Over the years, the increasing globalization has massively emphasized the adoption of sustainable supply chain strategies, fundamentally opening new avenues in the era of increased competitiveness. However, understanding this source of sustainable competitiveness has led organizations to embrace novel strategies for accelerating firms' advancement. The sustainable supply chain strategy is a robust strategical plan that helps firms defeat the market rivalry, thus gaining a sustainable competitive edge. Given the illustration, the study states that the sustainability approach develops value across the production chain, potentially discovering new sources for distinctive advantages (19). Accordingly, the study appreciating SSCS as a sustainable benefit states that in the supply chain network, the sustainable strategies enable the organizations to foster competitiveness, thus acquiring sustainable competitive advantage (20).

In particular, the effective SSCS enables the firms to harmonize their business activities, thereby strategically intensifying their business position. Given the illustration, the research reveals that the sustainability triple-bottom-line dimensions (e.g., social, economic, and ecological) make SSCS accomplish a dominant position in the marketplace (5). As a result, today, sustainability strategies have become critical to function internally, thereby accomplishing the organization's sustainable goal (21). The key to gaining sustainability is to sustain in the increasingly competitive environment, substantially obtaining long-term competitive stability. In the supply chain business environment, the SSCS facilitates a business operation, proactively regulating market changes. Based on this statement, the study shows that the SSCS provides competitive benefits to the firms', thus making them operate in a dynamic business environment (22). Significantly, the SSCS provides a first-mover advantage to the firms by getting ahead of other firms (23). Hence, based on this literature, we conclude the following hypothesis:

H1: Sustainable supply chain strategy has a positive and significant impact on sustainable competitive advantage.

In recent years, the increasing environmental concerns have made the sustainability practices receive management attention. In the supply chain, ecological issues severely affect the value chain system, thus demanding the need for effective strategies and sustainability practices across the supply chain network. Therefore, today, numerous firms have adopted SSCS for improving ecological welfare. Given the articulation, the study shows that the firms' sustainability strategies reduce the environmental cost, thereby maximizing the social welfare with sustainable practices (24).

In particular, sustainable supply chain strategies assist the firms in attaining the sustainable triple-bottom-line dimension. In supply chain modeling, organizations' enduring plans and sustainable practices devote to improving the organizations' function. Perhaps, understanding this multi-dimensional sustainability helps companies to support organizations' practices with a sustainability vision. The firms' sustainability strategies lead to the effective implementation of sustainable practices. For this reason, many companies have started embracing the concept of sustainable practices complementing the firms' sustainable goals (3). In the illustration, the study shows that the SSCP makes the organizations achieve the sustainability objectives by exhibiting superior organizational performances (25).

Arguably, many issues elevate the demand for sustainable approaches. In the pharmaceutical industry, to reach sustainability standards, companies have realized the need for sustainability practices to accomplish a business goal. The effort to improve the competitiveness in the pharmaceutical industry has made the organizations implement sustainability practices, significantly minimizing the increasing impact of ecological concerns (i.e., chemical waste, inhibitors) (25). In particular, according to the world health organization, the support of environmentally friendly strategic plans, strategies, practices, and policies help the organization guide the management, thus securing the environment (26). Consequently, based on the prior consideration, we have developed the following hypothesis:

H2: Sustainable supply chain strategy has a positive and significant impact on sustainable supply chain practice.

Over the past decades, environmental sustainability has received increasing significance in supply chain management. In recent years, the high escalation of environmental deterioration has made the stakeholders adopt eco-friendly practices for securing the long-term advantage. The firms' sustainable characteristics (e.g., actions, policies, processes) help firms to obtain a sustainable competitive advantage. Given the articulation, the study shows that the adoption of SSCP makes the companies encompass the sustainability dimensions, thus exhibiting high competitiveness and superior organizational performance (27).

