Selective detection of azelnidipine in pharmaceuticals via carbon dot mediated spectrofluorimetric method: A green approach.

A spectrofluorimetric method using fluorescent carbon dots (CDs) was developed for the selective detection of azelnidipine (AZEL) pharmaceutical in the presence of other drugs. In this study, N-doped CDs (N-CDs) were synthesized through a single-step hydrothermal process, using citric acid and urea as precursor materials. The prepared N-CDs showed a highly intense blue fluorescence emission at 447 nm, with a photoluminescence quantum yield of ~21.15% and a fluorescence lifetime of 0.47 ns. The N-CDs showed selective fluorescence quenching in the presence of all three antihypertensive drugs, which was used as a successful detection platform for the analysis of AZEL. The photophysical properties, UV-vis light absorbance, fluorescence emission, and lifetime measurements support the interaction between N-CDs and AZEL, leading to fluorescence quenching of N-CDs as a result of ground-state complex formation followed by a static fluorescence quenching phenomenon. The detection platform showed linearity in the range 10-200 µg/ml (R2 = 0.9837). The developed method was effectively utilized for the quantitative analysis of AZEL in commercially available pharmaceutical tablets, yielding results that closely align with those obtained from the standard method (UV spectroscopy). With a score of 0.76 on the 'Analytical GREEnness (AGREE)' scale, the developed analytical method, incorporating 12 distinct green analytical chemistry components, stands out as an important technique for estimating AZEL.

Hydrochloride salt co-crystals: preparation, characterization and physicochemical studies.

Co-crystallization approach for modification of physicochemical properties of hydrochloride salt is presented. The objective of this investigation was to study the effect of co-crystallization with different co-crystal formers on physicochemical properties of fluoxetine hydrochloride (FH). FH was screened for co-crystallization with a series of carboxylic acid co-formers by slow evaporation method. Photomicrographs and melting points of crystalline phases were determined. The co-crystals were characterized by FTIR, DSC and PXRD methods. Solubility of co-crystals was determined in water and buffer solutions. Powder and intrinsic dissolution profiles were assessed for co-crystals. Physical mixtures of drug and co-formers were used for comparisons at characterizations and physicochemical properties evaluation stages. Four co-crystals of FH viz. Fluoxetine hydrochloride-maleic acid (FH-MA), Fluoxetine hydrochloride-glutaric acid (FH-GA), Fluoxetine hydrochloride-L-tartaric acid (FH-LTA) and Fluoxetine hydrochloride-DL-tartaric acid (FH-DLTA) were obtained from screening experiments. Physical characterization showed that they have unique crystal morphology, thermal, spectroscopic and X-ray diffraction properties. Solubility and dissolution studies showed that Fluoxetine hydrochloride-maleic acid co-crystal possess high aqueous solubility in distilled water, pH 4.6, 7.0 buffer solutions and dissolution rate in distilled water than that of pure drug. Co-crystal formation approach can be used for ionic API to tailor its physical properties.

Chemometric and DoE-Based Analytical Quality Risk Management to HPTLC Method for Simultaneous Estimation of Metronidazole and Norfloxacin.

According to the upcoming ICH Q14 guideline, the development of an analytical method by the implementation of the AQbD approach based on analytical quality risk management and design of experiments will become a regulatory requirement for the registration of new drug substances and products. In literature, the HPTLC method has not been reported yet for simultaneous estimation of metronidazole and norfloxacin. Hence, the robust HPTLC method has been developed and validated for simultaneous estimation of metronidazole and norfloxacin using QRM and the DoE-based enhanced AQbD approach. The principal component analysis was applied for chemometric-based risk assessment of method risk parameters. The high-risk method parameters were optimized by a DoE-based full-factorial design. The MODR and control strategy was estimated for quality risk management throughout the lifecycle of the HPTLC method. The HPTLC method was developed using silica gel 60 F254 as stationary phase and acetonitrile-methanol-formic acid-ammonia (9.5 + 0.5 + 0.5 + 0.3, v/v) as mobile phase. The developed method was validated as per ICH Q2 (R1) guideline. The developed method was applied for the assay of combined pharmaceutical dosage forms of metronidazole and norfloxacin and results were found in compliance with their respective labeled claim.

