physical mixtures were prepared for comparison purposes. The samples were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The solubility and dissolution of the treated and untreated curcumin were also determined. Antisolvent crystallization of curcumin led to the formation of particles with no definite geometric shape. It was interesting to note that the DSC and XRPD studies indicated the formation of a new polymorph and less crystallinity for particles crystallized in the absence of PVP. However, the crystallized curcumin in the presence of PVP was completely amorphous. All crystalized curcumin samples showed much higher dissolution rate compared to untreated curcumin. The amount of curcumin dissolved within 10 for treated curcumin in the presence of PVP (1:1 curcumin:PVP) was 7 times higher than untreated curcumin and this enhancement in the dissolution for curcumin samples crystallized in the absence of PVP was around 5 times. Overall‚ the results of this study showed that antisolvent crystallization method in the absence or presence of small amounts of PVP is very efficient in increasing the dissolution rate of curcumin to achieve better efficiency for curcumin

FORMULATION OF SOLID DISPERSIONS FOR ENHANCEMENT OF SOLUBILITY AND DISSOLUTION RATE OF SIMVASTATIN

Objective: The objective of the present work was to formulate the solid dispersions of simvastatin for enhancement of its aqueous solubility and dissolution rate. Methods: In the present study, solid dispersions of simvastatin were prepared by Kneading and Solvent evaporation methods. The polymeric carriers like Polyethylene glycol (PEG) 6000 and Polyvinyl Pyrrolidone (PVP) K30 were used in different ratios (ratio of drug: carrier was 1:1, 1:2) to formulate solid dispersions. The prepared solid dispersions were characterized by differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FTIR), and evaluated for drug content, percentage yield, saturation solubility, in vitro dissolution studies. The best formula of the solid dispersion was selected according to the solubility and dissolution data. Results: The F7 formulation was found to be an optimized formulation containing PVP K30 in the ratio 1:1 prepared by solvent evaporation technique. The Drug content was found to be higher i.e. 94.89 in the F7 batch. The FT-IR spectra revealed that there was no interaction between drugs and carriers. DSC thermogram indicated entrapment of simvastatin in PVP K30 and the conversion of crystalline simvastatin into an amorphous form. The F7 formulation showed maximum drug release i.e. 98.60% in 60 min which is 2 times greater than pure drug making it an optimized formulation. Conclusion: The solubility of simvastatin was successfully enhanced through the solid dispersion technique. Solid dispersions prepared with solvent evaporation method were more soluble than solid dispersions prepared with kneading method with carrier PVP K30

DEVELOPMENT AND EVALUATION OF BILAYER MUCOAHESIVE GASTRORETENTIVE TABLET OF DILTIAZEM HYDROCHLORIDE

Objective: The objective of present study was to formulate an oral mcoadhesive tablet of diltiazem hydrochloride. Methods: Investigate the effect of amount of HPMC K4M and sodium alginate on the sustained release and gastric residence time of dosage form. The mucoadhesive tablet prepared by direct compression method was used varying concentrations of HPMC K4M and Sodium alginate and (1:1, 1:1.5, 1:2) Drug and Polymer ratio. Results: The formulations were evaluated and results revealed that FTIR studies showed no evidence of interactions between drug and excipients used. The mucoadhesive strength, residence time and drug content of formulation F3 was found to be 26.35 ± 1.15 mg, >7.5hrs, and 98.75 ± 0.05 % respectively. The formulation F3 exhibited sustained drug release i.e. 75.71% in 12 h. The In Vitro release kinetics studies reveal that formulations fit well with zero order kinetics and mechanism of drug release is Super case II transport. Conclusion: The study was concluded that formulation of mucoadhesive tablets from the cumulative % drug release study reveals that increase in the concentration of adhesive polymers cause slow the drug release. Sustained release tablet of DTZ can be beneficial in treatment of hypertension