Undoubtedly, competition is the most influential driver for incorporating sustainability in the supply chain. Organizations under its influence feel the pressure of adopting sustainable practices for gaining a competitive edge. The sustainable competitive advantage makes firms differentiate themselves from their rivals. Indeed, SSCP plays a vital role in maintaining market competitiveness. The sustainability practices enable the organizations to outperform their competitors by focusing on long-term stability. Given the illustration, the study found that sustainable supply chain practices provide the company with a sustainable competitive advantage with improved organizational performance (28).

However, the business's success largely depends on the firms' competitive benefit. By embedding the sustainability practices into firms' functions, the organizations can maintain a differential edge over its peer. Accordingly, the research shows that the SSCP enhances the firms' strategic assets, thus leading to SCA (29). Indeed, the supply chain sustainability practice leverages the firms' operations by providing competitive benefits. Therefore, due to its increasing significance (i.e., SSCP), the study suggests that companies should focus on sustainability practices to maintain a differential advantage over the other firms' (30). Therefore, based on these systematic reviews, our hypothesis states:

H3: Sustainable supply chain practice has a positive and significant impact on sustainable competitive advantage.

Today, numerous organizations are increasingly facing challenges regarding environmental deterioration. In such a situation, the sustainability practices potentially help the companies to neutralize the prevailing damage. Significantly, the collaborative supply chain network exhibiting sustainability development had reduced the ecological footprint spoiling the motherland. Indeed, building on this concept, organizations' have ensured establishing supply chain sustainability on multiple levels for gaining sustainable competitive advantage (31). Given the illustration, the study showed that the supply chain had highlighted the demand for incorporating the sustainable agenda in the business strategy, thereby exploring the market benefits, performance indicators, and sustainable advantage (32).

However, investigating this agenda in the pharmaceutical company shows that SSCS makes the firms acquire long-term stability and competitive advantage (33) with cleaner practices. This strategy of boosting the firm's sustainability performance helps the organization recognize the significance of developing sustainable supply chain practices. However, developing sustainable supply chain strategies ensures the development of sustainable practices, capabilities, and processes driving the competitive advantage. Given the illustration, the study shows that SSCS provides an enduring edge to organizations by ensuring cleaner production practices (34). The implementation of sustainable practices varies from organization to organization. Sustainable practices improve the firms' vision, thus achieving higher competitive standards (35). In particular, the sustainability practices enable the firms to take over the market competition by providing a sustainable competitive edge. Hence, from the prior study findings, we have inferred the following hypothesis:

H3a: Sustainable supply chain practice mediates the relationship between sustainable supply chain strategy and sustainable competitive advantage.

The international supply chain has increasingly faced environmental issues that need human visibility. In particular, these complexities have facilitated the need for environmentally friendly approaches to balance the ecological footprint (36). Ecological sustainability demands adopting sustainable practices as the motivators for combating the barriers (i.e., unsustainable inhibitors). Unsurprisingly, the pharmaceutical industry is colossally affected by the adversity of intoxicate inhibitors, which forms the foundation of poor economic stability. Given the explanation, the study reveals that for combating the unsustainable inhibitors, eco-friendly tools (e.g., technology) had widely adopted, reducing the ecological waste, potentially fulfilling is the fundamental goal of firms' strategy (37).

Indeed, today organizations have widely emphasized the implementation of sustainable inhibitors as a part of the firms' strategy. Given the articulation, the study findings suggest that management should invest in sustainable supply chain practices (38) to minimize the adversity of unsustainable pollutants. In contrast, the study shows that the sustainable supply chain practice provides a theoretical lens to the firms' enabling them to relish the benefit of sustainability inhibitors (39). Accordingly, in the supply chain, the pharmaceutical industry produces considerable waste throughout the production process. This excessive ecological burden (e.g., drugs and intoxicants) makes the managers implement sustainability inhibitors throughout the manufacturing process. The pharmaceutical model of sustainability practices reduces the effect of non-value additions activities, thus eliminating the waste. Given the illustration, the study states that the sustainability inhibitors drive the sustainability practices (40) to improve the socio-ecological welfare. Subsequently, the hypothesis built on the above consideration concludes:

H4: Sustainability inhibitors strengthen or moderate the relationship between sustainable supply chain strategy and sustainable supply chain practice.