Analytical Quality Risk Assessment and Design of Experiments to Green HPTLC Method for Simultaneous Estimation of Sildenafil Citrate and Dapoxetine Hydrochloride.

A green and robust high-performance thin-layer chromatographic method has been developed for the simultaneous estimation of sildenafil citrate and dapoxetine hydrochloride. A fractional factorial design was applied for analytical quality risk assessment of potential analytical risk factors. The identified critical analytical risk factors were optimized using the design of experiment-based response surface analysis by full factorial design. The analytical design space was navigated for the optimization of the method and the control strategy was framed for low-risk life-cycle management of the chromatographic method. The chromatographic analysis of sildenafil and dapoxetine was carried out on a TLC plate coated with silica gel G60 F254 using n-butanol:ethyl acetate:ethanol (8.0 + 2.0 + 0.5, v/v) as mobile phase. The chromatographic peaks of sildenafil and dapoxetine were found to be at Rf 0.29 and 0.69, respectively. The method was found to be accurate, precise, robust, specific and sensitive. The fixed-dose combinations of sildenafil and dapoxetine were assayed and results were found in compliance with their labeled claim. The present method was developed using safe and eco-friendly organic solvents for the safety of analysts and the protection of the environment. The greenness profiles of developed and reported methods were evaluated using the NEMI scale and AGREE software.

DoE-Based Analytical-FMCEA for Enhanced AQbD Approach to MEER-RP-HPLC Method for Synchronous Estimation of 15 Anti-Hypertensive Pharmaceutical Dosage Forms.

BACKGROUND: In the recent scenario of green chemistry, the usage of organic solvents should be minimized in the development of analytical methods for the safety of the environment and analysts. OBJECTIVE: An RP-HPLC method has been developed as an economical and eco-friendly alternative to published RP-HPLC methods for the analysis of fixed-dose combinations (FDCs) of anti-hypertensive drugs, for saving time, resources, costs, and organic solvent. METHODS: The method has been developed through the implementation of an enhanced analytical quality by design (AQbD) approach using a design of experiment (DoE)-based analytical failure mode critical effect analysis (AFMCEA). The AFMCEA was performed by identifying potential analytical failure modes and assessing their risk using risk priority number ranking and filtering. The DoE-based AFMCEA was implemented for response surface analysis and mitigation of high-risk analytical failure modes by Box-Behnken design (BBD). The method operable design ranges and control strategy were set for lifecycle management of the developed method. RESULTS: The RP-HPLC method was developed using a Shimpack octadecyl silane (ODS) C18 column and acetonitrile-water (pH 6.2; 42:58 %, v/v). The method was validated as per ICH Q2 (R1) guidelines. The method was applied for the synchronous assay of 15 FDCs of anti-hypertensive drugs. CONCLUSION: The developed method has fulfilled the requirements of numerous published RP-HPLC and HPTLC methods. Hence, this method is a multipurpose chromatography method for synchronous estimation of FDC products of anti-hypertensive drugs. This method can be used as a multipurpose (M), economical (E), eco-friendly (E), and rapid (R), MEER-RP-HPLC for quality control of multiple FDCs of anti-hypertensive drugs in the pharmaceutical industry. HIGHLIGHTS: Development of a MEER-RP-HPLC method for synchronous estimation of 15 pharmaceutical dosage forms of anti-hypertensive drugs. Implementation of an enhanced AQbD approach using a DoE-based AFMCEA to develop the method which was applied to the assay of 15 anti-hypertensive dosage forms.

DoE-Based Analytical Failure Modes Critical Effect Analysis (AFMCEA) to a Multipurpose-RP-HPLC Method for the Estimation of Multiple FDC Products of Metformin Hydrochloride Using an Analytical Quality by Design Approach.