DEVELOPMENT AND CHARACTERIZATION OF TRANSDERMAL DELIVERY SYSTEM OF DOXAZOSIN MESYLATE

Objective: The study involved development of transdermal delivery system (TDDS) of doxazosinmesylate (doxa) to achieve effective systemic delivery of the drug.Methods: TDDS of doxa was prepared using hydroxypropyl methyl cellulose (HPMC) K100LV and polyvinyl pyrrolidone (PVP) K30 in 3:1 ratio solvent casting method. The formulation was evaluated for folding endurance, moisture uptake, pH, drug content and in vitro permeation. Various permeation enhancers were incorporated at 5% w/w concentration into the patch formulationto study their impact on the drug permeation. The TDDS made with Transcutol® as an enhancer was subjected to accelerated stability studies and in vivo skin irritation studies.Results: The developed TDDS showed folding endurance of 170, moisture uptakeof 15.7%, pH of 6.3, and drug content of 99±1.1% and 66% in vitro permeation of doxa over 24h. The effect of various enhancers expressed in terms of average flux can be summarized as Transcutol® (10.6±2.1 µg/cm2h)>dimethyl sulfoxide(10.17±1.2 µg/cm2h)>benzyl alcohol (9.55±1.3 µg/cm2h)>no enhancer (8.86±1.1 µg/cm2h)>dimethyl isosorbide (8.21±1.5 µg/cm2h)>Isostearic acid (7.82±1.4 µg/cm2h)>propylene carbonate (7.67±1.4 µg/cm2h)>oleic acid (7.12 µg±0.8/cm2h). The formulation was found to be stable during the accelerated stability studies. In vivo studies indicated absence of skin irritation effect the TDDS containing Transcutol®.Conclusion: TDDS of doxa comprising HPMC K100LV and PVPK30 in the ratio of 3:1 and 5% Transcutol® could serve as a potential TDDS in the treatment of benign prostatic hyperplasia (BPH) and hypertension

VISCOELASTIC, SWELLING KINETIC AND DRUG RELEASE CHARACTERIZATION OF POLY (ACRYLIC ACID)-GRAFTED-GELLAN

Lyophilic, viscoelastic, swelling kinetic and drug release characterizations of poly (acrylic acid) –grafted-gellan (PAAc-g-GG) were the main objective of this study. At first, a suitable solvent for PAA-g-GG was found out by lyophilicity study followed by viscoelastic study on PAAc-g-GG with different degree of grafting. The study showed that the degree of grafting greatly influences the viscoelastic nature of copolymer, which further governs the drug release pattern from the polymer matrix. The copolymer with highest grafting showed much higher starting % strain (17.73%), stress (53.3 Pa) for structural breakdown at Gꞌ = Gꞌꞌ (213.5 Pa), higher storage modulus (G’), much higher values of complex viscosity (11.46 Pa.s) and cross-over point (Gꞌ = Gꞌꞌ =271.86 Pa) compared to that of low-grafted copolymer. In 0.1N HCl, swelling index (%WE) is found to be directly proportional to percentage grafting (%G) and batches with higher grafting exhibited lowest initial swelling rate demonstrating its inversely proportional relation to %G. Equilibrium swelling and hydration are also found to be proportional to %G. The same effect has been observed in PBS with exception that the magnitude of the parameters obtained in PBS is very much higher compared to that in 0.1N HCl. The copolymer showed sustained drug release over 10 hours period and the study revealed Case-1 Fickian diffusion or square root of time kinetic based release mechanism. The study reveales that viscoelastic and swelling study might be useful to understand how the degree of grafting governs the drug release

Preparation and evaluation of famotidine nanosuspension

Famotidine (FM) is a potent H2-receptor antagonist used for the treatment of peptic ulcer. It has a low and variable bioavailability which is attributed to its low water solubility. There are many methods used to increase dissolution rate of drug and in this study, the dissolution of the drug was enhanced by the preparation of nanosuspension. Famotidine nanosuspension was prepared by antisolvent precipitation method, where famotidine dissolved in methanol at room temperature and emptied into water containing different types of stabilizers (single and in combination). The optimum formula (F9) was selected according to particle size (362.8nm) and release profile (80 % of drug release within the 10 minutes) in comparison to pure famotidine powder release. The influence of formulation variables like the type and concentration of stabilizers Polyvinyl pyrrolidone K30, polyvinyl alcohol and poloxamer 188 (PVP K-30, PVA and poloxamer 188) in addition to combination of stabilizers on particle size of drug nanosuspensions were studied. The result showed that single stabilizer (poloxamer 188) has perfect surface affinity and could form a substantial mechanical and thermodynamic barrier at the interface of dug molecule. As the concentration of stabilizer increases the particle size decreases at fixed drug concentration (drug: stabilizer ratio 1:2)