Figure 1 shows the study's theoretical framework (independent, dependent, mediator, and moderator variables).

The research adopted a survey research design to collect data to investigate the influence of sustainable supply chain strategy on sustainable competitive advantage, mediating the role of sustainable supply chain practice and moderating the role of Sustainability Inhibitors. Through the convenience sample technique, questionnaires were distributed among the managers of 25 pharmaceutical companies located in Pakistan; data was collected from January-February 2022. Approximately 250 managers were contacted and requested to participate in this time-lagged study, whereas 180 complete responses were received.

To control the common method bias, this research conducted a time-lagged study with 15 days intervals. Responses on sustainable supply chain strategy and sustainability inhibitors were collected at time 1; after a gap of 15 days, responses on sustainable supply chain practice were collected, i.e., time-2; and after a gap of 15 days, data was collected on sustainable competitive advantage, i.e., time-3. This research also applied the common method bias using Harman's single-factor approach. The variance extracted using one factor is 6.835%, less than 50%, indicating no common method bias in this study (41). Table 1 depicts the demographic characteristics of the study participants, revealing 52% male and 48% female. In total 13% of participants were in the age group 19–30; 28% were from 31–40. In total 36% of participants were Bachelor's degree holders, and 36% were master's.

Sustainable supply chain strategy was measured using 3 item scale developed by Nayal et al. (42). Sample items include: “The industry markets the same products with minor variations as per consumer demand and trends of the market”; “The industry has relevant IT-related knowledge and skills to adapt to recent sustainable market trends.” Sustainability inhibitors was measured using 5 item scale developed by Gopal and Thakkar (43). Sample items include: “Resistance to technology advancement adoption” and “Unawareness of customers.” The dependent variable sustainable competitive advantage was measured using Nayal et al. (42) developed using a five-item scale. Sample items include: “Application of digital technologies and collaboration improves process efficiency”; “The digitalized Supply Chain responsible for improved collaboration and coordination improves flexibility.” Five-point Likert scale ranging from strongly disagree to strongly agree was used to measure the study variables. The mediating variable of sustainable supply chain practice was measured using a five-item scale developed by Gopal and Thakkar (43). It was measured using five Likert scales ranging from 1-not at all implemented 5-fully implemented. Sample items include: “Lean practices” and “Eco-design practices.”

Data cleaning and screening were performed before conducting the reliability and validity analysis. Table 2 depicts the results of model fit, reliability, and validity analysis. Results of CFA- four-factor model depicts values within the acceptable range CFI = 0.999; TLI = 0.998; SRMR = 0.0394; NFI = 0.938; RMSEA = 0.011; hence confirming model fitness.

Figure 2 depicts the CFA - measurement model with a factor loading of each item above 0.4 (as shown in Table 2), confirming convergent and content validity.

Results of hypothesis H1 H2, H3, and H3a (mediation analysis) is shown in Table 4. Hypothesis 1 states that sustainable supply chain strategy is positively related to sustainable competitive advantage with β = 0.484, p < 0.001; Hypothesis 2 states that sustainable supply chain strategy is positively related to sustainable supply chain practices with β = 0.693, p < 0.001; whereas Hypothesis 3 states that sustainable supply chain practices are positively related to sustainable competitive advantage with β = 0.320, p < 0.001. Hence Hypothesis 1, 2, and 3 are statistically proven. For mediation analysis, indirect effects were calculated. Table 4 shows that sustainable supply chain practices mediate the relationship between sustainable supply chain strategy and sustainable competitive advantage with β = 0.222, p < 0.001. Hence hypothesis 3a is proved.

In line with hypothesis 4, the interaction term of sustainable supply chain strategy and sustainability inhibitors was significant (β = 0.315. p < 0.05). Moreover, Table 5 illustrates that the relationship between sustainable supply chain strategy and sustainable supply chain practices strengthens when sustainability inhibitors are low (β = 0.976, p < 0.001). Figure 3 shows the interaction effect of SSCS^*SIF0E8SSCP.