BACKGROUND: Metformin hydrochloride is the first-choice antihyperglycemic agent and its several fixed-dose combinations (FDCs) with pioglitazone hydrochloride, sitagliptin phosphate, and gliclazide are used for the management of type II diabetes. Numerous reversed-phase HPLC (RP-HPLC) and HPTLC methods have been reported for estimation of FDCs of metformin but each FDC needs separate and dedicated chromatographic conditions for analysis. No RP-HPLC method has been reported yet which promotes synchronous estimation of FDC products of metformin to save time, resources, cost, and organic solvent for analysis. OBJECTIVE: Hence, an economical and eco-friendly RP-HPLC method was developed for the synchronous estimation of FDCs of metformin hydrochloride using an enhanced analytical quality by design (AQbD) approach. METHODS: The AQbD approach was implemented using analytical-failure modes critical effects analysis (FMCEA) as per International council for harmonisation (ICH) Q8 and Q9 guidelines. The analytical-FMCEA was applied by identification of potential analytical failure modes followed by their risk assessment by a risk priority number (RPN) ranking and filtering method. Further, the risk of critical failure modes was controlled and mitigated by a design of experiments (DoE)-based Box-Behnken design by navigation of method operable design ranges (MODR). RESULTS: From the set of control strategies, the RP-HPLC method was developed using a Shim-Pack ODS C18 column and acetonitrile-0.1% triethylamine (40:60, v/v) triethylamine in water (pH 3.2 adjusted by perchloric acid). The method was found to be validated as per ICH Q2 (R1) guideline. The synchronous estimation of different FDCs of metformin hydrochloride was carried out by the developed method. CONCLUSION: The developed method can be used as a multipurpose chromatography method as an alternative to published chromatography methods for QC of FDCs of metformin hydrochloride in the pharmaceutical industry. HIGHLIGHTS: The multipurpose RP-HPLC method has been developed and validated for the synchronous estimation of multiple combined pharmaceutical dosage forms of metformin hydrochloride. The method was developed by the implementation of the AFMCEA-based AQbD approach as per the regulatory requirements of ICH.

Advances on nanoformulation approaches for delivering plant-derived antioxidants: A case of quercetin.

Oxidative stress has been implicated in tumorigenic, cardiovascular, neuro-, and age-related degenerative changes. Antioxidants minimize the oxidative damage through neutralization of reactive oxygen species (ROS) and other causative agents. Ever since the emergence of COVID-19, plant-derived antioxidants have received enormous attention, particularly in the Indian subcontinent. Quercetin (QCT), a bio-flavonoid, exists in the glycosylated form in fruits, berries and vegetables. The antioxidant potential of QCT analogs relates to the number of free hydroxyl groups in their structure. Despite presence of these groups, QCT exhibits substantial hydrophobicity. Formulation scientists have tested nanotechnology-based approaches for its improved solubilization and delivery to the intended site of action. By the virtue of its hydrophobicity, QCT gets encapsulated in nanocarriers carrying hydrophobic domains. Apart from passive accumulation, active uptake of such formulations into the target cells can be facilitated through well-studied functionalization strategies. In this review, we have discussed the approaches of improving solubilization and bioavailability of QCT with the use of nanoformulations.

Development and Validation of Stability-indicating RP-HPLC Method for Estimation of Pranlukast Hydrate in its Laboratory Mixture.

Pranlukast hydrate is an anti-asthmatic drug and used in the treatment of acute asthma. Stability-indicating RP-HPLC method for pranlukast hydrate has been developed and validated. The reverse phase high performance liquid chromatographic method was developed using Shimadzu Column: Kromosil 100 C18 (150 mm × 4.6 mm × 5 µm) and mobile phase Acetonitrile: 0.1% Glacial acetic acid (85: 15% v/v). Eluent was monitored with UV-detector at 262 nm with a flow rate of 0.5 mL/min, temperature maintained at 30°C. Stress testing was carried out in acidic, alkaline, oxidative, photolytic and dry heat degradation conditions. The method was validated as per the International Conference for Harmonization guidelines and includes specificity, accuracy, precision, linearity and limit of quantitation and detection parameters. A relative standard deviation <2% indicates the developed method was precise. The accuracy of the method was represented by recovery studies ranging between 99.41 and 99.72%. In acid, alkaline, oxidative stress conditions, pranlukast hydrate degrades significantly and in photolytic, dry heat, hydrolytic conditions remain stable. This proposed method is suitable for the analysis of pranlukast hydrate in its laboratory mixture.

Application of Quality Risk Assessment and DoE-Based Enhanced Analytical Quality by Design Approach to Development of Chromatography Method for Estimation of Combined Pharmaceutical Dosage Form of Five Drugs.

The high-performance liquid chromatography method was only reported for simultaneous estimation of aspirin, simvastatin, ramipril, atenolol and hydrochlorothiazide in polycap capsule. High-performance thin-layer chromatography (HPTLC) method is now accepted as a method of analysis by many pharmaceutical industries and included as an official method in monographs of pharmacopeias of many countries. Hence, HPTLC method was developed and validated for the estimation of polycap capsule using enhanced analytical quality by design based on principles of quality risk management and design of experiment (DOE). Quality risk management was performed by the identification and assessment of risky method parameters. DoE was carried out by Placket-Burman screening design and Box-Behnken response surface methodology using resolution and tailing factor as critical method attributes. Method operable design region was navigated for optimization and development of the method. The developed method was validated as per ICH Q2 (R1) guideline. The method was found accurate, specific, precise and sensitive for the said estimation. The developed method was applied for the assay of polycap capsule and results were found in good agreement with the labeled claim. The developed method can be used as an alternative to reported HPLC methods for quality control of polycap capsule.

Risk and DoE-Based DMAIC Principle to the Multipurpose-RP-HPLC Method for Synchronous Estimation of Anti-Hypertensive Drugs Using AQbD Approach.

BACKGROUND: Hypertension is a major health problem found in people throughout the world and numerous fixed-dose combination (FDC) products of telmisartan are available in the local market for its treatment. Several chromatography methods such as reversed-phase (RP)-HPLC and HPTLC methods have been published for estimation of FDC products of telmisartan with hydrochlorothiazide, atorvastatin, and amlodipine. No RP-HPLC method has been reported yet for synchronous estimation of FDC products of telmisartan, which would save analysis time, cost, and solvent. OBJECTIVE: A multipurpose RP-HPLC method has been developed for synchronous estimation of FDC products of telmisartan using the analytical quality by design approach based on risk- and design of experiment (DoE)-based define, measure, analyse, improve, control (DMAIC) principles. METHOD: The risk-based DMAIC principle was implemented by risk parameter identification and assessment as per the ICH Q9 guideline. The DoE-based DMAIC principle was applied by response surface analysis using a Box-Behnken design. The method operable design ranges were navigated and a control strategy was set for the development of the method as per the analytical target profile (ATP). RESULTS: Chromatographic separation was performed using Shimpack ODS C18 column and acetonitrile: 0.1% (v/v) triethylamine (pH 6.5), keeping a flow rate of 1.0 mL/min. The method was validated as per the ICH Q2 (R1) guideline. The developed method was applied for synchronous estimation of seven different anti-hypertensive products. CONCLUSIONS: The developed method is an eco-friendly and economical alternative to published chromatography methods for the analysis of anti-hypertensive products. Hence, the developed method can be used as a multipurpose RPLC method for quality control of anti-hypertensive products in the pharmaceutical industry. HIGHLIGHTS: A multipurpose RPLC method for synchronous estimation of antihypertensive products of telmisartan was developed, saving analysis time, cost, and solvent. The developed method was applied to the synchronous estimation of seven different anti-hypertensive products.

DoE and Risk-Based DMAIC Principle for Implementation of Enhanced Analytical Quality by Design Approach to Multipurpose-Chromatography Method for Simultaneous Estimation of Multiple Fixed-Dose Combination Products of Aspirin.

BACKGROUND: Numerous RP-HPLC and HPTLC methods have been reported for estimation of fixed-dose combination (FDC) products of aspirin with anti-hypertensive and anti-lipidemic drugs. Each FDC of aspirin needs separate and dedicated chromatographic conditions for analyses. No chromatographic method has been reported for simultaneous estimation of FDC products of aspirin using a single chromatography condition. OBJECTIVE: A multipurpose HPTLC method was developed for simultaneous estimation of some FDC products of aspirin using an enhanced analytical quality-by-design approach based on a design of experiment (DoE) and risk-based define, measure, analyse, improve and control (DMAIC) principle to save solvent, cost, and time of analysis. METHOD: The risk-based DMAIC process was carried out with identification of potential method risk parameters and their assessment using risk priority number (RPN) ranking and filtering. The DoE-based DMAIC process was carried out by the implementation of fractional factorial and full factorial design. RESULTS: The mobile phase composition and volume of modifier were found to be critical method risk parameters for resolution of all peaks. The developed method was found to be validated, and assay results of all FDC products of aspirin were found to be in good agreement with their respective labelled claim. CONCLUSIONS: The developed method is found to be solvent, cost, and time saving and also fulfilled the analytical requirements of many reported chromatography methods. Hence, the developed method is a multipurpose chromatography for analysis of FDC products of aspirin. HIGHLIGHTS: DoE and risk-based DMAIC principle to development of the multipurpose-chromatography method. The developed method was applied for the estimation of eight different FDC products of aspirin.

Estimation of Multiple Fixed-Dose Combination Products of Ramipril and Aspirin by GERV-Chromatography Using DoE and Risk-Based Enhanced Analytical Quality by Design Approach.

BACKGROUND: Numerous chromatographic methods have been published for estimation of fixed-dose combinations (FDCs) of aspirin and ramipril with other drugs. But no published report has been found which promotes simultaneous estimation of FDCs of aspirin and ramipril with other drugs using a single chromatography condition. OBJECTIVE: Hence, the HPTLC method was developed for simultaneous estimation of FDCs of aspirin and ramipril with the drugs under study to save solvent, cost, and time for analysis using a risk- and DoE-based AQbD approach. METHOD: The risk-based AQbD approach was implemented using the risk priority number (RPN) ranking and filtering method as per the ICH Q9 guideline. The DoE-based AQbD approach was applied through a screening study using Placket-Burman design, followed by response surface analysis by Box-Behnken design as per the ICH Q8 guideline. RESULTS: The risks from critical method risk parameters were mitigated by navigating method operable design ranges and framing the control strategy for the target method. The method was validated as per ICH Q2 (R1) guidelines. The developed method was applied for simultaneous assay of six different FDCs of aspirin and ramipril and results agreed with the label claims. CONCLUSIONS: The developed method is the best alternative to published chromatographic methods for estimation of the FDC products under study and saves solvent, time, and cost of analysis. Hence, the developed "GERV"-chromatography method is found to be green (G), economical (E), robust (R), and versatile (V), for estimation of the said FDC products. HIGHLIGHTS: Development of GERV-chromatography for simultaneous estimation of multiple FDCs of ramipril and aspirin using a risk-based AQbD approach. Application of the developed method for simultaneous estimation of six different FDC products.

Quality Risk Management-Based AQbD Approach to Development of VEER Chromatography Method for the Estimation of Multiple Combined Formulations of Anti-Hypertensive Drugs.

BACKGROUND: A number of chromatography methods for estimating combined dosage forms of telmisartan have been published in the literature, but each combined dosage form needs separate chromatography conditions for analysis. OBJECTIVE: The versatile, economical, eco-friendly, and robust chromatographic method has been developed for simultaneous estimation of multiple combined pharmaceutical dosage forms of anti-hypertensive drugs using the analytical quality by design approach based on principles of quality risk management (QRM) and design of experiment (DoE). METHOD: Analytical QRM was performed by identifying probable method risk parameters and risk assessment for the development of the method. DoE was performed by Taguchi Orthogonal Array (OA)  screening design and Box-Behnken response surface design using Design-Expert software (trial version). Chromatographic separation was performed using silica gel 60 GF254 as stationary phase and toluene-ethyl acetate-methanol-glacial acetic acid (5.5 + 2 + 1 + 0.2, v/v/v/v) as a mobile phase keeping saturation time of 15 min. The developed method was applied for the assay of six combined pharmaceutical dosage forms of anti-hypertensive drugs. RESULTS: The developed method was found to be validated for accuracy, precision, specificity, linearity, LOD, LOQ, and robustness as per ICH guideline. The results of the assay were found in good agreement with the labelled claim. CONCLUSIONS: The developed method can be applied for analysis and quality control of multiple combined dosage forms of telmisartan. HIGHLIGHTS: A QRM and DoE-based AQbD approach was applied for development of chromatography method for simultaneous estimation of multiple combined dosage forms of telmisartan. The developed method was successfully applied for simultaneous estimation of six different multiple combined dosage forms of temisrtan.

Controlled bimatoprost release from graphene oxide laden contact lenses: In vitro and in vivo studies.

Ocular drug delivery using contact lenses may be able to substitute for eye drop therapy. However, issues with hydrophobic drugs (like bimatoprost that is used to treat glaucoma) such as low drug uptake using a simple soaking method into preformed contact lenses and alteration in the swelling and transmittance of lenses restricts the application for drug delivery. This research uses graphene oxide (GO) to control the release of bimatoprost from contact lenses along with improvements in the drug uptake, and lens swelling and transmittance. GO was loaded into silicone hydrogel contact lenses by adding the GO at the same time as lenses were polymerized. These lenses were soaked in bimatoprost. Alternatively contact lenses, either with or without GO, were produced by adding bimatoprost during lens polymerization. GO improved contact lens swelling due to its water binding capacity and lens transmittance due to the molecular dispersion of bimatoprost on the surface of the GO which prevented the local precipitation of the drug. The bimatoprost uptake was not improved in the presence of GO. However, its in vitro release profile was improved. Adding bimatoprost and GO at the same time as lenses were polymerized (DL-GO-BMT) significantly decreased the loss of drug during extraction and sterilization in comparison to contact lenses (DL-BMT) without GO. As the amount of GO was increased, the DL-GO-BMT lenses showed a significant decrease in the burst and cumulative release of bimatoprost. Ocular irritation and histopathology reports demonstrated the safety of GO contact lens. The in vivo pharmacokinetic studies in the rabbit tear fluid showed significant improvement in mean residence time (MRT) and area under the curve (AUC) with DL-GO-0.2 µg-BMT-100 contact lens in comparison to eye drop solution. The study demonstrated that the addition of GO to contact lenses can control the release of bimatoprost as well as improved the lens swelling and transmittance. However, further optimization is needed to modulate the release of drug within the therapeutic level to manage glaucoma.

Laparoscopic pyelovesicostomy for giant hydronephrosis in a solitary kidney.

Pyelovesicostomy has rarely been described in the literature. Most of the time this procedure has been performed in cases of ureteral obstruction in an ectopic kidney or in a transplanted kidney. We report the case of a 16-year-old male who presented with a history of large abdominal swelling and pain. On investigation he was found to have a solitary right kidney with giant hydronephrosis and to be in renal failure. An initial percutaneous nephrolithotomy diversion was performed followed 1 month later by right laparoscopic pyelovesicostomy. The postoperative period was uneventful. We describe laparoscopic pyelovesicostomy in the management of giant hydronephrosis for the first time. Our case illustrates that laparoscopic pyelovesicostomy is a feasible option in the management of giant hydronephrosis.

Lidocaine tripotassium phosphate complex laden microemulsion for prolonged local anaesthesia: In vitro and in vivo studies.

Lidocaine is widely used as a local anaesthetic in the clinical practice to manage pre- and post-operative pain, skin burns, etc. However, the short duration of action (< 2 h) of marketed dosage forms limit their ability to meet clinical needs. Herein, we prepared a lidocaine-tPP(tri potassium phosphate)-complex loaded microemulsion to achieve greater penetration, followed by destabilization of microemulsion in the skin layer to precipitate oil-complex to produce a depot effect in the skin for prolonging the effects of anaesthesia. The lidocaine-tPP-complex-microemulsion was compared with lidocaine base loaded microemulsion, marketed ointment USP and lidocaine HCl. The pseudo ternary phase diagrams at three Smix ratios (1:2, 1:3 and 1:4; Pluronic F127: PEG 400) were constructed using Capmul MCM C8 EP as oil phase. The Smix at 1:4 ratio showed large microemulsion area in comparison to 1:2 and 1:6 ratio. The lidocaine base (LD-1:4-ME10O45SM and LD-1:4-ME20O45SM) and lidocaine-tPP-complex (LDC-1:4-ME10O45SM and LDC-1:4-ME20O45SM) loaded microemulsion batches (1:4 ratio) were thermodynamically stable. The ex vivo diffusion study showed sustained release up to 12 h with microemulsion batches, in comparison to lidocaine HCl (4 h) and ointment base (7 h). The selected LDC-1:4-ME20O45SM batch was non-irritating on the rabbit skin. In drug retention studies, LD-1:4-ME20O45SM and LDC-1:4-ME20O45SM batches showed 2.68- and 3.93-fold greater lidocaine retention in comparison to ointment USP. The radiant heat tail-flick test showed prolong local anaesthesia using LDC-1:4-ME20O45SM in comparison to ointment USP. The findings suggest that lidocaine-tPP-complex loaded microemulsion could be a potential strategy for providing prolong local anaesthesia.

Novel Poly(vinylpyrrolidone)-Coated Silicone Contact Lenses to Improve Tear Volume During Lens Wear: In Vitro and In Vivo Studies.

Poly(vinylpyrrolidone) (PVP-K90) is widely used to manage dry eye syndrome (DES). The marketed eye drop solutions (high dose) need frequent instillation, affecting the routine lifestyle of patients. PVP-K90-laden contact lenses can be used to overcome the limitations of eye drop solutions (low bioavailability and frequent instillation). However, the conventional methods of PVP-K90 loading show poor loading capacity and short duration of effect. In the present study, we have developed PVP-K90-coated contact lenses via a short curing approach to increase the PVP-K90 loading capacity with a sustained release profile to manage dry eye syndrome. PVP-K90 was loaded by a soaking method (SM-PVP), direct loading (during fabrication, DL-PVP), a combination of soaking and direct loading (DL-SM-PVP), and a novel coating process (SM-PVP-C and DL-SM-PVP-C). The swelling studies suggested improvement in the water uptake (hydration) property of the contact lenses due to the presence of PVP-K90. The optical transparency was within an acceptable range. The in vitro release of PVP-K90 was in the following order: PVP-coated contact lens (168 h) > DL-SM-PVP (168 h) > DL-PVP (96 h) > SM-PVP (72-96 h). PVP-coated contact lenses showed a high burst effect (lubricating effect) and sustained release (3161-448 ng/h between 24 and 168 h) due to high PVP loading/coating in comparison to the uncoated respective contact lenses (964-113 ng/h between 24 and 96 h). In animal studies, the PVP-K90-coated contact lens showed higher tear volume in comparison to the respective uncoated contact lenses and an eye drop solution. This study demonstrates a novel approach of coating a high amount of PVP-K90 on contact lenses for sustained release to manage several ocular diseases like dry eye syndrome, conjunctivitis, and other ocular injuries.

Multiple drug delivery from the drug-implants-laden silicone contact lens: Addressing the issue of burst drug release.

A fixed combination of bimatoprost/timolol eye drop solution is used to manage the elevated intra-ocular pressure in glaucoma patients, including individuals whose condition is poorly controlled by monotherapy. Eye drop solutions are generally given in high dose, due to poor ocular bioavailability. The high ocular dose of bimatoprost and timolol lead to hyperaemia and systemic cardiac side effects respectively. Here, we introduce multiple implant-laden contact lenses (IM) to passively deliver timolol, bimatoprost and hyaluronic acid at therapeutically relevant doses without high burst release. The drug-loaded implants were individually implanted in the outer periphery of the silicone contact lenses. Atomic force microscopy showed the smooth surface of the implant contact lens, as the implants were inside the contact lens matrix. The implant lens (IM) showed major loss of drugs [timolol = 60.60%, bimatoprost = 61.75% and HA = 46.03%] during the monomer extraction and wet sterilization, while the option of dry radiation sterilization (IM-R lens) and hydration for 24 h prior to use showed relatively lower loss of drugs [timolol = 16.87%, bimatoprost = 47.95% and HA = 24.41%]. The in-vitro drugs release data of IM-R lens, showed sustained release for 72 h, with low burst release in comparison to the soaked (SM) and direct drug-laden contact lenses (DL). The in vivo drug release data in the rabbit tear fluid showed sustained release using IM-R lens in comparison to the SM lens and eye drop therapy. The burst release with the IM-R lens was many folds reduced, which could bypass the side effects associated with multiple eye drop therapy. The in vivo pharmacodynamic study in the rabbit model showed peak and valley profile with multiple eye drop therapy, while IM-R lens showed prolong reduction in intra ocular pressure (IOP) for 120 h. The study demonstrates the application of implantation technology to deliver multiple drug through contact lenses to treat glaucoma.

Tailored gatifloxacin Pluronic® F-68-loaded contact lens: Addressing the issue of transmittance and swelling.

Loading of gatifloxacin in contact lenses affects critical lens properties (optical and swelling) owing to drug precipitation in the contact lens matrix. The presence of Pluronic® F-68 in the packaging solution creates in-situ micelles in the contact lens to dissolve gatifloxacin precipitates and provide sustained drug release. The micelles further improved the drug uptake from the drug-packaging solution to create an equilibrium of drug between the lens matrix and the packaging solution. In this study, we optimized gatifloxacin-pluronic-loaded contact lenses to achieve the desired optical transmittance, swelling, and gatifloxacin loading capacity as well as sustained drug delivery. Optimization of gatifloxacin-pluronic-loaded contact lens was carried out using a 32 factorial design by tailoring the concentration of Pluronic® F-68 in the packaging solution (X1) and the amount of gatifloxacin in the monomer solution (X2) to achieve the desired lens properties. The optimized batch (X1 = 0.3%w/v and X2 = 0.3%w/v) showed an optical transmittance of 92.84%, swelling of 92.36% and gatifloxacin loading capacity of 92.56 µg. The in vitro flux data of the optimized batch (GT-Pl-CL) showed sustained release up to 72 h, whereas soaked contact lenses (SM-CL) and direct gatifloxacin-loaded contact lenses (DL-CL) showed a sustained release up to 48 h. The in vivo gatifloxacin release data for rabbit tear fluid showed sustained release with a high gatifloxacin level for the GT-Pl-CL lens in comparison to the SM-CL and the eye drop solution. This study demonstrates the application of the 32 full factorial design to optimize gatifloxacin-pluronic-loaded contact lenses to achieve the desired optical transmittance, swelling, and drug loading capacity.

Plackett-Burman design for screening of critical variables and their effects on the optical transparency and swelling of gatifloxacin-Pluronic-loaded contact lens.

The optical and swelling properties of gatifloxacin-loaded contact lens decrease owing to the precipitation of gatifloxacin (on hydration) in the matrix structure of the contact lens. This paper focuses on the use of Pluronic F68 both inside and outside (in the packaging solution) the contact lens to form micelles to dissolve the gatifloxacin precipitates and not limited to sustain the release of gatifloxacin. The aim of this study was to screen the critical variables affecting the optical and swelling properties of gatifloxacin-loaded contact lens. The independent variables investigated were the concentration of Pluronic F68 incorporated in the monomer solution to fabricate the lens (X1, %w/v), the concentration of Pluronic F68 in the packaging solution (X2, %w/v), the concentration of gatifloxacin incorporated in the monomer solution (X3, %w/v), the concentration of gatifloxacin incorporated in the packaging solution during autoclave (X4, %w/v), the concentration of gatifloxacin incorporated in the packaging solution during extraction (X5, %w/v), the time (stabilization time) after the addition of gatifloxacin and Pluronic F68 to the monomer solution before the fabrication of the lens (X6, h), the pH of the packaging solution (X7), the temperature of the extracted solution (X8, °C), and the curing time for fabricating the contact lens (X9, min). The gatifloxacin-loaded contact lenses were characterized for their optical transmittances after sterilization on day 1 (Y1, %), optical transmittances after 7 days of sterilization (Y2, %) and swelling percentages after 7 days of sterilization (Y3, %). The selected variables showed responses that were in the ranges 53.5% to 97.2%, 51.3% to 92.6%, and 50.3% to 83.7% for Y1, Y2, and Y3, respectively. The data suggest that the presence of Pluronic F68 inside the contact lens (X1) reduced the optical and swelling properties of the contact lens, whereas the presence of Pluronic F68 in the packaging solution (X2) improved them through micelle formation. The other variables (X3 to X9) did not exhibit significant effects on the swelling and transmittance. This study revealed the potential of Plackett-Burman design to screen the selected critical variables that affected the optical and swelling properties of gatifloxacin-loaded contact lens.